NEMATODE TAXONOMIC DIVERSITY AND COMMUNITY STRUCTURE: INDICATORS OF ENVIRONMENTAL CONDITIONS AT KEETHAM LAKE, AGRA

THESIS

SUBMITTED FOR THE AWARD OF THE DEGREE OF

DOCTOR OF PHILOSOPHY

IN

ZOOLOGY

BY

MALKA MUSTAQIM

UNDER THE SUPERVISION OF

PROF. QUDSIA TAHSEEN

DEPARTMENT OF ZOOLOGY

ALIGARH MUSLIM UNIVERSITY

ALIGARH-202002 (INDIA)

2017

1 Dedicated to my Beloved Parents and Brothers

2 Qudsia Tahseen, Professor Department of Zoology,

PhD, FASc, FNASc Aligarh Muslim University,

Aligarh-202002, India

Tel: +91 9319624196

E-mail: [email protected]

Certificate

This is to certify that the entire work presented in the thesis entitled, ‘‘ taxonomic

diversity and community structure: indicators of environmental conditions at Keetham Lake, Agra’’

by Ms. Malka Mustaqim is original and was carried out under my supervision. I have permitted Ms.

Mustaqim to submit the thesis to Aligarh Muslim University, Aligarh for the award of degree of

Doctor of Philosophy in Zoology.

(Qudsia Tahseen)

Supervisor

3 ANNEXURE-Ι CANDIDATE’S DECLARATION

I, Malka Mustaqim, Department of Zoology, certify that the work embodied in this Ph.D. thesis is my own bonafide work carried out by me under the supervision of Prof. Qudsia Tahseen at Aligarh Muslim University, Aligarh. The matter embodied in this Ph.D. thesis has not been submitted for the award of any other degree. I declare that I have faithfully acknowledged, given credit to and referred to the research workers wherever their works have been cited in the text and the body of the thesis. I further certify that I have not willfully lifted up some others work, para, text, data, results, etc. reported in the journals, books, magazines, reports, dissertations, theses, etc., or available at web-sites and included them in this Ph.D. thesis and cited as my own work.

Date: ...... (Signature) Malka Mustaqim ………………………………………………………………………………………… Certificate from the Supervisor

This is to certify that the above statement made by the candidate is correct to the best of my knowledge.

Prof. Qudsia Tahseen Signature of the Chairman Department of Zoology with seal Aligarh Muslim University Aligarh-202002

4 ANNEXURE-ΙΙ

ALIGARH MUSLIM UNIVERSITY DEPARTMENT OF ZOOLOGY

COURSE/COMPREHENSIVE EXAMINATION/PRE-SUBMISSION SEMINAR COMPLETION CERTIFICATE

This is to certify that Ms. Malka Mustaqim, Department of Zoology, Aligarh

Muslim University, Aligarh has satisfactorily completed the course work/comprehensive examination and pre-submission seminar requirement which is part of her Ph.D. programme.

Date: ……………….. (Signature of the Chairman)

5 ANNEXURE-ΙΙΙ

COPYRIGHT TRANSFER CERTIFICATE

Title of the Thesis: Nematode taxonomic diversity and community structure: indicators of environmental conditions at Keetham Lake, Agra.

Candidate’s Name: Malka Mustaqim

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The undersigned hereby assigns to the Aligarh Muslim University, Aligarh copyright that may exist in and for the above thesis submitted for the award of the Ph.D. degree.

Signature of the Candidate

Note: However, the author may reproduce or authorize others to reproduce material extracted verbatim from the thesis or derivative of the thesis for author’s personal use provide that the source and the University’s copyright notice are indicated.

6 ACKNOWLEDGEMENT

First and foremost I should thank to the Almighty, who blessed me with innumerable favour of academic work. I would like to express my sincere gratitude to my respected supervisor, Prof. Qudsia Tahseen, Department of Zoology, Aligarh Muslim University, Aligarh, for her guidance, support, encouragement and advice during this work. At all stages, in the course of this research work, I was benefitted by her advice, particularly so, when exploring new ideas. Her positive outlook and confidence in my research inspired me and gave me confidence. Her careful editing contributed enormously to the production of this thesis. I have been extremely fortunate to have a supervisor who cared so much about my work and responded to my questions and queries at its earliest. I am also indebted to Prof. Wasim Ahmad, Chairman, Department of Zoology, Aligarh Muslim University, Aligarh, for providing me the facilities and co-operation to me at the various stages of my research work. I am also having a great pleasure to express my indebtedness to my respected teachers Prof. Irfan Ahmad and Prof. Mahalaqa Chaudary for their valuable suggestions and support. I extend my sincere thanks to my labmates Mr. Mohammad Asif, Ms. Rehmat Jahan, Ms. Numreen Nazir and Mr. Mohammad Mahboob. My labmates stood by my side throughout thicks and thins of life. I am also thankful to other juniors, Ms. Zarrin Imran, Ms. Sabia Mumtaz, Ms. Hiba Fatima, Mr. Wajih Jamal, Ms. Sobia Khatoon, Mr. Sumit Kumar, Mr. Niraul Islam and Ms. Shahnaz. I am also thankful to my friends Uzma, Taiba, Sharba, Dania, Arjumend, Sayma, Rushda for their good and cordial company and my classmate Prince for the help whenever needed. Many scientists were kind enough to send their research publications especially Dr. A. Zullini, Dr. S. Boström, Dr. V. Gagarin, Dr. K. Kiontke, Dr. D. Fitch, Dr. T. Naumova, Dr. O. Holovachov, Dr. J. Abolafia, Dr. E. Abebe and Dr. E. Shokoohi. Their timely help is gratefully acknowledged. At last but not the least, I want to express my humble feelings and gratitude to my ever loving and dearest Parents, who lit the flame of learning in me and whose prayers, love, affection, motivation and constant encouragement, helped me to complete this work. My heartiest gratitude to my brothers Mr. Aamir Hussain Kaki, Mr. Ali Husain Kaki and Mr. Daood Mustaqim for their encouragement and moral support. I am grateful for the financial assistance granted by Ministry of Environment & Forest and University Grants Commission, New Delhi. Malka Mustaqim

7 CONTENT S.No Title Page No. Introduction 1-5 Some important landmarks in nematode 6-27 Materials and Methods (Taxonomic study) 28-32 PART A- TAXONOMY 1. Osche, 1952 39-40 C. heptalineata sp. n. 41-48 2. Genus Diploscapter Cobb, 1913 49 D. coronatus(Cobb, 1893) Cobb, 1913 50-55 3. Genus Metarhabditis Tahseen et. al., 2004 56 M. amsactae (Ali et. al., 2011) Sudhaus, 2011 57-62 4. Genus Oscheius Andrássy, 1976 63-64 O. keethamensis sp. n. 65-73 5. Genus Protorhabditis (Osche, 1952) Dougherty, 1953 74 P. mucronata sp. n. 75-80 6. Genus Mesorhabditis Osche, 1952 83-84 M. anisospicula sp. n. 85-92 7. Genus Oigolaimella Paramonov, 1952 96 O. paraninae sp. n. 97-103 O. indica sp. n. 104-111 8. Genus Acrobeles Linstow, 1877 117-118 A. complexus Thorne, 1925 119-125 9. Genus Chiloplacus Thorne, 1937 126-127 C. subtenuis Rashid & Heyns, 1990 128-133 10. Genus Drilocephalobus Coomans & Goodey, 1965 135 D. mustaqimi sp. n. 136-142 D. saprophilus sp. n. 143-149 11. Genus Macrolaimellus Andrássy, 1966 151 M. iucundus Andrássy, 1966 152-156 12. Genus Panagrolaimus Fuchs, 1930 159-160 P. hygrophilus (Bassen, 1940) Andrássy, 2005 161-167

8 13. Genus Tricephalobus Steiner, 1936 168 T. longihystera sp. n. 169-175 14. Genus Achromadora Cobb, 1913 179 A. indica Tahseen, 2001 180-184 15. Genus Geomonhystera Andrássy, 1981 188-189 G. villosa (Bütschli, 1873) Andrássy, 1981 190-194 16. Genus Monhystrella Cobb, 1918 195-196 M. dorsicurvata sp. n. 197-202 17. Genus Neotylocephalus Ali et. al., 1969 207 N. annonae Ali et. al., 1969 208-212 18. Genus Tylocephalus Crossman, 1933 213 T. aprimitivus sp. n. 214-219 19. Genus Chronogaster Cobb, 1913 221-222 C. glandulata sp. n. 223-229 20. Genus Ironus Bastian, 1865 235-236 I. dentifurcatus Argo & Heyns, 1972 237-241 21. Genus Prismatolaimus de Man, 1880 244-245 P. intermedius (Bütschli, 1873) de Man, 1880 246-250 PART B- ECOLOGY Some landmarks in ecological research 251-255 Description of selected wetland, Keetham Lake 256-267 Protocol and Parameters used for nematode community 268-270 analysis Results 271-309 Discussion 310-314 References 315-379

9 INTRODUCTION

Water is a vital resource to life on the planet Earth. Early civilizations sprang fast mainly in the fertile flood plains along the banks of the rivers. Freshwater habitats occupy only 0.8 percent of Earth’s surface, about 12% of all species are estimated to inhabit freshwater ecosystems (Abramovitz, 1996) while many others are closely associated. Wetlands are one of the most diverse and productive ecosystems in the world which are intermediate forms of terrestrial and aquatic ecosystems or can also be regarded as a link between the two. However, the unique hydrological conditions distinguish wetlands from other land and water bodies (Butler, 2010). Wetlands are ecologically sensitive systems, filled or soaked with water for at least a part of the year or during certain seasons or during a part of the day. Wetlands can be defined as the land areas of poor surface drainage, such as marshes, swamps, bogs etc. Earlier, wetlands were considered the source of immense human suffering harbouring organisms of various diseases, however, their importance could be realized later when they turned out to be great revenue earners as tourist spots due to supporting diverse range of flora and fauna. A huge variety of species of microbes, plants and particularly , fishes, amphibians, reptiles, birds, mammals etc. are the part of wetland ecosystems. Wetlands not only provide habitats to wildlife and plants, act as water reservoir, provide place for many recreational activities but also are the basis of various ecological inferences and simulation studies as they show complex interaction of both terrestrial and aquatic species of plants and animals and their participation in the nutrient cycling and energy flow.

The increasing demand and pressures on wetlands without understanding their nature and dynamics have often led to their exploitation and degradation, thereby, threatening the survival and sustenance of wetland communities. The consequences are disastrous in a country like India with varied habitats demonstrating rich biodiversity. The failure to protect these productive and diverse areas have resulted in more than 30 percent of the world's freshwater species becoming extinct, endangered or threatened due to their vulnerability to habitat loss and pollution. However, any work related with bio-conservation, eco-regeneration, eco-restoration and environmental impact assessment cannot be done without the correct identification of test species. The physical alteration, habitat loss and degradation, water withdrawal, overexploitation, pollution and the introduction of non-native species all contribute

10 directly or indirectly to declines in wetland/ freshwater species. The proper identification/ inventorization is absolutely essential for the conservation of these resources.

Consumers play a subtle but important role in wetlands. They range from the tiniest microscopic protists to the largest mammalian representatives, consume energy yielding biomass, convert part of this energy into new biomass and recycle unused organic matter and nutrients. are one such consumers which unarguably are the most abundant and diverse metazoans on Earth (Lambshead, 1993; Platt & Warwick 1983). Known for more than 3000 years, nematodes have been greatly neglected by the zoologists until twentieth century. Nematoda represents one of the largest animal phyla on Earth (Poinar, 1983) constituting about 80-90% of all the metazoans in number. Four out of five multicellular animals on earth are nematodes (Lambshead, 1993; Platt & Warwick, 1983). Due to their ecological and biological abilities, they are present in almost all conceivable habitats wherever life can exist. They are present in cultivated fields, in sand dunes, in the sediments beneath the oceanic floor, in glaciers, in groundwater, in plants, animals and even in humans and can withstand freezing and desiccation in more or less inactive stages and resume their activities when the environment becomes favourable again.

Nematodes, the vermiform, triploblastic, unsegmented, bilaterally symmetrical and pseudocoelomate animals have flexible, elongate and cylindrical to fusiform bodies with tapering ends. In absence of an endoskeleton, nematodes solely rely on the pseudocoelomic fluid that forms the hydrostatic skeleton for the movement or functioning of somatic musculature. They lack circulatory and respiratory systems but possess nervous and secretory-excretory systems. The nematodes are mostly diaceous with members usually exhibiting sexual dimorphism. Being immensely diverse in their distribution, the nematodes also vary in their sizes and shapes. The plant parasitic nematodes may range from 0.3-0.5 mm (Paratylenchus pratensis) to 11 mm ( maximus) in size while animal parasites are much bigger e.g., Ascaris lumbricoides (40 cm) and the whale parasite Placentonema gigantissima (8.5 m) (Gibbons, 2001).

The soil nematodes are usually microscopic and move through pore spaces between the soil particles. Although placed at a very low level of taxonomic hierarchy in the animal kingdom, nematodes are an ecologically successful group of lower

11 invertebrates showing immense variation in community structure and diversity. They are known to occupy important positions in the soil detritus food chain and food web (Ingham et al, 1985; Freckman, 1988) and are crucial organisms responsible for flow of energy and cycling of nutrients in the soil ecosystem (Abebe et al., 2011). The food of nematodes can be the source of protoplasm either from plants, fungi, , , protozoa or even nematodes. On the basis of their diets and feeding habits, the nematodes may be divided into five main guilds: bacterial feeders or bactrivores, predators, plant feeders or phytoparasites and fungal feeders or fungivores and the omnivores. The latter is considered to have unspecified diet. The bacterivores and fungivores are the key components of soil to enhance soil fertility as they also take part in degradation of organic matter (Ferris & Matute, 2003; Ruess & Ferris, 2004). They increase the crop productivity and ecosystem functioning, thus maintaining the soil ecosystem health.

Free-living nematodes are highly diverse in their structure and adaptability to different environment types. The popular nematode has attained prominence as a model to provide insights into many areas of biology due to its simple genetic structure, prolific reproduction, transparent body, relatively smaller cell number and ease in culturing.

All organisms have their own level of tolerance for environmental disturbances or pollutants that varies from species to species. Bioindicators are the organisms or group of organisms, whose reactions are inferred to study the functional status of the whole ecosystem. In general, a bioindicator readily reflects the abiotic or biotic state of an environment and indicates the impact of environmental change. There has been an increasing interest in the identification of robust ecological indicators especially the invertebrates that can be readily incorporated into land monitoring and assessment programs because of their dominant biomass and diversity and their fundamental importance in ecosystem functioning. Due to their high species richness, abundance and short generation time, the nematodes serve as excellent tools to monitor changes in environment and to study interactions between biodiversity and ecosystem. Nematode communities significantly respond to soil physiochemical conditions, such as temperature, moisture content (Pen-Mouratov et al., 2004) and organic matter (Yeates & Coleman, 1982). Some nematode species are virtually the last animals to die in polluted or disturbed habitats (Freckman, 1988; Samoiloff, 1987), mainly due

12 to various life sustaining strategies. Due to their semipermeable cuticle being in direct contact with dissolved chemicals in the soil water, the nematodes show immense sensitivity to various changes in the soil ecosystem and are considered useful organisms for ecotoxicological research (Porazinska et al., 1999). Their community composition indicates the biotic and functional status of soils and helps to assess soil responses to agricultural practices (Porazinska et al., 1999), forestry (Forge & Simard, 2001) and mining (Hohberg, 2003). Some in situ studies on faunal analyses of nematodes at family level provide abundant information on benthic ecosystems. Nematodes can be better models compared to other meiofaunal organisms as the functional guilds of nematodes can be easily categorized by morphology of feeding apparatus and pharynx reflecting their various modes of feeding (Freckman, 1988; Yeates & Coleman, 1982; Bongers & Bongers, 1998; Neher, 2001; Yeates et al., 2009). The relative abundance and size of nematodes also make sampling and extraction easier and less costly than for other soil fauna.

Nematodes are primarily aquatic animals that adjust naturally to a variety of terrestrial habitats and require adequate moisture for sustenance. In the soil, their aquatic requirements are met by the water films around soil particles. However, those inhabiting the freshwater environment show specific adaptations. Besides having a strong protective cuticle, many freshwater forms are long and slender with enhanced swimming abilities. They usually have setose sensilla and photoreceptive eyespots. Many possess caudal glands that open at the tail tip and discharge a sticky secretion for anchorage to substratum. This specific adaptation enables the nematodes to forage and withstand turbulent and fast flowing waters. Despite their importance in the functioning of aquatic ecosystems (Coull & Chandler, 1992) nematodes are prominent among taxa grossly under represented in conservation/biotic survey research (Clark & May, 2002). The wetland/ freshwater nematodes remain one of the largest omissions from global biodiversity research. A major factor for this neglect has been the difficulty in the extraction of nematodes from these water bodies and their identification due to small number of experts working in the area.

Extensive work has been carried out so far on animal and plant parasitic species of nematodes along with some free-living terrestrial nematodes. The estimates suggest that merely 0.3-5.3% of the world’s nematode fauna has been described (Hugot et al., 2001) and a larger proportion is yet to be explored and identified. Nematodes are

13 inherently small animals and specimens that are identified at the resolution limits of light microscopy. Artefacts due to inadequate preservation, low resolution microscope and environmental conditions may affect the process of identification (Coomans, 2002). It is worthwhile to mention here that habitat-wise, the major share of new species is expected from the scarcely explored aquatic habitats and from those ecosystems of the world which have remained largely inaccessible to taxonomists, till recently. Indian wetlands and fresh water ecosystems are some of such unexplored habitats. Therefore, the task of inventorisation of species should be accomplished fast as many of them may disappear, without being identified. Wetland habitats, predicted to have millions of species, are grossly under-sampled for nematodes. In various ecological studies, the descriptions of many species are inadequate or poor and usually a large proportion of types is improperly preserved or lost. It is also a fact that discussions on species-wise global distribution are still largely premature although generic identification of freshwater nematodes in most of the cases is in place.

The present work envisages the study of the nematode fauna of a nationally conserved wetland, Keetham Lake. The work was undertaken keeping in view the paucity of knowledge on wetland nematodes. The aim of the present work, therefore, is to study the unexplored nematode fauna found in the wetland Keetham Lake, Agra, to investigate and describe the species, to analyse the nematode community structure in order to infer the quality of environment and substrate condition. The present thesis has been divided into two parts: Part A deals with the taxonomic study of the nematodes found in the wetland Keetham Lake. A detailed taxonomic study has been made on the select species of nematodes found, belonging to the orders , , , Monhysterida, and in order to add to the existing taxonomic information. In Part B, the community structure of nematodes of Keetham Lake has been analysed. Various ecological indices have been calculated for assessing the diversity and food web interactions that may reflect the climatic and substrate conditions at Keetham Lake.

Seven research papers published during the tenure have also been appended along with one accepted that is in press.

14 SOME IMPORTANT LANDMARKS IN NEMATODE TAXONOMY

Nematological investigations date back from the time of Aristotle or even earlier as parasitic nematodes were reportedly known in ancient Egypt. The “Papyrus Ebers” to 1500 BC holds accounts of roundworms and guinea worms. An old technique, followed by ancient Egyptians to pull out the guinea worm by gently winding it on a stick is still followed by some tribes of Indian State, Rajasthan. Despite earlier knowledge, Nematology as an independent discipline was recognized in the mid to late 19th century mainly due to their microscopic sizes and non-availability of good, high resolution microscopes in early times, their hidden mode of life, lack of trained personnel, etc.

Some important contributions of 17th and 18th centuries that can be regarded as important landmarks in the field are stated here. The first free-living nematode Turbatrix aceti, also referred as vinegar eelworm, was discovered by Borellus in 1656. Needham (1743) discovered the first plant parasitic nematode, wheat gall nematode (Anguina tritici ) although the nematode was mentioned in Shakespeare’s play, “Love’s Labour’s Lost” when he wrote, “sowed cockle, reaped no corn” describing the infected seeds in wheat. Later Müller (1786) described several freshwater nematode species. Linnaeus (1758) as per his classification scheme listed eight genera in the Order Intestina of Class Vermes. After a considerable time gap, the first account on systematics of nematodes was published by Rudolphi (1819). It was only in the middle of the nineteenth century that works on the free-living nematodes started with greater pace. Dr. Johannes Govertus de Man (1850-1930), a renowned Nematologist, published over 160 papers on terrestrial, freshwater and marine nematodes. Another pioneer N.A. Cobb (1890-1933) joined the U.S. Department of Agriculture in 1907 and contributed immensely to the taxonomy of fresh water, marine, soil and plant nematodes. Dujardin (1845) was the first to recognize the close relationship of free-living and plant parasitic nematodes. Bastian (1865) made outstanding contributions in the field of Nematology by including 100 nematode species as new to science, in a single paper. Schneider (1866) gave a detailed anatomical and histological account of free-living nematodes whereas Bütschli (1873, 1874, 1876) gave a detailed account of free-living nematodes. He (l.c.) also gave

15 preliminary information on the developmental progress in the fertilized egg of nematodes. Örley (1880, 1885) published a monograph on nematodes and studied on the genus Rhabditis. Maupas (1899) gave an encyclopaedia of nematodes and later in 1915 and 1916 described new species of the genus Rhabditis. Daday (1894) studied the lake microfauna including nematodes etc. and also studied (1899, 1905) the free- living nematodes of New Guinea.

In the late nineteenth and early twentieth century, Nematology experienced rapid growth. Paramanov and Filipjev brought Nematology to maturity as a zoological science with their hypotheses on nematode evolution and classification. Filipjev (1918, 1921) distinguished five families based on the structure of the cuticle, amphids, pharynx, somatic musculature, female gonads and tail and raised (1934) these families to the rank of orders with inclusion of parasitic nematodes. Steiner (1914) worked mostly on the nematodes of Switzerland. Füchs (1931) elaborated the history of nematodes and some other parasites. Rahm (1937) reported the nematode genera found in Yan Chia Ping Valley of North China while Allgén (1933, 1935, 1952) reported the free-living and freshwater nematodes from Niederkongo, Ordens and Mt. Kenya. A comprehensive record of free-living marine nematodes of Belgian coast was also published by De Coninck & Schuurmans Stekhoven (1933).

Chitwood (1933, ′37) treated ‘Nematoda’ as a Phylum with two classes, ‘Phasmidia’ and ‘Aphasmidia’, based on the presence or absence of phasmids. Later, he (1958) replaced these names with Secernentea and Adenophorea and presented the entire system of classification including both free-living and parasitic nematodes. His book (1950) ‘An Introduction to Nematology’ is a milestone in the history of Nematology. Later, the dichotomy proposed by Chitwood was rejected by Goodey (1963), accepted by Pearse (1936); De Coninck (1965); Maggenti (1963, ′70, ′81) and Lorenzen (1981) or further replaced by another dichotomy as proposed by Gadea (1973) and Adamson (1987) or by trichotomy as proposed by Andrássy (1976); Inglis (1983); Malakhov (1994). Altherr (1938) studied the fauna of the Bex mines with special emphasis on nematodes. He (1950, 1952, 1953) studied the free-living soil nematodes of the Swiss National Park, Vaudois and French Jura. Further, in 1963 and 1976, he contributed to the knowledge of fauna of the submerged sands in Lorraine and of the stygorhitral waters of the Austrian Alps. Pearse (1942) published his work entitled “An introduction to Parasitology” and described nine orders: Rhabditida,

16 Strongylida, Ascarida, Spirurida, Dioctophymatida, , Monhysterida, Camallanida and Spirurina. Kirjanova (1951) studied the soil nematodes of Hungry Steppe (Uzbekistan). Hirschmann (1952) studied fresh-water nematodes of Central Franconian. Thorne’s monograph on Dorylaims (1936, 1939), Cephalobidae (1937) and Tylenchida (1949) as well as his book (1961) entitled, ‘Principles of Nematology’ are considered important contributions in Nematology. Schneider’s (1939) ‘Die Tierwelt Deutschlands’ and Meyl’s (1960) ‘Die Tierwelt Mitteleuropas’ on free-living nematodes are essential literature resources for nematologists. Likewise Goodey’s (1951) ‘Soil and Freshwater Nematodes’ (revised in 1963 by J. B. Goodey) also is a rewarding publication for Nematode taxonomists. Baker’s (1962) ‘Checklists of the nematode superfamilies Dorylaimoidea, Rhabditoidea, Tylenchoidea and Aphelenchoidea’, the monumental series of ‘Traité de Zoologie’, Grasse (1965) and De Coninck’s (1965) contribution, ‘Class des Nematodes’ in: Traité de Zoologie are considered great assets in Nematode taxonomy.

Loof (1961) worked on the nematode collection of de Man. He (1964, 1971, 1973) worked on the free-living and plant parasitic nematodes of Venezuela, Spitzbergen and Suriname. Brzeski (1962) worked on the nematodes of peat-mosses of the Bialowieza Forest while Baker (1962) presented checklists of nematode superfamilies Dorylaimoidea, Rhabditoidea, Tylenchoidea, and Aphenlenchoidea. Inglis (1983) gave an outline classification of the phylum Nematoda whereas Coomans (1962, 1971, 2002) reviewed the morphology and systematic of nematodes and their status in current scenario and in near future. Lorenzen (1981) drafted a phylogenetic system for free-living nematodes. Later, Jacob (1984) presented a classification scheme that included animal parasites, free-living and phytoparasites of marine and continental origin. Heyns (2002) gave a checklist of free-living nematodes recorded from fresh water habitats in South Africa. Gagarin (1993, 2001) studied free- living freshwater nematodes of the order Monhysterida, Areaolaimida, Chromadorida, Enoplida and Mononchida from Russia and adjacent countries. Loof (1999, 2001) worked on the freshwater fauna of Central Europe and wrote two taxonomic books within the series “Süsswasserfauna von Mitteleuropa” (Freshwater fauna from Central Europe). Thorp & Covich (2001) studied the freshwater invertebrates of North America and published with the title, “Ecology and Classification of North American Freshwater Invertebrates”.

17 Istvan Andrássy made significant contributions (1952-2012) to nematode taxonomy through his innumerable scholarly publications and extremely useful compilations on nematode systematics and classification. He (1971) studied the nematodes from Vietnam and further in 1976 subdivided the nematodes into three subclasses: Torquentia, Secernentia and Penetrentia, in his book entitled, ‘Evolution as a basis for the systematization of nematodes’. His extremely useful compilation, ‘Klasse Nematoda’ (1984) was based on the diagnosis of orders of , Enoplida, Chromadorida, Monhysterida and Rhabditida and their subordinate taxa. He also authored another book, “Free-living nematodes of Hungary” in three volumes (2005, 2007 & 2009).

The first molecular phylogeny was produced by Blaxter et al. (1998) who proposed three fundamental clades for the Phylum Nematoda namely , and Chromadoria. De Ley & Blaxter (2002, 2004) suggested a new classification scheme for the nematodes based on molecular phylogeny. Phylogenies proposed by Aleshin et al. (1998), Holterman et al. (2006) and Meldal et al. (2007) expanded the framework with additional molecular data. The phylogeny by Van Megen et al. (2009) represented the first large-scale nematode tree, incorporating 1215 taxa and subdividing nematodes into 12 major clades.

Several taxonomists who made significant contributions in the field of Nematology for certain span of time with their outstanding publications are Allgén (1933-52), Brzeski (1960-89), Clark (1961-63), Coomans and co workers (1962-88), Dougherty (1953, ´55), Franklin (1951-62), Füchs (1915-38), Geraert (1967-84), Golden (1956-86), Heyns (1962-80), Hirschmann (1951-56), Inglis (1961-83), Kirjanova (1951-58), Lamberti (1975), Rahm (1928-37), Sher (1961-70), Taylor (1964-66), Timm (1956-71), Wieser (1953, ´54)), Yeates (1967-70) etc.

It would be difficult and beyond the scope of this thesis to enumerate the comprehensive history of taxonomy of all orders of Phylum Nematoda. As the species found in the soil and water samples of the Keetham Lake belong to both classes and , few orders were being focused upon for taxonomic studies viz., the Orders Rhabditida, Plectida, Monhysterida and Chromadorida of Subclass Chromadoria and the Orders Enoplida and Triplonchida belonging to Subclass Enoplia. The important taxonomic contributions have been discussed hereunder with an emphasis on continental species largely reported from freshwater systems or

18 wetlands and a duplication of the information is sometimes inevitable due to the common and inclusive nature of these taxonomic studies.

ORDER RHABDITIDA

Order Rhabditida was raised by Chitwood (1933) while Dujardin (1845) proposed the genus Rhabditis with Rhabditis terricola as its type species. Later, Bastain (1865) described four new species of the genus. Chitwood & Chitwood (1950) assigned four suborders under Rhabditida: Rhabditina, Tylenchina, Strongylina and Ascaridina. Bütschli (1873) in his compilation “Beiträge Zur Kenntniss der freilebenden Nematoden” gave detailed account on the morphology of rhabditid nematodes. Örley (1880) in his monograph “Az anguillulidak maganrajza” proposed a family , listed 36 valid species and discussed the biology, taxonomy and pathology of the genus Rhabditis. de Man (1876, 1880, 1884) added thirty-seven species to the genus Rhabditis. Micoletzky (1922) described seven species of the family Rhabditidae while Osche (1952) described three new and thirty- two known species of Rhabditis. Dougherty (1953, 1955) consulted with Osche, accomplished nomenclatural corrections for 138 species of Rhabditinae, excluding Brevibucca incertae sedis with two species. Hirschmann (1952) described five new and fourteen known species of the genus Rhabditis and one species of Diploscapter. Körner (1954) described thirteen new and three known species of Rhabditis and proposed a new genus Rhabditonema. Dougherty (1953, 1955) gave detailed descriptions of the taxa of subfamily Rhabditinae and added a note on family Rhabditidae. Goodey (1963) accepted three superfamilies, Diplogastroidea, Pseudodiplogastroidea and Rhabditoidea under the suborder Rhabditina and considered subfamilies Pterygorhabditinae and Bunonematinae under Bunonematidae. Paramonov (1964) proposed the family Odontorhabditidae for the genus Odontorhabditis. Sudhaus (1974-2011) worked on the taxonomy of rhabditids and diplogastrids and made significant contribution by publishing a series of papers on the systematics, phylogeny, ecology and biology of the genera of Rhabditidae. He (1976) also studied cladistic relationships of this group based on morphological characters. Kiontke & Sudhaus (2000) wrote an article on phasmids in male rhabditid nematodes.

Andrássy (1983) gave a taxonomic review of the suborder Rhabditina. Earlier, he (1976) accepted three superfamilies Alloionematoidea, Bunonematoidea, Rhabditoidea under the suborder Rhabditina. He also proposed three families:

19 Rhabditonematidae, Rhabditidae and Odontorhabdtidae under the superfamily Rhabditoidea with Rhabtitidae divided into seven subfamilies including newly raised Mesorhabditinae, Peloderinae and Ablechroiulinae. Further, in 1984, he revised classification scheme and also proposed new genera Dolichorhabditis, Rhomborhabditis, Discoditis, Rhitis and Rhodonema and in 2005, splitted the order Rhabditida into five suborders: Teratocephalina, Cephalobina, Myolaimina, Rhabditina and Diplogastrina in his book “Free-living nematodes of Hungary (Nematoda Errantia) Volume I”.

Many authors contributed to the taxonomy and classified Rhabditida in their own way but in the present study, the latest classification based on the molecular studies given by De Ley & Blaxter (2004) is followed. According to which, order Rhabditida is divided into four suborders: Spirurina, Myolaimina, Tylenchina and Rhabditina. Suborder Rhabditina has three infraorders i.e., Bunonematomorpha, Diplogasteromorpha and Rhabditomorpha whereas Tylenchina consists of four infraorders: Panagrolaimomorpha, Cephalobomorpha, Tylenchomorpha and Drilonematomorpha. The present work envisages taxonomic studies on the nematodes of the infraorders Rhabditomorpha, Diplogasteromorpha, Cephalobomorpha and Panagrolaimomorpha, that are largely non parasitic or free-living. Only few important studies undertaken by the workers on these representative taxa are given hereunder due to paucity of space.

As per new scheme, Rhabditomorpha consists of three superfamilies: Mesorhabditoidea Andrássy, 1976; Rhabditoidea Örley, 1880 and Strongyloidea Baird, 1853. Only the first two consist of bacterial feeding nematodes while the last one consists of primarily the parasites of ruminants, birds and marsupials. Sudhaus (2011) did not approve these divisions and considered Rhabditidae as a distinct clade with inclusion of the representatives of the three superfamilies.

Many scientists contributed to the taxonomy of rhabditid nematodes. Artigas (1927) proposed a new genus Cruznema with a new species C. cruznema. Fuchs (1931) described few new species of Rhabditis. Timm (1959; 1961) proposed various new genera like Cheilorhabditis, Odontorhabditis and Prodontorhabditis. Goodey (1963) wrote a comprehensive volume on soil and fresh water nematodes. Farkas (1973) described a new species of Teratorhabditis from mushroom cultures. Belogurov (1977) proposed genus Marispelodera while Anderson (1979) described a

20 new species of Teratorhabditis with emended diagnosis of the genus. Andrássy (1982) described six new species of suborder Rhabditina. Dasonville & Heyns (1984) while studying the nematodes from South Africa described many new and known species. Schulte (1989) described a new species of Rhabditis (Pelodera) and gave redescription of its sibling species. Zeiden & Geraert (1989) studied the free-living nematodes of Sudan. Gerber & Giblin-Davis (1990) described a new species of Teratorhabditis. Gagarin (1977) studied nematodes of sewage discharge and described three new species of order Rhabditida. Later, in 2000, while studying the fauna of Lake Kurilskoe, he described a new species of Rhitis.

Sudhaus (1991) provided a checklist of species of Rhabditis discovered between 1976-1986. In 1996, he studied the phylogeny of Caenorhabditis with Kiontke while in 2001, studied the phylogeny and systematics of Rhabditidae with Fitch. Smart & Nguyen (1994) described new species of Rhabditis (Oscheius) whereas Kiontke (1997) reported two new species of Rhabditis (Caenorhabditis) from Arizona. Eyualem-Abebe & Coomans (1997) recorded Diploscapter coronatus from Ethiopia whereas few rhabditid species were recorded by Abolafia & Pena-Santiago (2001) from Peninsular Spain and Balearic Islands. Later, in 2007, they (l.c.) described new species of Protorhabditis and with key to species and further in 2009, described three new species of the genus Ablechroiulus with key to its species. Kiontke (1999) studied Rhabditis (Rhabditella) octopleura and described three new species. Fitch (2000) worked on evolution of Rhabditidae and the development of male tail. Eroshenko (2002) reported a new species of Cuticularia from Siam Bay Island whereas Tabassum & Shahina (2002, 2008) described two new species of Oscheius i.e. O. maqbooli and O. andrassyi, respectively from Pakistan. Kiontke et al. (2003) described a new species of Caenorhabditis from Japan. Sudhaus & Kiontke (2007) compared the cryptic species (C. brenneri and C. remanei) with the stem pattern of C. elegans group. Sudhaus (2011) provide a catalogue of paraphyletic clade ‘Rhabditidae’ with phylogenetic systematisation. Huang et. al. (2015) described a new species Phasmarhabditis i.e. P. huizouensis from South China and gave its molecular characterisation. Later, De Ley et al., (2016) reported and described a new species Phasmarhabditis i.e. P. californica, from slug. Later Nermut et al. (2016a, b; 2017) added more species to the genus. Stock et al. (2005) described a new species of Rhabditis (Oscheius) from a bug Cyrtomenus bergi while Kanzaki et al. (2008)

21 recorded Teratorhabditis synpapillatus Sudhaus, 1985 from red palm weevil Rhynchophorus ferrugineus. He (2009, 2011) further reported new apecies of Poikilolaimus associated with termites. Ye et al. (2010) described Oscheius carolinensis as a potential entomopathogen. Abolafia & Pena-Santiago (2011) described two new rhabditid species from Spain. New species were added to genus Caenorhabditis by Sudhaus & Kiontke (2007), Sudhaus et al. (2011) and Huang et al. (2014). Slos et al. (2016) described a new species of Caenorhabditis, C. monodelphis with its stem morphology and genomics and Yang et al. (2016) desribed C. tropicalis.

With context to India, very little information on rhabditids is available. The worker who initially reported new species and even new genera of order Rhabditida was Khera (1968, 1969, 1971). Khera (1971) described Paradoxorhabditis in the subfamily Protorhabditinae. Later Tahseen & Jairajpuri (1988) described a new species Teratorhabditis andrassyi. Huseni et al. (1997) described three species Bunonema irregularis, Bunonema minutum and Pterygorhabditis superbus under the Superfamily Bunonematoidea. Tahseen et al., (2002) described a new species of Diploscapter. Later Tahseen et al. (2004) proposed a new genus Metarhabditis. She along with coworkers added new species to genera Oscheius (2006) and Poikilolaimus (2009). In 2012, they described a new and a known species of Cruznema and a new species of the closely related Rhabpanus. Khan & Tahseen, 2005 reported two new species of superfamily Bunonematoidea while Ahmad et al. (2007) proposed a new genus Sclerorhabditis. Later, Mahamood & Ahmad (2009) and Ahmad et al. (2010), added new species under the genera Mesorhabditis, Diplogasteroides and Rhabditidoides. Lately, Tahseen et al. (2015) described two new bunonematid species.

Diplogasteromorpha represents mainly the predators with wide buccal cavity and armature. Under the new scheme of classification, it has three superfamilies: Cylindrocorporoidea Goodey, 1939; Odontopharyngoidea Micoletzky, 1922 and Diplogasteroidea Micoletzky, 1922.

Taxonomic work on diplogastrids started almost at the same time as that on rhabditids. Schultze in Carus (1857) described the genus Diplogaster while de Man (1876) described the genus Tylopharynx and in 1912, proposed the genera Diplogasteroides and Odontopharynx. Micoletzky (1922) placed Odontopharynx in

22 the subfamily Odontopharynginae while Steiner (1929) raised the latter to family rank. Cobb proposed the genus Myctolaimus in 1920 and Neodiplogaster in 1924 while the genera Mononchoides and Butlerius were proposed by Rahm (1928) and Goodey (1929) respectively.

Sachs (1950) studied the biology and ecology of free-living nematodes specially rhabditids, diplogastrids and cephalobids and described new and known species of the genus Diplogaster. Later, Körner (1954) described several more species of Diplogaster. Paramonov (1952) proposed the subfamily Neodiplogastrinae and described five new genera viz., Pareudiplogaster, Fictor, Paroigolaimella, Oigolaimella and Diplogasteritus. Weingartner (1955) divided diplogastrids into nine groups viz., gracilis, schneideri, nudicapitatus, rivalis, inaequidens, coprophagus, lheritieri, levidentus and striatus groups. Goodey (1963) proposed three superfamilies: Diplogastroidea, Pseudodiplogastroidea and Rhabditoidea under the suborder Rhabditina and proposed the subfamilies Diplogasterinae, Odontopharynginae and Tylopharynginae under the family besides synonymising the subfamilies Cephalobiinae, Diplogasteroidinae, Demaniellinae and Neodiplogasterinae with Diplogasterinae. Zullini & Loof (1980) and Zullini (1981) published systematic notes on species of family Diplogastridae with descriptions of new species. Inglis (1983) regarded Diplogastrida as a separate order and divided it into five suborders: Diplogastrina, Alaninematina, Cephalobina, Rhabdiasina and Strongyloidina.

Anderson (1983) proposed a new genus Distolabrellus with a new species. Giblin & Kaya (1984) proposed genus Aduncospiculum while Dassonville & Heyns (1984) described new species of Mononchoides from South Africa. Ebsary (1986a, b) proposed the genus Parabutlerius and described some new species to the genera Butlerius, Mononchoides and Koerneria from Canada. Sudhaus & Rehfeld (1990) described two species of Diplogaster with notes on distribution, ecology and phylogeny. Kiontke & Sudhaus (1996) described Diplogastrellus cerea with a revision of subgenus Diplogastrellus.

Fürst von Lieven & Sudhaus (2000) gave an account of the comparative functional morphology of the buccal cavity in Diplogastrina. The former worker (2002a) studied the detailed feeding mechanism of Tylopharynx and suggested a close relationship of bunonematids with diplogastrids (2002b). He later (2003) described

23 two new species of Oigolaimella. Sudhaus & Fürst von Lieven (2003) using cladistic method classified Diplogastrid nematodes and accepted only 28 out of the 83 published genera under only one family Diplogastridae. Fürst von Lieven (2008) described a new species of the genus Koerneria (K. sudhausi). Kanzaki et al. (2009) established a new genus Teratodiplogaster under the family Diplogastridae, with T. fignewmani as its type species. In 2009 and 2010, they described new species of the genus Acrostichus. Recently in 2012, they described new species of Teratodiplogaster and Parasitodiplogaster from Africa and proposed a new genus Parapristionchus with P. giblindavisi its type species. Kanzaki et al. (2015; 2016a, b) reported new species of Diplogasteroides. Some other important publications of Kanzaki & co- workers on diplogastrids include raising of a new genus Leptojacobus (2014a) and revision of Koerneria (2014b). Other workers who added lately to the taxonomy of diplogstrids include Shokoohi et al. (2015), Wöhr et al. (2014; 2015), Herrmann et al. (2013; 2016) etc.

Khera, 1965 proposed a new genus Tridontus longicaudatus of subfamily Diplogastrinae. Khera (1969) described Mesodiplogasteroides, Operculorhabditis, Saprorhabditis and Praeputirhabditis and in 1970, he further described two new genera viz. Paradoxogaster and Gobindonema. Suryawanshi (1971) described Tawdenema and Syedella which later on synonymized with Acrostichus and Pareudiplogaster respectively. Jairajpuri et al. (1973) redescribed Tridontus longicaudatus (Mononchoides longicaudatus) and synonymised Syedella with Tridontus. Tahseen et al. (1992) elucidated structural details of Mononchoides fortidens using scanning electron microscopy. Hussain et al. (2004) reported two new species of Myctolaimus. Ahmad et al. (2004) proposed a new genus Peterngus. Ahmad et al. (2005) described a new and a known species of Diplogastrellus. Tahseen et al. (2008) discussed the described species of Diplogastrellus and Fictor. Mahamood & Ahmad (2009) first reported Paroigolaimella bernensis and Oigolaimella longicauda from India. Later in 2010, they described males of Koerneria filicaudata for the first time. Singh et al. (2014) described a new species of Goffartia. Later Acrostichus nudicapitatus (Ahlawat & Tahseen, 2016), Paroigolaimella bernensis (Tahseen et al., 2015) and Acrostichus medius (Tahseen et al., 2016) were some of the species described in detail.

24 Cephalobomorpha represents mainly the bacterial feeders and the opportunists which are capable of surviving extreme conditions. It consists of only one superfamily Cephaloboidea Filipjev, 1934. The record of cephalobid nematodes can be traced back to 1656 when Borellus observed “vinegar eel worms”; later Muller (1783) named these worms as Vibrio aceti. Peters (1927) proposed the genus Turbatrix and accepted T. aceti as its type species. First cephalobid species “Cephalobus persegnis” was described by Bastian (1865). Cobb (1924) reinstated the genus Acrobeles von Linstow, 1877 and suggested the subgenera Acrobeles and Acrobeloides. Thorne (1925) accepted the subgenera proposed by Cobb and produced a detailed account on morphology, systematics and taxonomy of the genus Acrobeles. He described thirty new species of Acrobeles and grouped them under two subgenera. Later, he (1937) revised Cephalobidae and proposed subfamily Acrobelinae for genera Placodira, Chiloplacus, Cervidellus and Zeldia and redescribed the genus Acrobeloides. Heyns (1962) published a series of papers on cephalobids and proposed a superfamily Elaphonematoidea with family Elaphonematidae for the genus Elaphonema. He also proposed family Osstellidae with subfamily Osstellinae for the genus Osstella. Later he (1968) described a genus Paracrobeles. Nesterov (1970) proposed a genus Acromoldavicus and redescribed Acrobeloides skrjabini. Allen & Noffsinger (1971; 1972) revised the genus Zeldia and added few species besides an identification key. They also proposed a new genus Nothacrobeles under Acrobelinae and described four new species viz., N. sheri, N. lepidus, N. maximus and N. subtilus and transferred Zeldia acrobeles to Nothacrobeles acrobeles as a new combination. Andrássy (1978) proposed two new genera and species, Bicirronema caledoniense and Amphidirhabditis longipapillata from New Caledonia.

Andrássy (1967) published detailed information on Cephalobinae and later in 1974, he proposed the suborder Cephalobina, to include the diverse array of free- living microbivores. He included three superfamilies Cephaloboidea Filipjev, 1934; Elaphonematoidea Heyns, 1962 and Panagrolaimoidea Thorne, 1937 under Cephalobina. In Cephaloboidea, he erected the family Metacrobelidae and placed Metacrobeles Loof, 1962 under it. Further, in 1984, he added two more superfamilies viz. Drilonematoidea Peirantoni, 1916 and Myolaimoidea Andrássy, 1958 under Cephalobina and accepted eight families and ten subfamilies in these five superfamilies. He also proposed the genera Acrobelophis, Ypsylonellus, Stegelletina,

25 Panagrocephalus and Panagrobelium. Several other workers who contributed to morphology and taxonomy of cephalobids were Fuchs (1930), Filipjev (1934), Timm (1956; 1960; 1971), Brzeski (1960) and Loof (1962) who added few more genera and species to the group.

Rashid et al. (1984) contributed on the morphology, taxonomy and systematic of Cephalobidae. They proposed genera Cephalonema and Heterocephalobellus. Rashid et al. (1989) synonymized Acrobelinae with Cephalobinae mainly on the basis of presence or absence of labial probolae and indentations of the head border. De Ley et al. (1990-97) added a good number of species besides publishing revision of genera and also revised the terminology of stoma components by studying the ultrastructure of the stoma in Cephalobidae, Panagrolaimidae and Rhabditidae. Holovachov & co workers (2011; 2014) carried out extensive studies on Cephalobidae. Abolafia & co workers (2014a, b; 2016) gave detailed descriptions of new species of the group. Nguyen et al. (2016) redescribed and transferred taxa of Cephalobidae.

Siddiqi (1993) proposed five new genera and eight new species of Cephalobina. He (2002) described a new genus Catoralaimellus and two new species of Macrolaimellus. Velde et al. (1994) elucidated the ultrastructure of buccal cavity and cuticle in three species of cephalobs. Morphology, oviposition and embryogenesis of Acrobeloides nanus was studied by Bird et al. (1994). Vinciguerra (1994) reported new genus Metacrolobus festonatus. Vinciguerra & Clausi (1996) reported two new species of Acrobelophis while Clausi (1998) reported new species of Cervidellus from Argentina. Heyns & Swart (1998) proposed a new genus Penjatinema. Holovachov et al. (2001) proposed a new genus Acroukrainicus. Further, Holovachov & Boström (2006) proposed two new genera Panagrolobus and Deleyia under subfamily Cephalobinae. Abolafia & Peña-Santiago (2002; 2003; 2006; 2009) besides adding new species, revised the genera, Acrobeloides, Chiloplacus, Pseudacrobeles, Nothacrobeles, Panagrolaimus, Cephalobus and also provided keys to species identification. Yushin et al. (2016) studied the sperm protein in Acrobeles complexus by immunogold localization.

Similarly the studies on the taxonomy of cephalobid nematodes have not been carried out extensively in India. Khera (1968) described the genus Acrobelinema (=Chiloplacus). Suryawanshi (1971) proposed the genus Alirhabditis and erected the subfamily Alirhabditinae for this genus. Joshi (1972) proposed a new genus

26 Pseudocephalobus (= Teratolobus) from Marathwada. Ali et al. (1973) described two new species of Drilocephalobus and proposed a new family Drilocephalobidae with a revised classification of the superfamily Cephaloboidea. Rathore & Nama (1992) described two new species viz., Acrobeloides conoidis and Chiloplacus jodhpurensis from Jodhpur. Tahseen et al. (1999) made the morphometric observations of three genera belonging to subfamily Acrobelinae viz., Zeldia punctata, Chiloplacus subtenius and Seleborca complexa through scanning electron microscopy.

Panagrolaimomorpha consists of two superfamilies: Panagrolaimoidea Thorne, 1937 and Strongyloidoidea Chitwood & McIntosh, 1934. The former consists of primarily free-living freshwater nematodes while the later one consist of parasitic forms. Thorne proposed superfamily Panagrolaimoidea with family Panagrolaimidae and subfamily Panagrolaiminae. Later on, he (1938; 39) described the genera Panagrobelus and Panagrellus under Panagrolaiminae. Steiner (1934; 1936; 1938) proposed the genus Procephalobus under the family Panagrolaimidae and the genera Eucephalobus, Tricephalobus and Pseudacrobeles in Cephalobidae. In 1989, Boström gave description of three populations of Pangrolaimus viz., P. superbus, P. rigidus and P. detritophagus. Boström (1995) described Panagrolaimus magnivulvatus from Antarctica. Abolafia & co-workers (2016) gave detailed description of few panagrolaimidae taxa whereas Atighi et al. (2015) reported a new genus Baldwinema from Iran.

ORDER CHROMADORIDA

Order Chromadorida was proposed by Chitwood, 1933 who (1950) also revised the classification and considered Order Chromadorida (Class: Aphasmidia) having two suborders Chromadorina and Monhysterina. Thorne (1961) placed Chromadorida in Adenophorea. De Coninck (1965) raised it to subclass Chromadoria of class Adenophorea and upgraded families Cyatholaimidae and Chromadoridae to subordinal rank. Andrássy (1976) in his classification scheme, considered Chromadorida in Torquentia and accepted three suborders Chromadorina, Cyatholaimina and Desmodorina. Lorenzen (1981) considered Chromadorina and Leptolaimina as suborders of Chromadorida. On the basis of recent classification based on molecular data, Eyualem et al. (2006) in their book ‘Freshwater Nematodes: Ecology and Taxonomy’ placed order Chromadorida in subclass Chromadoria and with only one suborder Chromadorina and one superfamily Chromadoroidea as the

27 subordinate taxa. Wieser (1954) studied the free-living marine nematodes of the superfamily Chromadoroidea. Yeates (1967) studied nematodes of the order Monhysterida and Chromadorida collected from the sand dune. Mulvey (1969) studied the soil-inhabiting nematodes of the orders Araeolaimida, Chromadorida, Enoplida and Monhysterida from the Canadian high Arctic. Inglis (1970) studied the nematodes of the family Cyatholaimidae of western Australian coast. Platt (1982) revised family Ethmolaimidae. Later, Jensen (1994) made further revision of family Ethmolaimidae and proposed a new genus and described three new species. Lemzina & Gagarin (1994) described a new free-living nematode species from thermal waters in Kyrghyzstan region. Eyualem & Coomans (1996) studied on the aquatic nematodes of Ethiopia and gave description of a new species of Achromadora and Ethmolaimus and a redescription of Prodesmodora nurta Zullini, 1988. Vinciguerra & Orselli (1997) worked on the nematodes of sand dunes of Italy and described four new and a rare species of Chromadorida. Ocãna et al., (1999) worked on the lakes of Spain and described a new species of Achromadora while redescribed Achromodora micoletzkyi and Ethmolaimus multipapillatus. Due to their common occurrence, most of the studies carried out on chromadorids include those of marine habitats that have not been accounted due to space contraint. Gagarin & Naumova (2012, 2016) described new species of chromadorids from Lake Baikal, Russia.

Not much work has been done on the taxonomy of Indian chromadorids. Khera (1975) published his work on the nematodes belonging to the orders Chromadorida and Enoplida from India. Tahseen et al., (1994) worked on the of Chromadorita gracilis while Tahseen (2001) described a new and a known species of Achromadora belonging to family Cyatholaimidae. Muthumbi & Vincx (1997, 1998) while working on the nematodes of the Indian redescribed seven species of Acantholaimus and description of a new and a known species belonging to the family Chromadoridae.

ORDER MONHYSTERIDA

Order Monhysterida was first proposed by Filipjev, 1929. Earlier, Bastian (1865) proposed the genus Monhystera with type species M. stagnalis and de Man (1876) proposed the family Monhysteridae for this genus. On the basis of recent classification based on molecular data, Eyualem et al. (2006) in their book ‘Freshwater Nematodes: Ecology and Taxonomy’ following De Ley & Blaxter (2004)

28 classification, considered order Monhysterida Filipjev, 1929 with two suborders Monhysterina and Linhomoeina. Filipjev (1918) gave the first classification of order Monhysterida, consisting mostly marine forms, while Cobb (1919) proposed another classification including the fresh water species of Monhysterida. Later, Micoletzky (1922) classified the continental species of the family Monhysteridae in his book “Die Freilebenden Erdnematoden” and listed 32 species of the genus Monhystera along with the key to identification.

From time to time, scientists contributed to the taxonomy by describing new and known species belonging to the order Monhysterida. Timm (1964) worked on the genus Monhystrella Cobb, 1918 and gave a description of a marine species. Yeates (1967) studied the nematodes of order Monhysterida and Chromadorida from sand dunes. Hopper (1970) reported a new species Diplolaimelloides brucei found from marsh grass Spartina. Gerlach & Reiman (1971) redescribed species of Monhystrella and Hofmaenneria while Argo & Heyns (1973) described new and known species of the families Monhysteridae and Tripylidae of South Africa. Andrássy (1981) worked on the nematodes inhabiting soil and inland waters and revised the order Monhysterida. Later, he (1984) described two species of the genus Mesotheristus Wieser, 1956 and Eumonhystera Andrássy, 1981 and (2006) proposed a new genus Halomonhystera. Jacobs (1987) gave identification key to the species of Monhystrella. Heyns & Coomans (1989) redescribed three species of Monhystrella from the inland waters of south-west Africa while Zeidan et al. (1989) studied the monhysterids from western Sudan and described two new species. Ocãna (1990) redescribed the species of Eumonhystera and Monhystrella whereas Jacobs & Heyns (1992) reported a new species of Monhystera from Algeria. Brzeski (1993) reported two new species of Geomonhystera with a description of Geomonhystera australis. Eyualem & Coomans (1996), while studying aquatic nematodes of Ethiopia, published descriptions of new species belonging to genera Monhystera Bastian, 1865, Monhystrella and Eumonhystera. A new species of Thallassomonhystera and species of Eumonhystera and Monhystrella were described by Abebe et al. (2001) from Li River, China. Yun Liang et al. (2002) also studied the nematodes of Li River, China to report a new species of Eumonhystera and three species of Monhystera. Siddiqi & Shahina (2004) described two new species of Geomonhystera from Karachi, Pakistan. Fonseca & Decraemer (2008) diagnosed and listed free-living marine Monhysteridae.

29 Gagarin along with Naumova (2010a, b; 2012) reported new monhysterid species from Lake Baikal, Russia. Eyualem-Abebe et al. (2012) described a new monhysterid genus from perianal folds of stinkpot turtle. Later Gagarin & Gusakov (2013) studies freshwater bodies of Vietnam and reported two new monhysterid species. While studying the nematodes from Kermadec Trench, South west Pacific, Leduc (2015) described new species of Thelonema, Metasphaerolaimus and Monhystrella.

In India, the studies on free-living nematodes of order Monhysterida are quite few. However, some authors contributed by describing new and old taxa. Khera (1966) studied nematodes from the banks of still and running waters and described a new species of genus Rogerus. He (1971) raised a new genus Sitadevinema found from the banks of running water in Jodhpur (Rajasthan). Khan & Araki (2001) described new species of Monhystrella and Geomonhystera from Japan. Khan et al. (2005) described two new monhysterid species, one of Monhystrella and the other of Hoefmaenneria from Ramsar wetland, Keoladeo National Park, Rajasthan whereas Khan & Tahseen (2006) described two new species namely Monhystera rolandi and Geomonhystera glandulata from sewage.

ORDER PLECTIDA

Malakhov (1982) proposed the order with the type genus Plectus being described by Bastian in 1865. This order was proposed for those families which were earlier placed in order Araeolaimida (Andrássy, 1976) or Chromadorida (Lorenzen, 1981) by other authors. Blaxter et al. (1998) raised the family Plectidae to the level of order on the basis of molecular phylogeny. Holovachov & Boström (2004) suggests five superfamilies for the order Plectida, i.e., Leptolaimoidea, Plectoidea, Camacolaimoidea, Ceramonematoidea and Haliplectoidea.

The other authors who contributed to this field include Kirjanova (1958) who studied the genus Plectus. Allen & Noffsinger (1968) gave revision of the genus Anaplectus. Kito et al. (1991), while working on plectids of Soya coast, East Antarctica, reported two species of Plectus i.e., P. antarcticus de Man, 1904 and P. frigophilus Kirjanova, 1958 with a report on male. Andrássy (1973) studied species of Plectus and Anaplectus and added (1985) detailed information on family Plectidae with notes on Plectus and its close relatives. He further (2003, 2008) studied new and rare plectids and described three plectid species from Alaska and reported a male of Plectus murrayi Yeates, 1970 from Antarctica. Heyns & Coomans (1980, 1983) while

30 studying fresh water nematodes of South Africa, described new and known specis of Chronogaster. Ebsary (1985) described two new and a known species of Plectus from Canada. Abdel-Rehman (1993) reported a new species of Plectus from California, USA while De Ley & Coomans (1994) studied three new species of Plectus from Galapagos Island. Later (1997), they described a new and a known species of Tylocephalus. Boström (1995) reported Plectus acuminatus Bastian, 1865 from east Antarctica. Eyualem & Coomans (1996) while studying aquatic nematodes from Ethiopia described two new species of Chronogaster whereas Gagarin & Nguyen, (2004) described a new species of Chronogaster from Vietnam.

In the recent years, order Plectida got much more attention. Many authors published their work on plectids. Holovachov contributed significantly to the morphology, phylogeny and evolution of the superfamily Plectoidea Orley, 1880. Holovachov & Susulovsky (1997) studied free-living nematodes of family Plectidae from Ukraine. Later, in 1999 and 2000, they (l.c.) added several new species of Plectus. Holovachov (2001; 2004; 2005; 2006; 2013; 2014) provided valuable information on the development and systematic of Pectids. In 2012, while studying nematodes of Skagerrak, Sweden, he described a new species of Domorganus. De Ley et al. (2002) did SEM studies on juvenile stages of members of subfamily Wilsonematinae. Holovachov & Hanel (2004) described a new species of Wilsonema from Poland. Holovachov & De Ley (2006) provided salient information on order Plectida in the book “Freshwater nematodes: Ecology and Taxonomy”.

Holovachov & Boström (2004) studied the morphology and systematics of superfamilies Leptolaimoidea and Camacolaimoidea of order Plectida. In 2010, they published an identification manual of order Plectida; and proposed a new genus Loveninema in 2012 while working together, the duo proposed two new genera, Neocamacolaimus and Yeatesinia in 2014. Holovachov et al. (2003) gave a comparative account of the morphology and systematic of Wilsonema, Ereptonema and Neotylocephalus whereas in 2004 published the revision of the genera Anaplectus and Tylocephalus separately. Later, Holovachov et al. (2009) discussed the morphology and systematic position of the genus Hemiplectus muscorum Zell, 1991 within the order Plectida. Holovachov (2014; 2015a, b) and coworkers (2012; 2013; 2014a, b) published a series of papers on nematodes from Sweden. Shokoohi et al.

31 (2013) reported Plectus Bastian, 1865 from Iran while Kim et al. (2017) emphasized on the sister group relationship between Plectida and Rhabditida.

Very little information is available from India on plectids. Ali et al. (1969) proposed a new genus Neotylocephalus from Marathwada while Chawla et al. (1969) proposed Wilsotylus from Bangalore, India. Later (1977), they proposed another genus Wilsereptus from Dalhousie. Ganguly & Khan (1986) described a new species of family Wilsonematidae while Tahseen et al. (1992) worked on the developmental biology and described a new species Plectus zelli. They, later, (2004) reported two new species from subfamily Plectinae. Khan & Araki (2001) described four new and five known species of Plectus from Japan. Tahseen & Mustaqim (2012) described six known species of Plectus with additional details.

ORDER ENOPLIDA

A good number of studies have been carried out on marine enoplids. The text hereunder highlights important landmarks in the taxonomy of enoplids with species reference to the continental/ wetland species.

Order Enoplida was proposed by Filipjev (1929) who in 1934 also proposed a comprehensive morphological classification of free-living nematodes. Kreis (1934) published a monograph on the subfamily Oncholaiminae while Chitwood & Chitwood (1950) classified Order Enoplida within the Class Aphasmidia having the suborders Enoplina, Dorylaimina and Dioctophymatina. Wieser (1953) elaborated the relationship between the shape of oral cavity, diet and occurrence of free-living nematodes. Clark (1961) revised the classification and divided order Enoplida into five suborders: Enoplina, Alaimina, Dorylaimina, Trichosyringina and Dioctophymatina. Later, in 1962, he discussed the systematic position of Alaimidae and Diptherophoroidea. De Coninck (1965) proposed a classification similar to that proposed by Clark and considered orders Enoplida (containing suborders Enoplina and Oncholaimina) and Dorylaimida (containing suborders Dorylaimina and Alaimina) under subclass Enoplia. The suborder Enoplina was further divided into the superfamilies Tripyloidea and Enoploidea. Platonova (1970) while studying the nematodes from Mediterranean and the adjacent Atlantic waters raised and revised new superfamily Leptosomatoidea with five families under it. Rachor (1970) studied the genera of Oncholaiminae in details with special emphasis on the demanian system. Later (1979), Coomans & Van der Heiden discussed the systematic position

32 of Ironidae and its relationship with Dorylaimida. Andrássy (1976) defined Enoplida as separate order within the class Penetrantia and considered three suborders Enoplina, Oncholaimina and Tripylina.

Maggenti (1981) defined the subclass Enoplia within the class Adenophorea. He raised the rank of several taxa and raised seven orders: Enoplida, Isolaimida, Mononchida, Dorylaimida, Trichocephalida, Mermithida and Muspiceida under Enoplia. Lorenzen (1981) considerably rearranged the classifications of nematodes; he defined the subclass Enoplia within the class Adenophorea and considered three orders under it namely Enoplida (containing the suborders Enoplina and Tripyloidina), Trefusiida and Dorylaimida (containing the suborders Dorylaimina, Mononchina and Bathyodontina). Later, he (1994) proposed phylogenetic systematics of free-living nematodes. Earlier, Belogurov & Belogurova (1977; 1978) studied the systematics of Oncholaiminae with emphasis on the structure, evolution and significance of demanian system. Later, Belogurov et al. (1980) while studying the nematodes of far eastern seas of USSR described three new species and gave an identification key to species of Pseudoncholaimus Kreis, 1932. Platt & Warwick (1983) contributed significantly to the taxonomy and identification of the British aquatic nematode genera with special reference to marine ones. Keppner (1987; 1988; 1989; 1991) while studying free-living marine nematodes from Florida, described at least twenty new species with a key to the species of genus Halalaimus.

Andrássy (1978) studied the inland aquatic nematodes of Europe while Jacobs (1984) gave a review on the free-living inland aquatic nematodes of Africa. Siddiqi (1983) gave a phylogenetic relationship of orders Dorylaimida, Mononchida, Triplonchida and Alaimida of the soil nematodes with revised classification of the subclass Enoplia Pearse, 1942. Later (1993) he studied the nematodes of tropical rain forests and proposed six new genera and eighteen new species of alaimids. Botha & Heyns (1992) reported and described nematodes belonging to the orders Enoplida, Chromadorida, Monhysterida, Mononchida and Araeolaimida from rivers in the Kruger National Park. Eyualem & Coomans (1995) studied the fresh water nematodes of Galapagos Island. Tsalolikhin (1998) gave an account of the nematodes of high mountain lakes in the Pamir and Himalayan region while Doucet & Doucet (1999) provided a checklist of soil and freshwater nematodes from Argentina. Gagarin (2000) published taxonomic information on the nematodes of Eurasia while Tsalolikhin

33 (2001) studied those of Singapore and Japan and Gagarin et al. (2003) studied the nematodes of Vietnam. Eyualem (2000, 2002) studied free-living aquatic nematodes of Ethiopian Rift Valley whereas Heyns (2002) worked on the freshwater habitats in South Africa and provided a checklist of free-living nematodes found. Decraemer & Coomans (1994) gave a compendium on free-living nematodes of ancient lakes.

Belogurov (1985) analyzed the organization of the stoma and worked on the origin and state of evolution of stoma of nematodes of suborder Oncholaimina. Belogurov & Belogurova (1980) described a new species of Belbolla while Alekseev & Linnik (1995) and Alekseev (1996) described new species of Halalaimus and Alaimus from Lake Khanka. Clausi & Vinciguerra (1995) proposed two new genera Metamphidelus and Scleramphidelus and further in 1998, published a revision of the genus Amphidelus. Andrássy (2011) described two new species of Trischistoma while Prado-Vera et al. (2012) described four new species of Tripylina from Mexico. Further, Prado-Vera et al. (2016) studied the nematodes from North and Central America and described five new species of nematodes belonging to family Trischistomatidae with keys to the species of Trischistoma and Tripylina. Genus Ironus Bastian, 1865 is largely reported from freshwater ecosystems. Argo & Heyns (1972) described four new species of the genus Ironus Bastian, 1865 from South Africa.

Ebsary (1985) described two new aquatic species of Ironus from Canada. Earlier Tsalolikhin (1987) gave a revision of the genus Ironus with description of twelve species while Shokoohi et al., studied Ironus with a comment on its phylogenetic relationship. Esquivel (2003) studied the nematode fauna of protected area of Costa Rica. Bik et al. (2010) gave a molecular framework of Nematode with emphasis on Enoplida. Andrássy (2011) studied the genus Ironus with description of two new and two known species. Gagarin & Thanh (2016) reported two new species from mangroves of Yen River delta inVietnam.

Siddiqi & Basir (1965) described two new species of the genus Amphidelus from India with a key to species. Siddiqi & Husain (1967) studied the genus Alaimus from India with description of six new species. Khera (1979) studied the genus Ironus along with a remark on the genus Cryptonchus. Tahseen & Mehdi (2009) while studying the nematodes of coal mines, described a new species of Trissonchulus i.e.

34 T. baldwini, as the first terrestrial representative of the genus and redescribed two species of Ironus.

ORDER TRIPLONCHIDA

Order Triplonchida was proposed by Cobb (1920) with the type genus Triplonchium. Brooks & McLennan (1993) placed order Triplonchida within subclass Enoplia (class Enoplomorpha). On the basis of recent classification based on molecular data, Eyualem et al. (2006) in their book ‘Freshwater Nematodes: Ecology and Taxonomy’, accepted Triplonchida as separate order with three suborders , Tobrilina and Tripylina. Diptherophorina and Tripylina were represented by a single superfamily each i.e. Diptherophoroidea and Tripyloidea, respectively whereas Tobrilina was represented by two superfamilies Prismatolaimoidea and Tobriloidea.

De Ley & Blaxter (2002) suggested that Prismatolaimoidea and Tobriloidea form a separate clade in triplonchids on the basis of small subunit (SSU) rDNA. Loof (1973) proposed genus Tobriloides of the family Tripylidae. Tsalolikhin (1980) worked on the free-living nematodes of lake Baikal, USSR and a year later, in 1981, he revised the genus Tobrilus and in 1983, studied the nematodes of families Tobrilidae and Tripylidae. In 2001, he published many papers simultaneously including those on Brevitobrilus and Paratrilobus. Later in 2005, he revised the genus Eutobrilus. Ocaña & Zullini (1988) described a new species of Tobrilus from spring water near Granada (Spain). Eyualem & Coomans (1997) studied the aquatic nematodes of Ethiopia and reported two new species of Brevitobrilus. Shoshin (1988; 1991; 1998) worked on the nematodes of the Lake Baikal and described few new species including those from genus Asperotobrilus. Shoshin & Shoshina (2003) worked on the free-living nematode fauna of the upper Saratov reservoir while Shoshina (2003) proposed a new genus Setsalia from Lake Baikal. Zullini & Villa (2006) conducted advanced study on the collection of Altherr using confocal microscopy and redescribed three species. Siddiqi (2006) described ten new species of Prismatolaimus while Gagarin (2009) revised the genus Eutobrilus. Gagarin & Naumova (2011a, b; 2012; 2013; 2016) described new species of Paratrilobus and Tobrilus and also reported male of Domorganus from Lake Baikal, Russia. Xu et al. (2013; 2017) reported several new Tripylidae from China and Australia. Earlier Zhao

35 et al. (2013, 2014) worked on the same group to report several new species. Lately Cid Del Prado-Vera and co-workers (2016a, b) also added new species to the group.

Scanty information is available on the taxonomy of Indian triplonchids. Khera (1970) is among the Indian taxonomists who studied few taxa of Tripylidae by describing the male of Tripyla glomerans and giving a revision of the genus. He considered Tripyla, Trischistoma and Paratripyla as subgenera of genus Tripyla. He further (1971) established a new genus Abunema under Monhysteridae that was later transferred to Tripylidae by Gerlach & Riemann (1974). Ali, et al. (1972) described a new species of Prismatolaimus and redescribed species of the genus Oncholaimus from Marathwada, India. Tahseen & coworkers (1993) provided SEM observations of Tobrilus paludicola; in 2007 described three new and one known species of Prismatolaimus while in 2009, they described three new species of Brevitobrilus. Tahseen & Nusrat (2010) also described new and known species of Tripylina and Trischistoma.

36 MATERIALS AND METHODS (TAXONOMIC STUDY)

The nematode faunal diversity of Keetham lake was studied by extensive collection of soil and water samples for extraction of nematode species. The sampling stations were identified and selected in the three already designated zones of the wetland: Zone A, Zone B and Zone C.

a) Zone A: Water samples, mud samples and coastal soil samples collected from main body of water, area submerged under water and the nearby coastal area covered by the mollusk shells (Figs. 66, 67, 68).

b) Zone B: The area represents a woodland, covered profusely mainly with Acacia nilotica plants away from the water zone (Figs. 69, 70).

c) Zone C: It is the most interior and undisturbed area of the wetland without any human intervention. It is also the restricted entry zone of the bird sanctuary and the place for many pythons (Figs. 71, 72, 73).

COLLECTION AND PROCESSING THE SAMPLES

Extensive sampling from all possible areas of the sites was done throughout the year to catch majority of nematode species that constitute the wetland fauna. The wetland showed highly variable climate with different types of substrate and vegetation. The grounds were at places water-logged and at places quite dried. Therefore, the samples collected from the sites were of two types.

a) Sediment samples and

b) Water samples

Sediment samples from the moist soil were taken from a depth of 5-12" using a shovel, while the samples from dry soil were obtained by digging beyond a depth of 10-12". Each sampling station marked a collection of 10 samples from its span of area. Of these samples, each represented the mean sample of three replicate samples, taken from ten thoroughly mixed samples. In each case the volume of soil/mud sample was 400 ml. In water-logged conditions, samples were taken from periphytons. Sediment samples were obtained from the shallow water collected by shovels or scoopers scratched along the bottom.

37 The flowing water samples from the top layers, were collected in stainless steel containers and passed through 325 mesh sieve (pore size= 45 m) kept at 45° angle. This reduced the volume of samples without affecting the total catch of organisms. For the floating debris, additional sieves in the sequence of 10 meshes (pore size= 2mm), 100 meshes (pore size= 150 m), 200 meshes (pore size= 53 m) and 325 meshes (pore size= 45 m) were used.

The collected samples were brought to the laboratory in coolers for their further processing. Such samples were kept in refrigerator and were soon processed to prevent their degradation and decomposition.

At the time of collection of samples, some preliminary information regarding temperature, pH and the vegetation type, was also recorded. Besides, the samples were labeled with information such as locality, date and month of collection. The GPS device, Garmin was used to accurately mark the coordinates of the sampling site for record.

SAMPLE PROCESSING

The soil samples were processed using Cobb’s (1918) sieving and decantation and modified Baerman’s funnel techniques. The soil was placed in a bucket and mixed with water. The debris and pebbles were taken out and soil crumbs were broken. The bucket was then filled with water and suspension was stirred to make it homogenous. The bucket was left undisturbed for about half a minute to allow the heavy soil particles to settle down at the bottom of bucket. The suspension was then passed into another bucket through a coarse sieve of 2 mm pore size, which retained debris, roots and leaves. The suspension in the second bucket was again stirred thoroughly and left for another half a minute and then poured through a 300-mesh sieve (pore size= 53 m). As a result, the nematodes and very fine soil particles were retained on the sieve. The process was repeated thrice for good recovery of nematodes.

ISOLATION / EXTRACTION OF NEMATODES

The residue on the sieve was collected in a beaker and poured on a small course sieve lined with tissue paper. The sieve was then gently placed on a Baerman’s funnel, having stoppered rubber tubing, fixed to stem and containing water sufficient to touch the bottom of the sieve. The nematodes migrated from the sieve into the

38 clean water of the funnel (motility of nematode separated them from the inert debris of the course sieve) and settled at the bottom of the funnel. After 24-48 hours, the nematode suspension was drawn from the funnel into a cavity block.

OBSERVATIONS

The nematodes extracted from processed samples, were examined under the Stereoscopic Zoom Microscope (Olympus-SZ61) with a range of magnifications for their generic identification for community analysis (please see the protocol for community analysis in Part B of this document).

The specimens were heat-killed or fixed or observed in a temporary mount, shortly after their death for studying structural details. Their tentative identification was done for estimation of indices and quantitative characteristics of the nematode communities. For confirmation of the species the nematodes were further processed for Light Microscopy or Scanning Electron Microscopy.

TEMPORARY MOUNT

For quick tentative identification of genera, the nematodes were studied in temporary mounts. They were transferred to the centre of drop of water on a glass slide. Three pieces of glass wool of thickness corresponding to nematode body width were placed around nematodes. Finally, a cover glass was placed gently and its edges sealed with nail varnish partially, leaving some space for introduction of water to prevent drying.

KILLING AND FIXATION

The extracted nematodes were collected from Baerman’s funnel in cavity blocks and left undisturbed for a few minutes to allow them to settle. Excess water was removed with the help of dropper and hot Formalin-glycerol fixative having 8 ml of 40% commercial formaldehyde + 2 ml glycerol + 90 ml distilled water, was added to the nematode suspension. This act killed and fixed the nematodes, simultaneously.

DEHYDRATION

Twenty-four hours after fixation, the nematodes were transferred to another cavity block containing a mixture of glycerin and alcohol (30% ethanol 95 parts + glycerol 5 parts) and were placed in a desiccator containing Calcium Chloride for

39 dehydration. The dilute ethanol evaporated completely, leaving dehydrated nematodes in anhydrous glycerol, after 3-4 weeks (Seinhorst, 1959). The master slides were prepared of nematode representative of taxa found in a sample for studying the species composition.

MOUNTING AND SEALING

In the absence of glyceel or any proper sealing material, the conventional method of slide preparation leads to the drying of mounted specimens within a short span of time. Therefore, wax ring method of De Maeseneer and D’Herde (1963) for mounting and sealing of nematodes was practiced. A wax ring was applied to the centre of slide surrounding the glycerine drop by heating 1.5 cm diameter metallic tube over flame, and dipping it in a thin solid layer of paraffin wax (M.P. 60°C). The nematodes were placed in the center of glycerol drop and pushed gently at the bottom. Three pieces of glass wool, with thickness corresponding to nematode body width, were arranged around the nematode. Then the cover glass was applied gently and slide was placed on a slide warming cabinet at about 65°C for few seconds. As the wax melted, the cover glass settled down and glycerol with nematodes got confined to the centre of mount, surrounded by the wax at periphery. The cover glass was further pressed to make it settled firmly. A secondary sealing with nail polish was done to prevent drying or dissolution of wax by immersion oil.

PROCESSING FOR SCANNING ELECTRON MICROSCOPY

The heat-killed or live nematodes were fixed in 2% glutaraldehyde, post-fixed in 2% osmium tetroxide and then dehydrated in alcohol grades (30% to 100%). The dehydrated nematodes were dried in Critical Point Dryer (CPD) using CO2. The nematodes were mounted on stub on double-sided adhesive tape and then coated with 10 nm gold in Ion Coater. They were later observed under Scanning Electron Microscope at 10kV.

MAINTENANCE OF CULTURES FOR FURTHER STUDIES

The culture plates were prepared using NGM medium. Nematodes were cultured at 25±2 °C), depending on the nematode species. To prepare NGM medium for culturing nematodes,15 g agar, 2.4 g NaCl, 2 g Tryptone and 2.72 g KH2PO4 were taken in 2 L conical flask with water added to make the volume up to 1 L. The

40 mixture was autoclaved and allowed to cool to 60° C in a water bath. Then 0.8 ml each of 1 M CaCl2, cholesterol (5 mg/ml in ethanol), and 1 M MgSO4 was mixed to the autoclaved suspension. The hot content was poured into the petri dishes and gelified. One gravid female and a male nematode were picked and transferred to the culture plates once the medium was cooled.

MEASUREMENT AND DRAWING

Nematodes were measured using ocular micrometer fitted within the eyepiece of microscope and de Man’s (1880) formula was used to represent linear and allometric values. Drawings of nematodes were made with drawing tube attached to Olympus CX41 microscope and LM photographs were taken with a Jenoptik ProgRes digital camera mounted on Olympus BX-51 DIC Microscope.

TYPE MATERIALS

The type materials including holotype and paratypes were labeled and deposited in ‘Nematode Collection’ of the Department of Zoology, Aligarh Muslim University, Aligarh, India.

ABBREVIATIONS USED IN THE TEXT

n = Number of specimens.

a = Body length/maximum body width.

b = Body length/total pharyngeal length.

c = Body length/tail length.

c′ = Tail length/anal body diameter.

V = Distance of vulva from anterior end x 100/body length.

T = Length of male genital tract x 100/body length.

G1 = Overall length of anterior genital branch x 100/ body length.

G2 = Overall length of posterior genital branch x 100/ body length.

Genital papillae formula used in the text: No. of (Precloacal/s)/ C (cloaca) No. of adcloacal/s)/ No. of (Postcloacals including P for phasmids). Phasmids shown darker than other papillae in figures.

41 SYSTEMATICS

Class: Chromadorea Inglis, 1983

Diagnosis. Nematoda. Cuticle annulated, sometimes ornamented with projections and setae. Amphidial aperture variable in shape from pore-like or slit-like to circular, open circular or spiral, present in labial region or post-labially. Pharynx generally divided into bulbs with three to five pharyngeal glands. Secretory-excretory system glandular or tubular. Phasmids may be present or absent, usually posterior to mid of tail. Female reproductive system didelphic, amphidelphic or monodelphic, prodelphic. Males with bursa present, absent or rudimentary. Subclass: Chromadoria Pearse, 1942

Diagnosis. Chromadorea. Body cuticle annulated, ornamented with projections, punctuations or setae. Amphidial aperture slit-like, pore-like, circular, open circular or spiral. Pharynx divided into bulbs, three to five pharyngeal glands present. Secretory- excretory system glandular or tubular. Phasmids present or absent, if present, posterior to mid level of tail. Female reproductive system didelphic, amphidelphic or monodelphic, prodelphic. Males with/ without bursa or sometimes bursa may be rudimentary. Order: Rhabditida Chitwood, 1933

Diagnosis. Chromadoria. Wide group of free-living and parasitic forms (parasites of plants, insects, annelids and vertebrates mainly amphibians and reptiles). Body size ranging from microscopic forms to large-sized animal parasites that can be seen from naked eyes. Cuticle smooth to finely or strongly annulated; longitudinal striae or punctations may also be present. Lip region continuous or offset, showing triradiate or hexaradiate symmetry; lips three or six, rarely four; labial probolae may also be present. Amphids labial or post-labial, amphidial aperture various-shaped, pore-like, circular or slit-like. Stoma composed of three basic elements-cheilostom, gymnostom and stegostom of variable shapes and sizes depending on the feeding habits: tubular, narrow or collapsed in free-living bacteriovores; more or less spacious with armature in predatory forms and protrusible fine needle-like stylet in plant parasitic forms. Lateral fields indistinct or distinct with two to seven incisures. Pharynx with corpus, isthmus and basal bulb. Corpus with or without median swelling. Basal bulb well-

42 developed or forming an overlap over intestine. Excretory system developed; excretory pore distinct or indistinct. Intestine with narrow or wide lumen. Female reproductive system didelphic, amphidelphic (with exception of didelphic prodelphic in Meloidogyne spp.) or monodelphic, prodelphic with or without post uterine sac. Males with or without genital papillae. Bursa present, absent or rudimentary. Spicules of various shapes, from small slender, arcuate to robust. Tail similar or different in both the sexes, of variable shapes.

Type suborder: Rhabditina Chitwood, 1933

Other suborders

Myolaimina Inglis, 1983

Spirurina Railliet & Henry, 1915

Tylenchina Thorne, 1949 Key to suborders of Rhabditida Chitwood, 1933

1. Stoma long tubular or wide with minute denticles, teeth or strong armature; pharynx with median bulb or swelling and basal bulb with or without grinder; female reproductive system didelphic or monodelphic; bursa well-developed, rudimentary or absent …………………………………………… Rhabditina

2. Stoma spacious, armed with teeth; pharynx without median swelling and developed basal bulb; female reproductive system generally monodelphic; bursa with large ribs or papillae ….………………...... Myolaimina

3. Stoma collapsed provided with cephalic hooks (parasites of animals); pharynx bottle-shaped with anterior narrow muscular and posterior broad glandular part; bursa weakly developed with ribs ………………………...... Spirurina

4. Stoma protrusible stylet to non-protrusible collapsed tubular stoma; pharynx with/ without median bulb and basal bulb/pharyngeo-intestinal overlap; female reproductive system didelphic or monodelphic; bursa well-developed or reduced …………………………………………………………... Tylenchina Suborder: Rhabditina Chitwood, 1933

Diagnosis. Rhabditida. Free-living and parasitic forms. Small- to large-sized. Cuticle finely or strongly annulated with transverse or longitudinal striations or punctations,

43 sometimes with fine warts. Lip region continuous or offset, lips three or six, rarely four, fused or separate. Labial papillae very small or setiform. Amphids pore-like, on lateral lips, discernible, rarely enlarged, circular shifted behind the labial region. Stoma variable, tubular, with/ without minute denticles in bacteriovores and spacious with armature (tooth, teeth or denticles) in predatory and parasitic forms. Pharynx with three distinct sections: corpus, somewhat swollen distally or forming a true valvular bulb, basal bulb strongly or poorly developed, with or without distinct valve plates. Excretory pore usually visible, at a level or slightly posterior to the nerve ring within the posterior part of pharynx. Female reproductive system mostly didelphic, amphidelphic, sometimes monodelphic, prodelphic, vulva equatorial or post- equatorial. Ovaries reflexed, rarely outstreched. Spicules separate or fused distally; gubernaculum present. Bursa well developed, reduced or absent; tail completely surrounded by bursa (peloderan) or projected beyond it (leptoderan). Bursal edges open or closed anteriorly. Genital papillae variable, seven to nine pairs. Tail in both the sexes similar or with sexual dimorphism with female tail longer than males. Phasmids distinct or indistinct.

Type infraorder: Rhabditomorpha De Ley & Blaxter, 2002

Other infraorders

Bunonematomorpha De Ley & Blaxter, 2002

Diplogasteromorpha De Ley & Blaxter, 2002

Key to infraorders of Rhabditina Chitwood, 1933

1. Bacteriovores/ animal parasitic; body symmetrical/ asymmetrical; cuticle smooth or finely annulated; stoma tubular or wide spacious with/ without armature, cheilostom not cuticularised; pharynx with median bulb or swelling, basal bulb weakly or strongly developed; female reproductive system didelphic or monodelphic ………...... Rhabditomorpha

2. Bacteriovores; body asymmetrical; cuticle with fine lattice structure and warts; stoma tubular or prismatic, cheilostom cuticularised; pharynx with strong

44 median and basal bulb; female reproductive system didelphic .…………………………………………………...…….. Bunonematomorpha

3. Bacteriovores/ predators; body symmetrical; cuticle smooth or longitudinally striated; stoma spacious with/ without armature; cheilostom may/ may not cuticularised; pharynx with muscular median bulb and weak basal bulb; female reproductive system didelphic or monodelphic …………………………………….…………….……… Diplogasteromorpha

Infraorder: Rhabditomorpha1 De Ley & Blaxter, 2002

Diagnosis. Rhabditina. Free-living and parasitic forms. Body bilaterally symmetrical. Anterior body region with three to six lips or leaf crown. Stoma tubular with small tooth/denticles or large sized buccal cavity with armature. Pharynx with median bulb/ swelling and basal bulb. Female reproductive system paired or unpaired. Female tail variable shaped, short-conoid to long filiform. Spicules separate or fused. Bursa present, absent or rudimentary.

Type superfamily: Rhabditoidea Örley, 1880

Other superfamilies

Mesorhabditoidea Andrássy, 1976

Strongyloidea Baird, 1853 Key to superfamilies of Rhabditomorpha De Ley & Blaxter, 2002

1. Small- to medium-sized nematodes; lip region continuous with three or six rarely four lips; stoma tubular, metastegostom with/ without teeth; female reproductive system didelphic; vulva equatorial …..…...... Rhabditoidea

1 Sudhaus did not consider the Infraorder Rhabditomorpha and its divisions Rhabditoidea, Mesorhabditoidea and Strongyloidea. Instead he divide the taxa into two main clades, Rhabditidae and Bunonematidae and Rhabditidae included rhabditids, strongylids as well as mesorhabditids together. The present document follows the new scheme of classification but with modification with context to rhabditids that include the view points of Sudhaus, a renowned expert on Rhabditidae. At places of ambiguities or uncertainties regarding the placement of taxa, Andrássy’s scheme (1984) has also been looked for solution.

45 2. Small-sized nematodes; lip region offset with 6 lips; stoma fairly long and slender, metastegostom with minute teeth; female reproductive system monodelphic; vulva post-equatorial ………….……………. Mesorhabditoidea

3. Large-sized nematodes, can be seen with naked eyes; lip region with hooks or suckers (animal parasites); stoma well developed with teeth or sometimes rudimentary; female reproductive system didelphic or monodelphic ………………………………………………………..………... Strongyloidea Superfamily: Rhabditoidea Örley, 1880

Diagnosis. Rhabditomorpha. Lip region offset or continuous with adjoining body. Lips usually six rarely four. Stoma tubular, longer than wide. Cheilostom weakly cuticularized; gymnostom cuticularized; stegostom surrounded by pharyngeal tissue. Metastegostom with/ without glottoid apparatus, small warts or denticles present or absent; telostegostom short. Pharyngeal corpus often with swollen metacorpus. Female reproductive system didelphic, amphidelphic or monodelphic, prodelphic. Spicules separate or fused distally. Bursa present, generally well-developed, rarely reduced.

Type family: Rhabditidae Örley, 1880

Other family

Diploscapteridae Micoletzky, 1922

Key to families of Rhabditoidea Örley, 1880

1. Lip region radially symmetrical, lips simple; stoma tubular with distinct glottoid apparatus and minute setose denticles; bursa leptoderan ….…………………………………………………………………. Rhabditidae

2. Lip region bilateral in symmetry, dorsal and ventral lips heavily cuticularized and transformed into hook like structures; stoma tubular without glottoid apparatus and teeth; bursa peloderan or pseudo-peloderan .…………………………………………………..………….. Diploscapteridae

46 Family: Rhabditidae Örley, 1880

Diagnosis. Rhabditoidea. Lip region generally with six distinct lips, rarely three lips in doublets. Stoma tubular or prismatic, usually three times longer than wide. Cheilostom weakly cuticularized. Gymnostom cuticularized, stegostom surrounded by pharyngeal collar. Metastegostom with glottoid apparatus bearing warts or denticles. Pharynx with corpus, swollen metacorpus, isthmus and basal bulb. Female reproductive system didelphic, amphidelphic or monodelphic, prodelphic. Ovary/ovaries reflexed. Spicules separate rarely fused. Bursa mostly well-developed, peloderan or leptoderan, rarely rudimentary. Genital papillae generally seven to nine pairs. Tails of both sexes similar or male tail shorter.

Type genus: Rhabditis Dujardin, 1845

Other genera

Caenorhabditis Osche, 1952

Cephaloboides Rahm, 1928

Cruznema Artigas, 1927

Diploscapter Cobb, 1913

Diploscapteroides Rahm, 1928

Metarhabditis Tahseen, Hussain, Tomar, Shah & Jairajpuri, 2004

Oscheius Andrássy, 1976

Pellioditis Dougherty, 1953

Poikilolaimus Fuchs, 1930

Protorhabditis Osche, 1952

Prodontorhabditis Timm, 1961

Rhabditella Cobb, 1929

Rhabditoides Goodey, 1929

Xylorhabditis Sudhaus, 1976

47 Genus: Caenorhabditis Osche, 1952

Diagnosis. Rhabditidae. Medium- to large-sized nematodes. Cuticle smooth or finely annulated. Lip region continuous or slightly offset. Lips amalgamated, hardly separate, labial sensilla small, slightly raised. Stoma tubular, cheilostom not cuticularized; gymnostom cuticularised; metastegostom with glottoid apparatus weakly developed, provided with one small tooth on each swelling. Pharyngeal collar present, short. Pharynx with swollen metacarpus and basal bulb with haustrulum. Female reproductive system didelphic, ovaries reflexed with flexures long nearly reaching vulva. Vulva equatorial with small lateral flaps. Spicules separate. Bursa peloderan, anteriorly closed with smooth or crenate margins. Bursal papillae nine pairs, two pairs precloacal. Precloacal lip with an anteriorly directed process and sensilla. Female tail conoid or elongate conoid, male tail short. Phasmids distinct, posteriorly located.

Type species: Caenorhabditis elegans (Maupas, 1899) Osche, 1952

Other species

C. afra Felix, Braendle & Cutter, 2014

C. angaria Sudhaus, Kiontke & Giblin-Davis, 2011

C. anthobia Schneider, 1937

C. auriculariae Tsuda & Futai, 1999

C. avicola Schmidt & Kuntz, 1972

C. bovis Kreis, 1964

C. brenneri Sudhaus & Kiontke, 2007

C. briggsae Dougherty & Nigon, 1949

C. castelli Felix, Braendle & Cutter, 2014

C. chinkari Mondal & Manna, 2015

C. clavopapillata Kreis & Faust, 1933

C. craspedocercus Völk, 1950

C. doughertyi Felix, Braendle & Cutter, 2014

C. drosophilae Kiontke, 1997

48 C. formosana Yokoo & Okabe, 1968

C. fruticicolae Shinohara, 1960

C. genitalis Scheiber, 1880

C. guadeloupensis Felix, Braendle & Cutter, 2014

C. imperialis Felix, Braendle & Cutter, 2014

C. japonica Kiontke, Hironaka & Sudhaus, 2003

C. kamaaina Felix, Braendle & Cutter, 2014

C. latens Felix, Braendle & Cutter, 2014

C. macrosperma Felix, Braendle & Cutter, 2014

C. monodelphis Slos, Sudhaus, Stevens, Bert & Blaxter, 2017

C. nigoni (Felix, Braendle & Cutter, 2014) Li, Ren, Bi & Zhao, 2016

C. nouraguensis Felix, Braendle & Cutter, 2014

C. oncomelaniae Yokoo & Okabe, 1968

C. perrieri Maupas, 1900

C. plicata Völk, 1950

C. portoensis Felix, Braendle & Cutter, 2014

C. remanei Sudhaus, 1974

C. scuri Mondal & Manna, 2013

C. sinica Huang, Ren, Qiu & Zhao, 2014

C. sonorae Kiontke, 1997

C. tropicalis (Felix, Braendle & Cutter, 2014) Yang, Li & Wang, 2016

C. virilis Felix, Braendle & Cutter, 2014

C. wallacei Felix, Braendle & Cutter, 2014

C. yunquensis Felix, Braendle & Cutter, 2014

49 Caenorhabditis heptalineata sp. n.

(Figs. 1, 2, 3)

Description

Measurements. Table 1.

Female: Body medium- to large-sized, straight to slightly curved upon fixation, tapering more towards posterior end. Cuticle 1.0-1.2 μm thick, very finely annulated, annules 0.6 to 0.8 μm wide. Lateral fields 3-4 μm wide with six ridges/ seven incisures. Lip region continuous with adjoining body; lips six, elevated, separate. Inner labial sensilla not discernible under LM; outer labial and cephalic sensilla small papilliform. Amphidial openings situated on lateral lips, usually not discernible under LM. Stoma tubular; cheilostom not cuticularised; gymnostom 7-8 μm long or 44.4- 50.0% of stoma length with parallel walls; stegostom 7-10 μm long or 50-55% of stoma length, metastegostom isotopic and isomorphic, each metastegostomal swelling bearing one setose denticle. Pharyngeal collar 7-10 μm high from base of stoma. Pharynx rhabditoid type with 60-72 μm long cylindrical procorpus; 18-22 μm long swollen metacorpus; 40-48 μm long, uniformly thick isthmus narrower than procorpus and pyriform to rounded basal bulb of 20-26 μm x 17-23 μm in dimension with grinder and double-chambered haustrulum. Nerve ring encircling isthmus in anterior half, at 56.6-65.2% of pharyngeal length from anterior end. Secretory- excretory pore slightly posterior to nerve ring at 61.5-75.7% of pharyngeal length from anterior end. Cardiac flaps 3-5 μm long. Intestine thin-walled with an anteriorly- dilated bacterial pouch. Pseudocoelomocytes not observed. Rectum as long as or slightly longer than anal body diam. Rectal glands present. Anus a crescent-shaped slit. Tail elongate conoid, tapering to a whip-like posterior part, 4.1-6.7 times anal body diam. long. Phasmidial openings at mid level of tail.

Reproductive system didelphic, amphidelphic; ovaries dorsally reflexed with distal tip of ovary not reaching vulval level. Oocytes arranged in 2-3 rows, distally followed by single row of cells proximally. Oviduct not distinctly differentiated. Spermatheca small ovoid, 15-30 μm long, filled with spermatozoa separated from uterus by a constriction. Uterus having distinct glandular (columella) and muscular parts. Vagina perpendicular to body axis, 12-17 μm long or 44.4-50.0% of corresponding body diam. Vulva equatorial, 49-55% from anterior end. Vulval lips

50 protruded with irregular margins bound by lateral cuticular flaps. One or two intra- uterine eggs of 28-51 μm x 17-22 μm dimension, occasionally present.

Male: Similar to female but slenderer, smaller with weakly developed pharynx and a pronounced posterior body curvature. Testis single, ventrally reflexed. Spermatocytes compactly arranged in 2-3 rows; seminal vesicle with maturing spermatozoa, followed by vas deferens. Large elongate ejaculatory glands opening into ejaculatory duct. Spicules slender, straight to slightly curved with rectangular or elongate head continuing into a slightly narrower neck, a ventral conoid process, distal end sharply acute. Gubernaculum trough-shaped, 70-75% of spicule length, curved proximally with dorsally-hooked distal tip. Tail short, conoid with oval, closed, peloderan bursa. Bursal margins smooth without any notch or depression at terminal end. Precloacal lip bearing an anterior hook-shaped projection appearing like an arrow head in ventral view with a basal bulge having precloacal sensillum. Bursal papillae nine pairs arranged in 2/1+3+3+P configuration: GP1 and GP2 precloacals, subventral. Among postcloacals, GP3 thick, elongate and subventral, GP4 slender and dorsally directed, nearly equal to GP5 and GP6 forming a group, GP5 almost overlapping GP6, GP7 slender, close to dorsally directed GP8 and elongate GP9. Phasmids small, subventral, opening next to GP9.

Diagnosis and relationship: Caenorhabditis heptalineata sp. n. is characterized by small-sized body (0.56-0.74 mm in females and 0.42-0.45 mm in males); lateral fields with seven incisures; metastegostom reduced, isotopic and isomorphic with one setose denticle on each swelling; vulval lips having irregular margins with cuticular flaps; males having slender, long cephalated spicules with elongate neck, ventral conoid process and acute distal tip; gubernaculum trough-shaped, proximally curved with dorsally-hooked distal tip; bursa oval, closed, peloderan with smooth margins without any notch or depression posteriorly; genital papillae GP4 almost equal to GP5, GP5 almost overlapping GP6.

Caenorhabditis heptalineata sp. n. comes closest to C. elegans Maupas, 1899 in most morphometric and morphological characteristics but differs in having smaller females (0.56-0.74 mm vs 1.0-1.8 mm); greater number of incisures (seven vs four); males with oval bursal outline (vs bursa with heart-shaped outline) and spicules smaller (22-27 μm vs 35 μm in C. elegans Maupas, 1899).

51 Caenorhabditis heptalineata sp. n. differs from C. remanei Sudhaus, 1974 in having smaller females (0.56-0.74 mm vs 0.83-1.60 mm); greater number of incisures (seven vs four); each metastegostomal plate with a fine setose (vs a large triangular) denticle; secretory-excretory pore located in isthmus region (vs at level of basal bulb); males smaller (0.42-0.45 mm vs 0.60-1.2 mm) and bursal margin smooth (vs prominently serrated anterior to cloacal level in C. remanei Sudhaus, 1974).

Caenorhabditis heptalineata sp. n. differs from C. brenneri Sudhaus & Kiontke, 2007 in having relatively smaller females (0.56-0.74 mm vs 0.74-1.7 mm); greater number of incisures (seven vs four); each metastegostomal plate with a setose denticle (vs triangular flap); males smaller (0.42-0.45 mm vs 0.56-0.95 mm) with relatively smaller (22-27 μm vs 27-38 μm) spicules; bursal outline oval (vs heart- shaped) with smooth margins (vs serrated margins up to level of GP6) and GP4 smaller than (vs equal to) GP5 in C. brenneri Sudhaus & Kiontke, 2007.

Caenorhabditis heptalineata sp. n. differs from C. bovis Kreis, 1964 in having smaller females (0.56-0.74 mm vs 0.99-1.0 mm); metastegostomal tooth prominent (vs indiscernible or absent); males smaller (0.42-0.45 mm vs 0.80-0.84 mm) with smaller spicules (22-27 μm vs 39-42 μm) and dissimilar configuration of genital papillae (2/1+3+3 vs 2/4+3 in C. bovis Kreis, 1964).

Caenorhabditis heptalineata sp. n. differs from C. sinica Huang et al., 2014 in having smaller females (0.56-0.74 mm vs 1.1-2.0 mm) with each metastegostomal plate bearing a setose denticle (vs flap); smaller males (0.42-0.45 mm vs 0.68-1.10 mm) with smaller (22.0-27.0 μm vs 38.6-45.9 μm) spicules; bursa oval (vs heart- shaped); bursal margin smooth (vs serrated up to level of GP6) and genital paillae GP6 thinner (vs thicker in C. sinica Huang et al., 2014).

Caenorhabditis heptalineata sp. n. differs from the Indian species C. scuri Mondal & Manna, 2013 in having smaller females (0.56-0.74 mm vs 0.86-1.10 mm) with metastegostom bearing a setose denticle (vs tooth of enormous size); males with smaller spicules (22-27 μm vs 35-50 μm); smaller gubernaculum (18-22 μm vs 25-30 μm) and GP6 thinner (vs thicker in C. scuri Mondal & Manna, 2013).

Caenorhabditis heptalineata sp. n. differs from C. chinkari Mondal & Manna, 2015 in having lateral fields with six ridges (vs three ridges); each metastegostomal wall with a setose denticle (vs triangular denticle of massive size); spicules smaller

52 (22-27 μm vs 39.6-42.9 μm) and smaller gubernaculum (18.0-22.0 μm vs 29.7-34.6 μm in C. chinkari Mondal & Manna, 2015).

Type locality and habitat: Samples having Caenorhabditis heptalineata sp. n. were obtained from moist shore soil of Keetham lake, Agra, Uttar Pradesh, India at coordinates 27°14.821’ N 077°51.239’ E.

Type specimens: Holotype female, eight paratype females and two paratype males on slides Caenorhabditis heptalineata sp. n. KL1-26/1-7 deposited in Nematode Collection, Department of Zoology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.

Etymology: The species name ‘heptalineata’ denotes the presence of seven incisures in lateral fields.

Remarks: Sudhaus (2011) divided the species of Caenorhabditis into two groups: ‘elegans’ group with closed bursa and gubernaculum with lateral ears and forked terminal pieces and ‘non-elegans’ group with open bursa and distally rounded gubernaculum. The present species falls in ‘elegans’ group, so the comparision has been made with closely related species of this group.

Although the present species differs markedly from the Indian species, C. scuri Mondal & Manna, 2013 and C. chinkari Mondal & Manna, 2015 in most characteristics, a dissimilarity in habitats was also found. The present species was extracted from coastal habitat whereas the other two species were collected from faecal samples of squirrel and chinkara, respectively. The figures of C. scuri Mondal & Manna, 2013 are not explanatory enough to give the structural details of spicules, metastegostomal teeth and female gonad.

The present species comes closest to C. elegans Maupas, 1899 in several characteristics but differs on account of habitat as C. elegans is mostly reported from places having decaying fruits.

53 Table 1. Morphometric characteristics of Caenorhabditis heptalineata sp. n. Measurements are in µm and in the form: mean±standard deviation (range).

Character Holotype Paratype Female Paratype Male Female (n=8) (n=2) Body length 671 670.2±65.3 (563-748) 443.5±20.5 (429-458) Body diam. 31 30.3±2.6 (27-34) 20.0±2.8 (18-22) a 21.6 22.1±1.9 (20.1-25.1) 22.3±2.1 (20.8-23.8) b 4.4 4.4±0.3 (3.7-4.7) 3.5±0.2 (3.3-3.7) c 6.7 7.0±0.9 (6.0-9.1) 18.1±0.7 (17.6-18.6) c' 6.2 5.6±0.8 (4.1-6.7) 1.4±0 (1.4-1.4) V/T 51.4 52.7±2.1 (49.2-55.1) 69.5±5.0 (65.9-73.1) G1 38.8 38.4±5.6 (33.1-51.4) -- G2 41.5 38.9±3.6 (32.6-43.5) -- Lip region height 2 3.2±0.8 (2-4) 3.5±0.7 (3-4) Lip region diam. 8 8.6±0.7 (8-10) 7.0±1.4 (6-8) Stoma length 14 15.4±1.3 (14-18) 14.0±1.4 (13-15) Stoma diam. 3 3±0 (3-3) 2±0 (2-2) Pharynx length 150 150.2±6.0 (143-161) 124.5±4.9 (121-128) Nerve ring-ant. 97 96.6±7.7 (81-105) 81.5±2.1 (80-83) end Secretory- 111 107.2±11.9 (88-122) 89.5±0.7 (89-90) excretory pore-ant. end Rectum length 17 17.5±2.0 (14-20) 22.5±2.1 (21-24) Anal body diam. 16 16.8±0.9 (15-18) 17.0±1.4 (16-18) Tail length 100 96.4±14.3 (73-110) 24.5±2.1 (23-26) Egg dimension 40 x 18 42.0±7.8 x 20.0±1.6 -- (28-51 x 17-22) Spicules length -- -- 24.5±3.5 (22-27) Gubernaculum -- -- 20.0±2.8 (18-22) length

54 Fig 1. Caenorhabditis heptalineata sp. n. A: Entire female. B: Entire male. C: Female anterior region. D: Female pharyngeal region. E. Female reproductive system. F: Female posterior region. G: Male posterior region.

55 Fig. 2. Caenorhabditis heptalineata sp. n. (Female). A: Anterior end (scanning electron microscopy). B: Anterior end. C: Anterior pharyngeal region. D: Posterior pharyngeal region. E: Posterior genital branch. F, H: Vulval region. G: Lateral lines (scanning electron microscopy). I: Vulval region (scanning electron microscopy). J: Anal region. K: Posterior end (scanning electron microscopy) (Scale bars= 10 μm).

56 Fig. 3. Caenorhabditis heptalineata sp. n. (Male). A: Anterior end. B: Anterior pharyngeal region. C: Posterior pharyngeal region. D: Genital branch. E-G: Cloacal region showing spicule. H: Cloacal region showing bursa and associated papillae (Scale bars= 10 μm).

57 Genus: Diploscapter Cobb, 1913

Diagnosis. Rhabditidae. Small-sized nematodes. Cuticle smooth or finely annulated, occasionally with fine longitudinal striae. Lip region bilaterally symmetrical, ventral and dorsal lips with paired cuticularized, hook-like appendages, lateral lips also modified to form membrane-like structure. Amphids small, on lateral lips. Stoma long, tubular, 3-4 times longer than labial diam. Cheilostom weakly cuticularized, gymnostom with parallel walls. Stegostom anisoglotoid, unarmed. Pharyngeal collar present, short. Pharynx with moderately to strongly swollen metacorpus and a basal bulb with hautrulum. Female reproductive system didelphic, amphidelphic, ovaries outstretched often with small flexures. Spicules robust, strongly cuticularised, separate. Bursa peloderan, open, moderately developed with six to nine pairs of papillae. Tail conoid to long whip-like.

Type species: Diploscapter coronatus (Cobb, 1893) Cobb, 1913

Other species

D. angolaensis Siddiqi, 1998 D. cannae Rahm, 1928 D. cornutus (Siddiqi, 1998) Sudhaus, 2011 D. cylindricus Rahm, 1929 D. formicidae Zhao, Davies, Brenton-Rule, Grangier, Gruber, Giblin-Davis & Lester, 2013 D. indicus Tahseen, Siddiqi & Rowe, 2002 D. libycus Penso, 1938 D. lycostoma Völk, 1950 D. nodifer Mihelčič, 1953 D. orientalis Kannan, 1960 D. pachys Steiner, 1942 D. rhizophilus Rahm, 1928 D. striatus Siddiqi, 1998 D. tentaculatus (Carter, 1859) Sudhaus, 2011 D. tokobaevi Lemzina & Gagarin, 1994

58 Diploscapter coronatus (Cobb, 1893) Cobb, 1913

(Figs. 4, 5, 6)

Description

Measurements. Table 2.

Female: Small-sized nematodes, almost straight to slightly curved upon fixation, tapering towards both extremities, more towards posterior end. Cuticle 1 μm thick, finely annulated, annules 0.5 to 0.6 μm wide, more prominent in anterior and tail region; 6-7 anterior annules close to lip region more prominent. Lateral fields comprising of two ridges 3-4 μm apart. Lip region offset; lips four in number: two subdorsals and two subventrals fused to form a dorsal and a ventral bifid cuticularised hook-shaped structure or hamulus. Lateral lips or laciniae with 7-9 pointed tines. Tip- to-tip distance of dorsal and ventral lips 8-10 μm. Labial and cephalic sensilla indistinct. Amphids on lateral lips, inconspicuous under LM. Stoma tubular, rhabditoid type; cheilostom not cuticularised; gymnostom cuticularised with parallel walls, 12-13 μm long or 57-63% of stoma length; stegostom shorter 4-6 μm long or 20-25% of stoma length, metastegostom isotopic and isomorphic, unarmed, metastegostomal swelling rudimentary or absent; glottoid apparatus absent. Pharyngeal collar 4-6 μm high or covering 20-25% of stoma length from its base. Pharynx with 53-60 μm long cylindrical corpus; moderately swollen metacorpus; 12- 20 μm long, uniformly thick isthmus and rounded basal bulb of 13-19 μm x 11-15 μm dimension with a grinder and single-chambered haustrulum. Corpus longer than isthmus and basal bulb together. Nerve ring encircling isthmus at 69.0-72.9% of pharyngeal length from anterior end. Secretory-excretory pore posterior to nerve ring at level of basal bulb or 77.3-81.2% of pharyngeal length from anterior end. Secretory-excretory duct not cuticularized. Hemizonid closely anterior to secretory- excretory pore. Cardial flaps 1-2 μm long. Intestine usually with an anteriorly dilated bacterial pouch. Intestinal lumen thickened. Pseudocoelomocytes not observed. Rectum 1.3-1.5 times anal body diam. long. Rectal glands obscure. Anus a crescent- shaped slit. Tail elongate conoid, 5.5-7.5 times anal body diam. Phasmids indistinct.

Reproductive system didelphic, amphidelphic. Length of genital branches unequal with anterior branch usually larger than posterior one. Ovaries largely outstretched with small flexure of 5-19 μm length observed in some specimens;

59 anterior ovary on right and posterior ovary on left side of intestine. Oocytes usually arranged in double rows. Oviduct not distinctly differentiated. Spermatheca ovoid to pear-shaped, filled with sperms. Columella with conspicuous cells, uterus usually without intra-uterine eggs. Vagina thick-walled, perpendicular to body axis, 8-10 μm long or occupying 45.4-47.0% of corresponding body diam. Vulva a transverse slit, equatorial, 49-55% from anterior end, vulval lips not protruded.

Male: Similar to female but relatively smaller in size with slight curvature in cloacal region. Testis single, ventrally reflexed, flexure on left side of intestine, pseudocoelomocyte at distal tip of testis. Spermatocytes arranged in two rows; seminal vesicle short and wide, filled with developing sperms. Ejaculatory glands not visible. Tail short, conoid. Spicules strongly built, strongly cuticularised with a pointed distal tip, dark brown in colour. Head funnel-shaped connected with a small neck; shaft strongly arcuate with median piece; a dorsal anterior velum present. Gubernaculum trough-shaped, 36.8-38.4% of spicule length, proximal end relatively broader than distal end. Bursa peloderan. Bursal papillae eight pairs including phasmids: two pairs precloacals and five pairs postcloacals arranged in 1+1/1+1+1+1+P+1 configuration. Of the precloacals, GP1 short, subventral distant from subventral GP2. Among postcloacals, GP3 subventral, elongate, touching bursal margin; GP4 subventral, thick and short, dorsally directed; GP5 and GP6 subventral, elongate, reaching bursal margin; GP7 subventral, slender, almost reaching bursal margin. Phasmids between GP6 and GP7.

Locality and habitat: Samples having D. coronatus (Cobb, 1893) Cobb, 1913 were obtained from base of a shrub near coast at Keetham lake, Agra, Uttar Pradesh, India at coordinates 27°15.324’ N 077°50.674’ E.

Voucher specimens: Ten females and six males on slides D. coronatus (Cobb, 1893) Cobb, 1913 KL4-22/1-5 deposited in Nematode Collection, Department of Zoology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.

Remarks: The present population shows conformity to D. coronatus (Cobb, 1893) Cobb, 1913 in most characteristics but with slight differences perhaps due to the cosmopolitan nature and wide occurrence of the species. The present population is having relatively smaller males (0.24-0.31 mm vs 0.28-0.40 mm); short pharyngeal collar present (vs pharyngeal collar absent) and gubernaculum straight [vs slightly curved proximally in D. coronatus (Cobb, 1893) Cobb, 1913].

60 Table 2. Morphometric characteristics of Diploscapter coronatus (Cobb, 1893) Cobb, 1913. Measurements are in µm and in the form: mean±standard deviation (range).

Character Female Male

(n=10) (n=6)

Body length 358.2±37.7 (285-416) 276.8±24.2 (248-318)

Body diam. 19.7±1.6 (17-22) 18.5±2.2 (16-22) a 18.1±1.3 (15.8-19.8) 14.9±0.7 (13.8-15.7) b 3.9±0.2 (3.3-4.3) 3.4±0.1 (3.3-3.7) c 5.6±0.2 (5.3-6.0) 16.5±0.4 (16.0-17.3) c' 6.3±0.5 (5.5-7.5) 1.1±0.07 (1.0-1.2)

V/T 52.0±1.6 (49-55) 61.9±5.0 (54.0-67.1)

G1 16.1±3.4 (11.3-21.3) --

G2 13.5±2.0 (10.5-16.5) --

Lip height 3.6±0.5 (3-4) 3.1±0.4 (3-4)

Lip diam. 9.1±0.5 (8-10) 8.3±0.5 (8-9)

Stoma length 20.5±1.3 (19-23) 18.6±1.5 (16-20)

Stoma diam. 2±0 (2-2) 2±0 (2-2)

Pharynx length 90.0±4.1 (84-96) 79.0±4.8 (73-84)

Nerve ring-ant. end 65.8±3.7 (58-70) 55.8±3.6 (50-60)

Secretory-excretory pore-ant. end 73.7±4.0 (65-78) 65.5±3.9 (62-72)

Rectum length 14.0±1.4 (12-16) 18.3±2.6 (14-22)

Anal body diam. 10.0±1.1 (8-12) 14.5±1.6 (12-17)

Tail length 63.8±8.1 (47-76) 16.6±1.5 (15-19)

Spicules length -- 22.0±2.9 (17-26)

Gubernaculum length -- 8.3±1.2 (7-10)

61 Fig 4. Diploscapter coronatus (Cobb, 1893) Cobb, 1913 A: Entire female. B: Entire male. C: Female anterior region (lateral view). D: Female anterior region (ventral view). E: Female pharyngeal region. F: Female reproductive system. G: Female posterior region. H: Male posterior region.

62 Fig. 5. Diploscapter coronatus (Cobb, 1893) Cobb, 1913 (Female). A, C: Anterior end (ventral). B: Anterior end (lateral). D: Posterior pharyngeal region. E: Lateral fields. F: Anterior genital branch. G: Posterior genital branch. H: Vulval region. I: Posterior end (Scale bars= 10 μm).

63 Fig. 6. Diploscapter coronatus (Cobb, 1893) Cobb, 1913 (Male). A: Genital branch. B: Lateral fields. C, D: Cloacal region showing spicule and gubernaculum. E-H: Cloacal region showing bursa and associated papillae (Scale bars= 10 μm).

64 Genus: Metarhabditis Tahseen, Hussain, Tomar, Shah & Jairajpuri, 2004

Diagnosis. Rhabditidae. Medium-sized nematodes. Body slender, gradually tapering towards extremities. Cuticle transversely and longitudinally striated. Lip region offset. Stoma tubular, cheilostom weakly cuticularised, gymnostom half of stoma length, metastegostom with bunch of setose denticles. Pharyngeal collar present. Pharynx without metacorpus, cylindroid corpus and basal bulb with haustrulum. Female reproductive system didelphic, amphidelphic, ovarian flexures long, vulva equatorial. Spicules separate; gubernaculum trough-shaped. Bursa pseudopeloderan with eight pairs of genital papillae. Female tail long and fine thread-like. Male tail short, conoid with terminal spike and copulatory muscle band.

Type species: Metarhabditis andrassyana Tahseen, Hussain, Tomar, Shah & Jairajpuri, 2004

Other species

M. adenobia (Poinar, 1971) Sudhaus, 2011

M. amsactae (Ali, Pervez, Andrabi, Sharma & Verma, 2011) Sudhaus, 2011

M. blumi (Sudhaus, 1974) Sudhaus, 2011

M. costai (Martins, 1985) Sudhaus, 2011

M. freitasi (Martins, 1985) Sudhaus, 2011

M. rainai (Carta & Osbrink, 2005) Sudhaus, 2011

65 Metarhabditis amsactae (Ali et al., 2011) Sudhaus, 2011

(Figs. 7, 8, 9)

Description

Measurements. Table 3.

Female: Medium- to large-sized, slender nematodes with body almost straight upon fixation, tapering more towards posterior region. Cuticle 1 μm thick, very finely annulated, annulations not discernible under LM. Lateral fields 4-5 μm wide with six incisures. Lip region continuous with body; lips in doublets around triradiate oral aperture. Labial sensilla indistinct; cephalic sensilla very minute, visible under SEM. Amphids inconspicuous. Stoma rhabditoid type; cheilostom weakly cuticularised; gymnostom cuticularised with parallel walls, 32-35% of stoma length; stegostom 55- 60% of stoma length, metastegostom isotopic and isoglottoid, each metastegostomal swelling bearing bunch of setose denticles. Pharyngeal collar covering 55-60% of stoma from base. Pharynx with 105-122 μm long corpus; indistinct metacorpus; 53-65 μm long, uniformly thick isthmus, narrower than corpus; rounded to ovoid basal bulb of 24-28 μm x 20-23 μm dimension with grinder and double-chambered haustrulum. Corpus longer than isthmus and basal bulb together. Nerve ring encircling anterior part of isthmus or corpus-isthmus junction at 60-62% of pharyngeal length from anterior end. Secretory-excretory pore closely posterior to nerve ring at 68-69% of pharyngeal length from anterior end. Secretory-excretory duct cuticularised distally. Hemizonid observed in few specimens at level of nerve ring. Cardial flaps 3-5 μm long. Intestine with an anteriorly-dilated bacterial pouch, intestinal lumen thickened. Three pseudocoelomocytes present in vicinity of gonad: one opposite distal tip of anterior genital branch, one at level of spermatheca of posterior genital branch and one slightly posterior to flexure of posterior genital branch. Rectum 1.5-1.6 times anal body diam. long. Rectal glands conspicuous. Anus a crescent-shaped slit. Tail elongate conoid, 4-5 times anal body diam. Phasmidial openings at mid level of tail with knobbed tip.

Reproductive system didelphic, amphidelphic; anterior genital branch relatively larger than posterior genital branch. Ovaries dorsally reflexed; ovarian flexures almost reaching vulva; anterior ovary on right and posterior ovary on left side of intestine; oocytes arranged in 2-3 rows distally. Oviduct short, 10-15 μm long,

66 separated from spermatheca by a constriction. Spermatheca rounded to ovoid, thick- walled, 24-28 μm x 20-22 μm in dimension. Spermatheca separated from uterus by a constriction. Uterus with distinct glandular and muscular parts. Vagina perpendicular to body axis, 17-21 μm long or 60-70% of corresponding body diam.; vulva slightly post-equatorial, 51.0-59.5% from anterior end. Vulval lips protruded, vulval flaps not observed. Two to three intra-uterine eggs of 39-50 μm x 22-28 μm dimension present in different stages of embryonation.

Male: Similar to female but relatively smaller. Testis single, ventrally reflexed with a club-shaped distal end. Spermatocytes arranged in 2-3 rows followed by single row of large-sized spermatocytes. Seminal vesicle distinct with stack of large-sized maturing sperms; proximally narrowing to vas deferens. A pair of ejaculatory glands present opening into ejaculatory duct. Spicules arcuate, cephalated, head rounded often with beak-like ventral projection. Gubernaculum trough-shaped, slightly curved, 45% of spicule length. Tail elongate conoid with a long and thick spike of 35-43 μm post bursal limits. Bursa leptoderan. Genital papillae eight pairs arranged in 1+1/1/3+2+P configuration: GP1 and GP2 subventral, spaced, precloacals. GP3 subventral, adcloacal. Among postcloacal pairs, GP4, GP5 and GP6 forming a group, subventral. GP7 subventral, dorsally directed. GP8 short, subventral. Phasmids posterior to GP8.

Locality and habitat: Samples having Metarhabditis amsactae (Ali et al., 2011) Sudhaus, 2011 were obtained from litter soil near and around Eucalyptus trees at Keetham lake, Agra, Uttar Pradesh, India at coordinates 27°15.246’ N 077°51.048’ E.

Voucher specimens: Nine females and nine males on slides Metarhabditis amsactae (Ali et al., 2011) Sudhaus, 2011 KL3-3/1-6 deposited in Nematode Collection, Department of Zoology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.

Remarks: The present population shows conformity to M. amsactae (Ali et al., 2011) Sudhaus, 2011 in most morphological and morphometric characteristics but with slight differences. Females having relatively greater ‘a’ value (23.1-25.7 vs 16.8- 23.5); relatively smaller ‘b’ (3.8-4.3 vs 4.0-5.5); usually anterior genital branch larger than posterior genital branch in present population (vs anterior genital branch smaller than posterior genital branch); eggs relatively smaller (39-50 μm x 22-28 μm vs 47-55 μm x 24-30 μm in M. amsactae (Ali et al., 2011) Sudhaus, 2011].

67 Table 3. Morphometric characteristics of Metarhabditis amsactae (Ali et al., 2011) Sudhaus, 2011. Measurements are in µm and in the form: mean±standard deviation (range).

Character Female Male (n=9) (n=9) Body length 836.2±59.5 (743-915) 777.3±57.4 (673-878) Body diam. 33.8±2.8 (29-36) 28.0±1.6 (26-31) a 24.6±1.0 (23.1-25.7) 27.7±2.3 (24.9-31.3) b 4.0±0.1 (3.8-4.3) 4.0±0.2 (3.7-4.3) c 9.8±0.8 (8.4-10.5) 12.1±1.4 (10.6-12.1) c' 4.5±0.3 (4.1-5.1) 3.4±0.3 (2.6-3.9) V/T 53.4±2.4 (51.1-59.5) 61.5±5.5 (53.0-68.9) G1 32.6±3.7 (29.5-41.4) -- G2 29.6±2.9 (24.8-35.4) -- Lip height 3.1±0.3 (3-4) 2.7±0.4 (2-3) Lip diam. 8.7±0.4 (8-9) 8.5±0.5 (8-9) Stoma length 21.0±0.8 (20-22) 19.8±0.9 (19-21) Stoma diam. 4±0 (4-4) 3±0 (3-3) Pharynx length 202.7±10.2 (185-216) 189.1±9.0 (178-202) Nerve ring-ant. end 123.3±4.5 (115-130) 116.2±7.5 (105-130) Secretory-excretory pore- 136.2±7.1 (126-149) 131.5±9.6 (113-147) ant. end Rectum length 30.0±2.7 (25-34) 28.5±3.3 (25-34) Anal body diam. 18.3±1.5 (16-21) 18.6±1.0 (18-20) Tail length 85.0±8.4 (74-104) 64.4±6.0 (52-71) Egg dimension 44.0±3.2 x 24.1±1.8 (39-50 x 22-28) Spicules length -- 30±2 (27-33) Gubernaculum length -- 12.3±1.2 (11-15)

68 Fig 7. Metarhabditis amsactae (Ali et. al., 2011) Sudhaus, 2011 A: Entire female. B: Entire male. C: Female anterior region. D: Female pharyngeal region. E. Female reproductive system. F: Male posterior region. G: Female posterior region.

69 Fig. 8. Metarhabditis amsactae (Ali et. al., 2011) Sudhaus, 2011 (Female). A: En face view (scanning electron microscopy). B: Anterior end. C: Anterior pharyngeal region. D: Posterior pharyngeal region. E: Basal bulb. F: Anterior genital branch. G: Posterior genital branch. H: Intra-uterine eggs. I: Vulval region. J: Anal region (Scale bars= 10 μm).

70 Fig. 9. Metarhabditis amsactae (Ali et. al., 2011) Sudhaus, 2011 (Male). A: Anterior end. B: Anterior pharyngeal region. C: Posterior pharyngeal region. D: Genital branch. E: Cloacal region showing spicule. F-H: Cloacal region showing bursa and associated papillae. I, J: Cloacal region showing bursa and associated papillae (scanning electron microscopy) (Scale bars= 10 μm).

71 Genus: Oscheius Andrássy, 1976

Diagnosis. Rhabditidae. Medium- to large-sized nematodes. Cuticle finely striated. Lip region slightly offset, lips separate with minute papillae. Amphids pore-like, on lateral lips. Stoma tubular, usually short, only slightly longer than wide. Cheilostom not cuticularised; each metastegostomal swelling with minute denticles or warts. Pharyngeal collar short. Pharyngeal corpus cylindrical or slightly swollen without metacorpus, basal bulb muscular with grinder and double haustrulum. Female reproductive system didelphic, amphidelphic, ovaries reflexed. Vulva equatorial. Rectum notably long, 1.5 times anal body diam. long. Spicules separate, robust with knobbed or hooked terminus. Bursa open, leptoderan to pseudopeloderan, provided with three precloacal and six postcloacal genital papillae. Tail in both sexes conical, sharply pointed. Phasmids distinct, posterior to anal opening.

Type species: Oscheius insectivorus Körner, 1954

Other species

O. andrassyi Tabassum & Shahina, 2008

O. bengalensis Timm, 1956

O. carolinensis Ye, Torres-Barragan & Cardoza, 2010

O. caulleryi Maupas, 1919

O. chongmingensis Zhang, Liu, Xu, Sun, Yang, An, Gao, Lin, Lai, He, Wu & Zhang, 2008

O. citri Tabassum, Shahina, Nasira & Erum, 2016

O. cobbi Tabassum, Shahina, Nasira & Erum, 2016

O. colombianus Stock, Caicedo & Calatayud, 2005

O. cynodonti Tabassum, Shahina, Nasira & Erum, 2016

O. dolichura Schneider, 1866

O. dolichuroides Anderson & Sudhaus, 1985

O. dux (Gorgadze, 2010) Sudhaus, 2011

O. esculentus Tabassum, Shahina, Nasira & Erum, 2016

O. esperancensis (Stock, 1991) Sudhaus, 2011

72 O. guentheri Sudhaus & Hooper, 1994

O. janeti (De Lacaze-Duthiers in Janet, 1894) Sudhaus, 2011

O. latus (Cobb, 1906) Sudhaus, 2011

O. lucianii Maupas, 1919

O. maqbooli Tabassum & Shahina, 2002

O. microvilli Zhou, Yang, Wang, Bao, Wang, Hou, Lin, Yedid & Zhang, 2017

O. myriophilus Poinar, 1986

O. necromenus Sudhaus & Schulte, 1989

O. onirici Torrini, Mazza, Carletti, Benvenuti, Roversi, Fanelli, de Luca, Troccoli & Tarasco, 2015

O. pheropsophi (Smart & Nguyen, 1994) Sudhaus, 2011

O. pseudodolichura Körner in Osche, 1952

O. punctata Tabassum, Shahina, Nasira & Erum, 2016

O. ragaoensis Zhang, Liu, Tan, Wang, Qiao, Yedid, Dai, Qiu, Yan, Tan, Su, Lai & Gao, 2012

O. rupaekramae (Khan, Singh & Kaushal, 2000) Sudhaus, 2011

O. sacchari Tabassum, Shahina, Nasira & Erum, 2016

O. sechellensis Potts, 1910

O. shamimi Tahseen & Nisa, 2006

O. tereticorpus (Kito & Ohyama, 2008) Sudhaus, 2011

O. tipulae Lam & Webster, 1971

O. wohlgemuthi (Völk, 1950) Sudhaus, 2011

O. zarinae (Khan, Singh & Kaushal, 2000) Sudhaus, 2011

73 Oscheius keethamensis sp. n.

(Figs. 10, 11, 12)

Description

Measurements. Table 4.

Female: Body medium- to large-sized, almost straight to slightly curved upon fixation, tapering towards both extremities, more towards posterior region. Cuticle 1 μm thick, prominently annulated, annules 1.0 to 1.5 μm wide in different parts of body. Lateral fields 3-5 μm wide with five incisures. Lip region continuous with body contour; lips forming doublets, flattened, around triradiate oral aperture. Inner labial sensilla indistinct, outer labial and cephalic sensilla papilliform. Stoma tubular, rhabditoid type, 5.5-7.0 times longer than wide; cheilostom weakly cuticularised; gymnostom 30-35% of stoma length with parallel walls; stegostom 55-60% of stoma length, metastegostom isotopic and isomorphic, each metastegostomal swelling bearing two minute denticles; glottoid apparatus present. Pharyngeal collar covering 55-60% of stoma from base. Pharynx with 85-120 μm long cylindrical corpus; 30-47 μm long isthmus narrowing towards basal bulb and relatively small and rounded basal bulb of 19-25 μm x 14-22 μm dimension with grinder and double-chambered haustrulum. Nerve ring encircling isthmus in anterior half, at 71.4-74.6% of pharyngeal length from anterior end. Secretory-excretory pore slightly posterior to nerve ring, at mid of isthmus, 81.6-83.5% of pharyngeal length from anterior end. Secretory-excretory duct cuticularised and clearly visible. Hemizonids at level of nerve ring. Cardial flaps 3-7 μm long. Intestine thin-walled with an anteriorly-dilated bacterial pouch. Three pseudocoelomocytes observed in vicinity of gonad, two just anterior or about one body diam. above flexure of anterior genital branch and one posterior to flexure of posterior genital branch. Rectum 2.4-2.9 times anal body diam. long. Rectal glands present. Anus a crescent-shaped slit. Tail long, filiform, 8.5-17.6 times anal body diam. Phasmidial openings about 1.0-1.5 anal body diam. posterior to anus.

Reproductive system didelphic, amphidelphic; ovaries dorsally reflexed; ovarian flexures almost reaching vulva or crossing each other; flexure of anterior genital branch 95-222 μm long and flexure of posterior genital branch 92-203 μm long; oocytes compactly arranged in multiple rows distally, followed by single row

74 proximally. Oviduct short; spermatheca ovoid to rounded, 15-17 μm x 10-12 μm in dimension, filled with large-sized spermatozoa. Uterus having distinct glandular (columella) and muscular parts. Vagina perpendicular to body axis, 14-23 μm long or half of corresponding body diam.; vulva, a transverse slit, just anterior to midbody, 42.5-46.2% from anterior end. Vulval lips protruded and bound by cuticular flaps. Two to eight intra-uterine eggs of 32-47 μm x 18-32 μm dimension present.

Male: Similar to female but smaller with pronounced curvature in cloacal region, cephalic sensilla slightly raised, relatively wider stoma (4.5-5.0 times longer than wide), nerve ring at mid of isthmus and secretory-excretory pore at level of basal bulb or slightly anterior to it. Testis single, ventrally reflexed. Spermatocytes compactly arranged in multiple rows; seminal vesicle filled with developing sperms, followed by vas deferens. Large-sized ejaculatory glands opening into ejaculatory duct. Four pseudocoelomocytes present in vicinity of gonad, two closely anterior to flexure; another at distal tip of testis and one in the region of seminal vesicle. Spicules robust, curved distally with sharp pointed distal tip, head narrow with dorsal shoulder and ventral conoid process. Gubernaculum small, trough-shaped, 40-50% of spicule length. Tail short, conoid. Bursa pseudopeloderan having a small spike, anteriorly open with smooth margins. Genital papillae nine pairs arranged in 3/3+3+P configuration: GP1 and GP2 subventral forming a group with slightly spaced subventral GP3, precloacals. Among postcloacals, GP4, GP5 and GP6 forming a group, subventrals; GP7 short, subventral, GP8 lateral, dorsally directed close to elongate subventral GP9. Phasmids small, posterior to GP9.

Diagnosis and relationship: Oscheius keethamensis sp. n. is characterized by having five incisures; papilliform outer labial and cephalic sensilla in females and slightly raised cephalic sensilla in males; stoma longer and narrower in females than males; each metastegostomal swelling with two minute denticles; secretory-excretory pore at mid level of isthmus in females and at level of basal bulb or slightly anterior to it in males; reflexed ovaries reaching vulva or crossing each other; female tail long, filiform; male with pseudopeloderan bursa with a short terminal spike. Genital papillae nine pairs: three precloacal pairs and six postcloacal pairs arranged in 3/3+3+P configuration.

Oscheius keethamensis sp. n. comes closest to O. tipulae (Lam & Webster, 1971) in most morphometric and morphological characteristics but differs in having

75 relatively larger females (0.71-1.16 mm vs 0.50-0.78 mm); relatively greater ‘a’ (21.0- 30.0 vs 16.3-22.1) and ‘ć’ (8.5-17.6 vs 4.2-6.4) values; smaller ‘c’ value (3.7-5.2 vs 6.2-9.7); lateral fields with (five vs four) incisures; tail long filiform (vs elongate conoid); vulva pre-equatorial (vs equatorial); males with greater ‘a’ value (20.3-23.4 vs 17.2); longer stoma (19-22 μm vs 17 μm); bursa pseudopeloderan (vs peloderan); bursal margins smooth (vs slightly notched terminally) and precloacal genital papillae closely placed [vs widely spaced in O. tipulae (Lam & Webster, 1971].

Oscheius keethamensis sp. n. differs from O. guentheri Sudhaus & Hooper, 1994 in having females with smaller ‘c’ value (3.7-5.2 vs 5.4-7.6); lateral fields with (five vs four) incisures; metastegostom isotopic (vs slightly anisotopic) with two minute denticles (vs three pointed tubercles); posterior genital branch well developed (vs rudimentary); vulva pre-equatorial (vs equatorial or post-equatorial); males having ejaculatory glands present (vs absent); bursal margins smooth (vs proximally crenate) and dissimilar arrangement of genital papillae (1+1+1/3+3 vs 1+1+1/1+2+2+1 or 1+1+1/1+2+1+2 in O. guentheri Sudhaus and Hooper, 1994).

Oscheius keethamensis sp. n. differs from O. onirici Torrini et al., 2015 in having relatively larger females (0.71-1.16 mm vs 0.58-0.80 mm); relatively greater ‘a’ (21.0-30.0 vs 15.8-22.5) and ‘ć’ (8.5-17.6 vs 3.5-5.0) values; smaller ‘c’ value (3.7-5.2 vs 8.6-11.8); lateral fields with (five vs four) incisures; longer stoma (18-23 μm vs 12-16 μm); vulva pre-equatorial (vs equatorial); tail long filiform (vs elongate conoid); relatively larger males (0.63-0.85 mm vs 0.44-0.64 mm); greater ‘a’ value (20.3-23.4 vs 14.6-18.2); longer stoma (19-22 μm vs 12-15 μm); bursa pseudopeloderan (vs peloderan bursa in O. onirici Torrini et al., 2015).

Oscheius keethamensis sp. n. differs from O. dolichura (Schneider, 1866) in having females with relatively smaller ‘b’ (4.6-6.2 vs 5.2-8.6) and ‘c’ (3.7-5.2 vs 7.7- 14.6) values; greater ‘ć’ value (8.5-17.6 vs 3.4-5.2); lateral fields with (five vs two) incisures; secretory-excretory pore in isthmus region (vs at level of basal bulb); vulva pre-equatorial (vs largely equatorial); tail long filiform (vs elongate conoid); males with relatively greater ‘ć’ value (1.2-2.5 vs 1.1-1.7); longer stoma (19.0-22.0 μm vs 12.0-18.4 μm); relatively smaller spicules (20.0-27.0 μm vs 23.0-73.8 μm); smaller gubernaculum (9-12 μm vs 19-28 μm) and precloacal genital papillae closer [vs widely spaced in O. dolichura (Schneider, 1866)].

76 Oscheius keethamensis sp. n. differs from O. dolichuroides Anderson & Sudhaus, 1985 in having smaller females (0.714-1.163 mm vs 1.167-1.580 mm); smaller ‘c’ value (3.7-5.2 vs 8.2-11.2); greater ‘ć’ value (8.5-17.6 vs 5.9-8.2); lateral fields with (five vs four) incisures; metastegostomal swelling with two denticles (vs one thin tooth); vulva pre-equatorial (vs post-equatorial); vulval region broad (vs constriction of body at vulva); males smaller (0.63-0.85 mm vs 1.04-1.28 mm); smaller ‘a’ (20.3-23.4 vs 27.0-35.0) and ‘c’ (15.6-32.1 vs 32.0-56.0) values; smaller spicules (20-27 μm vs 41-48 μm) without knobbed (vs knobbed) terminus; smaller gubernaculum (9-12 μm vs 22-29 μm); postcloacal lip simple (vs bilobed each with long spine) and precloacal genital papillae closer (vs widely spaced in O. dolichuroides Anderson & Sudhaus, 1985).

Oscheius keethamensis sp. n. differs from O. janeti (De Lacaze-Duthiers in Janet, 1894) Sudhaus, 2011 in having females with greater ‘a’ (21.0-30.0 vs 20.0- 20.9) and ‘b’ (4.6-6.2 vs 4.5-4.6) values; smaller ‘c’ value (3.7-5.2 vs 14.7-16.6); pre- equatorial (vs post-equatorial) vulva; long, filiform (vs short, conoid) tail and males with smaller spicules (20-27 μm vs 35 μm) and smaller gubernaculum [9-12 μm vs 17 μm in O. janeti (De Lacaze-Duthiers in Janet, 1894) Sudhaus, 2011].

Oscheius keethamensis sp. n. differs from O. pseudodolichura Körner in Osche, 1952 in having females with greater ‘a’ (21.0-30.0 vs 15.4-19.9) and ‘ć’ (8.5- 17.6 vs 3.1) values; smaller ‘b’ (4.6-6.2 vs 6.6-8.0) and ‘c’ (3.7-5.2 vs 7.3-8.3) values; lateral fields with (five vs four) incisures; smaller stoma (18-23 μm vs 24 μm); each metastegostomal plate with (two vs five) denticles; tail long filiform (vs elongate conoid); males with greater ‘a’ value (20.3-23.4 vs 20.1); smaller ‘b’ value (4.5-5.4 vs 6.4) and precloacal genital papillae closer (vs widely spaced in O. pseudodolichura Körner in Osche, 1952).

Oscheius keethamensis sp. n. differs from O. tereticorpus (Kito & Ohyama, 2008) Sudhaus, 2011 in having females with smaller ‘c’ value (3.7-5.2 vs 7.6-12.7); larger ‘ć’ value (8.5-17.6 vs 4.6-6.3); lateral fields with (five vs four) incisures; long, filiform (vs elongate conoid) tail; pre-equatorial (vs equatorial) vulva and males present in fairly large numbers in present population [vs not reported in O. tereticorpus (Kito & Ohyama, 2008) Sudhaus, 2011].

Oscheius keethamensis sp. n. differs from O. zarinae (Khan, Singh & Kaushal, 2000) Sudhaus, 2011 in having females with smaller ‘c’ value (3.7-5.2 vs 7.8-23.2);

77 greater ‘ć’ value (8.5-17.6 vs 1.6-6.8); two setose metastegostomal denticles (vs 2-4 small warts); long filiform (vs elongate conoid) tail; pre-equatorial (vs largely post- equatorial) vulva; relatively smaller males (0.63-0.85 mm vs 0.75-1.24); smaller spicules (20-27 μm vs 32-48) and dissimilar arrangement of genital papillae [1+1+1/3+3+P vs 1+2/3+3+P configuration in O. zarinae (Khan, Singh & Kaushal, 2000) Sudhaus, 2011].

Type locality and habitat: Samples having Oscheius keethamensis sp. n. were obtained from dark, moist shore-soil with remains of mollusck shells at Keetham lake, Agra, Uttar Pradesh, India at coordinates 27°15.323’ N 077°50.724’ E.

Type specimens: Holotype female, thirteen paratype females and eight paratype males on slides Oscheius keethamensis sp. n. KL1-3/1-10 deposited in Nematode Collection, Department of Zoology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.

Etymology: The species epithet ‘keethamensis’ represents the place (Keetham lake) from where the sample was collected.

Remarks: Sudhaus (2011) divided the species of Oscheius into two groups, ‘dolichura’ group with females having rectum proximally dilated forming a bladder- like expansion of hind gut, peloderan bursa, phasmids inconspicuous and males having spicules with probe-head like distal end, and ‘insectivora’ group with females having numerous embryonating uterine eggs, leptoderan bursa, phasmids conspicuous and males having spicules tips distally hooked like a crochet needle.

The present species demonstrates the characters of both ‘dolichura’ and ‘insectivora’ groups and can be considered an intermediate or transitional species linking the two groups. It shows the characters of ‘dolichura’ group in having relatively lesser number of intra-uterine eggs (upto ten only), bladder-like expansion of hind gut and spicules with distal end resembling a probe head but does not possess a peloderan bursa and inconspicuous phasmids, the other features of ‘dolichura’ group. It shows affinities with the species of ‘insectivora’ group in having four ridges (five incisures), triangular oral aperture and conspicuous phasmids.

Tabassum and Shahina (2002) reported four precloacal papillae in O. dolichura Schneider, 1866 which is atypical of the genus characteristics.

78 Table 4. Morphometric characteristics of Oscheius keethamensis sp. n. Measurements are in µm and in the form: mean±standard deviation (range).

Character Holotype Paratype Female Paratype Male (n=12) (n=8) Female Body length 914 917.9±124.8 (714-1163) 720.7±67.8 (634-855) Body diam. 41 37.2±7.1 (25-50) 33.8±4.2 (30-42) a 22.2 25.0±2.8 (21-30) 21.3±0.9 (20.3-23.4) b 5.8 5.5±0.4 (4.6-6.2) 4.9±0.3 (4.5-5.4) c 5 4.4±0.4 (3.7-5.2) 21.2±6.4 (15.6-32.1) c' 10.7 13.1±2.5 (8.5-17.6) 1.8±0.4 (1.2-2.5) V/T 43.5 44.1±0.9 (42.5-46.2) 83.4±3.3 (78.4-87.4) G1 34.4 36.1±4.5 (28.3-43.2) -- G2 38.4 33.3±5.4 (21.8-39.4) -- Lip region height 3 3.0±0.6 (2-4) 3±0 (3-3) Lip region diam. 9 8.3±0.6 (7-9) 9.1±0.3 (9-10) Stoma length 20 20.0±1.7 (18-23) 20.0±1.0 (19-22) Stoma diam. 4 3.2±0.5 (2-4) 3.2±0.4 (3-4) Pharynx length 155 163.0±19.2 (134-196) 142.6±5.7 (138-156) Nerve ring-ant. end 116 117.3±11.6 (100-140) 109±7 (105-125) Secretory-excretory 128 130.6±15.0 (112-160) 130.3±9.8 (124-154) pore-ant. end Rectum length 42 46.8±7.5 (34-59) 31.7±2.7 (29-36) Anal body diam. 17 15.6±1.7 (14-20) 19.1±1.5 (16-21) Tail length 182 204.9±31.9 (167-265) 35.8±7.6 (23-45) Egg dimension 45 x 22 40.2±4.1 x 24.2±4.9 (32- -- 47 x 18-32) Spicules length -- -- 23.1±2.5 (20-27) Gubernaculum -- -- 10.0±1.1 (9-12) length

79 Fig 10. Oscheius keethamensis sp. n. A: Entire female. B: Entire male. C: Female anterior region. D: Female pharyngeal region. E. Female reproductive system. F: Female posterior region. G: Male posterior region.

80 Fig. 11. Oscheius keethamensis sp. n. (Female). A, B: En face view (scanning electron microscopy). C: Anterior end. D: Anterior pharyngeal region. E: Posterior pharyngeal region. F: Anterior genital branch. G: Posterior genital branch. H: Intra-uterine eggs. I: Vulval region. J: Anal region showing dilated rectum. K: Posterior end (Scale bars= 10 μm).

81 Fig. 12. Oscheius keethamensis sp. n. (Male). A, B: Anterior end. C: Anterior pharyngeal region. D: Posterior pharyngeal region. E: Genital branch. F, G: Cloacal region showing spicule. H: Cloacal region showing bursa and associated papillae. I, J: Cloacal region showing bursa and associated papillae (scanning electron microscopy). K: Cloacal region showing bursa and associated papillae (ventral) (Scale bars= 10 μm).

82 Genus: Protorhabditis (Osche, 1952) Dougherty, 1953

Diagnosis. Rhabditidae. Stout nematodes of very small size. Body almost straight after fixation. Cuticle with distinct transverse annulations. Lip region continuous with adjacent body or slightly offset, lips amalgamated; labial and cephalic papillae poorly visible under LM. Stoma tubular, lacking glottoid apparatus: cheilostom weakly to moderately cuticularised; gymnostom with straight walls, stegostom short. Pharyngeal collar very small or absent. Pharynx rhabditoid with swollen metacorpus; basal bulb round to ovoid with haustrulum. Female reproductive system didelphic, amphidelphic, ovaries outstretched or reflexed. Tail short conoid to long filiform. Phasmids situated at middle of tail length. Males with stout spicules and peloderan bursa with genital papillae ranging from eight to nine.

Type species: Protorhabditis xylocola Körner, 1954

Other species

P. agilis (von Linstow, 1876) Sudhaus, 2011

P. cervi (Andrássy, 1985) Sudhaus, 1991

P. elaphri (Hirschmann, 1952) Dougherty, 1955

P. filiformis (Bütschli, 1873) Sudhaus, 1976

P. hortulana Abolafia & Peña-Santiago, 2016

P. lepida (Kreis, 1930) Sudhaus, 1976

P. macrovelata Sudhaus, 1974

P. minuta Cobb, 1893

P. oxyuroides Sudhaus, 1974

P. parvovelata Körner, 1954

P. postneri Körner, 1954

P. ruehmi Körner, 1954

P. spiculocrestata Abolafia & Peña-Santiago, 2007

P. tristis Hirschmann, 1952

P. virgo Körner, 1954

83 Protorhabditis mucronata sp. n.

(Figs. 13, 14)

Description

Measurements. Table 5.

Female: Small and stout nematodes. Body spindle-shaped, straight upon fixation, narrowing towards both extremities, more towards posterior end. Cuticle 0.5-0.6 μm thick at different body regions, transversely annulated; inner layer striated; annules 1- 2 μm wide with tail region having relatively coarser and flattened annules. Lateral fields 2.0-2.5 μm wide or 13.3-14.7% of maximum body diam., with two ridges slightly apart from each other. Lip region narrow, trapezoid, continuous with adjoining body; lips small, fused at bases. Labial and cephalic sensilla inconspicuous. Amphids usually not discernible under LM. Stoma long and narrow, 11-12 times as long as wide; cheilostom cuticularized, small straight, rod-like; gymnostom 40-50% of stoma length with parallel walls; stegostom short, 27-33% of stoma length, metastegostom inconspicuous, unarmed; glottoid apparatus absent. Pharyngeal collar 3-4 μm from base of stoma. Pharynx rhabditoid type, well developed with 21-27 μm long, cylindrical corpus; 9-11 μm long strongly swollen metacorpus having thickened lumen; 13-17 μm long isthmus and rounded basal bulb of 10-12 μm x 8-10 μm dimension with grinder and single-chambered haustrulum. Nerve ring encircling isthmus at 67-76% of pharyngeal length from anterior end. Secretory-excretory pore posterior to nerve ring, at level of basal bulb or at 81-92% of pharyngeal length from anterior end. Secretory-excretory duct weakly cuticularized. Hemizonid visible in few specimens, slightly posterior to secretory-excretory pore. Body at pharyngeal end 3.2- 3.5 times lip region diam. wide. Cardia small with conical flaps, 2-3 μm long, covered by intestinal tissue. Intestine granular with a small anterior bacterial pouch; intestinal lumen thickened. Rectum 1.0-1.1 times anal body diam. long. Rectal glands present. Tail short conoid, 1.5-2.0 times anal body diam. abruptly ending in a mucro. Phasmids indistinct. Reproductive system didelphic, amphidelphic. Length of genital branches unequal with either of them conspicuously larger. Ovaries largely outstretched with very small flexure of 4-8 μm length in few specimens, length of ovarian flexure usually greater in posterior ovary. Both ovaries on right side of intestine; oocytes arranged in 2-3 rows at distal end leading to single row proximally.

84 Oviduct not distinctly differentiated; spermatheca small, ovoid, axial, 6-8 μm x 3-4 μm in dimension, filled with spermatozoa. Uterus elongate tubular, 20-23 μm x 3-4 μm in dimension. Uterine eggs not observed. Vagina perpendicular to body axis, 6-8 μm in length or 40-47% of corresponding body diam., with conspicuous muscles. Vulva a transverse slit, slightly post-equatorial, at 59-62% from anterior end. Vulval lips protruded with smooth margins without cuticular flap. Vulva-anus distance 59-86 μm or 4.3-4.5 times tail length.

Male: Not found.

Diagnosis and relationship: Protorhabditis mucronata sp. n. is characterized by small-sized body; prominently annulated with inner layer striated and tail region having relatively coarser and flattened annules; lateral fields with two ridges; lip region truncate or trapezoid with small lips fused at bases and distinguishable labial apices; cheilostom straight, rod-like, cuticularised; metastegostom isotopic and isomorphic; metacorpus strongly swollen with thickened lumen; secretory-excretory pore at level of basal bulb; ovaries largely outstretched, with very small flexure of 4-8 μm length and short conoid tail abruptly narrowing to a mucro.

Protorhabditis mucronata sp. n. comes closest to P. hortulana Abolafia & Pena-Santiago, 2016 in most morphometric and morphological characteristics but differs in having lateral fields with two ridges far apart (vs two wings seen as three incisures); trapezoid (vs truncate or weakly rounded) lip region; lips fused only at bases (vs amalgamated lips); straight, rod-like (vs bean-like) cheilostom; gymnostom with (parallel vs slightly divergent walls at posterior end); ovaries usually with small flexure (vs outstretched); tail with coarser and flattened 10-12 annules (vs 9 annules) at ventral side and tail tip abruptly narrowing to a mucro (vs tail tip without mucro in P. hortulana Abolafia & Pena-Santiago, 2016).

Protorhabditis mucronata sp. n. comes close to P. virgo Körner, 1954 in most morphometric and morphological characteristics but differs in having smaller females (0.18-0.25 mm vs 0.43-0.53 mm); smaller ‘a’ (10.8-17.2 vs 21.9-26.4); ‘b’ (3.4-3.8 vs 4.3-5.5) and ‘ć’ (1.5-2.5 vs 3.6-5.0) values; greater ‘c’ value (11.4-14.2 vs 6.0-9.1) and smaller stoma (11-12 μm vs 15-26 μm in P. virgo Körner, 1954).

Protorhabditis mucronata sp. n. differs from P. parvovelata Körner, 1954 in having smaller females (0.18-0.25 mm vs 0.58-0.87 mm); smaller ‘a’ (10.8-17.2 vs

85 19.6-24.0); ‘b’ (3.4-3.8 vs 4.0-5.9) and ‘ć’ (1.5-2.5 vs ~3.3) values; lips with conical (vs rounded) apices; tail short conoid (vs spicate to elongate with sudden narrowing after 1/3rd of its length) and males absent (vs males reported in P. parvovelata Körner, 1954).

Type locality and habitat: Samples having Protorhabditis mucronata sp. n. were obtained from soil having leaves and dry twigs litter from region of densely populated Acacia trees of Keetham lake, Agra, Uttar Pradesh, India at coordinates 27°14.792’ N 077°51.169’ E.

Type specimens: Holotype female and eight paratype females on slides Protorhabditis mucronata sp. n. KL3-12/1-5 deposited in Nematode Collection, Department of Zoology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.

Etymology: The species name ‘mucronata’ denotes the presence of short mucro at tail terminus.

Remarks: Most species of Protorhabditis Osche in Dougherty, 1955 possess a long tail in females with the exception of P. hortulana Abolafia & Pena-Santiago, 2016 which shows a short conoid tail. Sudhaus (2011) divided all the species of Protorhabditis Osche in Dougherty, 1955 primarily into two species groups, ‘xylocola’ group and ‘oxyuroides’ group on the basis of presence and absence of pharyngeal collar, respectively; only two species, P. elaphri Hirschmann in Osche, 1952 and P. tristis Hirschmann, 1952 with females having long and filiform tail were considered to fall apart and could not be placed in any of the two groups. The present species by having a pharyngeal collar falls in ‘xylocola’ group. Hence, comparision has been made with closely related species of this group, which are markedly distinct from the present species.

86 Table 5. Morphometric characteristics of Protorhabditis mucronata sp. n. Measurements are in µm and in the form: mean±standard deviation (range).

Character Holotype Female Paratype Female (n=8) Body length 209 213.1±19.6 (185-259)

Body diam. 16 16.2±0.8 (15-17) a 13 13.1±1.7 (10.8-17.2) b 3.4 3.4±0.1 (3.4-3.8) c 13 13.0±0.8 (11.4-14.2) c' 1.7 1.8±0.3 (1.5-2.5)

V 61.2 61.0±0.9 (59-62)

G1 17.7 20.9±2.5 (16.5-23.9)

G2 19.1 19.5±3.1 (15.1-26.6)

Lip height 2 2±0 (2-2)

Lip diam. 4 4.6±0.5 (4-5)

Stoma length 12 11.5±0.5 (11-12)

Stoma diam. 1 1±0 (1-1)

Pharynx length 60 60.0±3.8 (54-68)

Nerve ring-ant. end 36 44.3±4.3 (36-52)

Secretory-excretory pore-ant. 44 51.8±5.6 (44-63) end

Rectum length 10 9.4±1.0 (8-11)

Anal body diam. 9 8.8±0.6 (8-10)

Tail length 16 16.3±2.1 (13-20)

87 Fig 13. Protorhabditis mucronata sp. n. A: Entire female. B: Female anterior region. C: Female pharyngeal region. D: Female reproductive system. E: Female posterior region.

88 Fig. 14. Protorhabditis mucronata sp. n. (Female). A, B: Anterior end (scanning electron microscopy). C: Anterior end. D: Anterior pharyngeal region. E: Posterior pharyngeal region. F: Anterior genital branch. G: Posterior genital branch. H: Lateral fields (scanning electron microscopy). I: Vulval region. J: Posterior end. K: Posterior end (scanning electron microscopy) (Scale bars= 5 μm).

89 Superfamily: Mesorhabditoidea Andrássy, 1976

Diagnosis. Rhabditomorpha. Cuticle finely annulated. Lip region offset. Lips well developed, conspicuous, each with a setiform outer labial sensilla. Amphids small, on lateral lips. Stoma tubular, long and narrow. Cheilostom cuticularised; gymnostom with parallel walls; metastegostom with glottoid apparatus and small denticles or warts. Pharyngeal collar absent or small. Pharynx with swollen metacorpus. Female reproductive system monodelphic or didelphic. Vulva equatorial or post-equatorial. Female tail conoid to cupola-shaped, male tail short conoid or elongate conoid. Spicules fused distally, sometimes very long and slender. Bursa peloderan, proximally closed or leptoderan or rudimentary. Genital papillae five to nine pairs.

Type family: Mesorhabditidae Andrássy, 1976

Other family

Peloderidae Andrássy, 1976 Key to families of Mesorhabditoidea Andrássy, 1976

1. Labial papillae setiform; female reproductive system monodelphic; vulva post- equatorial; bursa peloderan or rudimentary ……..………… Mesorhabditidae

2. Labial papillae minute; female reproductive system didelphic; vulva equatorial; bursa peloderan ………………………………..…… Peloderidae Family: Mesorhabditidae Andrássy, 1976

Diagnosis. Mesorhabditoidea. Cuticle finely annulated. Lip region offset. Lips globular, separate with setiform papillae. Stoma tubular, long and slender with small or no pharyngeal collar; cheilostom not cuticularized; gymnostom with parallel walls; metastegostom with glottoid apparatus and small denticles. Pharynx with swollen metacorpus. Female reproductive system monodelphic, prodelphic, vulva posterior. Tail elongate, conoid. Spicules separate or distally fused. Bursa peloderan; occasionally rudimentary. Genital papillae five to nine pairs. Phasmids located anteriorly in tail region.

Type genus: Mesorhabditis Osche, 1952

Other genera

Crustorhabditis Sudhaus, 1974

90 Cruznema Artigas, 1927

Distolabrellus Anderson, 1983

Parasitorhabditis Fuchs, 1937

Rhabpanus Massey, 1971

Teratorhabditis Osche, 1952

91 Genus: Mesorhabditis Osche, 1952

Diagnosis. Mesorhabditidae. Small- to medium-sized nematodes. Cuticle transversely annulated. Lip region offset. Lips separated, rounded to globular, each with raised setiform outer labial sensilla. Amphids small, on lateral lips. Stoma tubular, long and narrow. Cheilostom small; gymnostom with parallel walls; stegostom with glottoid apparatus, each wall bearing two setose denticles. Pharyngeal collar small. Pharynx rhabditoid type with cylindrical corpus, swollen metacorpus, usually with lumen appearing like zipper and basal bulb with haustrulum. Female reproductive system monodelphic, prodelphic; ovary reflexed, a short post-vulval uterine sac may be present. Vulva post-equatorial. Males with spicules separate or distally fused, short to very long and slender. Bursa well developed, peloderan or rudimentary, anteriorly open; gential papillae 5-9 pairs. Tail short conoid to elongate conoid, moderately long. Phasmids at level of anus.

Type species: Mesorhabditis spiculigera Steiner, 1936

Other species

M. acidophila Borgonie, Dierick, Houthoofd, Willems, Jacobs & Bert, 2010

M. acuminata Kreis, 1929

M. acuticauda Ahmad, Shah & Mahamood, 2010

M. africana Andrássy, 1982

M. anisomorpha Sudhaus, 1978

M. belari Nigon, 1949

M. capitata Loof, 1964

M. carmenae Abolafia & Pena-Santiago, 2009

M. cranganorensis Khera, 1968

M. dunensis Khera, 1971

M. franseni Fuchs, 1933

M. inarimensis Meyl, 1953

M. irregularis Körner in Osche, 1952

M. kherai (Sudhaus, 1976) Sudhaus, 2011

92 M. kinchegensis Nicholas, 1998

M. labiata Völk, 1950

M. littoralis Yeates, 1969

M. longespiculosa Schuurmans Stekhoven, 1951

M. longistomis Massey, 1974

M. megachilis Sudhaus, 1978

M. microbursaris Steiner, 1926

M. minuta Boström, 1991

M. miotki Sudhaus, 1978

M. monhystera Bütschli, 1873

M. oschei Körner, 1954

M. paucipapillata Paetzold, 1955

M. riparia (Brzeski, 1985) Sudhaus, 2011

M. sambharensis Khera, 1971

M. scanica (Allgén, 1949) Sudhaus, 2011

M. signifera Baranovskaya, 1959

M. simplex Cobb, 1893

M. striatica Dassonville & Heyns, 1984

M. sudhausi Andrássy, 1982

M. szunyoghyi Andrássy, 1961

M. vernalis Andrássy, 1982

93 Mesorhabditis anisospicula sp. n.

(Figs. 15, 16, 17)

Description

Measurements. Table 6.

Female: Small- to medium-sized nematodes, straight upon fixation, tapering more towards posterior end. Cuticle 1 μm thick with very fine annulations, annules 0.7 to 1.0 μm wide. Lateral fields 2-3 μm wide with four ridges in midbody merging into two in anterior and posterior region, clearly visible in SEM images. Lip region offset; lips prominent, globular. Inner labial and cephalic sensilla obscure; outer labial sensilla about 1 μm long with pointed apices. Amphidial openings usually not discernible under LM. Stoma tubular; cheilostom not cuticularised; gymnostom 7-9 μm long or 50.0-53.8% of stoma length with parallel walls; stegostom small, 3-4 μm long or 22.2-23.0% of stoma length, metastegostom isotopic and isomorphic, each metastegostomal swelling bearing two minute denticles; glottoid apparatus present. Pharyngeal collar small, 3-4 μm high from base of stoma. Pharynx rhabditoid type with 46-60 μm long cylindrical procorpus having faint zipper-like lumen; 15-20 μm long swollen metacorpus with moderately thickened lumen; 24-33 μm long isthmus gradually narrowing posteriorly into an ovoid to rounded basal bulb of 18-28 μm x 13-19 μm dimension having grinder and double-chambered haustrulum. Nerve ring encircling isthmus at 65-70% of pharyngeal length from anterior end. Secretory- excretory pore slightly posterior to nerve ring or at 74.7-76.4% of pharyngeal length from anterior end. Hemizonid closely posterior to secretory-excretory pore. Cardial flaps 3-5 μm long. Intestine thin-walled, usually with an anteriorly-dilated bacterial pouch and constricted in the region of uterus. Three pseudocoelomocytes in vicinity of gonad; anterior one 1.5-2.0 times body diam. anterior to reflexed part, middle one at level of oviduct, posterior one close to distal tip of ovary. Rectum 1.2-1.5 times anal body diam. Rectal glands present. Anus a crescent-shaped slit. Tail elongate conoid, 3.8-4.8 times anal body diam. Phasmidial openings at level of anus.

Reproductive system monodelphic, prodelphic; ovary dorsally reflexed; distal tip cell conspicuous. Oocytes arranged in two rows in distal region followed by single tier proximally. Oviduct thin tube leading to an elongate-ovoid axial spermatheca of 20-21 μm x 9-10 μm dimension, filled with spermatozoa and connected to prominent

94 columella. Uterus spacious with thick walls, 15-35 μm x 7-15 μm in dimension. Vagina usually obliquely-oriented, 7-8 μm long or 32.0-38.8% of corresponding body diam. with supporting muscles appearing as cuticularised pieces in cross section. Vulva posterior, 71-75% from anterior end. Vulval lips radially ridged in SEM, slightly protruded without any cuticular flap. Post uterine sac absent. Uterine eggs not observed.

Male: Similar to female except smaller body size. Testis single, dorsally reflexed, reflexed germinal part short and conspicuously swollen. Pseudocoelomocyte often large and conspicuous, lying close to distal tip of testis. Spermatocytes arranged in double rows, polygonal in shape; seminal vesicle elongate. A pair of ejaculatory glands opening into ejaculatory duct. Spicules dimorphic, unequal and dissimilar in appearance; slender, straight, cephalated with small, rounded head or short, stout with prominently large head. Gubernaculum thin, trough-shaped, half of spicule length. Bursa rudimentary. Bursal papillae seven pairs including phasmids arranged in 1/1+1+2+1+P configuration: GP1 subventral, precloacal. Among postcloacals, GP2 subventral; GP3 ventrolateral; GP4 subventral close to lateroventral GP5; GP6 subventral, at level of lateral phasmids.

Diagnosis and relationship: Mesorhabditis anisospicula sp. n. is characterized by small-sized body (0.38-0.60 mm in females and 0.28-0.42 mm in males); offset lip region; lateral fields with four ridges in midbody merging into two anteriorly and posteriorly; metastegostom with two minute denticles on each wall; small pharyngeal collar; narrow oviduct; elongate ovoid spermatheca; vulval lips radially ridged (visible in SEM); males having short and conspicuously swollen reflexed germinal part of testis; spicules dimorphic, unequal and dissimilar in appearance; bursa rudimentary with seven pairs of papillae in 1/1+1+2+1+P configuration.

Mesorhabditis anisospicula sp. n. comes closest to the Indian species M. cranganorensis Khera, 1968 in most morphometric and morphological characteristics but differs in having smaller ‘a’ (18.5-23.0 vs 26.2-45.3) and ‘ć’ (3.8-4.8 vs 5.3-7.7) values; lip region offset (vs continuous); each metastegostomal wall with two (vs three) denticles and males in large numbers [vs males not reported in M. cranganorensis apud (Khera, 1968].

Mesorhabditis anisospicula sp. n. comes close to M. microbursaris (Steiner, 1926) Andrássy, 1983 in most morphometric and morphological characteristics but

95 differs in having females with relatively smaller ‘ć’ value (3.8-4.8 vs 4.6-6.9); short pharyngeal collar present (vs absent); males with dimorphic and dissimilar (vs similar) spicules and genital papillae six [vs five pairs in M. microbursaris (Steiner, 1926) Andrássy, 1983)].

Mesorhabditis anisospicula sp. n. differs from M. vernalis (Andrássy, 1982) in having females with smaller ‘ć’ value (3.8-4.8 vs ~5.3-5.8); short pharyngeal collar present (vs absent); males with greater ‘a’ value (15.9-21.1 vs 14); smaller spicules (15-21 μm vs 22-23 μm); dimorphic and dissimilar (vs similar) spicules and genital papillae six pairs with one precloacal and five postcloacals pairs [vs genital papillae seven pairs with three precloacal, one adcloacal and two postcloacals pairs in M. vernalis (Andrássy, 1982)].

Mesorhabditis anisospicula sp. n. differs from M. labiata Völk, 1950 in having relatively smaller females (0.38-0.60 mm vs 0.58-0.94 mm); smaller ‘b’ value (3.4-4.3 vs 5.0-6.3); greater ‘ć’ value (3.8-4.8 vs ~3.7); lips six (vs four); males with greater ‘a’ value (15.9-21.1 vs 13.4-14.6); smaller ‘c’ value (7.1-10.5 vs 13.9-20.9); spicules smaller (15-21 μm vs 22-24 μm); dimorphic and dissimilar (vs similar spicules); rudimentary (vs peloderan) bursa and dissimilar arrangement of postcloacal genital papillae (vs postcloacal genital papillae arranged in groups of 3+2 in M. labiata Völk, 1950).

Mesorhabditis anisospicula sp. n. differs from M. littoralis Yeates, 1969 in having relatively smaller females (0.38-0.60 mm vs 0.60-0.72 mm) with greater ‘a’ value (18.5-23.0 vs 15.0-18.0); smaller ‘b’ value (3.4-4.3 vs 5.2-6.0); relatively smaller ‘ć’ value (3.8-4.8 vs 4.5-6.4); small pharyngeal collar present (vs absent); secretory-excretory pore in isthmus region (vs at level of basal bulb); males with relatively smaller ‘b’ (3.0-3.8 vs 3.6-4.2) and ‘ć’ (2.6-3.5 vs 3.3-4.9) values; relatively greater ‘c’ value (7.1-10.5 vs 6.6-7.1); relatively smaller spicules (15-21 μm vs 19-27 μm); dimorphic and dissimilar (vs similar) spicules; smaller gubernaculum (7-10 μm vs 13-16 μm) and genital papillae six (vs five pairs in M. littoralis Yeates, 1969).

Type locality and habitat: Samples having Mesorhabditis anisospicula sp. n. were obtained from soil from base of a shrub of Keetham lake, Agra, Uttar Pradesh, India at coordinates 27°15.326’ N 077°50.679’ E.

96 Type specimens: Holotype female, nine paratype females and nine paratype males on slides Mesorhabditis anisospicula sp. n. KL1-21/1-7 deposited in Nematode Collection, Department of Zoology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.

Etymology: The species name ‘anisospicula’ denotes its dissimilar and dimorphic spicules.

Remarks: Andrássy separated genus Bursilla Andrássy, 1976 from Mesorhabditis Osche, 1952 having male possessing a rudimentary bursa with lesser number of genital papillae (five to seven pairs). However, Sudhaus (2011) did not consider Bursilla as a separate genus and placed its species with reduced bursa under a separated species group ‘monhystera’ of the genus Mesorhabditis Osche, 1952 while placed rest of the species with conspicuous bursa, and long and slender spicules under ‘spiculigera’ group. The present species by having a rudimentary bursa falls in ‘monhystera’ group, therefore, is being compared with closely related species of this group.

M. labiata Völk, 1950 is the only species of the genus showing unusual labial design with four lips. The Indian species, M. cranganorensis as reported by Khera (1968) was stated to lack males but the drawings of species (Figure 1) reflect presence of rounded sperms in the spermatheca of female suggesting hermaphroditism to be reproductive mode, presumably. In another publication of the same species by Tabassum et al. (2004), the drawings (Figure 3) of female reproductive system lack details and appear to be inadequate; also in the same figure, pharynx does not show the characteristically swollen metacorpus as found in the species of genus Mesorhabditis Osche, 1952.

97 Table 6. Morphometric characteristics of Mesorhabditis anisospicula sp. n. Measurements are in µm and in the form: mean±standard deviation (range).

Character Holotype Paratype Female Paratype Male Female (n=9) (n=9) Body length 485 480.2±62.8 (388- 356.3±47.9 (287-422) 606) Body diam. 21 23.7±3.0 (20-29) 20.1±2.7 (17-24) a 23 20.2±1.2 (18.5-23.0) 17.7±1.6 (15.9-21.1) b 4 4.0±0.2 (3.4-4.3) 3.4±0.3 (3.0-3.8) c 8.3 8.2±0.5 (7.6-9.2) 8.0±1.1 (7.1-10.5) c' 4.8 4.3±0.3 (3.8-4.8) 2.9±0.2 (2.6-3.5) V/T 72.9 73.3±1.1 (71.3-74.9) 53.4±5.2 (47.4-62.7) G1 31.7 44.1±12.1 -- (29.8-65.5) Lip height 3 3±0 (3-3) 2.4±0.5 (2-3) Lip diam. 7 7.3±0.8 (6-9) 6.4±0.5 (6-7) Stoma length 16 15.1±1.5 (13-18) 12.8±1.5 (10-15) Stoma diam. 3 2.8±0.4 (2-3) 2±0 (2-2) Pharynx length 120 118.6±9.0 (111-140) 102.2±8.7 (93-121) Nerve ring-ant. 78 76.8±5.6 (70-91) 65.8±6.2 (60-80) end Secretory- 89 91.0±6.6 (83-107) 74.8±8.6 (63-87) excretory pore- ant. end Rectum length 16 21.1±4.4 (15-29) 16.8±1.7 (14-20) Anal body diam. 12 13.4±1.7 (11-17) 14.6±1.5 (12-17) Tail length 58 58.0±5.3 (50-66) 44.1±5.2 (38-51) Spicules length -- -- 18.6±2.1 (15-21) Gubernaculum -- -- 7.8±1.2 (7-10) length

98 Fig 15. Mesorhabditis anisospicula sp. n. A: Entire female. B: Entire male. C: Female anterior region. D: Female pharyngeal region. E. Female reproductive system. F: Female posterior region. G: Male posterior region. H, I: Dimorphic spicules.

99 Fig. 16. Mesorhabditis anisospicula sp. n. (Female). A, B: Anterior end (scanning electron microscopy). C: Anterior end. D: Pharyngeal region. E: Isthmus region. F: Lateral fields. G: Lateral fields (scanning electron microscopy). H. Genital branch. I: Vulval region. J: Vulval region (scanning electron microscopy). K: Posterior end (scanning electron microscopy) (Scale bars=10 μm).

100 Fig. 17. Mesorhabditis anisospicula sp. n. (Male). A: Anterior end. B: Pharyngeal region. C: Genital branch. D: Cloacal region showing spicule. E, F: Cloacal region showing bursa and associated papillae (scanning electron microscopy). G-I: Cloacal region showing bursa and associated papillae (Scale bars=10 μm).

101 Infraorder: Diplogasteromorpha De Ley & Blaxter, 2002

Diagnosis. Rhabditina. Cuticle smooth or transversely and longitudinally striated with punctations. Lip region continuous. Lips fused. Labial sensilla setose, males occasionally with four cephalic setae. Stoma symmetrical or asymmetrical; spacious; stegostom anisomorphic, metastegostom with well-developed dorsal tooth and subventral armature. Pharynx with muscular procorpus, strongly swollen metacorpus with thickened lumen and weakly developed basal bulb. Female reproductive system didelphic, amphidelphic or monodelphic, prodelphic. Spicules separate, occasionally fused distally. Bursa usually absent, if present, rudimentary. Genital papillae often bristle-like, nine pairs. Tail in both sexes usually long filiform.

Type superfamily: Diplogastroidea Micoletzky, 1922

Other superfamilies

Cylindrocorporoidea Goodey, 1939

Odontopharyngoidea Micoletzky, 1922 Key to superfamilies of Diplogasteromorpha De Ley & Blaxter, 2002

1. Procorpus and metacorpus fused to form long muscular corpus ……………………………………………………………………………… 2

- Procorpus and metacorpus distinct ….………………….… Diplogastroidea

2. Stoma excessively long, narrow and tubular, one-fourth of pharyngeal length or longer, without tooth or denticles ………………… Cylindrocorporoidea

- Stoma short and more spacious, with distinct tooth and denticles ………………………………………………………... Odontopharyngoidea

Superfamily: Diplogastroidea Micoletzky, 1922

Diagnosis. Diplogasteromorpha. Lip region continuous. Lips hardly separate. Labial sensilla papilliform or setiform. Females with/ without cephalic setae and males with cephalic setae. Amphids either small, indistinct or large located in posterior region of stoma. Stoma wide and spacious. Cheilostom and gymnostom cuticularized. Stegostom asymmetrical, dorsal wall with tooth, subventral walls with variable armature. Pharynx with muscular procorpus and well-developed valvate metacorpus

102 with distinguishable basal bulb. Female reproductive system didelphic, amphidelphic, rarely monoprodelphic. Bursa rudimentary or absent.

Type family: Diplogastridae Micoletzky, 1922

Other families

Diplogasteroididae Filipjev & Schuurmans Stekhoven, 1941

Neodiplogastridae Paramonov, 1952

Pseudodiplogasteroididae Körner, 1954

Tylopharyngidae Filipjev, 1934 Key to families of Diplogastroidea Micoletzky, 1922

1. Stoma tubular, cheilostom short, cuticularized, metastegostom with small teeth …………………………………………………… Pseudodiplogasteroididae

2. Stoma stylet-like, cheilo- and gymnostom very short, telostegostom long and narrow with basal knobs ………………………………….. Tylopharyngidae

3. Stoma more or less spacious, gymnostom tubular, three to six times as long as wide, metastegostom with small teeth ………………….. Diplogasteroididae

4. Stoma anteriorly wide and posteriorly narrow; dorsal and right subventral teeth movable, claw-like; left subventral wall possess plain or serrated plate; telostegostom elongate ………………………………….... Neodiplogastridae

5. Stoma spacious, twice as long as wide; dorsal tooth immovable, plate-like or setose, right and left subventral teeth similar; telostegostom short …………………………………………………………..……... Diplogastridae Family: Neodiplogastridae Paramonov, 1952

Diagnosis. Diplogasteroidea. Lip region with setose papillae. Stoma with wider anterior and narrower posterior part. Cheilostom divided into plates, usually equal to gymnostom. metastegostom anisomorphic, dorsal wall with large, claw-like, movable tooth, right subventral walls with two or more pointed saw-like teeth or small tooth or occasionally unarmed. Telostegostom occasionally elongate with variable length. Pharynx with anterior part muscular and posterior part non-muscular, metacorpus strong. Female reproductive system didelphic, amphidelphic. Males without bursa, if

103 present, rudimentary. Spicules separate. Genital papillae nine pairs. Tails of both sexes elongate to filiform.

Type genus: Neodiplogaster Cobb, 1924

Other genera

Fictor Paramonov, 1952

Koerneria Meyl, 1960

Micoletzkya Weingärtner, 1955

Mononchoides Rahm, 1928

Oigolaimella Paramonov, 1952

Pristionchus Kries, 1932

104 Genus: Oigolaimella Paramonov, 1952

Diagnosis. Neodiplogastridae. Large-sized nematodes. Cuticle smooth or very finely annulated. Struts within cuticle at limits of optical resolution and barely visible as punctuations forming longitudinal rows having a species specific pattern. Lateral field indistinct. lip region continuous with adjoining body. Lips amalgamated each with six labial sensilla. Cephalic sensilla present in males. Amphidial opening located behind posterior end of stoma. Stoma slightly longer than wide. Cheilostom complex, comprising a collar-like cuticularisation, continuous with inner layer of body cuticle and surrounding base of more than ten lancet-shaped liplets. Liplets continuous with outer layer of body cuticle and directed anteriorly to form a stoma encircling corona. Gymnostom forming a short ring, wider than long. Stegostom with claw-like dorsal tooth, a right subventral tooth and a left subventral ridge usually with rows of minute denticles. Female reproductive system didelphic, amphidelphic, ovaries reflexed. Males with nine pairs of genital papillae. Spicules short and separate. Tail long filiform in both sexes.

Type species: Oigolaimella longicauda (Claus, 1862) Fürst von Lieven, 2003

Other species

O. attenuata Fürst von Lieven & Sudhaus, 2008

O. diplogaster (Linstow, 1890) Fürst von Lieven, 2003

O. kruegeri Fürst von Lieven, 2003

O. ninae Fürst von Lieven, 2003

105 Oigolaimella paraninae sp. n.

(Figs. 18, 19, 20)

Description

Measurements. Table 7.

Female: Large-sized slender nematodes, almost straight upon fixation, tapering more towards posterior region. Cuticle 1 µm thick with very faint transverse and longitudinal lines and punctations. Lateral fields not differentiated. Lip region low and flat, continuous with body; lips six, amalgamated. Inner labial and cephalic sensilla inconspicuous; outer labial sensilla long, bristle-like. Amphidial aperture 4 µm wide, located posterior to base of stoma, 8-10 µm from anterior end. Stoma longer than wide, 7 μm x 5-6 μm. Cheilostom cuticularized; cheilostomal flaps projecting beyond labial contour, forming a number of lancet-shaped liplets, ranging from 14-16, not clear under LM; liplets continuous with outer layer of body cuticle and directed towards oral aperture encircling stoma. Gymnostom wider than long. Stegostom 45- 50% of stoma length, metastegostom anisotopic and anisomorphic, dorsal wall bearing moderately developed, thorn-shaped dorsal tooth, right subventral wall with triangular tooth and left subventral wall with ridge having denticles not visible under LM. Pharyngeal collar 45-50% from base of stoma. Pharynx with 52-65 μm long cylindrical and muscular corpus, 14-19 μm long strongly muscular metacorpus with thickened lumen, 21-25 μm long, short and narrow isthmus separated from metacorpus by a constriction, posteriorly expanding to form an elongate, pyriform basal bulb of 20-26 μm x 11-15 μm dimension. Nerve ring encircling middle of isthmus at 67.9-70.3% of pharyngeal length from anterior end. Secretory-excretory pore located slightly posterior to nerve ring, 79.2-91.5% of pharyngeal length from anterior end. Cardia small, 1-2 μm long. Intestine granular with wide lumen. Rectum 1.1-1.2 times anal body diam. long. Rectal glands obscure. Anus a crescent-shaped slit. Tail long, filiform, 10.8-16.9 times anal body diam. long, constituting 22.6-25.7 % of body length.

Reproductive system didelphic, amphidelphic; ovaries dorsally reflexed; anterior branch on right and posterior on left side of intestine; oocytes arranged in 2-3 rows distally followed by single row proximally. Oviduct 33-35 µm long, narrow tube, constricted at junction with spermatheca; 35 µm long, ovoid spermatheca

106 separated from uterus by a constriction, usually filled with oval semi-spheroid sperms. Uterus muscular, occasionally with one or two intra-uterine eggs of 39-50 μm x 19-22 μm dimension. Vagina perpendicular to body axis, 35-40% of corresponding body diam. Vulva pre-equatorial, 42.6-47.6% from anterior end, vulval opening circular.

Male: Similar to female except having a relatively smaller body with strong posterior curvature, relatively narrower and shorter stoma, cheilostomal flap relatively straight not diverging externally. Testis single, laterally reflexed, flexure very small, 24-37 μm, on right side of intestine. Spermatocytes arranged in a single row; seminal vesicle with compactly arranged polygonal maturing sperms, almost occupying corresponding body diam., vas deferens leading to ejaculatory duct. Ejaculatory glands indistinct. Spicules strongly arcuate, ridged, with knobbed head proximally and with pointed, ventrally curved distal tip. Gubernaculum short, keeled with antero- dorsal notch, 32-35% of spicule length. Genital papillae nine pairs: three precloacal pairs and six postcloacal pairs arranged in v1, v2, v3d/ v4, ad, (v5+v6, v7), pd configuration: v1 subventral, 26-45 µm or 1.3-1.8 times spicule length anterior to cloaca; v2 subventral, closely anterior to cloaca; v3d lateral, located at mid level of spicule. Among postcloacals, v4 subventral, slightly posterior to cloaca; ad subdorsal; v5 and v6 small forming a group with slightly spaced v7, subventral; pd subdorsal, far posterior from cloaca.

Diagnosis and relationship: Oigolaimella paraninae sp. n. is characterized by cuticularized cheilostom with outwardly diverging flaps in females and relatively straight flaps in males; gymnostom wider than long; spermatheca usually filled with oval semi-spheroid sperms; flexure of testis very small, 24-37 μm; strongly arcuate spicules with knobbed head and sharp pointed ventrally curved distal end. Gubernaculum less than half of spicule length having antero-dorsal notch.

Oigolaimella paraninae sp. n. comes closest to O. ninae Fürst von Lieven, 2003 in most morphometric and morphological characteristics but differs in having greater ‘a’ (32.8-39.8 vs 27.0-30.0) and ‘c’ (3.4-4.9 vs 2.7) values; relatively smaller ‘ć’ value (10.8-16.9 vs 16.0-19.2); stoma longer than wide (vs as long as wide); spermatheca usually filled with non-flagellate large-sized sperms (vs flagellate small- sized sperms); males with relatively smaller gubernaculum (7.0-8.0 μm vs 8.0-9.5 μm); v1 far anterior from cloacal opening (1.3-1.8 times vs 0.8-1.0 times spicule length in O. ninae Fürst von Lieven, 2003).

107 Oigolaimella paraninae sp. n. differs from O. attenuata Fürst von Lieven & Sudhaus, 2008 in having females with longer (33.0-35.0 µm vs 10.4-20.9 µm) oviduct; longer (35 µm vs 16 µm) spermatheca usually filled with oval semi-spheroid sperms without any prominent outline (vs fusiform sperms with outer margins thickened); males with longer stoma (7 μm vs 4-6 μm); longer spicules (20-25 µm vs 15-17 µm); with sharp pointed (vs blunt) tip; v5 and v6 closely placed (vs slightly spaced), v7 slightly spaced from v5 and v6 (vs v7 far from v5 and v6 in O. attenuata Fürst von Leiven & Sudhaus, 2008).

Oigolaimella paraninae sp. n. differs from O. longicauda (Claus, 1862) Fürst von Lieven, 2003 in having relatively greater ‘c’ value (3.4-4.9 vs 2.3-3.6); relatively smaller ‘ć’ value (10.8-16.9 vs 13.9-22.7); oviduct longer (33-35 µm vs ~9 µm); males with smaller ‘a’ (36.3-40.4 vs 41.6-46.3) and ‘ć’ (9.3-12.5 vs 15.2-19.4) values; greater ‘c’ value (3.9-4.9 vs 2.3-3.6); gubernaculum having antero-dorsal notch [vs notch absent in O. longicauda (Claus, 1862) Fürst von Lieven, 2003].

Type locality and habitat: Samples having Oigolaimella paraninae sp. n. were obtained from rotten log of fallen tree at Keetham lake, Agra, Uttar Pradesh, India at coordinates 27°15.307’ N 077°50.838’ E.

Type specimens: Holotype female, six paratype females and five paratype males on slides Oigolaimella paraninae sp. n. KL5-164/1-5 deposited in Nematode Collection, Department of Zoology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.

Etymology: The species epithet ‘paraninae’ is based on its close similarity to Oigolaimella ninae.

Remarks: Fürst von Lieven & Sudhaus (2008) very lucidly differentiated the species of Oigolaimella on the basis of stoma morphology, punctations, position of male genital papillae, spicule and gubernaculum and the morphology, size and shape of sperms in the spermatheca. These differentiating characters were considered for comparing the present population with existing species to confirm its distinctness from others.

108 Table 7. Morphometric characteristics of Oigolaimella paraninae sp. n. Measurements are in µm and in the form: mean±standard deviation (range).

Character Holotype Paratype Female Paratype Male Female (n=4) (n=4) Body length 788 838.6±114.7 (758-970) 742.0±56.7 (688-800) Body diam. 24 23.0±3.6 (19-26) 19.2±2.2 (17-22) a 32.8 36.6±3.5 (32.8-39.8) 38.6±1.7 (36.3-40.4) b 7.4 6.8±0.7 (6.0-7.4) 6.6±0.1 (6.4-6.8) c 3.7 4.0±0.7 (3.4-4.9) 4.3±0.4 (3.9-4.9) c' 13.1 13.6±3.0 (10.8-16.9) 10.6±1.3 (9.3-12.5) V/T 43.3 44.5±2.7 (42.6-47.6) 56.6±3.6 (52.6-60.5) G1 31.4 30.1±6.2 (23.3-35.7) -- G2 29.5 26.6±6.4 (19.3-31.2) -- Lip height 3 3±0 (3-3) 3±0 (3-3) Lip diam. 10 10.6±1.1 (10-12) 9.0±1.4 (8-11) Stoma length 7 7±0 (7-7) 7±0 (7-7) Stoma diam. 6 5.6±0.5 (5-6) 5±0 (5-5) Pharynx length 106 122.3±14.8 (106-135) 110.5±7.0 (102-118) Nerve ring-ant. 72 84.6±11.6 (72-95) 71.0±8.4 (63-82) end Secretory- 98 100.6±5.5 (97-107) 82.5±11.9 (68-95) excretory pore- ant. end Rectum length 16 18.6±2.3 (16-20) 20.2±1.2 (19-22) Anal body diam. 16 15.6±2.5 (13-18) 16.0±1.8 (14-18) Tail length 210 208.3±12.5 (195-220) 170.7±21.9 (140-192) Egg dimension 39 x 19 44.5±4.9 x 20.5±1.7 -- (39-50 x 19-22) Spicules length -- -- 22.7±2.2 (20-25) Gubernaculum -- -- 7.7±0.5 (7-8) length

109 Fig 18. Oigolaimella paraninae sp. n. A: Entire female. B: Entire male. C: Female anterior region. D: Female pharyngeal region. E. Female reproductive system. F: Female posterior region. G: Male posterior region.

110 Fig. 19. Oigolaimella paraninae sp. n. (Female). A-F: Anterior end. G: Anterior pharyngeal region. H: Posterior pharyngeal region. I: Cuticle showing punctations. J, L: Vulval region. K: Anterior genital branch. M: Anal region (Scale bars= 10 μm).

111 Fig. 20. Oigolaimella paraninae sp. n. (Male). A-C: Anterior end. D: Pharyngeal region. E: Genital branch. F: Cloacal region showing spicules and gubernaculum (ventral). G, H: Cloacal region showing spicules and gubernaculum (lateral). I: Cloacal region showing associated papillae (Scale bars= 10 μm).

112 Oigolaimella indica sp. n.

(Figs. 21, 22, 23)

Description

Measurements. Table 8.

Female: Large-sized nematodes, slightly arcuate upon fixation, tapering towards both extremities, more towards posterior region. Cuticle 1 μm thick, moderately annulated, annulations 1.5-2.0 µm wide, transverse and longitudinal striations faint, crossing each other making rectangular brick-like structure. Lateral fields not differentiated. Lip region continuous with body contour, lips amalgamated, each bearing a moderately developed outer labial sensilla. Inner labial and cephalic sensilla indistinct. Oral aperture circular and narrow. Amphidial apertures large oval, 4 µm wide, located posterior to base of stoma, 13-14 μm or at level of eighth annule from anterior end. Stoma longer than wide; cheilostom thick cuticularized, cheilostomal walls arched, 40.0-41.6% of stoma length, cheilostomal flap extending beyond the labial contour forming a number of lancet-shaped liplets, ranging from 14-16, not clear under LM; gymnostom cuticularised, wider than long, 25-30% of stoma length, stegostom anisotopic and anisomorphic, dorsal wall bearing moderately developed thorn-shaped tooth, right subventral wall with triangular tooth slightly larger than dorsal at a lower level and left subventral wall with a ridge having minute denticles. Pharynx with 62-65 μm long cylindrical, muscular procorpus, expanding posteriorly to form strongly muscular metacorpus; a constriction present at junction of metacorpus and isthmus. Isthmus 22-30 μm long, expanding into an elongate basal bulb of 26-30 μm x 13-16 μm dimension. Nerve ring encircling middle of isthmus, at 68.3-70.4% of pharyngeal length from anterior end. Secretory-excretory pore located closely posterior to nerve ring, at 84-88% of pharyngeal length from anterior end. Hemizonid at level of basal bulb. Cardia small, 1-2 μm long. Intestine granular, intestinal lumen wide. Three pseudocoelomocytes present in vicinity of gonad, one slightly anterior to flexure of anterior genital branch, another at level of spermatheca of anterior genital branch and one slightly posterior to flexure of posterior genital branch. Rectum 1.2-1.5 anal body diam. long. Rectal glands obscure. Tail long, filiform, 23.5-26.1% of body length.

113 Reproductive system didelphic, amphidelphic; ovaries reversed dorsally, anterior branch on right and posterior branch on left of intestine; oocytes arranged in 2-3 rows. Ovary constricted proximally to separate grown oocyte/s. Oviduct narrow, 25-45 µm long, leading to 19-34 µm long ovoid spermatheca, usually containing 1-4 oval to spindle-shaped sperms. Spermatheca separated from uterus by a constriction. Uterus serving as sperm storage organ, highly muscular, much longer, more than 2 times length of spermatheca. Vagina perpendicular to body axis, 28.5% of corresponding body diam. Vulva pre-equatorial, 40.7-43.5% from anterior end, vulval opening small eliptical.

Males: Similar to female except in having slenderer body and posterior curvature. Cheilostom covering approximately 30% of total stoma length. Testis single, laterally reflexed, flexure very small. Spermatocytes arranged in 2-3 rows distally followed by single row proximally. Seminal vesicle filled with maturing sperm cells. Ejaculatory glands present. Two pseudocoelomocytes present in vicinity of gonad: one near distal tip of testis and another about 3 body diam. posterior to flexure. Spicules stout, ridged, ventrally arcuate with rounded head. Gubernaculum dorsally keeled with a smooth margin, ventral arm of gubernaculum heavily sclerotised, 35.0-42.8% or less than half of spicule length. Genital papillae nine pairs, three pairs precloacals and six pairs postcloacals arranged in v1, v2, v3d/ v4, ad, (v5+v6, v7), pd configuration: v1 subventral, 30-38 µm or 1.5-1.8 times spicule length or 15-18 annules anterior to cloaca; v2 relatively small, subventral, just anterior to cloaca; v3d lateral, at mid level of spicule. Among postcloacals, v4 subventral, 4-5 annules posterior to cloaca; ad subdorsal; v5, v6 and v7 forms a group, subventral, with v5 and v6 smaller and closely placed and v7 slightly spaced from v5 and v6; pd subdorsal, far posterior from cloaca.

Diagnosis and relationship: Oigolaimella indica sp. n. is characterized by having thick cuticularized cheilostom, constituting 40.0-41.6% of stoma length. Cheilostomal flap extending beyond labial contour, forming a number of lancet-shaped liplets, ranging from 14-16, not clear under LM; gymnostom wider than long, 25-30% of stoma length; stegostom anisomorphic, dorsal wall bearing moderately developed thorn-shaped tooth, right subventral wall with triangular tooth and left subventral wall with ridge having minute denticles not discernible under LM; amphidial apertures 4 µm wide; proximal part of ovary showing a constriction; oviduct 25-45 µm long,

114 tubular; spermatheca elongate with large-sized ovoid sperms. Male genital branch with very short flexure.

Oigolaimella indica sp. n. comes closest to O. longicauda (Claus, 1862) Fürst von Lieven, 2003 in most morphometric and morphological characteristics but differs in having females with greater ‘c’ value (3.7-4.3 vs 2.3-3.6); labial sensilla moderate (vs long); amphidial aperture wide (4 µm vs 2 µm); cheilostom with respect to cheilostomal flap (71-80% vs 50%); oviduct longer (25-45 µm vs 9 µm); males with greater ‘c’ value (4.3-4.5 vs 2.3-3.6); smaller ‘ć’ value (10.0-11.5 vs 15.2-19.4); stoma longer (10 μm vs 6-9 μm); short flexure of testis [4.0-5.2 µm vs 6.0-20.0 µm in O. longicauda (Claus, 1862) Fürst von Lieven, 2003].

Oigolaimella indica sp. n. differs from O. attenuata Fürst von Lieven & Sudhaus, 2008 in having larger females (0.97-1.16 mm vs 0.61-0.88 mm); longer stoma (10-12 μm vs 5-6 μm); cheilostom 40.0-41.6% of stoma length (vs cheilostom 60-65% of stoma length); vulva pre-equatorial (vs post-equatorial); males larger (0.82-0.91 mm vs 0.54-0.76 mm); longer spicules (20-21 μm vs 15-17 μm); gubernaculum without antero-dorsal notch (vs antero-dorsal notch present in O. atenuata Fürst von Lieven & Sudhaus, 2008).

Oigolaimella indica sp. n. differs from O. ninae Fürst von Lieven, 2003 in having larger females (0.97-1.16 mm vs 0.67-0.82 mm); greater ‘a’ (34.8-40.7 vs 27.0-30.0), ‘b’ (7.0-8.5 vs 5.6-6.5) and ‘c’ (3.7-4.3 vs 2.7) values; relatively smaller ‘ć’ value (12.7-16.0 vs 16.0-19.2); stoma longer (10-12 μm vs 7-8 μm); males with smaller spicules (20-21 μm vs 23-28 μm); gubernaculum without antero-dorsal notch (vs antero-dorsal notch present in O. ninae Fürst von Lieven, 2003).

Type locality and habitat: Samples having Oigolaimella indica sp. n. were obtained from rotten log of fallen tree at Keetham lake, Agra, Uttar Pradesh, India at coordinates 27°15.307’ N 077°50.838’ E.

Type specimens: Holotype female, six paratype females and four paratype males on slides Oigolaimella indica sp. n. KL5-164/1-5 deposited in Nematode Collection, Department of Zoology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.

Etymology: The species name ‘indica’ indicates the country of origin i.e., India.

Remarks: According to Fürst von Lieven & Sudhaus (2008), some characters hold immense diagnostic value for differentiation of species of Oigolaimella viz.,

115 morphology of stoma, spicules and gubernaculum, cuticular ornamentation, morphology of sperms in the spermatheca and position of male genital papillae. Based on the above characters, the present population falls apart from other congeners.

116 Table 8. Morphometric characteristics of Oigolaimella indica sp. n. Measurements are in µm and in the form: mean±standard deviation (range).

Character Holotype Paratype Female Paratype Male Female (n=5) (n=4) Body length 1028 1066.0±77.6 869.7±41.6 (825-916) (977-1165) Body diam. 29 28.3±1.6 (26-31) 21.2±2.0 (19-23) a 35.4 37.5±2.2 (34.8-40.7) 41.0±2.5 (38.7-44.5) b 7.4 7.8±0.5 (7.0-8.5) 7.0±0.4 (6.7-7.6) c 3.7 4.0±0.2 (3.7-4.3) 4.4±0.09 (4.3-4.5) c' 13.7 14.2±1.3 (12.7-16.0) 10.5±0.6 (10.0-11.5) V/T 40.7 42.1±1.2 (40.7-43.5) 59.5±1.9 (56.9-61.2) G1 27.2 27.7±1.8 (25.2-30.7) -- G2 32.3 27.4±2.7 (24.2-32.3) -- Lip height 3 3±0 (3-3) 3±0 (3-3) Lip diam. 12 12.1±0.7 (11-13) 10.2±0.9 (9-11) Stoma length 11 11.3±0.8 (10-12) 10±0 (10-10) Stoma diam. 8 8.6±0.5 (8-9) 6.2±0.5 (6-7) Pharynx length 138 135.6±5.8 (125-142) 123.7±2.9 (120-127) Nerve ring-ant. 91 93.3±3.2 (88-97) 84.7±2.8 (81-88) end Secretory- 116 113.0±6.8 (105-125) 100.2±4.5 (97-107) excretory pore- ant. end Rectum length 20 25.0±3.3 (20-30) 19.0±1.8 (17-21) Anal body 20 18.5±1.5 (16-20) 18.5±1.9 (16-20) diam. Tail length 275 264.1±28.5 (230- 194.0±12.7 (182-209) 305) Egg dimension 35 x 25 35.6±1.9 x 23.4±2.0 -- (33-38 x 20-25) Spicules length -- -- 20.5±0.5 (20-21) Gubernaculum -- -- 8.0±0.8 (7-9) length

117 Fig 21. Oigolaimella indica sp. n. A: Entire female. B: Entire male. C: Female anterior region. D: Female pharyngeal region. E. Female reproductive system. F: Female posterior region. G: Male posterior region.

118 Fig. 22. Oigolaimella indica sp. n. (Female). A-C: Anterior end. D: Anterior pharyngeal region. E: Posterior pharyngeal region. F: Anterior genital branch. G: Vulval region. H: Anal region (Scale bars= 10 μm).

119 Fig. 23. Oigolaimella indica sp. n. (Male). A: Anterior region. B: Genital branch. C: Cloacal region showing spicules and gubernaculum. D, E: Posterior region showing genital papillae (Scale bars= 10 μm).

120 Suborder: Tylenchina Thorne, 1949

Diagnosis. Rhabditida. Wide group of free-living bacteriovores, fungal-feeders and parasitic forms (parasites of plants, insects, annelids, molluscs and vertebrates mainly amphibians and reptiles). Body small to large-sized, slender, stout or obese. Cuticle smooth or finely to strongly annulated, sometimes with double cuticle. Transverse annulations generally interrupted by longitudinal striations. Lip region distinctly offset or continuous with the body. Amphids indistinct, rarely visible. Stoma fine needle-like protrusible stylet to non-protrusible tubular stoma depending on the kind of feeding habits. Pharynx with cylindrical corpus; metacorpus present or absent; if present, with well developed valve plates; basal bulb variable in shape, from round to oval or pyriform, sometimes elongate forming an overlap over intestine with or without valve/ grinder. Female reproductive system didelphic, amphidelphic or monodelphic, prodelphic with post-uterine sac; spermatheca axial or distinctly offset. Males present rarely absent, monorchic, genital papillae present or absent. Bursa present, sometimes rudimentary or absent.

Type infraorder: Tylenchomorpha De Ley & Blaxter, 2002

Other infraorders

Cephalobomorpha De Ley & Blaxter, 2002

Drilonematomorpha De Ley & Blaxter, 2002

Panagrolaimomorpha De Ley & Blaxter, 2002 Key to infraorders of Tylenchina Thorne, 1949

1. Parasites of plants; stoma stylet-shaped; pharynx with cylindrical corpus, median bulb with valve plates, basal bulb pyriform to elongate sometimes forming an overlap over intestine …………………...... Tylenchomorpha

2. Free-living bacterial feeders; stoma elongate, narrow, tubular; pharynx with cylindrical corpus without metacorpus, basal bulb with grinder …………………………………………………………... Cephalobomorpha

3. Parasites of annelids; stoma small, tubular, weakly cuticularised walls; pharynx with cylindrical corpus strong basal bulb …….. Drilonematomorpha

4. Free-living bacterial feeders and parasites of insects and vertebrates; stoma of various shapes, partially narrow, unarmed or with small denticles; pharynx

121 with cylindrical corpus, with/ without metacarpus and well-developed basal bulb ………………………………………………….. Panagrolaimomorpha Infraorder: Cephalobomorpha De Ley & Blaxter, 2002

Diagnosis. Tylenchina. Lip region offset, often bearing projections (probolae) of various shapes and appearances. Lips three or six, mostly separate. Amphids minute, pore-like, on lateral lips. Stoma narrow, elongate; cheilostom rounded to oval, cuticularised; gymnostom shorter than cheilostom and stegostom about 75-80% of stoma length, surrounded by pharyngeal collar. Metastegostom with a minute tooth- like projection on dorsal wall. Pharynx with well separated corpus and isthmus, basal bulb well developed with grinder. Excretory pore conspicuously distinct along with some part of excretory duct. Female reproductive system monodelphic, prodelphic, ovarian flexure beyond vulva. Spermatheca generally offset, present at anterior flexure of gonad. Spicules robust, separate, gubernaculum present. Male genital papillae papilloid, arranged in pairs. Bursa absent. Tail generally short, conoid. Phasmids visible.

Type superfamily: Cephaloboidea Filipjev, 1934

Other superfamily

Chambersielloidea2 Thorne, 1937 Key to superfamilies of Cephalobomorpha De Ley & Blaxter, 2002

1. Lip region with complex processes or probolae; stoma quite narrow with distinct cuticularized parts ………………………………….. Cephaloboidea

2. Lip region with two to six cirri; labial papillae setiform; stoma more or less spacious with cheilo- and gymnostom wider than stegostom ………………………………………………..……………. Chambersielloidea

Superfamily: Cephaloboidea Filipjev, 1934

Diagnosis. Cephalobomorpha. Cuticle distinctly annulated. Lip region varies from simple amalgamated type to those having elaborate modified structures. Stoma narrow with uniformly cuticularised parts, metastegostom with or without tooth or denticle. Pharynx with cylindrical corpus without metacorpus, narrower isthmus and

2 According to the classification of Andrássy (2005) as the taxon was not indicated in the new scheme.

122 basal bulb with grinder. Female reproductive system monodelphic, prodelphic, ovary reflexed extending beyond vulva, postvulval part sometimes showing double flexures; spermatheca offset, present anterior to flexure. Testis single, reflexed. Spicules ventrally curved with velum and capitulum. Gubernaculum present. Bursa absent. Genital papillae present or absent.

Type family: Cephalobidae Filipjev, 1934

Other families

Alirhabditidae Suryawanshi, 1971

Bicirronematidae Andrássy, 1978

Elaphonematidae Heyns, 1962

Osstellidae Heyns, 1962 Key to families of Cephaloboidea Filipjev, 1934

1. Stoma elongate, very narrow with distinct cuticularized parts; cephalic and labial probolae present with labial probolae larger …………… Cephalobidae

2. Stoma very long and narrow without distinct parts; cephalic and labial probolae absent ……………………………………………….. Alirhabditidae

3. Stoma with wider anterior and narrower posterior part; cephalic and labial probolae absent but head with two lateral ciliated cirri ………………………………………………………..…..... Bicirronematidae

4. Stoma moderately long, not tubular without distinct parts; cephalic and labial probolae present with cephalic probolae larger, leaf-shaped ………………………………………………………..……. Elaphonematidae

5. Stoma very small or practically absent; cephalic and labial probolae absent …………………………………………………………………….. Osstellidae Family: Cephalobidae Filipjev, 1934

Diagnosis. Cephaloboidea. Cuticle transversely annulated. Lateral fields with sharp border, occasionally divided by longitudinal lines. Lip region with three labial probolae and six cephalic probolae. Amphids located on lateral lips, hardly visible under LM. Stoma tubular, generally very narrow, with distinct cheilo-, gymno- and stegostom, uniformly cuticularized; cheilostom wider than others. Metastegostom

123 with minute tooth-like projection on dorsal wall. Pharynx consisting of cylindrical corpus, narrower isthmus and strong basal bulb with grinder and haustrulum. Female reproductive system monodelphic, prodelphic, ovary reflexed far posterior to vulva, its postvulval section in most cases with double flexures. Vulva post-equatorial. Post- uterine sac present, generally short, rarely absent. Males nearly as frequent as females. Spicules robust. Genital papillae present. Phasmids distinct. Tail similar in both sexes, short conoid to elongate conoid.

Type genus: Cephalobus Bastian, 1865

Other genera

Acrobeles Linstow, 1877

Acrobeloides Cobb, 1924

Acrolobus Boström, 1986

Acroukrainicus Holovachov, Boström & Susulovsky, 2001

Cervidellus Thorne, 1937

Chiloplacoides Heyns, 1994

Chiloplacus Thorne, 1937

Cribronema Siddiqi, 1993

Eucephalobus Steiner, 1936

Heterocephalobellus Rashid, Geraert & Sharma, 1985

Metacrobeles Loof, 1962

Metacrolobus Vinciguerra, 1994

Nothacrobeles Allen & Noffsinger, 1971

Panagrolobus Holovachov & Boström, 2006

Panagroteratus Andrássy, 1986

Paracrobeles Heyns, 1968

Placodira Thorne, 1937

Pseudacrobeles Steiner, 1938

Scottnema Timm, 1971

124 Stegelleta Thorne, 1938

Stegelletina Andrássy, 1984

Teratolobus Andrássy, 1968

Zeldia Thorne, 1937

125 Genus: Acrobeles von Linstow, 1877

Diagnosis. Cephalobidae. Medium- to large-sized nematodes. Cuticle single or double, usually with prominent transverse annulations, with or without longitudinal lines, punctations or pores. Lateral fields with three to four incisures. Amphids relatively distinct, elliptical. Labial probolae long, deeply bifurcated. Each prong with at least seven tines, its tip usually with two elongate, separated apical tines. Cephalic probolae high, triangular, fringed by numerous tines, demarcated by equally deep cephalic axils. Primary axils with two guard processes resembling tines. Radial ridges each with dentate process. Stoma cephaloboid, cheilostom cuticularized. Pharyngeal corpus cylindrical to fusiform, basal bulb with grinder and haustrulum. Secretory- excretory pore located anterior to or at level of basal bulb. Female reproductive system monodelphic, prodelphic, ovary reflexed, flexure extending beyond vulva. Spermatheca offset. Post-uterine sac present. Males with three pairs of precloacal and five pairs of postcloacal genital papillae and one median papilla on the pre-cloacal lip. Tail in both sexes conical, usually with acute tip. Phasmids in male usually at anterior to posterior two-third level of tail.

Type species: Acrobeles ciliatus von Linstow, 1877

Other species

A. andalusicus Abolafia & Peña-Santiago, 2004

A. annulatus Heyns & Hogewind, 1969

A. bushmanicus Heyns, 1969

A. canalis Andrássy, 1985

A. capensis Heyns, 1969

A. cephalatus (Cobb, 1901) Thorne, 1925

A. chelatus Thomas & Allen, 1965

A. complexus Thorne, 1925

A. crossotus Steiner, 1929

A. ctenocephalus Thorne, 1925

A. cylindricus Ivanova, 1968

A. dimorphus Heyns & Hogewind, 1969

126 A. elaboratus Thorne, 1925

A. emmatus Shahina & De Ley, 1997

A. ensicaudatus Thomas & Allen, 1965

A. farzanae Heyns, 1995

A. geraerti (Rashid, Heyns & Coomans, 1990) Shahina & De Ley, 1997

A. ilidzensis Paesler, 1941

A. iranicus Shokoohi, Abolafia & Zad, 2007

A. kotingotingus Yeates, 1967

A. mariannae Andrássy, 1968

A. oasiensis Boström, 1985

A. ornatus Thorne, 1925

A. proximus Andrássy, 1964

A. raoi Kannan, 1961

A. recurvus Heyns, 1969

A. seelyae Rashid, Heyns & Coomans, 1990

A. serricornis Thorne, 1925

A. sheasbyi Heyns & Hogewind, 1969

A. singulus Heyns, 1969

A. sparsus Heyns, 1969

A. taraus Yeates, 1967

A. thornei Heyns, 1963

A. timmi Chaturvedi & Khera, 1979

A. undulatus Loof, 1964

A. welwitschiae (Rashid, Heyns & Coomans, 1990) Shahina & De Ley, 1997

A. zapatai Mundo-Ocampo, Baldwin, Dorado-Ramirez & Morales-Ruiz, 2003

127 Acrobeles complexus Thorne, 1925

(Figs. 24, 25, 26)

Description

Measurements. Table 9.

Female: Medium-sized nematodes with body slightly arcuate upon fixation, tapering more towards posterior end. Cuticle double, 2 μm thick, inner and outer layers with prominent transverse annulations, annules 1.5 to 2.0 μm wide in different parts of body. Lateral fields 5-6 μm wide appearing as four incisures under LM: inner two crenate and outer two straight. Lateral fields appearing a single band under SEM indicating crenate lines to be optical illusion under LM. Lip region offset; lips with six labial and four cephalic papilliform sensilla. Labial probolae three, 9-10 μm high, bifurcated to about 40-45% of its length, bearing 5-6 tines on outer and 4-5 tines on inner edges excluding terminal ‘T’-shaped tine. Cephalic probolae six, demarcated by primary and secondary cephalic axils. Primary cephalic axils with larger guarding processes. Each cephalic probola with 7-8 tines along its edges and one terminal tine; fourth tine of the complementary cephalic probolae towards primary cephalic axil largest and attenuated. Amphidial openings circular with prominent outline, at base of lateral lips. Stoma cephaloboid type; cheilostom cuticularised, ovoid, 2-3 μm long; gymnostom smaller than cheilostom, 1.5-2.0 μm long; stegostom with usual parts: prostegostom with thick and parallel walls, mesostegostom thin walled, metastegostom with minute denticle on dorsal wall, telostegostom widest with dorsal wall thicknings. Pharyngeal collar 11-12 μm or covering 80-85% of stoma from base. Pharynx cephaloboid type: 111-123 μm long cylindrical, slightly swollen corpus with wide lumen, demarcated from isthmus by a constriction; 23-36 μm long isthmus and ovoid basal bulb of 31-33 μm x 21-25 μm dimension with grinder and single- chambered haustrulum. Corpus almost double the length of isthmus and basal bulb together. Nerve ring encircling isthmus in anterior half at 67.9-72.2% of pharyngeal length from anterior end. Secretory-excretory pore at level of nerve ring or slightly posterior, at 72.7-75.3% of pharyngeal length from anterior end. Hemizonid indistinct. Dierids in middle of incisures, at level of isthmus-basal bulb junction. Cardia small, conoid, 2-5 μm long. Intestine thin-walled with wide lumen. Two pseudocoelomocytes present in vicinity of gonad: one closely anterior to offset

128 spermatheca and another close to junction of oviduct and spermatheca. Rectum 1.2- 1.4 times anal body diam. long. Rectal glands present. Anus a crescent-shaped slit. Tail uniformly sigmoid-conoid, with acute tip, 2.8-3.2 times anal body diam. long. Phasmids one anal body diam. posterior to anus.

Reproductive system cephaloboid-type, monodelphic, prodelphic; ovary dorsally reflexed, on right side of intestine; flexure extending far posterior to vulva. Oocytes arranged in single row; constriction at ovary-oviduct junction. Oviduct thick, as long as spermatheca. Spermatheca offset, elongate, 30-60 μm long, filled with sperm cells. Uterus with glandular and muscular parts. Vagina usually obliquely oriented, 11-16 μm long or 2.3-2.9 times corresponding body diam. Vulva slightly post-equatorial, at 57.0-59.8% from anterior end, vulval lips not protruded. Post- uterine sac present, 2.1-2.9 times vulval body diam. long. Uterine eggs not observed.

Male: Similar to female but strongly arcuate in cloacal region. Testis single, ventrally reflexed, flexure on right side of intestine; distal tip cell conspicuous, spermatocytes arranged in 2-3 rows distally and single row proximally. One pseudocoelomocyte closely anterior to flexure. Seminal vesicle with growing sperm cells. Ejaculatory glands indistinct. Spicules arcuate, cephalated with rounded head and ventral conoid process, a pointed distal end. Gubernaculum trough-shaped, almost 50% of spicule length, proximally curved and distally with lateral flaps. Tail strongly arcuate, short and conoid with pointed tip. Postcloacal lip large and swollen. Genital papillae eight pairs arranged in 1+1+1/1+1+(1+2) configuration: GP1 ventro-sublateral, two times spicule length anterior to cloaca; GP2 ventro-sublateral, closely anterior to spicule head; GP3 ventro-sublateral at level of two-third of spicule length. Among postcloacals, GP4 subventral, 4-5 annules posterior to cloaca; GP5 lateral, closely anterior to phasmids; GP6 subdorsal, GP7 subventral and GP8 lateral, all three far posterior to cloaca almost near tail tip.

Locality and habitat: Samples containing Acrobeles complexus Thorne, 1925 were obtained from rotten leaves at Keetham lake, Agra, Uttar Pradesh, India at coordinates 27°15.153’ N 077°51.219’ E.

Voucher specimens: Eight females and eight males on slides Acrobeles complexus Thorne, 1925 KL2-16/1-5 deposited in Nematode Collection, Department of Zoology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.

129 Remarks: A. complexus is a cospolitan species hence it shows wide range of values due to variable geographical locations. The present population shows conformity to A. complexus Thorne, 1925 in most morphometric and morphological characteristics with minor differences. The females possess elongate and slender guarding processes; vulval lips not protruded and males with five pairs of postcloacal genital papillae whereas guarding processes in form of cutinous points; vulval lips protruded and four pairs of postcloacal genital papillae are stated in original description of species by Thorne (1925). Rashid et al. (1990) reported faint longitudinal striae, gubernaculum with hooked distal tip and unusually long (172 μm) post-uterine sac. The present population shows some minor differences with population reported by Shokoohi et al. (2007) viz., rectum 1.2-1.4 times (vs 0.8-1.0 times) anal body diam. long; gubernaculum with (vs without) lateral flaps and three (vs two) pairs of precloacal genital papillae in Shokoohi et al. (2007).

130 Table 9. Morphometric characteristics of Acrobeles complexus Thorne, 1925. Measurements are in µm and in the form: mean±standard deviation (range).

Character Female Male (n=8) (n=8) Body length 685.7±41.7 (610-753) 671.0±21.8 (640-706)

Body diam. 34.3±1.6 (33-37) 32.5±2.1 (30-37) a 19.9±1.2 (18.4-21.4) 20.6±0.8 (19.0-21.5) b 3.7±0.1 (3.6-4.0) 3.7±0.08 (3.7-3.9) c 10.7±0.8 (9.9-12.4) 12.4±0.6 (11.7-13.8) c’ 2.9±0.1 (2.8-3.2) 2.0±0.1 (1.8-2.2)

V/T 58.5±0.9 (57.0-59.8) 59.5±2.4 (55.4-61.6)

G1 53.6±4.3 (47.8-59.6) --

Post uterine sac 88.2±12.4 (68-108) --

Lip height 8.0±0.7 (7-9) 7.3±0.5 (7-8)

Lip diam. 14.8±0.3 (14-15) 14.2±0.7 (13-15)

Stoma length 14.5±0.7 (13-15) 13.1±0.6 (12-14)

Stoma diam. 1.3±0.5 (1-2) 1.5±0.5 (1-2)

Pharynx length 179.6±7.5 (166-187) 174.8±5.2 (169-186)

Nerve ring-ant. end 123.7±2.6 (120-127) 118.0±3.4 (112-122)

Secretory-excretory pore- 131.0±3.4 (125-136) 130.2±5.9 (122-140) ant. end

Rectum length 28.2±2.4 (25-32) 30.8±3.0 (27-36)

Anal body diam. 21.1±0.9 (20-22) 25.8±1.2 (24-28)

Tail length 63.7±5.0 (56-69) 53.7±3.0 (48-57)

Spicules length -- 40.6±1.9 (38-44)

Gubernaculum length -- 20.1±1.2 (18-22)

131 Fig 24. Acrobeles complexus Thorne, 1925 A: Entire female. B: Entire male. C: Female anterior region (lateral view). D: Female anterior region (surface view). E: Female pharyngeal region. F: Female reproductive system. G: Female posterior region. H: Male posterior region.

132 Fig. 25. Acrobeles complexus Thorne, 1925 (Female). A: En face view (scanning electron microscopy). B, C: Anterior end (scanning electron microscopy). D, E: Anterior end. F: Posterior pharyngeal region. G: Lateral fields. H: Lateral fields (scanning electron microscopy). I: Offset spermatheca. J: Vulval region. K: Post-uterine sac. L: Posterior end. M: Posterior end (scanning electron microscopy) (Scale bars= 10 μm).

133 Fig. 26. Acrobeles complexus Thorne, 1925 (Male). A: Anterior end. B: Posterior pharyngeal region. C: Genital branch. D-F: Posterior region. G, H: Posterior region (scanning electron microscopy) (Scale bars= 10 μm).

134 Genus: Chiloplacus Thorne, 1937

Diagnosis. Cephalobidae. Medium- to large-sized nematodes. Cuticle annulated. Lateral field with 3-5 incisures; ending at the tail terminus. Lip region slightly offset. Pairs of lips separated by weak or well-developed primary axils; guarding processes usually absent; secondary axils weakly developed. Cephalic probolae absent, small setose, rectangular or conical. Labial probolae blunt or elongate-conoid with broad basis, bicornuate or biacute to a certain degree. Six outer labial and four cephalic papilliform sensilla arranged in a cephaloboid manner. Amphidial aperture slit-like or rounded, located on lateral lips. Stoma divided into cheilo-, gymno- and stegostom: cheilostom cuticularised; gymnostom weakly developed, as wide as stegostom; stegostom consists of a funnel-shaped prostegostom and variably shaped meso-, meta and telostegostom. Metastegostom with minute denticle usually present. Pharynx cephaloboid; procorpus cylindrical; metacorpus not differentiated; strongly developed basal bulb with grinder and haustrulum. Nerve ring encircling corpus or isthmus. Excretory pore in isthmus region. Dierids present. Female reproductive system monodelphic; prodelphic; posterior part of ovary occasionally with double flexure; spermatheca present, offset; postvulval uterine sac present. Male with single testis. Genital papillae present, variable in number. Phasmids located at mid level of tail in both sexes. Tail short, conoid with bluntly rounded terminus of variable thickness.

Type species: Chiloplacus symmetricus (Thorne, 1925) Thorne, 1937

Other species

C. bathycolpus Andrássy, 1967

C. bisexualis (Micoletzky, 1916) Thorne, 1937

C. coarticaudatus Truskova, 1972

C. demani (Thorne, 1925) Thorne, 1937

C. denticulatus (Thorne, 1925) Thorne, 1937

C. hexalineatus Ali & Joshi, 1969

C. incurvus (Thorne, 1925) Thorne, 1937

C. indicus Ali & Joshi, 1969

C. insularis Orselli & Vinciguerra, 2002

135 C. jodhpurensis Rathore & Nama, 1992

C. kralli Bagaturija, 1973

C. lentus (Maupas, 1900) Thorne, 1937

C. longiuterus Rashid & Heyns, 1990

C. maginensis Abolafia & Pena-Santiago, 2003

C. magnus Rashid & Heyns, 1990

C. membranifer Holovochov, 2012

C. mongolicus Andrássy, 1984

C. obsticaudatus (Kreis, 1930) Thorne, 1937

C. obtusus Baranovskaja & Khak, 1968

C. paradoxus Nesterov, 1973

C. propinquus (de Man, 1921) Thorne, 1937

C. quadricarinatus (Thorne, 1925) Thorne, 1937

C. quinquesulcus Ivanova, 1968

C. quintastriatus Sumenkova & Razzhivin, 1968

C. saccatus Loof, 1971

C. scelerovaginatus Sumenkova & Razzhivin, 1968

C. serenus (Kirjanova, 1951) Andrássy, 1959

C. similis Holovochov, 2012

C. subtenuis Rashid & Heyns, 1990

C. tauricus Holovachov, 2010

C. tenuis Rashid & Heyns, 1990

C. topali Andrássy, 1963

C. trifurcatus (Thorne, 1925) Thorne, 1937

C. trilineatus Steiner, 1940

C. truncatus (Thorne, 1925) Thorne, 1937

136 Chiloplacus subtenuis Rashid & Heyns, 1990

(Figs. 27, 28, 29)

Description

Measurements. Table 10.

Female: Medium-sized nematodes with body slightly curved upon fixation, blunt at both ends. Cuticle 1.0-1.5 μm thick with prominent transverse annulations, annules 2.0-2.5 μm wide in different parts of body. Lateral fields 5-6 μm wide with four ridges/ five incisures. Lip region slightly offset; lips with labial and cephalic sensilla papilliform. Primary axils deep without guarding process and secondary axils marked by a fine fissure. Labial probolae three, 3-4 μm high, bicornuate with broad base and rounded edges. Amphidial openings eliptical, at base of lateral lips (visible in SEM). Stoma cephaloboid-type: cheilostom cuticularised, rounded; gymnostom short, weakly-cuticularised, 1-2 μm long; stegostom 80-85% of stoma length; prostegostom with parallel walls, mesostegostom thin-walled, metastegostom with dorsal wall without denticle, telostegostom weakly cuticularised, almost indistinct, continuous with pharyngeal lumen. Pharyngeal collar 8-10 μm long covering 80-85% of stoma from its base. Pharynx cephaloboid-type with 125-145 μm long cylindrical corpus without any distinct metacorpus; 23-25 μm long isthmus and ovoid basal bulb of 21- 23 μm x 15-18 μm dimension with grinder and single-chambered haustrulum. Corpus 2.5-3.0 times longer than isthmus and basal bulb together. Nerve ring encircling posterior corpus at 62.1-66.3% of pharyngeal length from anterior end. Secretory- excretory pore at level or slightly posterior to nerve ring at 67.8-69.4% of pharyngeal length from anterior end. Secretory-excretory duct cuticularized. Hemizonids one or two annules posterior to secretory-excretory pore. Dierids posterior to secretory- excretory pore in region of posterior corpus or at level of corpus-isthmus junction. Cardia small, 2-5 μm long. Intestinal wall thin, intestinal lumen wide. Rectum 1.0-1.2 times anal body diam. long. Rectal glands present. Anus a crescent-shaped slit. Tail short and cylindrical with bluntly rounded tip, 1.7-2.0 times anal body diam. Phasmids at mid level of tail. Vulva-anus distance 5.1-5.5 times tail length.

Reproductive system cephaloboid-type, monodelphic, prodelphic; ovary dorsally reflexed, on right side of intestine; flexure reaching beyond vulva. Oocytes arranged in two rows. Oviduct short, almost indistinct. Spermatheca offset, elongate,

137 65-75 μm long, filled with sperms. Muscular part of uterus thick-walled, connected to 87-104 μm long post-uterine sac. Vagina thick-walled, usually obliquely oriented, 12- 15 μm long or one-fourth of corresponding body diam. Vulva post-equatorial, at 66.1- 69.2% from anterior end, vulval lips slightly protruded. Uterine eggs not observed.

Male: Similar to female except strong body curvature in cloacal region. Testis single, ventrally reflexed, flexure on left side of intestine; spermatocytes arranged in 2-3 rows. Seminal vesicle with dense and compactly arranged developing spermatozoa. Ejaculatory glands present. Spicules elongate, slightly arcuate with narrow head and pointed distal tip. Gubernaculum trough-shaped, 48-50% of spicule length with broad and curved proximal part and pointed distal part. Tail ventrally arcuate, short and conoid with bluntly rounded tip. Postcloacal lip large and swollen. Genital papillae eight pairs, arranged in 1+1+1+1/1+1+1+1 configuration. GP1 latero-subventral, 2 times spicule length anterior to cloaca; GP2 latero-subventral, 1.5 times spicule length anterior to cloaca; GP3 latero-subventral, at level of spicule head; GP4 subventral, closely anterior to cloaca. Among postcloacals, GP5 subventral, at midlevel of tail; GP6 lateral, closely anterior to phasmids; GP7 subdorsal and GP8 subventral, closely anterior to tail tip.

Locality and habitat: Samples containing Chiloplacus subtenuis Rashid and Heyns, 1990 were obtained from base of a tree trunk at Keetham lake, Agra, Uttar Pradesh, India at coordinates 27°15.263’ N 077°50.984’ E.

Voucher specimens: Seven females and nine males on slides Chiloplacus subtenuis Rashid and Heyns, 1990 KL-30/1-7 deposited in Nematode Collection, Department of Zoology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.

Remarks: The allometric ratios totally conform with those of original population (Rashid and Heyns, 1990) and subsequent population described from India by Tahseen et al. (1999). However, areolations are absent in the present population as reported by Tahseen et al. (1999). Present population also shows obscure/ faintly visible genital papillae.

138 Table 10. Morphometric characteristics of Chiloplacus subtenuis Rashid & Heyns, 1990. Measurements are in µm and in the form: mean±standard deviation (range).

Character Female Male

(n=7) (n=9)

Body length 781.0±35.2 (731-826) 698.4±78.7 (605-812)

Body diam. 33.7±1.9 (31-37) 29.3±4.3 (20-35) a 23.1±1.0 (21.4-24.7) 24.1±3.4 (18.3-30.3) b 4.0±0.2 (3.7-4.4) 3.9±0.2 (3.6-4.6) c 19.0±0.9 (17.7-20.7) 16.8±1.5 (14.4-18.4) c' 1.9±0.1 (1.7-2.1) 1.7±0.1 (1.6-2.1)

V/T 67.8±1.0 (66.1-69.2) 55.7±3.7 (49.7-61.6)

G1 52.1±5.9 (40.3-59.3) --

Post-uterine sac 92.8±5.9 (87-104) --

Lip height 3.7±0.4 (3-4) 3.3±0.5 (3-4)

Lip diam. 10.1±0.3 (10-11) 9.3±0.5 (9-10)

Stoma length 12.2±0.9 (11-14) 11.4±1.3 (10-14)

Stoma diam. 1±0 (1-1) 1±0 (1-1)

Pharynx length 190.5±8.6 (177-199) 172.6±12.2 (155-194)

Nerve ring-ant. end 123.1±7.0 (110-132) 114.2±7.3 (106-128)

Secretory-excretory pore- 128.8±4.5 (123-135) 121.8±10.0 (112-139) ant. end

Rectum length 24.8±1.3 (23-26) 29.4±3.8 (22-36)

Anal body diam. 21.1±1.9 (19-25) 22.7±2.2 (18-25)

Tail length 41.0±2.6 (37-43) 41.4±3.6 (37-48)

Spicules length -- 33.3±2.9 (29-37)

Gubernaculum length -- 18.1±1.6 (15-20)

139 Fig 27. Chiloplacus subtenuis Rashid and Heyns, 1990 A: Entire female. B: Entire male. C: Female anterior region D: Female pharyngeal region. E: Female reproductive system. F: Female posterior region. G: Male posterior region.

140 Fig. 28. Chiloplacus subtenuis Rashid & Heyns, 1990 (Female). A: En face view (scanning electron microscopy). B, C: Anterior end (scanning electron microscopy). D: Anterior end. E: Posterior pharyngeal region. F: Vulval region (scanning electron microscopy). G: Lateral fields (scanning electron microscopy). H, J: Vulval region. I: Genital branch showing flexure. K: Posterior end. L: Posterior end (scanning electron microscopy) (Scale bars= 10 μm).

141 Fig. 29. Chiloplacus subtenuis Rashid & Heyns, 1990 (Male). A: Anterior end. B: Posterior pharyngeal region. C: Lateral fields. D-F: Posterior end showing spicules. G, H: Posterior end (scanning electron microscopy) (Scale bars= 10 μm).

142 Family: Osstellidae Heyns, 1962

Diagnosis. Cephaloboidea. Cuticle annulated. Lateral fields with two to four ridges. Lip region slightly to strongly offset, with/ without cuticularised framework. Lips small, amalgamated. Amphidial opening large oval to transverse slit. Stoma small to minute, tubular without cuticularized components or practically indistinct. Pharynx cephaloboid-type but not distinctly sub-divided into sections, procorpus cylindrical, metacorpus slightly fusiform, isthmus narrower than metacorpus, basal bulb weakly developed without valvular apparatus. Female reproductive system monodelphic, prodelphic, ovary reflexed, ovarian flexure reaching beyond vulva. Spermatheca offset. Post-uterine sac present. Genital papillae present or absent in males. Tail in both sexes short conoid or elongate conoid, tail terminus finely rounded to sharp, spicate.

Type genus: Osstella Heyns, 1962

Other genus

Deficephalobus De Ley & Coomans, 1990

Drilocephalobus Coomans & Goodey, 1965

143 Genus: Drilocephalobus Coomans & Goodey, 1965

Diagnosis. Osstellidae. Cuticle annulated, without distinctly annulated internal layer, annuli smooth. Lateral field with 3-5 incisures. Lip region offset, rounded, lips fused. Six outer labial and four cephalic sensilla papilliform. Amphidial aperture wide, slit- like, extending across lateral sides of the head. Stoma small, undifferentiated; cheilostom small; gymnostom and stegostom not developed. Pharynx cephaloboid but not distinctly subdivided into sections: corpus cylindrical; metacorpus not distinctly separated, slightly fusiform; isthmus narrower than metacorpus; basal bulb elongate- ovoid, weakly developed. Nerve ring encircling isthmus. Excretory pore located at level of nerve ring. Deirids present or absent. Female reproductive system cephaloboid, monodelphic, prodelphic; posterior part of ovary straight; spermatheca offset; postvulval uterine sac present. Males with single testis. Genital papillae absent or present, variable in number. Phasmids located at mid level of tail in both sexes. Tail conoid or elongate conoid, straight, tail terminus bluntly or finely rounded to acute type.

Type species: Drilocephalobus congoensis Coomans & Goodey, 1965

Other species

D. alykhani Siddiqi, 2001

D. brevicercus Siddiqi, 2001

D. cameroonensis Siddiqi, 2001

D. coomansi Ali, Suryawanshi & Chisty, 1973

D. filicauda Siddiqi, 2001

D. goodeyi Ali, Suryawanshi & Chisty, 1973

D. moldavicus Lisetskaya, 1968

D. vicinus Siddiqi, 2001

D. ziauddini Siddiqi, 2001

144 Drilocephalobus mustaqimi sp. n.

(Figs. 30, 31, 32)

Description

Measurements. Table 11.

Female: Small-sized nematodes with body straight to slightly curved upon fixation, tapering towards posterior end. Cuticle 1 μm thick with transverse annulations, annules 1 μm wide. Lateral fields 1-2 μm wide with two ridges (three incisures) in mid body merging into one ridge anteriorly and posteriorly. Lip region offset, dome- shaped; lips fused. Inner labial sensilla indistinct. Outer labial and cephalic sensilla papilliform. Amphidial openings transverse slit, at base of lateral lips, almost occupying corresponding body diam. Stoma very small, almost indiscernible under LM, appearing not deeper than cuticle thickness. Pharynx cephaloboid but not distinctly subdivided into sections: corpus cylindrical; metacorpus not distinctly separated, slightly fusiform; isthmus narrower than metacorpus; basal bulb elongate- ovoid, weakly developed. Pharyngeal area showing aggregation of cells in pseudocoelom. Nerve ring at 58.4-63.2% of pharyngeal length from anterior end. Secretory-excretory pore slightly posterior to nerve ring, at 64.9-70.1% of pharyngeal length from anterior end. Large secretory-excretory gland cell lying close to secretory-excretory pore in anterior region of intestine. Hemizonid closely posterior to secretory-excretory pore. Dierids indistinct. Cardia very small, 1-2 μm long. Intestine thin-walled with wide lumen having prominent microvilli visible under LM. Pseudocoelomocytes not observed. Rectum 1.0-1.2 times anal body diam. long. Rectal glands present. Anus a crescent-shaped slit. Tail short conoid with rounded tip, 2.5-3.1 times anal body diam. Phasmids at nearly half of tail length.

Reproductive system cephaloboid type, monodelphic, prodelphic; ovary dorsally reflexed, on right side of intestine; flexure reaching beyond vulva, up to level of rectum. Oocytes arranged in 2-3 rows distally followed by single row proximally. Oviduct short; spermatheca offset, elongate ovoid, 15-24 μm long, filled with sperms; spermatheca separated from uterus by a constriction. Vagina perpendicular to body axis, 4-5 μm long or 25.0-26.6% of corresponding body diam. with thick muscles appearing in cross section. Vulva post-equatorial, 60.3-62.7% from anterior end,

145 vulval lips protruded. Post uterine sac present, 20-26 μm or 1.3 times vulval body diam. long. Uterine eggs not observed.

Male: Similar to female but more curved in posterior body region. Testis single, ventrally reflexed, flexure on right side of intestine with spermatocytes arranged in single row. Pseudocoelomocyte not observed. Seminal vesicle filled with growing spermatozoa. Ejaculatory glands indistinct. Spicules arcuate with slightly elongate head, undifferentiated neck, a ventral conoid process and a ventral velum starting from conoid process and terminating closely anterior to spicule tip. Gubernaculum trough-shaped, almost 50% of spicule length with proximal end slightly curved. Tail short conoid, 2.5-2.9 times anal body diam. Genital papillae seven pairs, one pair precloacal and six pairs postcloacals arranged in 1/1+P+1+1+1+1+1 configuration. GP1 lateral, slightly anterior to cloaca. Among postcloacal pairs, GP2 subventral and GP3 subdorsal, at same level with phasmid; GP4 subdorsal, at mid level of tail; GP5 about one spicule length posterior to cloaca; GP6 subdorsal, slightly anterior to level of subventral GP7 close to tail terminus.

Diagnosis and relationship: Drilocephalobus mustaqimi sp. n. is characterized by small-sized individuals with dome-shaped lip region; lateral fields with two ridges in mid body; small and obscure stoma; amphids often covered by pouch-like protrusions, presumably formed by a gelatinous substance; pharynx covered by compactly arranged cells; a large secretory-excretory gland cell in anterior region of intestine; elongate ovoid spermatheca; protruded vulval lips; distal end of ovary nearly one rectum length anterior to anus; males with one precloacal pair and six postcloacal pairs of genital papillae.

Drilocephalobus mustaqimi sp. n. comes closest to D. moldavicus Lisetskaya, 1968 in most morphometric and morphological characteristics but differs in having females with relatively greater ‘a’ value (16.5-21.8 vs 14.3-17.0); lateral fields with two (vs four) ridges; males smaller (0.27-0.32 mm vs 0.33-0.37 mm) with six pairs of postcloacal genital papillae (vs only five pairs present in D. moldavicus Lisetskaya, 1968).

Drilocephalobus mustaqimi sp. n. comes close to D. congoensis Coomans & Goodey, 1965 in most morphometric and morphological characteristics but differs in having females with greater ‘c’ value (10.1-12.0 vs 10.0); smaller ‘ć’ value (2.5-3.1 vs ~3.5); pharynx covered by compactly arranged cells (vs cells not present); males

146 smaller (0.27-0.32 mm vs 0.33-0.34 mm) with greater ‘a’ value (21.2-24.9 vs 19.0- 21.0); smaller ‘ć’ value (2.5-2.9 vs ~3.0); smaller spicules (14-15 μm vs 16.5 μm); smaller gubernaculum (7-9 μm vs 10 μm); precloacal genital papillae present (vs absent) and postcloacal genital papillae six pairs (vs one pair in D. congoensis Coomans & Goodey, 1965).

Drilocephalobus mustaqimi sp. n. differs from D. coomansi Ali, Suryawanshi & Chisty, 1973 in having females with greater ‘a’ value (16.5-21.8 vs 14.0-16.0); lip region without disc-like structure (vs lip region with disc-like structure); post-uterine sac present (vs absent); males relatively smaller (0.27-0.32 mm vs 0.32-0.35 mm) with relatively greater ‘a’ (21.2-24.9 vs 19.0-22.0) and ‘c’ (10.5-11.5 vs 8.3-10.2) values; smaller ‘b’ value (3.6-4.0 vs 4.4-5.2); spicules relatively smaller (14-15 μm vs 15-18 μm) and seven pairs of genital papillae present (vs genital papillae not observed in D. coomansi Ali, Suryawanshi & Chisty, 1973).

Type locality and habitat: Samples having Drilocephalobus mustaqimi sp. n. were obtained from soil from base of a tree at Keetham lake, Agra, Uttar Pradesh, India at coordinates 27°15.314’ N 077°50.837’ E.

Type specimens: Holotype female, nine paratype females and five paratype males on slides Drilocephalobus mustaqimi sp. n. KL2-1/1-6 deposited in Nematode Collection, Department of Zoology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.

Etymology: The species is named after my father who is a great source of motivation for me.

Remarks: The species is unique in wide variation of male genital papillae in the same population. De Ley & Coomans, 1990 examined only two males of D. moldavicus Lisetskaya, 1968 and gave doubtful explanation of genital papillae. They described one male with single unpaired precloacal genital papilla and another male with paired precloacal genital papillae.

147 Table 11. Morphometric characteristics of Drilocephalobus mustaqimi sp. n. Measurements are in µm and in the form: mean±standard deviation (range).

Character Holotype Paratype Female Paratype Male Female (n=9) (n=5) Body length 298 326.8±19.7 (294-352) 304.8±20.6 (274-324) Body diam. 18 17.2±1.6 (15-20) 13.4±1.3 (11-14) a 16.5 19.0±1.8 (16.5-21.8) 22.8±1.4 (21.2-24.9) b 3.8 3.9±0.2 (3.6-4.4) 3.8±0.1 (3.6-4.0) c 10.2 10.8±0.6 (10.1-12.0) 11.0±0.4 (10.5-11.5) c' 2.9 2.8±0.2 (2.5-3.1) 2.6±0.1 (2.5-2.9) V/T 61.7 61.8±0.6 (60.3-62.7) 48.2±0.8 (47.3-49.6) G1 63.4 55.7±5.7 (47.7-63.4) -- Post-uterine 21 22.1±2.1 (20-26) -- sac Lip height 4 4.2±0.4 (4-5) 4.2±0.4 (4-5) Lip diam. 4 4.8±0.4 (4-5) 4.6±0.5 (4-5) Stoma length 1 1±0 (1-1) 1±0 (1-1) Stoma diam. 1 1±0 (1-1) 1±0 (1-1) Pharynx 77 81.5±3.3 (77-87) 79.2±3.1 (74-82) length Nerve ring- 45 50.0±3.4 (45-55) 48.8±3.1 (45-52) ant. end Secretory- 50 56±4 (50-61) 53.0±2.4 (49-55) excretory pore-ant. end Rectum length 10 11.9±1.7 (10-15) 17.2±1.9 (14-19) Anal body 10 10.4±0.6 (10-12) 10.2±0.8 (9-11) diam. Tail length 29 30.0±1.5 (27-32) 27.6±1.5 (25-29) Spicules -- -- 14.6±0.5 (14-15) length Gubernaculum -- -- 8.2±0.8 (7-9) length

148 Fig 30. Drilocephalobus mustaqimi sp. n. A: Entire female. B: Entire male. C: Female anterior region. D: Female pharyngeal region. E. Female reproductive system. F: Female posterior region. G: Male posterior region.

149 Fig. 31. Drilocephalobus mustaqimi sp. n. (Female). A: Anterior end (scanning electron microscopy). B: Anterior end. C: Anterior region (scanning electron microscopy). D: Pharyngeal region. E: Genital branch. F: Vulval region (scanning electron microscopy). G: Lateral fields (scanning electron microscopy). H: Posterior end (scanning electron microscopy). I: Posterior end (Scale bars= 10 μm).

150 Fig. 32. Drilocephalobus mustaqimi sp. n. (Male). A: Anterior end. B: Pharyngeal region. C, E: Cloacal region showing spicule and gubernaculum. D: Genital branch. F: Posterior end (scanning electron microscopy) (Scale bars= 10 μm).

151 Drilocephalobus saprophilus sp. n.

(Figs. 33, 34, 35)

Description

Measurements. Table 12.

Female: Small-sized nematodes with body slightly curved upon fixation, tapering more towards posterior end. Cuticle 1 μm thick with transverse annulations, annules 0.8-1.0 μm wide. Lateral fields 1-2 μm wide with two ridges/ three incisures in mid body and merging into one ridge anteriorly and posteriorly. Body structures obscured by presence of numerous cells and vacuoles in pseudocoelom particularly in pharyngeal region. Lip region offset, dome-shaped; lips fused. Inner labial sensilla indistinct, outer labial and cephalic sensilla papilliform. Amphidial openings transverse slit, at base of lateral lips, almost occupying corresponding body diam. Stoma very small, almost indiscernible under LM, not deeper than thickness of cuticle. Pharynx cephaloboid but not distinctly subdivided into sections: corpus cylindrical; metacorpus not distinctly separated, slightly fusiform; isthmus narrower than metacorpus; basal bulb elongate-ovoid, weakly developed. Nerve ring located at 60.9-70.0% of pharyngeal length from anterior end. Secretory-excretory pore located at level or slightly posterior to nerve ring at 68.9-74.0% of pharyngeal length from anterior end. Hemizonid present at level of secretory-excretory pore. Dierids located at anterior region of expanded part located between two lateral ridges. Cardia very small, 1-2 μm long. Intestine thin-walled with lumen without conspicuous microvilli. Pseudocoelomocyte not observed. Rectum 1.0-1.3 times anal body diam. long. Rectal glands present. Anus a crescent-shaped slit. Tail elongate conoid with sharp spicate terminal end, 3.3-4.0 times anal body diam. Phasmids present at a level 55-60% posterior to anus.

Reproductive system cephaloboid type, monodelphic, prodelphic; ovary dorsally reflexed, on right side of intestine; ovarian flexure reaching beyond vulva. Oocytes arranged in single row distally with one largely grown oocyte proximally placed. Oviduct short. Spermatheca offset, ovoid, 12-34 μm long, filled with sperms; columella with conspicuous cells. Uterus spacious with thick walls, occasionally with single egg of 41-50 x 16-21 μm dimension. Vagina perpendicular to body axis, 6-8 μm or 33.3-36.3% of corresponding body diam. long. In few specimens, vagina lining

152 conspicuously folded to form epiptygma. Vulva a transverse slit, post-equatorial, 58.9-62.1% from anterior end, vulval lips protruded. Post-uterine sac 20-29 μm or 1.1-1.3 times vulval body diam. long.

Male: Similar to female except being more curved in posterior body region. Testis single, ventrally reflexed, flexure on right side of intestine, spermatocytes arranged in 2-3 rows followed by single row proximally. Pseudocoelomocyte not observed. Seminal vesicle filled with growing spermatozoa. Vas deferens opening into narrower ejaculatory duct. Ejaculatory glands indistinct. Spicules slightly curved, head forming an angular shoulder dorsally, ventral conoid process and pointed distal tip. Gubernaculum trough-shaped, almost 50% of spicule length, slightly curved proximally. Tail elongate conoid, 3.0-3.3 times anal body diam.long with sharp spicate tip. Genital papillae only three pairs postcloacal, arranged in 0/1+P+1+1 configuration: GP1 lateral, slightly posterior to cloaca and anterior to phasmid; GP2 subdorsal, at level of subventral GP3, close to tail tip.

Diagnosis and relationship: Drilocephalobus saprophilus sp. n. is characterized by small-sized individuals with dome-shaped lip region, lateral field with two ridges (three incisures), small and obscure stoma, amphids usually not enveloped by conspicuous gelatinous pouches, small ovoid spermatheca, tail elongate conoid ending in sharp digitate spicate tip, males with only three pairs of postcloacal genital papillae and spicular head forming an angular shoulder dorsally.

Drilocephalobus saprophilus sp. n. comes closest to D. goodeyi Ali, Suryawanshi & Chisty, 1973 in most morphometric and morphological characteristics but differs in having lateral fields with three (vs five) incisures; lip region offset (vs continuous); males smaller (0.34-0.39 mm vs 0.40-0.46 mm) with smaller spicules (15 μm vs 17-19 μm) and genital papillae three pairs postcloacal (vs not reported in D. goodeyi Ali, Suryawanshi & Chisty, 1973).

Drilocephalobus saprophilus sp. n. differs from D. alykhani Siddiqi, 2001 in having relatively smaller females (0.37-0.41 mm vs 0.39-0.45 mm); smaller ‘a’ (18.0- 21.1 vs 21.9-23.6) and ‘ć’ (3.3-4.0 vs 4.6-5.4) values; stoma very small (vs indistinct); post-uterine sac small (20-29 μm vs 30-36 μm) and males present (vs males not found in D. alykhani Siddiqi, 2001).

153 Drilocephalobus saprophilus sp. n. differs from D. cameroonensis Siddiqi, 2001 in having larger females (0.378-0.417 mm vs 0.325-0.375 mm) with smaller ‘a’ (18.0-21.1 vs 23.0-26.0) and ‘ć’ (3.3-4.0 vs 4.0-5.4) values; greater ‘c’ value (8.2-9.6 vs 6.3-7.8); lateral fields with three (vs five) incisures; stoma very small (vs indistinct); males with relatively smaller ‘a’ (22.2-24.8 vs 24.0-26.0) and ‘ć’ value (3.0-3.3 vs 4.0-4.5) values and greater ‘c’ value (8.7-9.9 vs 7.4-7.6 in D. cameroonensis Siddiqi, 2001).

Type locality and habitat: Samples having Drilocephalobus saprophilus sp. n. were obtained from rotten leaves and litter at Keetham lake, Agra, Uttar Pradesh, India at coordinates 27°15.235’ N 077°51.044’ E.

Type specimens: Holotype female, four paratype females and five paratype males on slides Drilocephalobus saprophilus sp. n. KL2-6/1-5 deposited in Nematode Collection, Department of Zoology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.

Etymology: The species epithet ‘saprophilus’ denotes its microhabitat i.e. decaying organic matter.

Remarks: The present population differs in the type of habitat as it obtained from decaying organic matter i.e. rotten leaves and litter whereas D. goodeyi, D. alykhani and D. cameroonensis were reported from soil around roots of Jasminum sambac, from rice field and around ensette roots, respectively.

154 Table 12. Morphometric characteristics of Drilocephalobus saprophilus sp. n. Measurements are in µm and in the form: mean±standard deviation (range).

Character Holotype Paratype Female Paratype Male Female (n=4) (n=5) Body length 407 394.8±16.7 (378-417) 365.8±22.7 (342-397) Body diam. 21 20.2±1.6 (18-22) 15.6±0.8 (15-17) a 19.3 19.5±1.2 (18.0-21.1) 23.4±1.0 (22.2-24.8) b 4 4.1±0.1 (3.9-4.3) 3.6±0.3 (3.2-4.0) c 9.2 9.1±0.5 (8.2-9.6) 9.3±0.4 (8.7-9.9) c' 4 3.6±0.2 (3.3-4.0) 3.1±0.1 (3.0-3.3) V/T 61.6 61.0±1.2 (58.9-62.1) 49.0±1.6 (46.4-50.3) G1 59.9 53.8±6.0 (44.4-59.9) -- Post-uterine sac 26 24.7±3.7 (20-29) -- Lip height 5 4.8±0.4 (4-5) 4.8±0.4 (4-5) Lip diam. 6 5.6±0.5 (5-6) 5±0 (5-5) Stoma length 0.5 0.6±0.2 (0.5-1) 0.6±0.2 (0.5-1) Stoma diam. 0.5 0.5±0 (0.5-0.5) 0.5±0 (0.5-0.5) Pharynx length 100 95.4±6.0 (87-100) 99.4±3.9 (96-105) Nerve ring-ant. end 62 60.6±6.2 (53-70) 58.2±4.4 (53-63) Secretory-excretory 68 65.2±5.9 (60-74) 63.0±2.3 (60-65) pore-ant. end Rectum length 18 15.8±2.2 (12-18) 16±1 (15-17) Anal body diam. 11 11.8±0.8 (11-13) 12.2±0.4 (12-13) Tail length 44 43.0±2.1 (41-46) 38.8±2.5 (36-43) Egg dimension 41 x 21 45.5±6.3 x 18.5±3.5 -- (41-50 x 16-21) Spicules length -- -- 15±0 (15-15) Gubernaculum -- -- 8.6±0.8 (8-10) length

155 Fig 33. Drilocephalobus saprophilus sp. n. A: Entire female. B: Entire male. C: Female anterior region. D: Female pharyngeal region. E. Female reproductive system. F: Female posterior region. G: Male posterior region.

156 Fig. 34. Drilocephalobus saprophilus sp. n. (Female). A: Anterior end (scanning electron microscopy). B, C: Anterior end showing amphidial opening. D: Anterior region showing lateral fields (scanning electron microscopy). E: Pharyngeal region. F: Genital branch with intra-uterine egg. G: Vulval region. H: Vulval region (scanning electron microscopy). I: Lateral fields (scanning electron microscopy). J: Anal region (scanning electron microscopy). K: Lateral fields. L: Posterior end (Scale bars= 10 μm).

157 Fig. 35. Drilocephalobus saprophilus sp. n. (Male). A: Anterior region. B: Genital branch. C, E: Posterior region. D: Cloacal region showing spicule (Scale bars= 10 μm).

158 Superfamily: Chambersielloidea Thorne, 1937

Diagnosis. Cephalobomorpha. Cuticle annulated. Lateral field with single ridge. Lip region slightly offset. Lips six, partly fused at bases. Outer labial sensilla setiform and cephalic sensilla papilliform. Amphidial opening transverse slit, located on lateral lips. Stoma relatively broad, cheilo- and gymnostom cuticularized and wider than stegostom. Pharynx having corpus well separated from isthmus and well developed basal bulb. Tail end usually hook-like dorsally curved.

Type and only family: Chambersiellidae3 Thorne, 1937 Family: Chambersiellidae Thorne, 1937

Diagnosis. Chambersielloidea. Small-sized nematodes. Cuticle finely annulated. Lip region slightly offset. Lips simple, smooth, fused at bases. Amphids small, oval. Stoma divided into two parts: anterior part (cheilo- and gymnostom) relatively spacious and more strongly cuticularized, posterior part (stegostom) narrow and weakly cuticularized. Pharynx with cylindrical corpus, fusiform metacorpus, narrower isthmus and well-developed basal bulb. Female reproductive system cephaloboid- type, monodelphic, prodelphic, ovary reflexed. Spermatheca offset. Male with single testis. Bursa absent. Genital papillae eight pairs.

Type genus: Macrolaimus Maupas, 1900

Other genera

Diastolaimus Rahm, 1928

Macrolaimellus Andrássy, 1966

Cornilaimus Truskova & Eroshenko, 1977

Geraldius Sanwal, 1971

Chambersiella Cobb, 1920

3 Not properly placed in new scheme, therefore, placed as per Andrássy’s (2005) classification.

159 Genus: Macrolaimellus Andrássy, 1966

Diagnosis. Chambersiellidae. Body ventrally arcuate upon fixation. Cuticle distinctly annulated. Lateral field marked by two incisures, fading away just anterior to tail region. Lip region slightly offset from adjoining body. Lips amalgamated, each with a setiform papilla. Cephalic and labial probolae absent. Amphidial opening slit-like, located on lateral lips. Stoma with wider and cuticularised cheilostom; gymnostom as wide as cheilostom with strongly cuticularised; stegostom consist of a funnel-shaped prostegostom and variable shaped meso, meta- and telostom. Pharynx cephaloboid, procorpus and metacorpus cylindrical, distinctly separated from isthmus. Basal bulb oval with grinder and haustrulum. Female reproductive system monodelphic, prodelphic; ovary reflexed; spermatheca offset; postvulval uterine sac present. Male with single testis. Genital papillae eight pairs. Phasmids located at level of anterior part of the tail in females, at around the mid tail in males. Female tail elongate-conoid to subcylindrical, straight or arcuate, tail terminus finely rounded to sharply pointed; male tail conoid, arcuate, tail terminus with long spike-like mucro.

Type species: Macrolaimellus iucundus Andrássy, 1966

Other species

M. crassus Siddiqi, 2002

M. filumicus Siddiqi, 2002

160 Macrolaimellus iucundus Andrássy, 1966

(Figs. 36, 37)

Description

Measurements. Table 13.

Female: Small-sized nematodes with body arcuate to almost ‘C’ shaped upon fixation, narrowing towards both ends, more towards posterior end. Cuticle 1.0-1.2 μm thick with transverse annulations, annules thickness ranging from 0.7-1.5 μm wide in different parts of body. Lateral fields 3-4 μm wide having single ridge/ two incisures. Lip region slightly offset; lips surrounding hexagonal oral aperture, fused at bases. Inner labial sensilla indiscernible, outer labial and cephalic sensilla small setose. Amphids small rounded at base of lateral lips, not visible under LM. Stoma cephaloboid type; cheilostom weakly cuticularised with straight to arched walls, 2-3 μm long or 18-20% of stoma length; gymnostom thick, strongly cuticularised with parallel walls, 1.5-2.0 μm or 16-18% of stoma length; stegostom 6-7 μm long or 65- 68% of stoma length, prostegostom small, mesostegostom funnel-shaped, narrowing at its junction with metastegostom; metastegostom with slightly swollen dorsal wall, telostegostom wider than metastegostom continuous with pharyngeal lumen. Pharyngeal collar 6-7 μm long or covering 65-68% of stoma from its base. Pharynx cephaloboid type with uniformly thick 66-80 μm long cylindrical corpus separated from 12-22 μm long slightly narrower isthmus by a constriction; ovoid basal bulb of 13-17 μm x 10-11 μm dimension with a grinder and single-chambered haustrulum. Corpus almost double the length of isthmus and basal bulb together. Nerve ring encircling posterior corpus at 62.3-63.9% of pharyngeal length from anterior end. Secretory-excretory pore at level or slightly posterior to nerve ring, at 64-67% of pharyngeal length from anterior end. Hemizonid 1-2 annules behind secretory- excretory pore. Dierids at mid level of isthmus. Cardia small, 2-3 μm long. Intestine thick-walled, intestinal lumen narrow. Pseudocoelomocyte not observed. Rectum 1.6- 1.9 times anal body diam. long. Rectal glands small, hardly visible. Anus a crescent- shaped slit. Tail elongate conoid with a sharp pointed tip, 7.2-12.5 times anal body diam. long. Phasmids at level of anus, not discernible under LM.

Reproductive system cephaloboid type, monodelphic, prodelphic; ovary dorsally reflexed, flexure on right side of intestine, extending beyond vulva. Oocytes

161 arranged in single row distally. Oviduct short, perpendicular to body axis. Spermatheca offset, 7-9 μm long filled with sperms. Uterus with differentiated glandular and muscular part. Vagina perpendicular to body axis or very slightly obliquely placed, 5-6 μm or 30-35% of corresponding body diam. Vulva slightly post- equatorial, located at 53.0-57.4% from anterior end, vulval lips not protruded. Post- uterine sac present, 9-19 μm long or slightly smaller to or as long as vulval body diam. One intra-uterine egg of 46 x 15 μm dimension observed in a single specimen.

Male: Not found.

Locality and habitat: Samples containing M. iucundus Andrássy, 1966 were obtained from soil from a ditch at Keetham lake, Agra, Uttar Pradesh, India at coordinates 27°15.313’ N 077°50.730’ E.

Voucher specimens: Ten females on slides M. iucundus Andrássy, 1966 KL5-170/1- 6 deposited in Nematode Collection, Department of Zoology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.

Remarks: The allometric ratios totally conform with original population M. iucundus (Andrássy, 1966) and subsequent population described by (Rashid et al., 1985) Rashid & Gereart, 1987. Cephalonema longicauda was described by Rashid et al. (1985), which was later synonymised with Macrolaimellus iucundus Andrássy, 1966. M. iucundus Andrássy, 1966 was reported to bear small teeth whereas present population shows very fine refractive warts. The present population also does not show double flexure in ovary as in M. iucundus Andrássy, 1966. Nerve ring was reported to be in corpus region as in M. iucundus (apud Rashid et al., 1985) whereas nerve ring was described to be present in isthmus region by Andrássy (1966). In the present population also, nerve ring was observed in corpus region.

162 Table 13. Morphometric characteristics of Macrolaimellus iucundus Andrássy, 1966. Measurements are in µm and in the form: mean±standard deviation (range).

Character Female

(n=10)

Body length 432.2±44.7 (345-496)

Body diam. 16.6±1.7 (14-20) a 26.1±3.0 (21.5-31.0) b 3.9±0.2 (3.5-4.4) c 4.8±0.3 (4.3-5.6) c' 9.7±1.5 (7.2-12.5)

V 54.7±1.5 (53.0-57.4)

G1 29.7±6.5 (19.3-40.0)

G2 3.2±0.6 (2.3-4.3)

Lip height 2.6±0.5 (2-3)

Lip diam. 4.9±0.3 (4-5)

Stoma length 10.1±1.1 (8-11)

Stoma diam. 2±0 (2-2)

Pharynx length 109.6±6.2 (97-117)

Nerve ring-ant. end 67.3±3.2 (62-73)

Secretory-excretory pore-ant. end 69.5±3.3 (65-75)

Rectum length 16.8±2.6 (13-21)

Anal body diam. 9.2±0.7 (8-11)

Tail length 89.2±13.0 (65-102)

Egg dimension 46 x 15

163 Fig 36. Macrolaimellus iucundus Andrássy, 1966 A: Entire female. B: Female anterior region. C: Female pharyngeal region. D: Female reproductive system. E: Female posterior region.

164 Fig. 37. Macrolaimellus iucundus Andrássy, 1966 (Female). A: Anterior end (scanning electron microscopy). B-D: Anterior end. E: Pharyngeal region. F: Genital branch. G: Vulval region with intra-uterine egg. H: Vulval region (scanning electron microscopy). I: Lateral fields (scanning electron microscopy). J: Lateral fields. K: Anal region (scanning electron microscopy). L: Posterior end (Scale bars= 10 μm).

165 Infraorder: Panagrolaimomorpha De Ley & Blaxter, 2002

Diagnosis. Tylenchina. Wide group of free-living bacteriovores and parasitic forms (parasite of insects and vertebrate mainly amphibians and reptiles). Cuticle smooth or finely annulated. Lip region continuous or slightly offset. Stoma fairly wide to partially narrow, unarmed or with small denticles. Pharynx with cylindrical corpus, metacorpus absent if present with valves, narrow isthmus and a basal bulb with grinder and haustrulum. Female reproductive system didelphic, amphidelphic or monodelphic, prodelphic. Males usually without bursa. Genital papillae 5-7 pairs. Tail elongate-conoid.

Type superfamily: Panagrolaimoidea Thorne, 1937

Other superfamily

Strongyloidoidea Chitwood & McIntosh, 1934 Key to superfamilies of Panagrolaimomorpha De Ley & Blaxter, 2002

1. Free-living bacteriovore nematodes; lips three or six; stoma anteriorly broad and posteriorly narrow; pharynx without metacorpus, rarely present; lateral field distinct; female reproductive system monoprodelphic .………………………………………………………….….. Panagrolaimoidea

2. Parasites of insects and vertebrates; lips three; stoma short narrow, funnel or cup-shaped; pharynx with well developed valvate metacorpus; lateral field indistinct or absent; female reproductive system amphidelphic …...... Strongyloidoidea Superfamily: Panagrolaimoidea Thorne, 1937

Diagnosis. Panagrolaimomorpha. Cuticle finely annulated. Lip region continuous or slightly offset. Stoma anteriorly wide, sometimes tapering towards base. Metastegostom anisoglottoid and anisomorphic, narrower than anterior part; telostegostom small and narrow. Pro-, meso- and telostegostom usually conspicuously thickened. Pharyngeal corpus cylindrical or with swollen metacorpus; a narrow isthmus and a basal bulb with grinder. Female reproductive system monodelphic, prodelphic, ovary reflexed, usually with or without double flexure; sometimes a short post-uterine sac present. Male genital papillae small, not setose, arranged in pairs. Bursa absent. Phasmids well discernible.

166 Type and only family: Panagrolaimidae Thorne, 1937 Family: Panagrolaimidae Thorne, 1937

Diagnosis. Panagrolaimoidea. Cuticle finely annulated, lateral fields distinct. Lips moderately developed, three or six. Amphids small, located on lateral lips. Stoma anterior section (cheilo- and gymnostom) spacious, less cuticularised, stegostom tapering, metastom with a small tooth-like projection. Pharynx consisting of cylindrical corpus with or without swollen metacorpus, narrower isthmus and well developed basal bulb. Female reproductive system monodelphic, prodelphic, reflexed part extending far behind vulva, with or without double flexure. Anterior separated portion of uterus serving as a spermatheca. Postvulval uterine sac present. Males mostly abundant, genital papillae 5-7 pairs. Tail conoid or elongate, in male generally shorter than in female. Phasmids always distinct.

Type genus: Panagrolaimus Fuchs, 1930

Other genera

Anguilluloides Rühm, 1956

Baujardia Bert, De Ley, Van Driessche, Segers & De Ley, 2003

Brevistoma Mukhina, 1981

Halicephalobus Timm, 1956

Panagrobeles Thorne, 1939

Panagrellus Thorne, 1938

Panagrobelium Andrássy, 1984

Plectonchus Fuchs, 1930

Procephalobus Steiner, 1934

Tricephalobus Steiner, 1936

Turbatrix Peters, 1927

167 Genus: Panagrolaimus Fuchs, 1930

Diagnosis. Panagrolaimidae. Medium- to large-sized nematodes. Cuticle smooth or very finely annulated. Lip region continuous or slightly offset. Lips six, amalgamated or more or less separate, with small papilliform sensilla. Cheilostom weakly cuticularised, gymnostom cuticularised, longer than wide, stegostom regularly tapering, with small denticle on dorsal wall, subventral wall with or without denticles. Pharynx consisting of cylindrical corpus with or without swollen metacorpus, narrower isthmus and well developed basal bulb. Female reproductive system monodelphic, prodelphic, ovary reflexed, flexure beyond vulva, sometimes reaching close anterior to rectum. Post-vulval uterine sac present. Female tail elongate conoid, male tail anteriorly conoid with abrupt narrowing posteriorly. Spicules stout with broad velum. Genital papillae five to seven pairs.

Type species: Panagrolaimus detritophagus Fuchs, 1930

Other species

P. apicatus Schuurmans Stekhoven & Teunissen, 1938

P. artyukhovskii Blinova & Mishina, 1975

P. australis (Cobb, 1893) Sudhaus, 1976

P. breviureus (Kakulija, 1968) Andrássy, 1984

P. chalcographi Fuchs, 1930

P. chararasi Rühm in Rühm & Chararas, 1957 P. concolor Massey, 1964 P. conophthori Massey, 1974 P. davidi Timm, 1971 P. dendroctoni (Fuchs, 1932) Rühm, 1954 P. facetus (Massey, 1971) Andrássy, 1984 P. filiformis (de Man, 1880) Andrássy, 2005 P. fuchsi Rühm, 1956 P. goodeyi Rühm, 1956 P. hermineae Karaptyan, 1997 P. hygrophilus (Bassen, 1940) Andrássy, 2005

168 P. impar (Cobb, 1924) Sudhaus, 1976 P. judithae Massey, 1964 P. labiatus (Kreis, 1929) Andrássy, 1960 P. laperisini Massey, 1974 P. magnivulvatus Boström, 1995 P. margaretae (Massey, 1964) Andrássy, 1984 P. migophilus Poinar & Bai, 1979 P. moehni Rühm, 1956 P. multidentatus (lvanova, 1958) Goodey, 1963 P. orientalis Korenchenko, 1986 P. ornatus (Mahajan, 1979) Andrássy, 1984 P. orthotomici Korenchenko, 1992 P. paetzoldi Goodey, 1963 P. papillosus Loof, 1971 P. paralongicaudatus (Altherr, 1938) Goodey, 1951 P. paradoxus (Kreis, 1963) Andrássy, 1984 P. peruensis (Steiner, 1939) Goodey, 1963 P. picei Fuchs, 1930 P. rigidus (Schneider, 1866) Thorne, 1937 P. ruffoi Andrássy, 1962 P. scheucherae Rühm, 1956 P. spondyli Körner, 1954 P. subelongatus (Cobb, 1914) Thorne, 1937 P. superbus Fuchs, 1930 P. tipulae Lam & Webster, 1971 P. trilabiatus Zell, 1987 P. verrucosus Fuchs, 1930 P. wichmanni Rühm, 1956

169 Panagrolaimus hygrophilus (Bassen, 1940) Andrássy, 2005

(Figs. 38, 39, 40)

Description

Measurements. Table 14.

Female: Medium- to large-sized nematodes with body almost straight upon fixation, tapering towards posterior region. Cuticle 1 μm thick, smooth, without transverse annulations. Lateral fields 3-4 μm wide with two ridges/ three incisures. Lip region continuous with adjoining body; lips fused, labial and cephalic sensilla indistinct. Amphidial openings small elliptical, at base of lateral lips, not discernible under LM. Stoma narrow, tubular: cheilostom weakly cuticularised, 18-20% of stoma length; gymnostom strongly cuticularised with parallel walls, 38-40% of stoma length; stegostom 38-40% of stoma length, pro- and mesostegostom indistinct, metastegostom having a minute denticle on each wall, telostegostom converging into pharyngeal lumen. Pharyngeal collar covering 38-40% of stoma from base. Pharynx panagrolaimoid type with 95-104 μm long cylindrical corpus without swollen metacorpus; corpus and isthmus separated by constriction; 42-46 μm long uniformly thick isthmus, slightly narrower than corpus and ovoid basal bulb of 21-23 μm x 16- 18 μm dimension, with grinder and single-chambered haustrulum. Corpus 1.5 times longer than isthmus and basal bulb together. Nerve ring encircling anterior isthmus at 69.2-69.9% of pharyngeal length from anterior end. Secretory-excretory pore slightly posterior to nerve ring at 72.2-73.5% of pharyngeal length from anterior end. Hemizonid at level of secretory-excretory pore. Dierids at mid level of isthmus. Cardia small, conoid, 3-5 μm long. Intestine thin-walled with wide lumen. Pseudocoelomocyte not observed. Rectum with slightly dilated lumen, 1.3-1.4 times anal body diam. Rectal glands present. Anus a crescent-shaped slit. Tail elongate conoid with pointed tip, 5.7-7.3 times anal body diam. long. Phasmids inconspicuous.

Reproductive system panagrolaimoid type, monodelphic, prodelphic; ovary dorsally reflexed, on right side of intestine; flexure reaching beyond vulva; oocytes arranged in 2-3 rows distally followed by single row proximally. Oviduct short, separated from spermatheca by a constriction; spermatheca, spindle shaped, elongate, 35-40 μm long, filled with variously shaped sperms from small rounded to elongate. Uterus spacious, occasionally containing one or two intra-uterine eggs of 46-59 μm x

170 18-21 μm dimension. Vagina perpendicular to body axis, 8-10 μm or 32-35% of corresponding body diam. with small round, cuticularised pieces. Vulva slightly post- equatorial, 53.8-55.8% from anterior end, vulval lips slightly protruded. Post-uterine sac present, 33-43 μm long or 1.0-1.5 times vulval body diam. long. Special canal-like structures present in the region of post-uterine sac.

Male: Similar to female but relatively smaller and slight curvature in cloacal region. Testis single, ventrally reflexed, flexure on right side of intestine. Pseudocoelomocyte not observed. Spermatocytes arranged in 2-3 rows distally followed by single row proximally; seminal vesicle short, 42-46 μm long filled with growing sperm cells. Vas deferens about 3 times the length of seminal vesicle leading to ejaculatory duct. Ejaculatory glands obscure. Spicules arcuate, robust with rounded head, dorsal shoulder, ventral conoid process, a median ridge, and pointed distal tip. Gubernaculum trough-shaped, 45-50% of spicule length with broad proximal part and narrow distal part. Tail elongate conoid with abrupt narrowing at about 55-60% of its length to pointed tip, appearing as spicate. Genital papillae seven pairs arranged in 1+1/1+P+1+1+1+1 configuration: GP1 subventral, 1.5 times spicule length anterior to cloaca; GP2 ventro-sublateral, at level of dorsal shoulder of spicules. Among postcloacals, GP3 subventral, slightly posterior to cloaca; GP4 subventral, mid of conoid part of tail, close to subventral GP5; GP6 subventral, slightly anterior to end of conoid part; GP7 subdorsal, at junction of conoid and spicate part. Phasmids at mid level of conoid part of tail.

Locality and habitat: Samples having Panagrolaimus hygrophilus (Bassen, 1940) Andrássy, 2005 were obtained from soil collected near base of Mulberry tree at Keetham lake, Agra, Uttar Pradesh, India at coordinates 27°15.263’ N 077°50.984’ E.

Voucher specimens: Ten females and ten males on slides Panagrolaimus hygrophilus (Bassen, 1940) Andrássy, 2005 KL-22/1-8 deposited in Nematode Collection, Department of Zoology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.

Remarks: The present population shows conformity to P. hygrophilus (Bassen, 1940) Andrássy, 2005 in most morphometric and morphological characteristics with minor differences. Females with relatively greater ‘c’ value (7.8-9.2 vs 6.2-8.9); relatively longer stoma (10-11 μm vs 7-10 μm); post-uterine sac relatively longer [33-43 μm vs 15-38 in P. hygrophilus (Bassen, 1940) Andrássy, 2005]

171 In 2005, Andrássy proposed a new genus Propanagrolaimus with very slender nematodes (a= 30-70) and separated it from Panagrolaimus (a= 14-30) with P. filiformis (de Man, 1880) as its type species. He transferred Panagrolaimus hygrophilus to Propanagrolaimus. Later, Abolafia & Peña-Santiago (2006) recorded Propanagrolaimus hygrophilus from western Sudan for the first time. In 2007, Shokoohi, Abolafia & Zad reported Propanagrolaimus hygrophilus for the first time from Iran. Khan, Hussain & Tahseen (2012) reported the same species from India sans male. Khan et al. (2012) also reported cluster of parallel canal-like structures in pseudocoelom whereas in present population, they are confined only to the region of post-uterine sac. The present population reported males of Panagrolaimus hygrophilus for the first time.

172 Table 14. Morphometric characteristics of Panagrolaimus hygrophilus (Bassen, 1940) Andrássy, 2005. Measurements are in µm and in the form: mean±standard deviation (range).

Character Female Male (n=10) (n=10) Body length 966.2±62.4 (887-1081) 888.4±38.4 (817-940) Body diam. 27.6±1.7 (25-31) 22.0±0.9 (21-23) a 34.9±1.1 (33.7-37.3) 40.4±2.7 (36.7-44.7) b 5.4±0.1 (5.2-5.7) 5.4±0.1 (5.2-5.7) c 8.5±0.4 (7.8-9.2) 9.9±0.1 (9.7-10.3) c’ 6.1±0.5 (5.7-7.3) 4.6±0.3 (4.2-5.1) V/T 54.7±0.6 (53.8-55.8) 54.9±3.1 (49.3-59.2) G1 55.1±3.1 (51.2-59.1) -- Post-uterine sac 38.9±2.8 (33-43) -- Lip height 3±0 (3-3) 3±0 (3-3) Lip diam. 8.4±0.5 (8-9) 7.7±0.6 (7-9) Stoma length 10.4±0.5 (10-11) 10.0±0.4 (9-11) Stoma diam. 3±0 (3-3) 2.9±0.3 (2-3) Pharynx length 175.3±7.7 (166-193) 161.4±5.8 (153-170) Nerve ring-ant. end 121.5±6.2 (115-135) 108.0±4.4 (100-115) Secretory-excretory pore- 128.9±5.4 (120-142) 116.4±5.6 (107-124) ant. end Rectum length 23.8±2.8 (20-30) 24.3±0.9 (23-26) Anal body diam. 18.1±1.9 (15-21) 19.2±0.6 (18-20) Tail length 112.1±8.1 (100-125) 88.9±5.1 (80-95) Egg dimension 52.7±5.1 x 19.2±0.9 (46-59 -- x 18-21) Spicules length -- 23.2±1.5 (21-26) Gubernaculum length -- 11.0±0.4 (10-12)

173 Fig 38. Panagrolaimus hygrophilus (Bassen, 1940) Andrássy, 2005 A: Entire female. B: Entire male. C: Female anterior region. D: Female pharyngeal region. E: Female reproductive system. F: Female posterior region. G: Male posterior region.

174 Fig. 39. Panagrolaimus hygrophilus (Bassen, 1940) Andrássy, 2005 (Female). A: En face view (scanning electron microscopy). B-D: Anterior end. E: Posterior pharyngeal region. F, H, I: Parts of genital branch. G: Vulval region with post-uterine sac. J: Vulval region (scanning electron microscopy). K: Vulval region. L: Lateral fields (scanning electron microscopy). M: Anal region. N: Vulva (ventral). O: Posterior region (scanning electron microscopy) (Scale bars= 10 μm).

175 Fig. 40. Panagrolaimus hygrophilus (Bassen, 1940) Andrássy, 2005 (Male). A: Anterior end. B: Posterior pharyngeal region. C: Genital branch showing reflexed testis. D-F: Cloacal region showing spicules. G: Posterior region with associated papillae. H: Posterior region with associated papillae (scanning electron microscopy) (Scale bars= 10 μm).

176 Genus: Tricephalobus Steiner, 1936

Diagnosis. Panagrolaimidae. Small- to medium-sized nematodes. Cuticle smooth or finely annulated. Lateral fields narrow. Lip region continuous with body or slightly offset, lips in three doublets, separate. Stoma panagrolaimoid type, cheilostom short weakly cuticularised, gymnostom well developed, stegostom funnel-shaped, tapering towards base. Pharynx with cylindrical corpus, swollen metacorpus, narrower isthmus and well-developed basal bulb. Female reproductive system panagrolaimoid, monodelphic, prodelphic, ovary reflexed, flexure very long, occasionally reaching anus level. Post-vulval uterine sac present. Both sexes equally common. Male with single testis. Spicules robust, gubernaculum thin and slender. Genital papillae six or seven pairs. Tail conoid in female, and strongly narrowed at posterior half in male with acute terminus.

Type species: Tricephalobus steineri (Andrássy, 1952) Rühm, 1956

Other species

T. aestivus (Andrássy, 1996) Andrássy, 2005

T. lignicolus Körner, 1954

177 Tricephalobus longihystera sp. n.

(Figs. 41, 42, 43)

Description

Measurements. Table 15.

Female: Small- to medium-sized nematodes, body slightly curved upon fixation, tapering towards both extremities, more towards posterior end. Cuticle 1 μm thick, transversely annulated, inner cuticular layer striated. Lateral fields 3-4 μm wide with single ridge/ two incisures. Lip region slightly offset; lips fused to form three doublets, appearing three lip, labial and cephalic sensilla indistinct. Amphidial openings small elliptical, at base of lateral lips, not clearly visible under LM. Stoma tubular; cheilostom weakly cuticularised, 15-20% of stoma length; gymnostom strongly cuticularised with parallel walls, 30-35% of stoma length; stegostom 45-50% of stoma length, prostegostom and mesostegostom not distinctly differentiated, metastegostom with a minute protuberance on dorsal wall, telostegostom funnel- shaped, continuous with pharyngeal lumen. Pharyngeal collar covering 45-50% of stoma from base. Pharynx with 39-55 μm long cylindrical corpus; 13-19 μm long swollen metacorpus with thickened lumen; 20-27 μm long uniformly thick isthmus, slightly narrower than corpus and ovoid basal bulb of 15-20 μm x 10-15 μm dimension with grinder and single-chambered haustrulum. Corpus 1.5 times longer than isthmus and basal bulb together. Nerve ring encircling anterior isthmus at 68.9- 72.0% of pharyngeal length from anterior end. Secretory-excretory pore located slightly posterior to nerve ring, at 75.2-79.8% of pharyngeal length from anterior end. Hemizonid just anterior to secretory-excretory pore. Dierids obscure. Cardia small, conoid, 3-5 μm long. Intestine thin-walled with wide lumen. Pseudocoelomocyte not observed. Rectum 1.1-1.2 times anal body diam. long. Rectal glands present. Anus a crescent-shaped slit. Tail elongate conoid with acutely pointed tip, 3.0-4.8 times anal body diam. long. Phasmids obscure.

Reproductive system panagrolaimoid type, monodelphic, prodelphic; ovary dorsally reflexed on right side of intestine; flexure very long with distal tip reaching close to rectum, occasionally reaching level of anus. Oocytes arranged in 2-3 rows distally followed by single row proximally. Oviduct short. Spermatheca elongate ovoid, 25-27 μm long, filled with growing spermatozoa. Uterus with glandular and

178 muscular part differentiated, muscular part spacious, thick-walled. Vagina 10-12 μm long or 33-35% of corresponding body diam., perpendicular to body axis with muscles appearing cuticularised pieces in cross section. Vulva post-equatorial, 59.1- 62.3% from anterior end, vulval lips slightly protruded. Post-uterine sac absent. Uterine eggs not observed.

Male: Similar to female in body posture but more curvature in posterior region and tail abruptly narrowing at about 55-60% of its length. Testis single with club-shaped distal end, ventrally reflexed, flexure on left side of intestine; spermatocytes arranged in 2-3 rows distally followed by single row proximally. Pseudocoelomocyte not observed. Seminal vesicle filled with growing sperm cells. Vas deferens opening into narrower ejaculatory duct. Ejaculatory glands absent. Spicules arcuate with narrow head, dorsal shoulder, ventral conoid process, a median ridge, large velum extending from ventral conoid process nearly up to pointed distal tip. Gubernaculum trough- shaped, 40-45% of spicule length with hooked proximal end. Genital papillae four pairs arranged in 1/1+P+1+1 configuration: GP1 subventral, anterior to cloaca at level of spicule head. Among postcloacals, GP2 subventral, at level of phasmid in mid level of conoid part; GP3 subventral and GP4 subdorsal, at same level, at junction of conoid and spicate part. Phasmids at level of GP2.

Diagnosis and relationship: Tricephalobus longihystera sp. n. is characterised by slightly offset lip region; lips fused in three doublets; labial and cephalic sensilla indistinct; ovarian flexure reaching beyond vulva with distal tip at level of anus; uterus with strong and thick walls without post-uterine extension; vagina perpendicular to body axis with muscles appearing cuticularised pieces in cross section; vulval lips slightly protruded. Males having distal region of testis club- shaped; short conoid tail with abrupt tapering at posterior half; spicules robust; gubernaculum hooked proximally and genital papillae one precloacal and three postcloacal pairs.

Tricephalobus longihystera sp. n. comes closest to T. steineri (Andrássy, 1952) Rühm, 1956 in most morphometric and morphological characteristics but differs in having relatively smaller females (0.37-0.57 mm vs 0.45-0.92 mm) with relatively smaller ‘b’ (3.5-5.0 vs 3.8-6.3) and ‘c’ (7.6-10.2 vs 8.5-15.0) values; smaller males (0.35-0.50 mm vs 0.74-0.98 mm) with smaller ‘a’ (16.1-20.8 vs 31.1-35.2); ‘b’

179 (3.7-4.4 vs 5.0-5.8); ‘c’ (9.3-10.8 vs 14.3-20.2) and ‘ć’ (2.2-2.9 vs 3.0-3.5) values and genital papillae four pairs [vs 6-7 pairs in T. steineri (Andrássy, 1952) Rühm, 1956].

Tricephalobus longihystera sp. n. differs from T. lignicolus Körner, 1954 in having relatively smaller females (0.37-0.57 mm vs 0.54-0.77 mm) with greater ‘c’ value (7.6-10.2 vs 4.7-6.1); smaller ‘ć’ value (3.0-4.8 vs 6.0-8.0); smaller stoma (10- 12 μm vs 14-15 μm); post-uterine sac absent (vs present); vulva post-equatorial (vs equatorial); males with smaller ‘a’ (16.1-20.8 vs 21.0-35.0) and ‘ć’ (2.2-2.9 vs 3.5- 4.0) values and genital papillae four pairs (vs 6-8 pairs in T. lignicolus Körner, 1954).

Tricephalobus longihystera sp. n. differs from T. aestivus (Andrássy, 1996) Andrássy, 2005 in having smaller females (0.37-0.57 mm vs 0.61-0.88 mm); lip region slightly offset (vs continuous); vulva post-equatorial (vs equatorial); post- uterine sac absent (vs present); males with smaller ‘a’ value (16.1-20.8 vs 21.0-22.0); smaller spicules (18-23 μm vs 26-30 μm); smaller gubernaculum (7-10 μm vs 13-15 μm) and genital papillae four pairs [vs seven pairs in T. aestivus (Andrássy, 1996) Andrássy, 2005].

Type locality and habitat: Samples having Tricephalobus longihystera sp. n. were obtained from soil of a small ditch at Keetham lake, Agra, Uttar Pradesh, India at coordinates 27°15.313’ N 077°50.730’ E.

Type specimens: Holotype female, nine paratype females and seven paratype males on slides Tricephalobus longihystera sp. n. KL3-18/1-7 deposited in Nematode Collection, Department of Zoology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.

Etymology: The species name ‘longihystera’ indicates unusually long genital branch in females.

180 Table 15. Morphometric characteristics of Tricephalobus longihystera sp. n. Measurements are in µm and in the form: mean±standard deviation (range).

Character Holotype Paratype Female Paratype Male Female (n=9) (n=7) Body length 388 439.6±60.0 (372-577) 424.4±46.9 (359- 501) Body diam. 24 24.6±3.3 (19-29) 22.4±3.2 (18-26) a 16.1 17.9±2.0 (16.1-22.2) 19.0±1.5 (16.1-20.8) b 3.7 4.1±0.4 (3.5-5.0) 4.1±0.2 (3.7-4.4) c 9.2 9.1±0.7 (7.6-10.2) 9.9±0.5 (9.3-10.8) c' 3.5 3.6±0.4 (3.0-4.8) 2.5±0.2 (2.2-2.9) V/T 61.5 60.5±1.1 (59.1-62.3) 62.3±4.0 (54.6-67.5) G1 71.9 65.8±9.1 (51.4-77.9) -- Lip height 2 3.0±0.4 (2-4) 3.1±0.3 (3-4) Lip diam. 7 7.4±0.5 (7-8) 7.1±0.6 (6-8) Stoma length 10 10.5±0.7 (10-12) 10.1±0.3 (10-11) Stoma diam. 2 2.3±0.4 (2-3) 2±0 (2-2) Pharynx length 103 106±8 (93-119) 101.4±10.3 (81-113) Nerve ring-ant. 70 74.0±5.2 (67-82) 71.5±9.1 (60-88) end Secretory- 80 82.5±7.5 (70-95) 79.4±5.3 (72-88) excretory pore- ant. end Rectum length 16 15.3±1.4 (13-18) 19.1±1.3 (17-21) Anal body diam. 12 13.3±1.8 (11-16) 16.4±1.7 (14-18) Tail length 42 48.2±7.1 (42-65) 42.4±5.3 (34-50) Spicules length -- -- 20.7±1.9 (18-23) Gubernaculum -- -- 8.5±1.2 (7-10) length

181 Fig 41. Tricephalobus longihystera sp. n. A: Entire female. B: Entire male. C: Female anterior region. D: Female pharyngeal region. E. Female reproductive system. F: Female posterior region. G: Male posterior region.

182 Fig. 42. Tricephalobus longihystera sp. n. (Female) A: Anterior end (scanning electron microscopy). B: Anterior end. C: Posterior pharyngeal region. D: Genital branch showing flexure. E: Vulval region. F: Intestinal lumen. G: Vulval region (scanning electron microscopy). H: Lateral fields (scanning electron microscopy). I: Posterior region. J: Posterior region (scanning electron microscopy) (Scale bars= 10 μm).

183 Fig. 43. Tricephalobus longihystera sp. n. (Male) A: Anterior end. B: Pharyngeal region. C: Genital branch showing reflexed testis. D: Posterior region (scanning electron microscopy). E-H: Cloacal region showing spicules and associated papillae (Scale bars= 10 μm).

184 Order: Chromadorida Chitwood, 1933

Diagnosis. Chromadoria. Cuticle annulated, usually with punctated ornamentation, making a pattern of dots, rods or basket weave. Lip region with four or (six + four) setose sensilla. Amphidial opening spiral, circular or slit-like. Ocelli occasionally present in marine forms. Stoma small, funnel-shaped always with teeth or denticles. Pharynx muscular, cylindrical, with or without basal bulb. Female reproductive system didelphic, amphidelphic; ovaries outstretched or reflexed. Males supplements, if present, cuticularized, small, knob-like. Tail with caudal glands and spinneret.

Type and only suborder: Chromadorina Filipjev, 1929 Suborder: Chromadorina Filipjev, 1929

Diagnosis. Chromadorida. Cuticle annulated with transverse rows of dots or other ornamented structures. Lip region with four or six + four setose sensilla. Amphids slit-like or multi-spiral. Stoma small, funnel-shaped always with teeth or denticles. Pharynx cylindrical with strong basal bulb, rarely absent. Female reproductive system didelphic, amphidelphic; ovaries reflexed. Tail with caudal glands and spinneret.

Type and only superfamily: Chromadoroidea Filipjev, 1917 Superfamily: Chromadoroidea Filipjev, 1917

Diagnosis. Chromadorina. Cuticle annulated with transverse rows of dots or other ornamented structures. Lip region with four or six + four sensilla, papilliform or setiform. Amphidial fovea oval, spiral or slit-like, located between the cephalic setae or posterior to them. Stoma with dorsal tooth larger than subventrals or equal to subventrals. Female reproductive system didelphic, amphidelphic; ovaries reflexed. Males diorchic or monorchic.

Type family: Chromadoridae Filipjev, 1917

Other families

Achromadoridae Gerlach & Riemann, 1973

Cyatholaimidae Filipjev, 1918

Ethmolaimidae Filipjev & Schuurmans Stekhoven, 1941

Neotonchidae Wieser & Hopper, 1966

Selachinematidae Cobb, 1915

185 Key to families of Chromadoroidea Filipjev, 1917

1. Stoma with three teeth of equal size or dorsal tooth larger; amphidial fovea transverse slit between cephalic sensilla ……………….…… Chromadoridae

2. Stoma with dorsal tooth, ventrosublateral teeth small or absent; amphidial fovea unispiral or multispiral posterior to cephalic sensilla ……………………………………………………………….. Achromadoridae

3. Stoma with dorsal tooth, ventrosublateral teeth small or absent; amphidial fovea multispiral posterior to cephalic sensilla ………..….. Cyatholaimidae

4. Stoma with three teeth of equal size; amphidial fovea unispiral or multispiral posterior to cephalic sensilla ………………………………. Ethmolaimidae

5. Stoma with large dorsal tooth, ventrosublateral teeth small or absent; amphidial fovea multispiral posterior to cephalic sensilla …………………………………………………………………. Neotonchidae

6. Stoma large, unarmed or with jaws; amphidial fovea multispiral posterior to cephalic sensilla ………….……………………………… Selachinematidae Family: Achromadoridae Gerlach & Riemann, 1973

Diagnosis. Chromadoroidea. Small-sized nematodes ranging from 0.5-0.6 mm in length. Cuticle with transverse striations and punctations. Six outer labial and four cephalic sensilla setose arranged in single circlet of 6+4, with outer labials longer than cephalic ones. Amphidial opening spiral, located posterior to cephalic setae. Stoma with a distinct dorsal tooth, with or without subventral teeth. Female reproductive system didelphic, amphidelphic; ovaries reflexed. Males rare. Precloacal supplements absent.

Type subfamily: Achromadorinae Gerlach & Riemann, 1973

Other subfamily

Kreisonematinae Khera, 1969

Key to subfamilies of Achromadoridae Gerlach & Riemann, 1973

1. Cuticle with transverse striations and punctations; amphidial aperture spiral………………..………………………………………. Achromadorinae

186 2. Cuticle with transverse striations and punctations obscure; amphidial aperture circular ……………………………………………………. Kreisonematinae Subfamily: Achromadorinae Gerlach & Riemann, 1973

Diagnosis. Achromadoridae. Terrestrial and fresh-water forms. Cuticle with transverse striations and punctations, ornamented with rows of fine dots. Amphideal fovea spiral. Lip region continuous with body, rounded, lips six each with an apical papilla; six outer labial and cephalic setae present at same level or cephalic setae slightly posterior to outer labials. Stoma funnel-shaped with dorsal tooth, subventral teeth present or absent. Pharynx cylindrical with a basal bulb. Female reproductive system didelphic, amphidelphic; ovaries reflexed. Males rare.

Type and only genus: Achromadora Cobb, 1913

187 Genus: Achromadora Cobb, 1913

Diagnosis. Achromadorinae. Cuticle with fine transverse striae, ornamented with rows of fine dots. Amphideal fovea multispiral, rarely unispiral, located anterior of stoma to slightly posterior. Lip region continuous with body, rounded, with six poorly developed lips, each with an apical papilla; six outer labial setae and four cephalic setae usually in a single row of ten setae but may also occur in two separate circlets with cephalic sensilla papilliform. Stoma funnel-shaped with distinct dorsal tooth anterior to middle of stoma and one or two small ventrosublateral teeth posteriorly. Pharynx cylindrical enlarged posteriorly to form a basal bulb. Female reproductive system didelphic, amphidelphic, ovaries reflexed. Tail conoid, tapering to a bluntly rounded terminus. Caudal glands and spinneret present. Male rare, diorchic Precloacal supplements absent, if present, small cup-shaped.

Type species: Achromadora ruricola (de Man, 1880) Micoletzky, 1925

Other species A. arenicola Vinciguerra & Orselli, 1997 A. chungsani (Hoeppli & Chu, 1932) Andrássy, 1984 A. gracilis Ocaña, Hernández & Monterrubio, 1999 A. granulata (Cobb, 1913) Goodey, 1952 A. indica Tahseen, 2001 A. inflata Eyualem & Coomans, 1996 A. inermis Altherr, 1952 A. longicauda Schneider, 1937 A. micoletzkyi (Stefanski, 1915) van der Linde, 1938 A. pseudomicoletzkyi van der Linde, 1938 A. sedata Gagarin, 2001 A. semiarmata Altherr, 1952 A. sudanensis Elbadri, Khan, Moon, Lee & Choo, 2008 A. tenax (de Man, 1876) Kreis, 1932 A. terricola (de Man, 1880) Micoletzky, 1925 A. thermophila Lemzina & Gagarin, 1994 A. walkeri Banna & Gardner, 1993

188 Achromadora indica Tahseen, 2001

(Figs. 44, 45)

Description

Measurements. Table 16.

Female: Small- to medium-sized nematodes, body strongly curved upon fixation, tapering towards both extremities, more towards posterior end. Cuticle 0.8 to 1.0 μm thick, transversely annulated bearing rows of minute dot-like punctuations; annules 1.0-1.2 μm wide in different body regions. Somatic setae not visible under LM. Lateral fields indistinct. Lip region 8-9 μm wide and 4-5 μm high, offset from adjoining body by slight constriction. Lips amalgamated; inner labial sensilla small papilloid, outer labial and cephalic sensilla elongate setose. Oral aperture round, surrounded by cheilostomal ribs. Amphids spiral, 2-3 μm wide and 5-8 μm or 1.1-1.6 times lip region diam. from anterior end, at level of subventral tooth in posterior half of stoma. Stoma funnel shaped, asymmetrical, 10 μm long, dorsal tooth sharp pointed directed upwards at mid level of stoma, subventral teeth minute, lying posterior to dorsal tooth, slightly anterior to base of stoma. Pharyngeal tissue covering entire stoma. Pharynx with 58-67 μm long cylindrical corpus of uniform thickness and well developed ovoid basal bulb of 12-14 μm x 9-10 μm dimension with thickened lumen. Nerve ring encircling pharynx at 61.4-65.4% of its length from anterior end. Secretory-excretory pore not visible. Cardia small 3-4 μm long. Intestine granular with thick walls. Intestinal lumen narrow and convoluted. Rectum as long as anal body diam. long. Rectal glands absent. Prerectum absent. Tail strongly arcuate, 5.9- 7.2 times anal body diam. long. Three linearly arranged caudal glands present with first one at level of anus, opening to exterior via a small 1-2 μm long spinneret at tail tip.

Reproductive system didelphic, amphidelphic, compactly built; ovaries reflexed, flexure on right side of intestine. Oocytes arranged in 2-3 rows distally followed by single row of larger oocytes proximally. Oviduct and spermatheca not differentiated. Uterus short and muscular with single intra-uterine egg of 46-51 μm x 10-15 μm dimension in few females. Vagina short, perpendicular to body axis, 4-5 μm or 28-30% of corresponding body diam. Vulva slightly pre-equatorial, 46.5-49.3% of body length from anterior end. Vulval lips not protruded.

189 Male: Not found.

Locality and habitat: Samples having Achromadora indica Tahseen, 2001 were obtained from sample of hollow tree trunk at Keetham lake, Agra, Uttar Pradesh, India at coordinates 27°14.780’ N 077°51.260’ E.

Voucher specimens: Six females on slides Achromadora indica Tahseen, 2001 KL- 25/1-3 deposited in Nematode Collection, Department of Zoology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.

Remarks: The present population shows conformity to A. indica Tahseen, 2001 with minor differences. Females smaller (0.39-0.45 mm vs 0.57-0.69 mm) with smaller ‘b’ (5.4-5.9 vs 6.3-7.3) and ‘c’ (5.5-6.4 vs 6.8-9.0) values; greater ‘ć’ value (5.9-7.2 vs 4.3-5.6); smaller stoma (10 μm vs 12-14 μm) and pre-rectum absent (vs present in A. indica Tahseen, 2001).

190 Table 16. Morphometric characteristics of Achromadora indica Tahseen, 2001. Measurements are in µm and in the form: mean±standard deviation (range).

Character Female (n=6) Body length 426.3±21.8 (397-456) Body diam. 16.3±1.8 (15-20) a 26.2±2.3 (22.2-28.6) b 5.6±0.1 (5.4-5.9) c 6.0±0.3 (5.5-6.4) c' 6.5±0.5 (5.9-7.2) V 47.5±1.0 (46.5-49.3) G1 14.6±1.6 (12.5-17.4) G2 14.0±3.6 (10.0-20.6) Amphid-ant. end 6.5±1.0 (5-8) Amphid diam. 2.6±0.5 (2-3) Lip height 4.1±0.4 (4-5) Lip diam. 8.6±0.5 (8-9) Stoma length 10±0 (10-10) Stoma diam. 2.1±0.4 (2-3) Pharynx length 74.8±3.5 (70-81) Nerve ring-ant. end 47.3±3.7 (43-53) Rectum length 11.5±1.0 (10-13) Anal body diam. 10.6±0.5 (10-11) Tail length 70.1±3.4 (65-75) Egg dimension 48.5±3.5 x 12.5±3.5 (46-51 x 10-15)

191 Fig 44. Achromadora indica Tahseen, 2001 A: Entire female. B: Female anterior region. C: Female pharyngeal region. D: Female reproductive system. E: Female posterior region.

192 Fig. 45. Achromadora indica Tahseen, 2001 (Female). A: Anterior end showing amphid. B, C: Anterior end. D: Pharyngeal region. E, F: Vulval region with intra-uterine egg. G: Posterior end. H: tail tip showing mucro (Scale bars= 10 μm).

193 Order: Monhysterida Filipjev, 1929

Diagnosis. Chromadoria. Small- to medium-sized, slender nematodes. Cuticle smooth or finely annulated. Body with scattered somatic setae. Lip region continuous with adjoining body; inner labial sensilla six, papilliform or setiform; six outer labial and four cephalic sensilla setiform, usually articulate. Amphidial aperture circular rarely unispiral. Stoma generally small, funnel-shaped, unarmed rarely spacious and armed; completely surrounded by muscular pharyngeal collar. Pharynx cylindrical with slight expansion at its base, rarely a basal bulb. Ocelli (eye spot) often present in marine forms. Cardia long. Female reproductive system monodelphic, prodelphic, ovary outstretched rarely didelphic, amphidelphic. Males usually rare. Testis single or double. Male precloacal genital papillae usually absent, if present, simple. Tail elongate, conoid. Three caudal glands arranged linearly, opening through terminal pore or spinneret.

Type suborder: Monhysterina De Coninck & Schuurmans Stekhoven, 1933

Other suborder

Linhomoeina Andrássy, 1974 Key to suborders of Monhysterida Filipjev, 1929

1. Pharynx without basal swelling; ovary single, outstretched; tail with cuticularized spinneret at the tip ………………………….…… Monhysterina

2. Pharynx with basal swelling; ovaries double, reflexed; tail with a fine pore at the tip without spinneret ………………………………………... Linhomoeina Suborder: Monhysterina De Coninck & Schuurmans Stekhoven, 1933

Diagnosis. Monhysterida. Cuticle smooth. Somatic setae present all over body. Lip region continuous or slightly offset from adjoining body. Labial sensilla in two circles; inner labial sensilla papilliform, outer labial and cephalic sensilla setose. Amphidial apertures circular, rarely spiral, at anterior or posterior level of stoma or beyond it. Stoma small, narrow, funnel-shaped, rarely armed with denticles. Pharynx cylindrical with or without basal bulb. Female reproductive system monodelphic, prodelphic, ovary outstretched. Males generally without precloacal supplements. Three linearly arranged caudal glands opening outside through spinneret.

Type superfamily: Monhysteroidea de Man, 1876

194 Other superfamily

Sphaerolaimoidea Filipjev, 1918 Key to superfamilies of Monhysterina De Coninck & Schuurmans Stekhoven, 1933

1. Cuticle smooth; stoma narrow, funnel-shaped, completely surrounded by pharyngeal tissue; tail without long terminal seta ………….. Monhysteroidea

2. Cuticle annulated; stoma wide, barrel-shaped, surrounded by pharyngeal tissue only at base; tail with 2-3 μm long terminal seta ……….. Sphaerolaimoidea Superfamily: Monhysteroidea de Man, 1876

Diagnosis. Monhysterina. Small-sized nematodes. Cuticle smooth. Inner labial sensilla papilliform; outer labial and cephalic sensilla setose. Amphidial opening circular. Stoma narrow, funnel-shaped or tubular, with or without denticles. Pharynx cylindrical rarely slightly expanded at base to form a basal bulb. Female reproductive system monodelphic, prodelphic, ovary outstretched. Males monorchic.

Type and only family: Monhysteridae de Man, 1876

Family: Monhysteridae de Man, 1876

Diagnosis. Monhysteroidea. Small-sized slender nematodes. Cuticle smooth with scattered somatic setae. Inner labial sensilla papilliform; outer labial and cephalic sensilla setose with cephalic sensilla shorter than outer labials. Amphidial opening circular, round or slightly oval, occupying 40-50% of corresponding body diam. Stoma narrow, funnel-shaped, with or without denticles, surrounded by pharyngeal tissue. Pharynx cylindrical, muscular, with or without basal bulb. Secretory-excretory pore anterior to nerve ring or in lip region. Ocelli often present in pharyngeal region. Female reproductive system monodelphic, prodelphic, ovary outstretched, located at right side of intestine. Males with single outstretched testis at right side of intestine. Precloacal papillae absent. Tail conoid to elongate conoid or filiform, with three caudal glands and terminal spinneret. Males usually rare.

195 Type genus: Monhystera Bastian, 1865

Other genera

Anguimonhystera Andrássy, 1981

Cryonema Tchesunov & Riemann, 1995

Diplolaimella Allgén, 1929

Diplolaimelloides Meyl, 1954

Eumonhystera Andrássy, 1981

Gammarinema Kinne & Gerlach, 1953

Geomonhystera Andrássy, 1981

Halomonhystera Andrássy, 2006

Hieminema Tchesunov & Portnova, 2005

Monhystrella Cobb, 1918

Monhystrium Cobb, 1920

Odontobius Roussel del Vauzème, 1834

Sinanema Andrássy, 1960

Sitadevinema Khera, 1971

Thalassomonhystera Jacobs, 1987

Tridentula (Eyualem-Abebe & Coomans, 1995) Andrássy, 2007

Tripylium Cobb, 1920

196 Genus: Geomonhystera Andrássy, 1981

Diagnosis. Monhysteridae. Medium-sized nematodes. Cuticle smooth or very finely annulated with few to numerous somatic setae present all over body. Lip region continuous with adjoining body. Lips amalgamated. Inner labial sensilla papilliform. Outer labial sensilla small setose. Cephalic sensilla fairly strong, larger than outer labials usually articulate. Amphidial opening round or circular. Ocelli absent. Stoma small, thin-walled, funnel-shaped, without denticles, surrounded by pharyngeal tissue. Pharynx muscular, cylindrical without basal bulb. Cardia rhomboid to triangular, pericardial cells well developed. Rectum strong and muscular. Female reproductive system monodelphic, prodelphic. Ovary relatively long, outstretched. Vulva post- equatorial, 75-80% of body length, close to anal opening. Vulva-anus distance about 2-3 anal body diam. Males rare. Precloacal supplements usually present. Tail short conoid, ventrally curved. Three caudal glands opening through a cuticularized spinneret.

Type species: Geomonhystera villosa (Bütschli, 1873) Andrássy, 1981

Other species

G. aenariensis (Meyl, 1953) Andrássy, 1981

G. altaica Gagarin, 2002

G. antarcticola Andrássy, 1998

G. australis (Cobb, 1893) Andrássy, 1981

G. auvillis Saha, Lal & Singh, 2002

G. breviseta Brzeski, 1993

G. dubia Siddiqi & Shahina, 2004

G. glandulata Khan & Tahseen, 2006

G. japonica Khan & Araki, 2001

G. karuni Siddiqi & Shahina, 2004

G. longicaudata Gagarin, 2002

G. media Gagarin, 2002

G. mexicana Brzeski, 1993

197 G. paravillosa (Meyl, 1954) Andrássy, 1981

G. pervaga (Argo & Heyns, 1973) Andrássy, 1981

G. rotundicaudatus (Filipjev, 1922) Jacobs, 1987

G. steineri (Micoletzky, 1922) Andrássy, 1981

G. taurica S.Ya. Tsalolikhin, 2007

G. tripyloides (Andrássy, 1968) Andrássy, 1981

198 Geomonhystera villosa (Bütschli, 1973) Andrássy, 1981

(Figs. 46, 47)

Description

Measurements. Table 17.

Female: Medium-sized nematodes, body slightly curved upon fixation, more tapering towards posterior region. Cuticle 1.0-1.2 μm thick, appearing smooth in LM with a very faintly striated inner cuticle in anterior region. Somatic setae scattered all over body, 8-10 in pharyngeal region, 25-27 from base of pharynx up to anus level and 5-7 in caudal region. Lip region continuous with adjoining body. Lips amalgamated, with six bristle-like setiform inner labial sensilla directed upwards, six elongate outer labial sensilla. Cephalic sensilla shorter than outer labials, four, setose, non-articulate. Amphidial apertures circular, 3-4 μm wide and 15-17 μm or 1.3 times lip diam. from anterior end. Stoma 4-10 μm long, funnel-shaped, entirely surrounded by pharyngeal tissue. Pharynx cylindrical with slight expansion in posterior region. Pharyngeal lumen thin. Nerve ring encircling pharynx at 46.3-47.5% of its length from anterior end. Secretory-excretory pore not visible. Body at pharyngeal end 1.4-1.5 times lip region diam. wide. Cardia 5-7 μm long. Intestine granular with equal-sized polygonal cells; intestinal lumen narrow. Rectum thick, muscular, 1.0-1.4 times anal body diam. long. Rectal glands absent. Anus a crescent-shaped slit. Tail elongate conoid, 6.1-7.0 times anal body diam. long uniformly narrowing to terminus. Three caudal glands arranged linearly with their ducts opening externally via 2-3 μm long spinneret at tail terminus.

Reproductive system monodelphic, prodelphic. Ovary outstretched. Oocytes arranged in two rows at distal end followed by single row of large sized maturing oocytes of 50-75 μm x 20-25 μm dimension. Oviduct and spermatheca not differentiated. Columella distinct, uterus short. Vagina obliquely placed, thin-walled, 5-6 μm or 29.4-30.0% of corresponding body diam. long. Vulva posterior, 81.0- 83.7% from anterior end, a transverse slit, 1.5-2.0 times anal body diam. anterior to anal opening; vulval lips not protruded. Vulva-anus distance 25-31 μm long. Post- uterine sac absent. One intra-uterine egg observed of 54-59 μm x 15-16 μm dimension.

199 Male: Not found.

Locality and habitat: Samples having Geomonhystera villosa (Bütschli, 1973) Andrássy, 1981 were obtained from rotten wood and litter at Keetham lake, Agra, Uttar Pradesh, India at coordinates 27°15.307’ N 077°50.838’ E.

Voucher specimens: Ten females on slides Geomonhystera villosa (Bütschli, 1973) Andrássy, 1981 KL2-9/1-4 deposited in Nematode Collection, Department of Zoology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.

Remarks: The present population conforms well to Geomonhystera villosa (Bütschli, 1973) Andrássy, 1981 in all morphological as well as morphometric characteristics of species as described by Bütschli (1973) and the subsequent description by Andrássy (1981). The original species has been reported from the moss grown over roots of plants. The present population was also collected from rotten wood where the presence of moss cannot be ruled out. The present population forms the first report of species from India.

200 Table 17. Morphometric characteristics of Geomonhystera villosa (Bütschli, 1973) Andrássy, 1981. Measurements are in µm and in the form: mean±standard deviation (range).

Character Female (n=10) Body length 732.5±40.8 (660-793) Body diam. 20.1±1.1 (18-22) a 36.5±2.8 (31.4-42.5) b 5.4±0.2 (5.2-6.0) c 7.0±0.3 (6.7-7.7) c' 6.5±0.2 (6.1-7.0) V 81.9±0.7 (81.0-83.7) G1 21.1±3.4 (17.0-25.5) Amphid-ant. end 16.1±1.1 (15-17) Amphid diam. 3.6±0.5 (3-4) Lip height 2.7±0.4 (2-3) Lip diam. 11.8±0.9 (11-13) Stoma length 6.6±2.2 (4-10) Stoma diam. 1±0 (1-1) Pharynx length 132.2±6.6 (123-145) Nerve ring-ant. end 62.9±3.8 (57-69) Rectum length 19.7±2.7 (14-25) Anal body diam. 15.8±0.6 (15-17) Tail length 103.7±7.3 (93-117) Egg dimension 56.5±3.5 x 15.5±0.7 (54-59 x 15-16)

201 Fig 46. Geomonhystera villosa (Bütschli, 1973) Andrassy, 1981 A: Entire female. B: Female anterior region. C: Female pharyngeal region. D: Female reproductive system. E: Vulva-anal region. F: Female posterior region.

202 Fig. 47. Geomonhystera villosa (Bütschli, 1973) Andrassy, 1981 (Female). A, B: Anterior end (scanning electron microscopy). C, D: Anterior end. E: Posterior pharyngeal region. F, G: Genital branch. H: Vulval region (scanning electron microscopy). I: Vulva and anal region. J: Tail tip (scanning electron microscopy). K: Tail tip (Scale bars= 10 μm).

203 Genus: Monhystrella Cobb, 1918

Diagnosis. Monhysteridae. Small-sized slender nematodes. Cuticle smooth. Somatic setae small, present all over the body or only present in caudal region. Lip region continuous or slightly offset. Inner labial sensilla papilliform. Outer labial sensilla setose, occasionally papilliform. Cephalic sensilla setose, at level of or slightly posterior to outer labials, longer than outer labials. Amphids circular. Stoma elongated, funnel-shaped to tubular, not markedly cuticularised, with a very small tooth on its base or sometimes absent. Pharynx muscular, cylindrical, expanding posteriorly, forming basal bulb without valve plates. Ocelli present in pharyngeal region. Female reproductive system monodelphic, prodelphic. Ovary often outstretched. Vulva equatorial to post-equatorial. Males relatively rare. Spicules short and slender. Tails in both sexes long, filiform. Three caudal glands opening terminally through spinneret. Male supplements rarely present.

Type species: Monhystrella plectoides Cobb, 1918

Other species

M. altherri Juget, 1969

M. anophthalma (Lorenzen, 1969) Jacobs, 1987

M. arsiensis Eyualem & Coomans, 1996

M. atteae Eyualem & Coomans, 1996

M. bulbifera (de Man, 1880) Steiner, 1920

M. ethiopica Eyualem & Coomans, 1996

M. fukiensis (Hoeppli & Chu, 1932) Andrássy, 1981

M. gracilis Khera, 1966

M. hastata Andrássy, 1968

M. hoogewijsi Eyualem & Coomans, 1996

M. inaequispiculum Lorenzen, 1979

M. iranica Schiemer, 1965

M. jacobsi Eyualem & Coomans, 1996

M. kermadecensis Leduc, 2015

204 M. kerryi Khan, Hussain, Sultana & Tahseen, 2005

M. lepidura (Andrássy, 1963) Andrássy, 1968

M. longistoma (Khera, 1971) Andrássy, 1981

M. macrura (de Man, 1880) Andrássy, 1981

M. marina Timm, 1964

M. microphthalma (de Man, 1880) Jacobs, 1987

M. monachilensis Picazo-Muñoz, 1988

M. paramacrura (Meyl, 1953) Andrássy, 1968

M. parelegantula (De Coninck, 1943) Andrássy, 1981

M. parvella (Filipjev, 1931) Jacobs, 1987

M. postvulvae Khan & Araki, 2001

M. raphae Ocaña, 1987

M. salina (Meyl, 1954) Andrássy, 1981

M. spiralis (Wu & Hoeppli, 1929) Andrássy, 1981

M. stewarti (Khera, 1971) Andrássy, 1981

M. thermophila (Meyl, 1953) Andrássy, 1981

M. woitorum Eyualem & Coomans, 1996

205 Monhystrella dorsicurvata sp. n.

(Figs. 48, 49)

Description

Measurements. Table 18.

Female: Small-sized, slender nematodes with body more tapering towards posterior end, ventrally curved with tail having a characteristic dorsal curvature, bent perpendicular to body axis, appearing ‘L’-shaped. Cuticle smooth without transverse striations as observed under LM. Somatic setae absent, caudal setae present, 4-5 in number. Lip region slightly offset. Lips amalgamated. Inner labial sensilla not discernible under LM; outer labial prominently raised; cephalic sensilla slightly raised, smaller than outer labials. Amphidial apertures circular, about 1/3rd-1/4th of corresponding body diam., located 8-10 μm or 1.6-2.0 times lip diam. from anterior end. Stoma funnel-shaped with a wide relatively thicker anterior and narrower posterior part, entirely surrounded by pharyngeal tissue; dorsal tooth not visible under LM. Pharynx with cylindrical and muscular corpus narrowing into an isthmus and subsequently into a posterior, strongly muscular pyriform bulb with thickened lumen, of 7-10 μm x 7-9 μm dimension. Nerve ring encircling isthmus at 57.1-67.5% of pharyngeal length from anterior end. Secretory-excretory pore hardly visible. Body at pharyngeal end 2.1-2.7 times lip diam. wide. Cardia 3-4 μm long. Intestine robust, thick-walled, granular with outer walls contricted 7-10 μm posterior to base of pharynx forming well developed progaster. Intestinal lumen very narrow, about 1-2 μm wide. Rectum as long as anal body diam. with dilated lumen. Anus a crescent- shaped slit. Tail elongate conoid, dorsally curved, bent perpendicular to body axis, tapering gradually to narrow terminus with spinneret of 1-1.5 μm. Three linearly arranged caudal glands opening terminally through spinneret.

Reproductive system monodelphic, prodelphic. Ovary outstretched, situated at right side of intestine. Oocytes arranged in two rows distally with large-sized maturing oocyte proximally. Oviduct and spermatheca not differentiated. Uterus without differentiation of glandular and muscular part. Vagina obliquely oriented, 4.0- 4.5 μm long or 33-35% of corresponding body diam. Vulva equatorial to slightly post-equatorial, at 50.4-56.5% from anterior end. Vulval lips slightly protruded. Vulva-anus distance 65-75 μm. Post-uterine sac absent. Uterine eggs not observed.

206 Male: Not found.

Diagnosis and relationship: Monhystrella dorsicurvata sp. n. is characterized by small-sized females; without somatic setae and 4-5 caudal setae; lip region offset; inner labial sensilla indistinct; cephalic sensilla slightly raised; outer labials prominently raised; stoma unarmed with funnel-shaped thicker anterior part and narrower posterior part; progaster in anterior intestinal region; ovary outstretched, occupying major portion of genital branch; uterus small; vagina obliquely oriented, rectum with dilated lumen and dorsally bent ‘L’-shaped long filiform tail with very small terminal mucro.

Monhystrella dorsicurvata sp. n. comes closest to M. jacobsi Abebe & Coomans, 1996 in most morphometric and morphological characteristics but differs in having somatic setae absent (vs present); lip region slightly offset (vs lip region conspicuously offset); stoma longer (7-8 μm vs 2.5-3.0 μm), elongate funnel-shaped (vs short conical) and unarmed (vs armed); three caudal glands linearly arranged (vs two caudal glands at same level and third one slightly posterior) and spinneret smaller (1.0-1.5 μm vs 4.0-6.0 μm in M. jacobsi Abebe & Coomans, 1996).

Monhystrella dorsicurvata sp. n. differs from M. paramacrura (Meyl, 1954) Andrássy, 1968 in having inner labial sensilla indistinct (vs conspicuous); stoma funnel-shaped (vs stoma with parallel walls); vagina without sphincter (vs sphincter present); tail longer with a long whip-like part (vs tail shorter with a small narrower part); smaller mucro (1.0-1.5 μm vs 10 μm) and tail ‘L’-shaped, heavily bent dorsally [vs slightly curved dorsally in M. paramacrura (Meyl, 1954) Andrássy, 1968].

Monhystrella dorsicurvata sp. n. differs from M. stewarti (Khera, 1970) Andrássy, 1981 in having females with relatively smaller ‘a’ (22.7-31.2 vs 31.0-34.0); ‘b’ (4.8-5.3 vs 6.3-6.5) and ‘ć’ (8.0-11.3 vs ~13.5-15.5) values; greater ‘c’ value (3.4- 4.4 vs 2.5-2.9); lip region slightly offset (vs distinctly offset); stoma longer (7.0-8.0 μm vs 2.0-2.5 μm); ovary much larger (54-87 μm vs 5-8 μm); vulva slightly post- equatorial (vs slightly pre-equatorial); rectum longer [7-10 μm vs 5 μm in M. stewarti (Khera, 1970) Andrássy, 1981].

Monhystrella dorsicurvata sp. n. differs from M. gracilis Khera, 1966 in having smaller females (0.31-0.37 mm vs 0.38-0.44 mm) with smaller ‘a’ (22.7-31.2 vs 31.0-42.0); ‘b’ (4.8-5.3 vs 5.4-5.7) and ‘ć’ (8.0-11.3 vs ~11.5) values; relatively

207 longer stoma (7-8 μm vs 7 μm); excretory pore inconspicuous (vs conspicuous) and rectum longer (7-10 μm vs 5 μm in M. gracilis Khera, 1966).

Type locality and habitat: Samples having Monhystrella dorsicurvata sp. n. were obtained from moist offshore soil at Keetham lake, Agra, Uttar Pradesh, India at coordinates 27°14.824’ N 077°51.240’ E.

Type specimens: Holotype female and nine paratype females on slides Monhystrella dorsicurvata sp. n. KL1-21/1-4 deposited in Nematode Collection, Department of Zoology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.

Etymology: The species epithet ‘dorsicurvata’ denotes strong dorsal curvature in tail region.

Remarks: The present population of Monhystrella dorsicurvata sp. n. is unique from earlier described Indian species in several features discussed in relationship. However, there also seems to be discrepancy in description of M. gracilis Khera, 1966 where a total of 12 sensilla have been reported of which six sensilla were setose and post- labial, in addition to one minute papillae on each lip. There is no mention of any terminal spinneret in the species. The species has also been reported from an aquatic habitat with high salinity. Our species also shows an aquatic habitat but with very low salinity as it is a fresh-water lake. In M. stewarti, ovary reported by Khera, 1970 is very small (5-8 μm) which is an unusual feature presumably large oocyte had been considered as an intra-uterine egg.

208 Table 18. Morphometric characteristics of Monhystrella dorsicurvata sp. n. Measurements are in µm and in the form: mean±standard deviation (range).

Character Holotype Female Paratype Female (n=9) Body length 319 332.8±22.6 (316-375) Body diam. 12 12.7±1.1 (11-14) a 26.5 26.3±2.5 (22.7-31.2) b 4.9 5.0±0.1 (4.8-5.3) c 3.7 3.7±0.2 (3.4-4.4) c' 10.6 10.1±1.4 (8.0-11.3) V 52.6 52.4±1.7 (50.4-56.5) G1 21 21.3±2.8 (17.0-25.1) Amphid-ant. end 10 9.1±0.7 (8-10) Amphid diam. 2 2±0 (2-2) Lip height 1 1.2±0.4 (1-2) Lip diam. 5 4.8±0.6 (4-6) Stoma length 7 7.6±0.5 (7-8) Stoma diam. 1 1±0 (1-1) Pharynx length 64 65.9±4.4 (63-77) Nerve ring-ant. end 42 42.3±3.6 (40-52) Rectum length 7 8.2±1.0 (7-10) Anal body diam. 8 8.9±0.8 (8-10) Tail length 85 89.7±9.4 (72-104)

209 Fig 48. Monhystrella dorsicurvata sp. n. A: Entire female. B: Female anterior region. C: Female pharyngeal region. D: Female reproductive system. E: Female posterior region.

210 Fig. 49. Monhystrella dorsicurvata sp. n. (Female). A: Anterior end (scanning electron microscopy). B, C: Anterior end. D: Pharyngeal region. E: Genital branch. F: Body cuticle (scanning electron microscopy). G: Vulval region. H: Posterior end (Scale bars= 10 μm).

211 Order: Plectida Malakhov, 1982

Diagnosis. Chromadoria. Cuticle annulated. Body pores, hypodermal glands and somatic sensilla usually present. Ocelli present only in several marine forms. Inner and outer labial sensilla usually papilliform. Cephalic sensilla setiform (with few exceptions, in members of subfamily Wilsonematinae, cephalic sensilla transformed into cornua). Amphids unispiral. Stoma cylindrical to funnel-shaped; cheilostom usually undifferentiated; gymnostom usually cylindrical; stegostom either undeveloped, funnel-shaped or cylindrical. Pharynx subdivided into corpus, isthmus and basal bulb with strongly sclerotized lining or valvular apparatus. Secretory- excretory pore usually present; opens to the exterior at the level of nerve ring. Female reproductive system didelphic, amphidelphic or monodelphic, prodelphic. Ovaries reflexed. Male reproductive system usually diorchic with opposed or outstretched testes; rarely one of the testes is reduced. Spicules paired and symmetrical. Gubernaculum present. Caudal glands present, opening separately or via a spinneret on tail tip.

Type superfamily: Plectoidea Örley, 1880

Other superfamilies

Ceramonematoidea Cobb, 1933

Haliplectoidea Chitwood, 1951

Leptolaimoidea Örley, 1880 Key to superfamilies of Plectida Malakhov, 1982

1. Cuticle coarsely annulated; labial sensilla papilliform or indistinct; cephalic sensilla setiform; stoma narrow cylindrical or absent; pharynx muscular without radial tubules and valvular apparatus; male with one pair precloacal supplements, postcloacal supplements absent ……………… Leptolaimoidea

2. Cuticle weakly to coarsely annulated; labial sensilla indistinct; cephalic sensilla setiform; stoma funnel-shaped; labial sensilla papilliform; cephalic sensilla setiform or modified; pharynx muscular with radial tubules and valvular apparatus; male precloacal supplements absent, postcloacal supplements one pair ……………………………………………… Plectoidea

212 3. Cuticle smooth or coarsely annulated; labial sensilla present or absent, if present, papilliform; cephalic sensilla papilliform or setiform; stoma narrow, elongate, tubular and armed with small teeth; pharynx with large elongate muscular basal bulb with valves; male pre- and postcloacal supplements absent, if present papilliform ………………………………….. Haliplectoidea

4. Cuticle smoothly annulated or ornamented giving appearance of crested tile- like plates; inner labial sensilla papilliform; outer labial and cephalic sensilla setiform; stoma funnel-shaped; pharynx cylindrical, muscular without radial tubules; midventral precloacal supplement papilliform; postcloacal supplements absent ……………………………………. Ceramonematoidea Superfamily: Plectoidea Örley, 1880

Diagnosis. Plectida. Cuticle weakly to coarsely annulated. Sub-cuticular ornamentation present or absent. Hypodermal glands and pores present or absent. Somatic and caudal setae present in both sexes. Labial region with six equal lips or biradially symmetrical. Amphids unispiral, open circular or transverse slit. Secretory- excretory duct forming loops on sides of pharynx. Pharynx with well-developed basal bulb having valve plates bearing numerous denticles and sometimes with post bulbar extension. Female reproductive system didelphic, amphidelphic, ovaries reflexed, located on alternate side of intestine. Male reproductive system diorchic or monorchic, anterior testis outstretched, posterior testis reflexed. Tubular supplements present or absent. Postcloacal sensilla absent or located at middle of tail. Caudal glands absent or present. Tail tip with a mucro or weakly cuticularized spinneret.

Type family: Plectidae Örley, 1880

Other families

Chronogastridae Gagarin, 1975

Metateratocephalidae Eroshenko, 1973 Key to families of Plectoidea Örley, 1880

1. Basal bulb sub-terminal with longitudinal denticulate ridges; posterior stegostom section long; female reproductive system monoprodelphic ………………………………………………………….……. Chronogastridae

213 - Basal bulb terminal or sub-terminal, with smooth/denticulate/corrugated transverse plates; posterior stegostom section short; female reproductive system didelphic ………………………………………………………………2

2. Lip region crown-shaped; lips leaf-like with cuticularized edges; outer labial sensilla setiform; male reproductive system monorchic ………………………………………………..………… Metateratocephalidae

3. Lip region with six equal lips or with biradially arranged cuticular outgrowths; outer labial sensilla papilliform; male reproductive system diorchic ……………………………………………………….………………. Plectidae Family: Plectidae Örley, 1880

Diagnosis. Plectoidea. Cuticle annulated. Sub-cuticular ornamentation absent. Lateral fields with two separated lateral alae. Hypodermal glands and pores present or absent. Somatic setae present in both sexes. Lip region with six equal lips or biradially symmetrical. Cephalic sensilla four, prominent. Amphids unispiral or transverse slit. Excretory duct forming loops on sides of pharynx, enveloped by renette cell. Stoma funnel-shaped, consisting of cheilostom, a cylindrical or arched gymnostom with sclerotized lining and a stegostom tapering posteriorly. Basal bulb terminal or slightly sub-terminal, with transverse or longitudinal valves bearing numerous denticles. Female reproductive system didelphic, amphidelphic; ovaries reflexed, located on alternate sides of intestine with anterior branch on right and posterior on left side of intestine. Male reproductive system diorchic, anterior testis outstretched, posterior testis reflexed. Additional to tubular supplements, precloacal and postcloacal sensilla also present. Caudal glands and spinneret present, spinneret sometimes surrounded by small papillae.

Type subfamily: Plectinae Örley, 1880

Other subfamilies

Anaplectinae Zell, 1993

Wilsonematinae Chitwood, 1951 Key to subfamilies of Plectidae Örley, 1880

1. Lip region with biradially arranged cuticular outgrowths; cervical expansions present; lateral outer labial sensilla elevated on mid-lateral projection; cephalic

214 sensilla leaf-shaped, sometimes with incised inner edge (cornua) ………………………………………………………………... Wilsonematinae

- Lip region with six equal lips; cuticular outgrowths and cervical expansions absent; outer labial sensilla papilliform or embedded in radial slits; cephalic sensilla setiform………….…………………………………………………. 2

2. Somatic sensilla restricted to tail only; cervical sensilla papilliform, present posterior to amphids; spermatheca and crustaformeria present; several pairs of precloacal papilliform sensilla present in male ……………… Anaplectinae

- Somatic sensilla present over whole body; cervical sensilla absent; spermatheca and crustaformeria absent …………………………….. Plectinae Subfamily: Wilsonematinae Chitwood, 1951

Diagnosis. Plectidae. Hypodermal glands absent. Somatic sensilla distributed over whole body. One or two pairs of somatic setae present at level of stoma. Lateral outer labial sensilla raised, on mid-lateral projections. Cephalic sensilla cylindrical or oval, sub-lateral edge incised (cornua). Anterior end with bilateral and dorsoventral symmetry. Cuticle inflated on dorsal and ventral sides of anterior end, forming bulbiform cervical expansions, annulated or smooth. Amphid unispiral or open circular. Gymnostom cuticularised, cylindrical or arched. Spermatheca and crustaformeria absent. Tubular supplements, pre- and post-cloacal sensilla absent.

Type genus: Wilsonema Cobb, 1913

Other genera

Ereptonema Anderson, 1966

Neotylocephalus Ali, Farooqui & Tejpal, 1969

Tylocephalus Crossman, 1933

215 Genus: Neotylocephalus Ali, Farooqui & Tejpal, 1969

Diagnosis. Wilsonematinae. Small-sized nematodes. Cuticle with smooth annulations. Lateral fields with two separate alae. Somatic and caudal setae present. Dierids present, close to excretory pore. Lip region with pronounced bilateral and dorsoventral symmetry. Cervical cuticular expansions bulbiform with smooth outline. Each expansion extends forward into two short submedian fimbriate flabella. Fimbriae only faintly visible under LM. Each lateral sector carrying a pair of sublateral cornua and a midlateral projection between lateral rim and oral opening. Cornua with narrow base and rims divided by deep incision into three tines. Midlateral projection of lateral lip short. Lateral rims without fimbriae. Amphidial apertures open circular. Stoma funnel-shaped with broad anterior part tapering towards base. Radial tubules present. Pharynx with cylindrical corpus, slightly narrower isthmus and well-developed basal bulb with small post bulbar extension. Female reproductive system didelphic, amphidelphic, ovaries reflexed. Tail short conoid, slightly curved. Caudal glands and spinneret present. Males rare.

Type species: Neotylocephalus annonae Ali, Farooqui & Tejpal, 1969

Other species

N. inflatus (Yeates, 1967) Holovachov, Boström, Tandingan De Ley, De Ley & Coomans, 2003

216 Neotylocephalus annonae Ali, Farooqui & Tejpal, 1969

(Figs. 50, 51)

Description

Measurements. Table 19.

Female: Small-sized nematodes, body ventrally arcuate upon fixation, gradually narrowing towards both extremities, more toward posterior region. Cuticle 1.0-1.5 µm thick with prominent transverse annulations, annules 1.0-1.2 µm wide in different parts of body. Lateral fields with lateral alae of 2.5-3.5 µm across, from mid-pharynx up to mid-tail. Lip region offset, lips amalgamated. Anterior region dorsoventrally flattened and bilaterally symmetrical. Peripheral cuticle expanding to form 5-6 μm long and 12-14 μm wide cervical cuticular expansion. Cervical cuticular expansion smooth, bulbiform, extending forward to form two submedian 2-3 μm long flabella. Each flabellum bearing fine fimbrae to all its length, not discernible or inconspicuous under LM. Lateral rim smooth, without fimbrae. A pair of 3.0-3.5 µm long cornua having three tines of which the median one is a longest and outwardly curved. Each lateral sector have a reduced and oval mid lateral projection. Amphidial apertures open circular, 2 µm wide, located 5-7 μm or mid level of stoma. Stoma plectoid-type with broad anterior and narrow posterior part; cheilostom strongly cuticularized with sloping walls; gymnostom cuticularized with parallel walls; stegostom unarmed, tapering towards base, surrounded by pharyngeal collar. Radial tubules present at base of stoma. Pharynx muscular with cylindrical corpus, relatively narrower isthmus and oval to rounded basal bulb of 9-12 μm x 8-10 μm dimension with grinder and haustrulum. Post-bulbar elongation 2.0-2.5 μm long. Nerve ring encircling posterior corpus at 58.7-65.7% of pharyngeal length from anterior end. Secretory-excretory pore slightly posterior to nerve ring in isthmus region, at 65.7-66.6% of pharyngeal length from anterior end. Hemizonid and dierids inconspicuous. Cardia 3-4 μm long surrounded by intestinal tissue. Intestine with thickened walls made of polygonal cells, intestinal lumen narrow. Rectum thick-walled, as long as anal body diam. Tail short conoid, more tapering in posterior two-third region, slightly arcuate, with 5 caudal setae: one pair subdorsal, one pair ventro-sublateral and a dorsal spur 7-8 μm anterior to tail terminus. Caudal glands three, linearly arranged open to exterior by short tubular spinneret.

217 Reproductive system didelphic, amphidelphic, compactly built, ovaries reflexed, anterior branch on right and posterior branch on left side of intestine. Oocytes diminishing in size towards distal end. Oviduct and spermatheca not differentiated. Uterus without distinct columella. Vagina thick-walled, slightly obliquely placed, 5-6 μm long or 1/3rd of corresponding body width. Vulva a transverse slit, slightly post-equatorial, 53.9-56.9% from anterior end, vulval lips not protruded. Epiptygma absent. Intra-uterine eggs of 33-35 μm x 12-15 μm dimension observed in few individuals.

Male: Not found.

Locality and habitat: Samples having Neotylocephalus annonae Ali, Farooqui & Tejpal, 1969 were obtained from soil near coast at Keetham lake, Agra, Uttar Pradesh, India at coordinates 27°15.062’ N 077°51.148’ E.

Voucher specimens: Six females on slides Neotylocephalus annonae Ali, Farooqui & Tejpal, 1969 KL4-15/1-4 deposited in Nematode Collection, Department of Zoology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.

Remarks: The present population shows conformity to the Indian species Neotylocephalus annonae Ali, Farooqui & Tejpal, 1969 in most morphometric and morphological characteristics with minor differences. Females with relatively smaller ‘ć’ value (2.2-2.7 vs 2.5-4.0); cervical cuticular expansion relatively small (5-6 μm vs 6-8 μm long and 12-14 μm vs 13-21 μm wide); cornua with outer tines rounded (vs conical) and amphids at mid level of stoma (vs posterior to middle of stoma in Neotylocephalus annonae Ali, Farooqui & Tejpal, 1969).

218 Table 19. Morphometric characteristics of Neotylocephalus annonae Ali, Farooqui & Tejpal, 1969. Measurements are in µm and in the form: mean±standard deviation (range).

Character Female (n=6) Body length 228.6±11.6 (215-241) Body diam. 16.1±1.1 (15-18) a 14.1±1.0 (13.1-15.8) b 3.3±0.2 (3.1-3.7) c 10.3±0.4 (9.6-10.8) c' 2.4±0.2 (2.2-2.7) V 55.5±1.0 (53.9-56.9) G1 14.9±3.0 (12.8-20.9) G2 17.8±3.6 (12.6-21.9) Amphid-ant. end 6.1±0.7 (5-7) Amphid diam. 2±0 (2-2) Lip height 2±0 (2-2) Lip diam. 6.6±0.5 (6-7) Stoma length 10.8±0.4 (10-11) Stoma diam. 2±0 (2-2) Pharynx length 67.5±4.8 (63-76) Nerve ring-ant. end 41.1±5.1 (37-50) Secretory-excretory pore-ant. end 45.8±2.9 (42-50) Rectum length 8.8±0.7 (8-10) Anal body diam. 8.8±0.4 (8-9) Tail length 22.1±1.9 (20-25) Egg dimension 34.0±1.4 x 13.5±2.1 (33-35 x 12-15)

219 Fig 50. Neotylocephalus annonae Ali, Farooqui and Tejpal, 1969 A: Entire female. B, C: Female anterior region. D: Female pharyngeal region. E. Female reproductive system. F: Female posterior region.

220 Fig. 51. Neotylocephalus annonae Ali, Farooqui & Tejpal, 1969 (Female). A-D: Anterior end. E: Pharyngeal region. F: Lateral fields. G: Vulval region and intra-uterine egg. H, I: Posterior end showing spinneret (Scale bars= 10 μm).

221 Genus: Tylocephalus Crossman, 1933

Diagnosis. Wilsonematinae. Small-sized nematodes. Cuticle with fine transverse annulations. Lateral fields with two separate alae. Somatic and caudal setae present. Lip region offset with bilateral and dorsoventral symmetry, lips amalgamated. Cervical cuticular expansions annulated, extends orally into a median ridge. Outer labial sensilla on inner edge of median ridge. Cornua four, setiform or flat. Mid-lateral projection short. Lateral rims without fimbriae. Amphidial apertures open circular. Stoma funnel-shaped with broad anterior part tapering towards base. Radial tubules present. Pharynx with cylindrical corpus, slightly narrower isthmus and well- developed basal bulb with small post bulbar extension. Dierids present, close to excretory pore. Female reproductive system didelphic, amphidelphic, ovaries reflexed. Tail short conoid, slightly curved. Caudal glands and spinneret present. Males rare. Spicules arcuate. Gubernaculum absent.

Type species: Tylocephalus auriculatus (Bütschli, 1873) Crossman, 1933

Other species

T. andinus Zell, 1985

T. annulatus Zell, 1985

T. becki Zell, 1985

T. cephalatus (Cobb, 1893) Anderson, 1966

T. cornutus Zell, 1985

T. laticollis Zell, 1985

T. longicornis Holovachov, Boström & Mundo-Ocampo, 2004

T. nimius De Ley & Coomans, 1998

T. palmatus Tahseen, Ahmad & Jairajpuri, 1995

T. primitivus Holovachov, Boström & Mundo-Ocampo, 2004

222 Tylocephalus aprimitivus sp. n.

(Figs. 52, 53)

Description

Measurements. Table 20.

Female: Small-sized nematodes, slightly curved upon fixation. Cuticle 1.0-1.2 µm thick with fine transverse annulations, annules 0.8-1.0 μm wide. Lateral fields 4-5 µm wide with two separate wings divided by striated cuticle, from mid of pharyngeal region up to level of caudal glands. Somatic setae sparsely distributed over whole body: one or two in pharyngeal region; one or two from basal bulb to vulva and one or two from vulva to anus. Lip region offset, lips amalgamated. Four cephalic sensilla modified to form one pair subdorsal and one pair subventral cornua, anteriorly directed with broad base and pointed tip. Cervical cuticular expansion reduced, appearing like a slight cuticular swelling, finely annulated with 8-9 annules faintly visible under LM, 3.0-3.5 times longer than cornua. Mid lateral projection rudimentary, faintly visible under LM. Lateral rim hardly visible. Amphidial aperture open circular, 2.0-2.5 µm wide, located 8-10 µm at mid level of stoma from anterior end. Stoma plectoid-type; cheilostom weakly cuticularised; gymnostom cuticularised with arched walls; stegostom less cuticularised than gymnostom, unarmed, gradually tapering towards base, often with curved walls at its junction with pharyngeal lumen. Radial tubules at base of stoma. Pharynx with slightly thicker and muscular corpus continuing into slightly narrower isthmus and rounded basal bulb of 13-16 μm x 10- 14 μm dimension with grinder and haustrulum. Post-bulbar extension 2.5-3.5 μm long. Nerve ring encircling corpus at 58-63% of pharyngeal length from anterior end. Secretory-excretory pore slightly posterior to nerve ring at 63.9-68.4% of pharyngeal length from anterior end. Secretory-excretory duct inconspicuous. Hemizonid absent. Dierids at mid of lateral field, 5-6 annules posterior to secretory-excretory pore. Cardia small, 3-5 μm long, surrounded by intestinal tissue. Intestine with wide lumen. Rectum thick-walled, as long as anal body diam. Anus a crescent-shaped slit. Tail short conoid, straight to strongly curved. Caudal setae seven: two pairs subdorsal, one pair ventro-sublateral and a dorsal spur present 4.0-4.5 µm anterior to tail terminus. Three linearly arranged caudal glands opening to exterior by 1.0-1.5 µm long tubular spinneret.

223 Reproductive system didelphic, amphidelphic, compactly built, ovaries dorsally reflexed, anterior genital branch at right and posterior on left side of intestine. Oocytes arranged in two rows distally and single oocyte at proximal end. Oviduct and spermatheca not differentiated. Uterus muscular. Vagina thick-walled, 5-7 μm long or occupying 1/3 of corresponding body diam. Vulva a transvers slit-like, equatorial at 50.6-52.7% from anterior end. Vulval lips slightly protruded. Epiptygma absent. Intra-uterine eggs not observed.

Male: Not found.

Diagnosis and relationship: Tylocephalus aprimitivus sp. n. is characterized by small-sized females; cuticle finely annulated; very few somatic and caudal setae present; reduced cervical cuticular expansion with 8-9 fine annules faintly visible under LM; rudimentary mid-lateral projection; four cephalic sensilla modified to form one pair subdorsal and one pair subventral cornua; reproductive system compact and a total of seven setae present in tail comprising of three paired and one unpaired sub- terminal seta.

Tylocephalus aprimitivus sp. n. comes closest to T. primitivus Holovachov, Boström & Mundo-Ocampo, 2004 in most morphometric and morphological characteristics but differs in having relatively smaller females (0.30-0.33 mm vs 0.31- 0.44 mm) with relatively greater ‘a’ value (14.0-22.7 vs 11.5-17.6); cornua with pointed tip (vs bilobed tip); relatively smaller stoma (14.0-19.0 μm vs 17.0-25.5); pharyngeal region with one or two somatic setae (vs six to seven); dierids 5-6 annules posterior to secretory-excretory pore (vs at level of secretory-excretory pore) and secretory-excretory duct faint (vs conspicuous in T. primitivus Holovachov, Boström & Mundo-Ocampo, 2004).

Tylocephalus aprimitivus sp. n. differs from Indian species T. palmatus Tahseen, Ahmad & Jairajpuri, 1995 in having smaller females (0.30-0.33 mm vs 0.47- 0.61 mm) with smaller ‘b’ (3.3-3.6 vs 3.6-4.3) and ‘c’ (8.6-10.7 vs 13.1-13.9) values; greater ‘ć’ value (3.3-4.6 vs 2.3-2.8); cervical cuticular expansion smaller (10-13 μm x 9-11 μm vs 15-21 μm x 18-20 μm) with lesser annules (8-9 vs 12-13) and smaller stoma (14-19 μm vs 21-23 μm in T. palmatus Tahseen, Ahmad & Jairajpuri, 1995).

224 Type locality and habitat: Samples having Tylocephalus aprimitivus sp. n. were obtained from offshore moist soil with algal growth at Keetham lake, Agra, Uttar Pradesh, India at coordinates 27°15.055’ N 077°51.150’ E.

Type specimens: Holotype female and seven paratype females on slides Tylocephalus aprimitivus sp. n. KL2-21/1-4 deposited in Nematode Collection, Department of Zoology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.

Etymology: The species name ‘aprimitivus’ denotes its close relationship with the congener T. primitivus.

225 Table 20. Morphometric characteristics of Tylocephalus aprimitivus sp. n. Measurements are in µm and in the form: mean±standard deviation (range).

Character Holotype Female Paratype Female (n=7) Body length 327 320.7±8.8 (308-332) Body diam. 17 19.1±2.8 (14-22) a 19.2 17.0±2.7 (14.0-22.7) b 3.4 3.4±0.09 (3.3-3.6) c 9 9.5±0.6 (8.6-10.7) c' 4 3.7±0.3 (3.3-4.6) V 51.9 51.8±0.6 (50.6-52.7) G1 9.7 14.9±3.5 (9.7-20.7) G2 13.7 15.0±1.5 (12.7-17.5) Amphid-ant. end 10 8.7±0.7 (8-10) Amphid diam. 2 2±0 (2-2) Lip height 3 3.1±0.8 (2-4) Lip diam. 6 5.8±0.6 (5-7) Stoma length 19 16.3±1.5 (14-19) Stoma diam. 2 2±0 (2-2) Pharynx length 95 90.7±3.4 (86-95) Nerve ring-ant. end 59 54.0±3.8 (50-60) Secretory-excretory pore-ant. 65 60.3±3.4 (55-65) end Rectum length 10 10.3±0.5 (10-11) Anal body diam. 9 8.8±0.8 (8-10) Tail length 36 33.6±2.5 (30-37)

226 Fig 52. Tylocephalus aprimitivus sp. n. A: Entire female. B: Female anterior region. C: Female pharyngeal region. D: Female reproductive system. E: Female posterior region.

227 Fig. 53. Tylocephalus aprimitivus sp. n. (Female). A-C: Anterior end. D: Pharyngeal region. E: Lateral fields. F, G: Vulval region and genital branches. H, I: Posterior end showing spinneret (Scale bars= 10 μm).

228 Family: Chronogastridae Gagarin, 1975

Diagnosis. Plectoidea. Cuticle annulated. Lateral fields indistinct. Hypodermal glands present or absent. Somatic setae present in both sexes or sometimes only in males. Lip region with six equal lips. Cephalic sensilla setiform. Amphids unispiral, stirrup- or horseshoe-shaped. Stoma funnel-shaped with elongate stegostom. Basal bulb sub- terminal, weakly to strongly developed with triradiate denticulate valves with rows of denticles present or absent. Post bulbar extension present. Excretory duct coiled around isthmus. Female reproductive system didelphic, amphidelphic or monodelphic, prodelphic. Male reproductive system diorchic, with opposed testes. Tubular supplements present or absent. Precloacal sensilla setiform or absent. Postcloacal sensilla usually present. Caudal glands present or absent. Tail tip with mucro or spinneret.

Type genus: Chronogaster Cobb, 1913

Other genera

Caribplectus Andrássy, 1973

Cynura Cobb, 1920

Keralanema Siddiqi, 2003

Kischkenema Siddiqi, Winiszewska & Malewski, 2013

Rugoster Siddiqi, Handoo & Siddiqi, 2013

229 Genus: Chronogaster Cobb, 1913

Diagnosis. Chronogastridae. Cuticle annulated, occasionally with longitudinal incisures, ridges and spines. Hypodermal glands present or absent. Somatic setae absent, caudal setae present only in males. Amphids unispiral, stirrup- or horseshoe- shaped. Stoma funnel-shaped. Pharynx cylindrical with well-developed basal bulb and post bulbar elongation. Basal bulb with triradiate denticulate valves. Female reproductive system monodelphic, prodelphic. Tubular supplements present or absent. Precloacal sensilla setiform or absent. Postcloacal sensilla present. Caudal glands and spinneret usually absent with exception of C. boettgeri. Tail terminus with differently shaped mucro.

Type species: Chronogaster gracilis Cobb, 1913

Other species

C. africana Heyns & Coomans, 1980 C. alata Gerlach, 1956 C. andrassyi Loof & Jairajpuri, 1965 C. aspinata Raski & Maggenti, 1985 C. bengalensis Saha, Lal & Singh, 2001 C. bigubernacula Khera, 1972 C. brasiliensis Meyl, 1957 C. cameroonensis Heyns & Coomans, 1984 C. carolinensis Eyualem-Abebe, Ferebee, Taylor, Mundo-Ocampo, Mekete & De Ley, 2013 C. chilkensis Khera, 1972 C. citri Khan & Nanjappa, 1973 C. costaricae Zullini, Loof & Bongers, 2002 C. daoi Loof, 1964 C. elegans Raski & Maggenti, 1985 C. ethiopica Eyualem-Abebe & Coomans, 1996 C. floridensis Raski & Maggenti, 1985 C. getachewi Eyualem-Abebe & Coomans, 1996

230 C. glandifera Heyns & Coomans, 1980 C. indica Bajaj & Bhatti, 1979

C. jankiewiczi Winiszewska-Slipińska, 1997 C. laxus Sultana & Bohra, 2011 C. lissa Loof, 1973 C. longicaudata Heyns & Coomans, 1980 C. longicollis (Daday, 1899) Andrassy, 1958 C. loofi Chaturvedi & Khera, 1979

C. mexicana Winiszewska-Slipińska, 1997 C. multispinata Heyns & Coomans, 1980 C. multispinatoides Heyns & Coomans, 1984 C. neoparva Tahseen & Siddiqi, 2003 C. neotypica Tahseen, Ahmad & Ahmad, 1994 C. parva Heyns & Coomans, 1984

C. polonica Winiszewska-Slipińska, 1997 C. pseudotypica Gagarin & Thanh, 2004 C. rotundicauda Heyns & Coomans, 1984 C. sclerostoma Tahseen & Siddiqi, 2003 C. serrulata Loof, 1973 C. spicata Heyns & Coomans, 1984 C. spinicauda Tahseen, Ahmad & Ahmad, 1994 C. subtilis Andrássy, 1958 C. tenuis Loof & Jairajpuri, 1965 C. troglodytes Poinar & Sarbu, 1994 C. typica (de Man, 1921) De Coninck, 1937 C. udaipurensis Sultana & Bohra, 2011 C. vacuoli Saha, Lal & Singh, 2001 C. zujarensis Ocaña & Coomans, 1991

231 Chronogaster glandulata sp. n.

(Figs. 54, 55)

Description

Measurements. Table 21.

Female: Medium-sized nematodes with body strongly curved to almost ‘C’-shaped upon fixation, tapering more towards posterior region. Cuticle 0.8-1.0 μm thick, transversely annulated, annules 1.0-1.2 μm in pharyngeal region and 1.2-1.5 μm in rest of body. 1.2-1.4 μm wide. Lateral fields not differentiated. Glandular bodies present making structures not clearly visible. Lip region continuous with adjoining body, unstriated, lips amalgamated. Inner and outer labial sensilla indiscernible under LM; cephalic sensilla fine, long setose, 7-8 μm long or about 1.2-1.5 times lip width long. Amphidial openings slit-like, 2-3 μm wide, situated 5.0-5.5 μm or a lip diam. from anterior end. Stoma funnel-shaped with anterior broad and posterior narrow part, 7-8 times as long as wide; cheilostom weakly cuticularised; gymnostom cuticularised, 5.0-5.5 μm long or 30-35% of stoma length; stegostom narrowing towards base, 10- 12 μm or 60-65% of stoma length. Radial tubules at base of stoma. Pharyngeal collar covering 60-65% of stoma from base. Pharynx with 131-135 μm long cylindrical anterior part without any differentiation of corpus and isthmus. Basal bulb ovoid, 15- 20 μm x 9-11 μm in dimension with triradiate valve in anterior region bearing 7-8 linearly arranged denticles in 8-9 vertical rows followed by a smaller chamber apparently containing few denticles as visible under LM. Post-bulbar extension 10-19 μm long. Nerve ring encircling pharynx at 43.5-48.8% of its length from anterior end. Secretory-excretory pore faintly visible, slightly posterior to nerve ring at 51.9-63.9% of pharyngeal length from anterior end. Cardia small, 3-4 μm long. Intestine thin- walled with wide lumen. Rectum thick-walled, 1.3-1.5 times anal body diam. long. with lining strongly cuticularised. Anus a crescent-shaped slit. Tail strongly arcuate, tapering posteriorly, 9.2-11.6 times anal body diam. long with claw-like 1.0-1.5 μm long dorsal mucro at terminus.

Reproductive system monodelphic, prodelphic; ovary dorsally reflexed with distal tip of ovary not reaching vulval level. Oocytes arranged in 2-3 rows distally with a large oocyte placed at proximal end. Oviduct and spermatheca not distinctly differentiated. Uterus muscular with intra-uterine egg of 63 μm x 14 μm dimension,

232 observed in one female. Vagina obliquely oriented, 4.5-5.5 μm long or 33-35% of corresponding body diam. Vulva pre-equatorial to nearly equatorial, 44.2-49.3% from anterior end. Vulval lips slightly protruded. Post-uterine sac absent.

Male: Not found.

Diagnosis and relationship: Chronogaster glandulata sp. n. is characterized by medium-sized females; cuticle transversely annulated with labial region non-striated; glandular bodies present in pseudocoelom; cephalic sensilla fine, long setose, 1.2-1.5 times labial diam. long; stoma funnel-shaped, 7-8 times as long as wide with cuticularised gymnostom; basal bulb with triradiate valve in anterior region bearing linearly arranged 7-8 denticles in 8-9 rows followed by a smaller chamber showing irregular denticles; secretory-excretory pore faintly visible; tail strongly arcuate with a claw-like dorsal mucro.

Chronogaster glandulata sp. n. comes closest to C. spicata Heyns & Coomans, 1983 in most morphological and morphometric characteristics but differs in having longer stoma (18-22 μm vs 5.0-6.5 μm); radial tubules at base of stoma (vs 11-17 μm posterior to base of stoma); post-bulbar extension relatively longer (10-19 μm vs 9.0- 11.5 μm); post-uterine sac absent (vs present) and smaller uterine eggs (63 x 14 μm vs 67 x 20 μm in C. spicata Heyns & Coomans, 1983).

Chronogaster glandulata sp. n. differs from C. cameroonensis Heyns & Coomans, 1983 in having smaller females (0.66-0.77 mm vs 0.92-0.95 mm) with smaller ‘b’ (4.2-4.7 vs 4.8-5.2) and ‘ć’ (9.2-11.6 vs 21.8-23.8) values; greater ‘c’ value (6.2-7.3 vs 4.0-4.3); longer stoma (18-22 μm vs 6.0-6.5 μm); radial tubules at base of stoma (vs 14.0-14.5 μm posterior to base of stoma); basal bulb with double denticulate valves (vs single denticulate valve); vulva nearly equatorial (vs pre-equatorial); post-uterine sac absent (vs present) and smaller eggs (63 x 14 μm vs 65-70 x 17 μm in C. cameroonensis Heyns & Coomans, 1983).

Chronogaster glandulata sp. n. differs from C. parva Heyns & Coomans, 1983 in having larger females (0.66-0.77 mm vs 0.40-0.48 mm) with greater ‘a’ (44.3-54.1 vs 28.0-39.0); ‘b’ (4.2-4.7 vs 3.7-4.3) and ‘c’ (6.2-7.3 vs 3.7-6.6) values; relatively smaller ‘ć’ value (9.2-11.6 vs 10.0-18.4); cephalic setae longer (7-8 μm vs 3-4 μm); longer stoma (18-22 μm vs 4-5 μm); radial tubules at base of stoma (vs 11-13 μm posterior to base of stoma); basal bulb with double denticulate valves (vs single

233 denticulate valve); post-bulbar extension longer (10-19 μm vs 5-7 μm) and rectum (1.3-1.5 vs 1.6-1.9 times anal body diam. long. in C. parva Heyns & Coomans, 1983).

Chronogaster glandulata sp. n. differs from C. getachewi Abebe & Coomans, 1996 in having smaller females (0.66-0.77 mm vs 0.82-0.95 mm) with smaller ‘b’ (4.2-4.7 vs 5.3) and ‘ć’ (9.2-11.6 vs 18.4-21.9) values; greater ‘c’ value (6.2-7.3 vs 4.5-4.7); cephalic setae longer (7.0-8.0 μm vs 4.5-5.0 μm); longer stoma (18-22 μm vs 6 μm); radial tubules at base of stoma (vs 10-13 μm posterior to base of stoma); post-bulbar extension smaller (10-19 μm vs 22-25 μm); secretory-excretory pore faintly visible (vs inconspicuous); post-uterine sac absent (vs present) and tail terminus with smaller dorsal mucro (1.0-1.5 μm vs 2.0 μm in C. getachewi Abebe & Coomans, 1996).

Chronogaster glandulata sp. n. differs from C. glandifera Heyns & Coomans, 1980 in having smaller females (0.66-0.77 mm vs 1.33-1.47 mm) with smaller ‘a’ (44.3-54.1 vs 55.0-75.0); ‘b’ (4.2-4.7 vs 5.0-5.7) and ‘c’ (6.2-7.3 vs 7.8-9.5) values; cephalic setae smaller (7.0-8.0 μm vs 9.0-12.5 μm); longer stoma (18-22 μm vs 5.5-7.5 μm); radial tubules at base of stoma (vs 20-24 μm posterior to base of stoma); rectum 1.3- 1.5 times anal body diam. (vs 1.6-2.1 times anal body diam.); post-uterine sac absent (vs present) and mucro present at tail terminus (vs absent in C. glandifera Heyns & Coomans, 1980).

Chronogaster glandulata sp. n. differs from C. brasiliensis Meyl, 1957 in having smaller females (0.66-0.77 mm vs 0.80-0.90 mm) with greater ‘c’ value (6.2-7.3 vs 4.2-4.5); smaller ‘ć’ value (9.2-11.6 vs 24.0); cephalic setae longer (7-8 μm vs 6 μm); post-bulbar extension smaller (10-19 μm vs 20 μm in C. brasiliensis Meyl, 1957).

Chronogaster glandulata sp. n. differs from C. tenuis Loof & Jairajpuri, 1965 in having smaller females (0.66-0.77 mm vs 1.06-1.18 mm) with smaller ‘a’ (44.3-54.1 vs 67.0-75.0) and ‘ć’ (9.2-11.6 vs 21-22) values; greater ‘c’ value (6.2-7.3 vs 4.8-5.2); cephalic setae smaller (7-8 μm vs 9 μm); post-bulbar extension smaller (10-19 μm vs 27-29 μm in C. tenuis Loof & Jairajpuri, 1965).

Type locality and habitat: Samples having Chronogaster glandulata sp. n. were obtained from soil of the shore of lake at Keetham lake, Agra, Uttar Pradesh, India at coordinates 27°15.307’ N 077°50.837’ E.

234 Type specimens: Holotype female and nine paratype females on slides Chronogaster glandulata sp. n. KL-26/1-4 deposited in Nematode Collection, Department of Zoology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.

Etymology: The species epithet ‘glandulata’ denotes the presence of glandular bodies in pseudocoelom.

Remarks: There are 46 valid species of Chronogaster Cobb, 1913 but they largely differ on various accounts including the mucro type, the morphology of which remains consistent in a species. Therefore, comparisions were made with those species having a similar/ dorsally extended linear mucro.

235 Table 21. Morphometric characteristics of Chronogaster glandulata sp. n. Measurements are in µm and in the form: mean±standard deviation (range).

Character Holotype Female Paratype Female (n=9) Body length 700 726.8±35.1 (669-777) Body diam. 15 15.5±1.2 (13-17) a 46.6 47.0±3.0 (44.3-54.1) b 4.2 4.4±0.1 (4.2-4.7) c 6.8 6.7±0.3 (6.2-7.3) c' 10.2 10.0±0.6 (9.2-11.6) V 49.2 48.1±1.4 (44.2-49.3) G1 26.8 19.7±4.9 (14.8-28.1) Lip height 2 2±0 (2-2) Lip diam. 5 5±0 (5-5) Stoma length 20 19.9±1.1 (18-22) Stoma diam. 2 2±0 (2-2) Pharynx length 165 163.1±6.2 (154-172) Nerve ring-ant. end 80 75.0±5.7 (67-84) Secretory-excretory pore- 104 91.8±12.2 (80-110) ant. end Rectum length 13 15.1±2.4 (13-19) Anal body diam. 10 10.6±0.6 (10-12) Tail length 102 106.8±5.8 (100-116) Egg dimension -- 63 x 14

236 Fig 54. Chronogaster glandulata sp. n. A: Entire female. B: Female anterior region. C: Female pharyngeal region. D: Female reproductive system. E: Female posterior region.

237 Fig. 55. Chronogaster glandulata sp. n. (Female). A: Anterior end (scanning electron microscopy). B: Anterior end. C: Posterior pharyngeal region showing basal bulb and post-bulbar elongation. D: Basal bulb showing denticulate valve. E, F: Genital branch and vulva. G: Vulval region (scanning electron microscopy). H, I: Tail tip showing dorsal mucro (Scale bars= 10 μm).

238 Class: Enoplea Inglis, 1983

Diagnosis. Nematode. Cuticle smooth or finely annulated. Amphids pocket-like, usually post labial. Pharynx cylindrical or bottle-shaped with three to five pharyngeal glands. Excretory system simple, non-tubular, usually with a single cell. Phasmids present or absent. Female reproductive system didelphic. Male generally with two testes. Bursa absent. Subclass: Enoplia Pearse, 1942

Diagnosis. Enoplea. Mainly consist of free-living forms except Trichodorids that are plant parasites. Inner labial sensilla papilliform. Outer labial and cephalic sensilla setiform. Stoma variable in shape with tooth, teeth or denticles, teeth sometimes movable (eg. Triplonchidae, Diptherophorina). Pharynx cylindrical, occasionally widened at base. Pharyngeal glands open in or close to stoma. Caudal glands usually present. Order: Enoplida Filipjev, 1929

Diagnosis. Enoplia. Large-sized nematodes. Cuticle mostly smooth or weakly striated, often provided with somatic setae. Metanemes present or absent. Lip region continuous or offset, often divided into three or six lips. Inner labial sensilla six, papilliform or setiform; outer labial sensilla six, setiform; cephalic setae four. Amphids typically non-spiral with amphidial fovea pocket-like, rarely circular or spiral. Stoma variable in shape, with armature, surrounded by pharyngeal collar to its entire length or at base. Pharynx cylindrical, sometimes slightly expanded at the base. Excretory system consist of a ventral gland and a duct opening anterior to nerve ring. The dorsal and two ventrosublateral pharyngeal glands open either in or slightly posterior to stoma or to nerve ring. Female reproductive system didelphic, amphidelphic rarely monodelphic, prodelphic with reflexed ovaries, rarely outstretched. Male reproductive system diorchic with opposed testes. Caudal glands, if present, open through a common pore, a tail terminus. Precloacal supplements present or absent, if present, one or two or numerous, papilloid, setose or tubular.

239 Type suborder: Enoplina Chitwood & Chitwood, 1937

Other suborders

Alaimina Clark, 1961

Campydorina Jairajpuri, 1983

Ironina Siddiqi, 1983

Oncholaimina De Coninck, 1965

Trefusiina Siddiqi, 1983

Tripyloidina De Coninck, 1965 Key to suborders of Enoplida Filipjev, 1929

1. Cuticle smooth with scattered setae; cephalic cuticle thickened cap-like; cephalic setae well-developed, non-articulate, sometimes very long; amphids indistinct; metanemes usually present; stoma funnel-shaped with teeth, completely surrounded by pharyngeal collar; excretory pore in cephalic region; female reproductive system didelphic; testis paired; precloacal supplements one or two, tubuliform; caudal gland cells in precaudal region ……………………………………………….…………………...... Enoplina

2. Cuticle smooth; cephalic cuticle thickened but not forming capsule; cephalic setae non-articulate; metanemes present; amphids pocket-like; stoma barrel- shaped with teeth, posterior end surrounded by pharyngeal collar; excretory pore close to lip region or anterior half of pharynx; female reproductive system monodelphic or didelphic; testes paired; precloacal male supplements setose or papilloid; caudal gland cells extending precaudally ………………………………..……...... Oncholaimina

3. Cuticle smooth; cephalic cuticle usually not forming capsule; cephalic sensilla small setiform; metanemes present; amphids pocket-like sometimes with longitudinal opening; stoma elongate tubular, surrounded by pharyngeal collar; excretory pore in pharyngeal region; female reproductive system didelphic rarely monodelphic; testes paired; male supplements setiform; caudal glands present or absent ………………………………………. Ironina

240 4. Lip region with setiform sensilla; cephalic setae articulate; amphidial opening circular; metanemes present; stoma funnel-shaped rarely barrel-shaped, with 2 or 3 chambers, teeth present or absent; female reproductive system didelphic; testis single; male supplements present papilliform or absent; caudal gland cells present in tail region ………………………………….…. Tripyloidina

5. Cuticle finely annulated with few longitudinal lines; labial and cephalic sensilla papilliform; metanemes absent; amphids small, obscure, pocket like with transverse aperture; stoma tubular with dorsal hollow tooth; female reproductive system didelphic; testis single; male supplements small not setose; caudal glands absent ………………………………….. Campydorina

6. Cuticle smooth, somatic setae absent; lip region simple; labial sensilla papilliform never setose; metanemes absent; amphids pore like or crescent shaped with transverse aperture; stoma quite small without armature entirely surrounded by pharyngeal collar; female reproductive system didelphic or monodelphic; testis single; male supplements papiliform; caudal glands absent ……………………………………………………………………….. Alaimina

7. Lip region simple; outer labial and cephalic sensilla setose; metanemes absent; amphids pocket-like rarely spiral; stoma conical or barrel-shaped without armature; excretory pore absent or sometimes present; female reproductive system didelphic; testis double; male supplements present or absent; caudal glands present …………………………………..……………….. Trefusiina Suborder: Ironina Siddiqi, 1983

Diagnosis. Enoplida. Large-sized nematodes. Cuticle smooth. Metanemes present. Lip region with three or six lips. Labial sensilla papilliform or setiform. Cephalic sensilla setiform, non-articulate. Amphids pocket-like, at base of lip region. Stoma narrow, tubular or funnel-shape with cuticularised walls, without teeth or having tooth-like structures or with three, four or five movable teeth at anterior end (normally three, but dorsal or ventrosublateral may be double). Pharyngeal glands do not open through the teeth but in posterior region of stoma. Stoma surrounded by pharyngeal collar. Pharynx cylindrical, strongly muscular. Female reproductive system didelphic- amphidelphic with reflexed ovaries or monodelphic-opisthodelphic. Males diorchic

241 with opposed testes or monorchic; supplements present, setose or knob-like or absent. Caudal glands present or absent.

Type and only superfamily: Ironoidea de Man, 1876 Superfamily: Ironoidea de Man, 1876

Diagnosis. Ironina. Cuticle smooth. Body occasionally very large. Lips region with three lips. Labial sensilla six and cephalic sensilla four, setose or papilliform, non- articulate. Metanemes present. Amphids stirrup-shaped. Stoma long, tubular with cuticularised walls and movable teeth, surrounded by pharyngeal collar. Dorsal and subventral glands opening at stoma base. Pharynx cylindrical. Female reproductive system didelphic, amphidelphic with reflexed ovaries or rarely monodelphic. Male supplements setiform. Caudal glands present or absent.

Type family: Ironidae de Man, 1876

Other families

Leptosomatidae Filipjev, 1916

Oxystominidae Chitwood, 1935 Key to families of Ironoidea de Man, 1876

1. Stoma long and tubular, walls strongly cuticularized, 3-5 movable teeth at anterior edge ………………………………………………………….. Ironidae

- Stoma very small, narrow, funnel-shaped, if large, then cylindrical with a complicated array of teeth and tooth like structures ………………………… 2

2. Small nematodes, stoma very small, amphids polymorphic, pharynx anteriorly not attached to body cuticle …………………………………... Oxystominidae

3. Large nematodes, stoma very small, funnel shaped or tubular; pharynx anteriorly attached to body cuticle; cephalic capsule variable ………………………………………………………………. Leptosomatidae Family: Ironidae de Man, 1876

Diagnosis. Ironoidea. Cuticle smooth. Inner labial, outer labial and cephalic sensilla papiliform or setose. Stoma elongate with three (one dorsal and two ventrosublateral), four (two smaller dorsal and two larger ventrosublateral) or five (one dorsal and two pairs of ventrosublateral) movable teeth in anterior region, surrounded by pharyngeal

242 collar. Pharynx cylindrical, sometimes inserts onto body cuticle in stomal region. Pharyngeal glands open slight posterior to the teeth, in stomal region. Female reproductive system didelphic, amphidelphic with reflexed ovaries, rarely monodelphic, opisthodelphic. Males diorchic with opposed testes or monorchic with anterior testis. Gubernaculum present. Males with only single precloacal supplement.

Type subfamily: Ironinae de Man, 1876

Other subfamily

Thalassironinae Andrássy, 1976 Key to subfamilies of Ironidae de Man, 1876

1. Fresh-water inhabiting; ventro-lateral orthometanemes present……… Ironinae

2. Marine forms; dorso-lateral loxometanemes present, occasionally absent ……………………………………………………………… Thalassironinae Subfamily: Ironinae de Man, 1876

Diagnosis. Ironidae. Delicately built, dorsolateral and ventrolateral orthometanemes occur in alternate manner. Stoma long, tubular with cuticularized walls and three or more movable teeth anteriorly. Cephalic setae present. Small pharyngo-intestinal valve present. Exclusively fresh-water forms.

Type and only genus: Ironus Bastian, 1865

243 Genus: Ironus Bastian, 1865

Diagnosis. Ironinae. Body slender, medium- to large-sized. Cuticle smooth. Lip region offset by shallow constriction, three lips. Amphidial opening slit-like, amphidial fovea cup-shaped. Stoma long, tubular and cuticularized, three strong eversible hook-like bifurcate teeth in anterior region. Pharynx gradually expanded posteriorly. Secretory-excretory pore in vicinity of lip region. Female reproductive system didelphic, amphidelphic with reflexed ovaries. Males with strong arcuate spicules with central strengthening piece, small gubernaculum and one mid-ventral precloacal seta. Tail long, filiform, tapering to a fine point.

Type species: Ironus ignavus Bastian, 1865

Other species

I. amabilis Andrássy, 2011

I. americanus Cobb, 1914

I. colourus Steiner, 1919

I. crassatus Argo & Heyns, 1972

I. dentifurcatus Argo & Heyns, 1972

I. elegans Colomba & Vinciguerra, 1979

I. ernstii Argo & Heyns, 1972

I. flagellatus Andrássy, 2011

I. gagarini Tsalolikhin, 1987

I. helveticus Daday, 1911

I. iarius Saha, Lal & Singh, 2004

I. indicus Sharma & Saxena, 1980

I. lautus Argo & Heyns, 1972

I. leoborkini Tsalolikhin, 1987

I. longicaudatus de Man, 1884

I. luci Andrássy, 1956

I. macramphis Schuurmans Stekhoven & Teunissen, 1938

244 I. paludicola Schneider, 1937

I. paramacramphis Alther, 1972

I. papuanus Daday, 1899

I. rotundicaudatus Kreis, 1924

I. sphincterus Ebsary, 1985

I. tenuicaudatus de Man, 1876

I. terranovus Ebsary, 1985

245 Ironus dentifurcatus Argo & Heyns, 1972

(Figs. 56, 57)

Description

Measurements. Table 22.

Female: Large-sized nematodes, strongly arcuate to almost ‘C’-shaped upon fixation, tapering more towards posterior region. Cuticle smooth without transverse or longitudinal striations. Hypodermal glands and body pores absent, occasionally present in tail region. Lip region offset, dome-shaped; lips rounded, amalgamated. Inner labial sensilla papilliform; outer labials slightly raised. Cephalic sensilla setose, fine bristle-like, located slightly posterior to outer labials. Amphids 4-5 μm wide, located 7-8 μm from anterior end. Crystalloids large-sized, rectangular, filled almost body diam. from posterior to female genital branch up to anus level. Stoma consist of short, eliptical anterior part and elongate cylindrical strongly cuticularised posterior part completely surrounded by pharyngeal tissue. Anterior part with a small claw-like, sharply-pointed dorsal tooth and two massive subventral teeth; a minute denticle present at base of each subventral tooth. Pharynx cylindrical with narrow anterior and relatively wider muscular posterior part with thickened lumen. Nerve ring encircling pharynx at 45.0-55.5% of its length. Secretory-excretory pore hardly visible under LM. Body at pharyngeal end 2.1-2.2 times labial diam. Cardia short, conoid, 3-5 μm long. Intestine granular with wide lumen. Pre-rectum indistinct. Rectum 1.0-1.2 times anal body diam. long with thick walls. Tail divided into two parts: short conoid anterior part and long filiform posterior part with fine terminus, 19.3-23.0 times anal body diam. long. two pairs of body pores present at conoid part of tail.

Reproductive system didelphic, amphidelphic, ovaries reflexed, on right side of intestine. Oocytes arranged in one or two rows distally followed by single row of large-sized oocytes proximally. Oviduct and spermatheca not differentiated. Uterus elongate with muscular part without differentiation of columella. Vagina perpendicular to body axis with strong muscles, 10-11 μm long or one-third of corresponding body diameter. Vulva a transverse slit, pre-equatorial, 39.8-41.3% from anterior end. Vulval lips smooth, not protruded. Intra-uterine eggs not observed.

Male: Not found.

246 Locality and habitat: Samples having Ironus dentifurcatus Argo & Heyns, 1972 were obtained from soil-water interface at Keetham lake, Agra, Uttar Pradesh, India at coordinates, 27°14.824’N 077°51.240’E.

Voucher specimens: Five females on slides Ironus dentifurcatus Argo & Heyns, 1972 KL1-1/1-3 deposited in Nematode Collection, Department of Zoology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.

Remarks: The present population shows conformity to Ironus dentifurcatus Argo & Heyns, 1972 in all morphometric and morphological characteristics. While Indian population were collected from coal mine area, the present population were collected from soil-water interface of Keetham lake, which is totally a different habitat.

247 Table 22. Morphometric characteristics of Ironus dentifurcatus Argo & Heyns, 1972. Measurements are in µm and in the form: mean±standard deviation (range).

Character Female (n=5) Body length 1682.2±62.9 (1599-1774) Body diam. 33.0±1.5 (31-35) a 50.9±0.8 (49.9-52.2) b 7.1±0.2 (6.9-7.5) c 3.7±0.1 (3.6-3.9) c' 21.3±1.3 (19.3-23.0) V 40.3±0.6 (39.8-41.3) G1 16.3±4.0 (11.8-21.5) G2 17.1±7.0 (10.1-28.6) Amphid-ant. end 7.4±0.5 (7-8) Amphid diam. 4.4±0.5 (4-5) Lip height 8.0±0.7 (7-9) Lip diam. 14.4±0.5 (14-15) Stoma length 82.6±14.3 (65-95) Stoma diam. 7.4±0.5 (7-8) Pharynx length 234.8±9.2 (222-245) Nerve ring-ant. end 119.8±13.6 (100-136) Rectum length 21.4±2.7 (19-26) Anal body diam. 20.6±0.8 (20-22) Tail length 440.0±13.2 (426-461)

248 Fig 56. Ironus dentifurcatus Argo and Heyns, 1972 A: Entire female. B: Female anterior region. C: Female pharyngeal region. D. Female reproductive system. E: Female posterior region.

249 Fig. 57. Ironus dentifurcatus Argo & Heyns, 1972 A-C: Anterior end. D: Posterior pharyngeal region. E, F: Vulval region. G: Anal region. H: Portion of a tail (Scale bars= 10 μm).

250 Order: Triplonchida Cobb, 1920

Diagnosis. Enoplia. Body short, obese to long. Cuticle usually loosely fitting or finely annulated. Amphids at the base of lip region. Stoma weakly or strongly cuticularized, with a buccal cavity or with symmetrical or asymmetrical spear. Pharynx cylindrical with or without elongate bulb. Female reproductive system didelphic, amphidelphic or monodelphic, prodelphic. Males with single testis. Protractor muscles between the spicule heads are absent and are replaced by suspensor muscles forming a capsule around the spicules.

Type suborder: Diptherophorina Micoletzky, 1922

Other suborders

Tobrilina Tsalolikhin, 1976

Tripylina Andrássy, 1974 Key to suborders of Triplonchida Cobb, 1920

1. Plant parasitic; body short and obese; cuticle loose; stoma weakly cuticularized, spear complex, asymmetrical ………………… Diptherophorina

- Free-living; body large-sized; stoma symmetrical without spear ………… 2

2. Pharynx cylindrical with three large cardiac glands; anterior end of spicules embedded in muscle tissue ……..………………………………… Tobrilina

- Pharynx cylindrical; prominent spicules with protrusion capsule …………………………………………………………………..…... Tripylina Suborder: Tobrilina Tsalolikhin, 1976

Diagnosis. Triplonchida. Free-living nematodes. Body very long. Cuticle thin, smooth or finely annulated with or without somatic setae. Lip region continuous with six outer labial and four cephalic setae, cephalic setae shorter than outer labials. Stoma funnel-shaped or prismatic. Amphids a transverse slit, located at base of lip region. Pharynx cylindrical with large cardiac glands. Female reproductive system didelphic, amphidelphic or monodelphic, prodelphic. Males diorchic or monorchic. Anterior end of spicules embedded in muscular tissue; small supplements present in posterior body region.

251 Type superfamily: Tobriloidea Filipjev, 1918

Other superfamily

Prismatolaimoidea Micoletzky, 1922 Key to superfamilies of Tobrilina Tsalolikhin, 1976

1. Stoma usually funnel-shaped; tail cylindroid with caudal glands and spinneret …………………………………………………………………... Tobriloidea

2. Stoma spacious, prismatic; tail filiform ending in a mucro ………………………………………………………..……. Prismatolaimoidea Superfamily: Prismatolaimoidea Micoletzky, 1922

Diagnosis. Tobrilina. Cuticle with fine transverse annulations. Somatic setae present all over body. Amphidial opening slit-like, lying far posterior to stoma. Stoma usually wide, prismatic or barrel-shaped with parallel cuticularized walls, teeth present or absent, if present, very minute at base of stoma. Female reproductive system didelphic or monodelphic. Tail in both sexes long filiform, ending in a mucro.

Type and only family: Prismatolaimidae Micoletzky, 1922 Family: Prismatolaimidae Micoletzky, 1922

Diagnosis. Prismatolaimoidea. Cuticle thin, finely annulated. Somatic and caudal setae present. Lip region continuous; inner labial sensilla papilliform; six outer labial sensilla articulate, setose; four cephalic sensilla setose, usually shorter than outer labials. Stoma usually wide, prismatic, cuticularized, with dorsal tooth and subventral teeth, if present, at the base of stoma. Amphids pocket-shaped. Pharynx cylindrical. Cardia large. Female reproductive system monodelphic or didelphic. Male very rare. Tail filiform in both sexes with a claw-like terminal mucro.

Type and only genus: Prismatolaimus de Man, 1880

252 Genus: Prismatolaimus de Man, 1880

Diagnosis. Prismatolaimidae. Small- to large-sized nematodes. Body length ranging from 0.4-1.9 mm. Cuticle thin, finely annulated with scattered somatic and caudal setae. Lip region with six long articulate outer labial sensilla and four short non- articulate cephalic sensilla. Stoma wide, prismatic, cuticularized, in its base a small dorsal tooth and two sub-ventral swellings with or without rasp-like structures. Amphidial opening transverse slits at about 2-3 times lip region diam. from anterior end. Pharynx cylindrical. Cardia large, spherical. Organellum dorsale may be present behind cardia. Female reproductive system monodelphic, prodelphic or didelphic, amphidelphic. Intra-uterin egg one at a time. Males very rare, diorchic. Spicules simple, gubernaculum thin. Genital papillae numerous, 11-46, either confined to posterior region or extending upto pharyngeal region. Tail filiform in both sexes; tail tip with a hook-like mucro.

Type species: Prismatolaimus intermedius (Bütschli, 1873) de Man, 1880

Other species

P. afer Andrássy, 2003

P. amphidialis Tahseen, Hussain & Khan, 2007

P. andrassyanus Coomans & Mulk, 1980

P. andrassyi Khera & Chaturvedi, 1967

P. brevicaudatus Wu & Hoeppli, 1929

P. chilensis Coomans & Raski, 1988

P. consimilis Siddiqi, 2006

P. cryptorgans Siddiqi, 2006

P. cylsaccus Siddiqi, 2006

P. dolichurus de Man, 1880

P. elongatus Siddiqi, 2006

P. exilis Andrássy, 2003

P. flagellatus Andrássy, 2003

P. hsuei Wu & Hoeppli, 1929

253 P. iucundus Andrássy, 2003

P. kenyensis Mulk & Coomans, 1979

P. lacustris Tahseen, Hussain & Khan, 2007

P. leptolaimus Andrássy, 1969

P. macrostomus Tahseen, Hussain & Khan, 2007

P. matoni Mulk & Coomans, 1979

P. megadontus Siddiqi, 2006

P. minisaccus Siddiqi, 2006

P. minor Siddiqi, 2006

P. mulcoomus Brzeski, 1997

P. novoporus Coomans & Raski, 1988

P. opithorgans Siddiqi, 2006

P. paraprimitivus Turpeenniemi, 1997

P. parvus Milne, 1963

P. primitivus Loof, 1971

P. stenolaimoides Loof, 1971

P. tareya Gagarin & Kuzmin, 1972

P. tenuicaudatus Schuurmans Stekhoven, 1951

P. verrucosus Hirschmann, 1952

P. villaensis Siddiqi, 2006

P. waipukeus (Yeates, 1967) Andrássy, 1969

P. yasminae Siddiqi, 2006

254 Prismatolaimus intermedius (Bütschli, 1873) de Man, 1880

(Figs. 58, 59)

Description

Measurements. Table 23.

Female: Small- to medium-sized nematodes, almost ‘C’-shaped upon fixation, tapering more towards posterior region. Cuticle 1.0-1.2 μm thick, prominently annulated, annules 1.2-1.5 μm wide. Somatic setae absent, 2-3 caudal setae present. Lateral fields not differentiated. Lip region continuous with adjoining body. lips amalgamated. Inner labial sensilla small, bristle-like, not discernible under LM; outer labial and cephalic sensilla setose with cephalic sensilla relatively slender and shorter than outer labials. Amphidial openings elliptical with single ridge anteriorly, 2-4 μm wide, situated 23-26 μm or 2.8-3.8 times lip diam. from anterior end. Stoma three times as long as wide; cheilostom not cuticularised; gymnostom barrel-shaped, cuticularised, 5-7 μm long or 50-55% of stoma length; stegostom funnel-shaped, 3.0- 3.5 μm or 25-30% of stoma length, metastegostom bearing a prominent dorsal tooth and subventral walls without armature. Pharyngeal collar covering 25-30% of stoma from base. Pharynx cylindrical with slight expansion posteriorly to form elongate pyriform basal bulb of 26-44 μm x 8-12 μm dimension. Nerve ring encircling anterior pharynx at 44.6-50.0% of pharyngeal length from anterior end. Secretory-excretory pore slightly posterior to nerve ring, at 50.0-55.8% of pharyngeal length from anterior end. Cardia conspicuous, 7-10 μm long. Organellum dorsale not observed. Intestine thin-walled with narrow lumen. Rectum thick-walled as long as anal body diam. long. Anus a crescent-shaped slit. Tail elongate tapering posteriorly, 11.0-13.4 times anal body diam. long with short and very fine mucro at tail terminus.

Reproductive system monodelphic, prodelphic; ovary dorsally reflexed with distal tip of ovary not reaching vulval level. Oocytes arranged in two rows distally followed by single row of cells proximally. Oviduct and spermatheca not differentiated. Uterus muscular with occasionally single intra-uterine egg of 55-65 μm x 15-16 μm dimension observed. Vagina obliquely oriented, 30-35% of corresponding body diam.; vulva post-equatorial, 52.4-62.0% from anterior end. Vulval lips not protruded.

255 Male: Not found.

Locality and habitat: Samples having Prismatolaimus intermedius (Bütschli, 1873) de Man, 1880 were obtained from shore soil mixed with mollusc shells at Keetham lake, Agra, Uttar Pradesh, India at coordinates, 27°15.305’N 077°50.836’E.

Voucher specimens: Eight females on slides Prismatolaimus intermedius (Bütschli, 1873) de Man, 1880 KL5-166/1-4 deposited in Nematode Collection, Department of Zoology, Aligarh Muslim University, Aligarh, Uttar Pradesh, India.

Remarks: The present population shows conformity to Prismatolaimus intermedius with original description by Bütschli (1873) and subsequent description by de Man (1880) in most morphometric and morphological characteristics with minor differences. Females smaller (0.41-0.71 mm vs 0.75mm) with relatively smaller ‘a’ value (29.7-39.5 vs 35.0-45.0); relatively greater ‘b’ (3.7-4.8 vs 3.5-4.0) and ‘c’ values [3.7-4.4 vs 3.5-4.0 in Prismatolaimus intermedius (Bütschli, 1873) de Man, 1880]. The species is cosmopolitan in nature and show wide range of values. So the comparision is made with the original description. This species is first report from India.

256 Table 23. Morphometric characteristics of Prismatolaimus intermedius (Bütschli, 1873) de Man, 1880. Measurements are in µm and in the form: mean±standard deviation (range).

Character Female (n=8) Body length 591.0±94.4 (416-711) Body diam. 16.5±1.5 (14-18) a 35.5±3.1 (29.7-39.5) b 4.3±0.3 (3.7-4.8) c 4.0±0.2 (3.7-4.4) c' 12.1±0.9 (11.0-13.4) V 57.7±2.9 (52.4-62.0) G1 30.6±6.9 (19.2-39.7) Amphid-ant. end 24.2±1.1 (23-26) Amphid diam. 3.2±0.7 (2-4) Lip height 3.5±0.5 (3-4) Lip diam. 7.6±0.9 (6-9) Stoma length 10.7±1.1 (9-12) Stoma diam. 3.8±0.3 (3-4) Pharynx length 134.2±13.8 (112-154) Nerve ring-ant. end 64.8±9.3 (50-77) Secretory-excretory pore-ant. end 72.5±9.7 (56-86) Rectum length 11.6±1.5 (10-14) Anal body diam. 11.8±1.1 (10-13) Tail length 145.1±19.3 (110-175) Egg dimension 60.0±7.0 x 15.5±0.7 (55-65 x 15-16)

257 Fig 58. Prismatolaimus intermedius (Bütschli, 1873) de Man, 1880 (Female). A: Entire female. B: Female anterior region. C: Female pharyngeal region. D. Female reproductive system. E: Female posterior region.

258 Fig. 59. Prismatolaimus intermedius (Bütschli, 1873) de Man, 1880 (Female). A-D: Anterior end (scanning electron microscopy). E: Posterior pharyngeal region. F, H: Vulval region and genital branch. G: Vulval region (scanning electron microscopy). I: Anal region (Scale bars= 10 μm).

259 PART B - ECOLOGY

260 SOME LANDMARKS IN ECOLOGICAL RESEARCH Soil is a natural body and a major component of the Earth’s ecosystem. It is a product of the influence of climate, minerals and organisms interacting over time. It continuously undergoes development by numerous physical, chemical and biological processes, which include weathering with associated erosion. It is a complex microhabitat regulating plant productivity and the maintenance of biogeochemical cycles by the activity of microorganisms that are able to degrade organic compounds. A gram of soil can contain billions of microbial organisms. Soil is an excellent habitat for nematodes particularly the plant-parasitic nematodes and the free-living nematodes. Nematodes occupy virtually all ecosystems including marine, freshwater and terrestrial environments. High adaptability of nematodes help them to flourish in extreme environments such as the polar region, saltpans; hydrothermal vents, cold seeps and many sulfidic types of sediment. Several nematode genera are important as parasites of plants and animals while others contribute to nutrient mineralization (Ferris & Matute, 2003) and control of pests of plants (Grewal et al., 2005). Nematodes occupy a central position in the soil food web occurring at multiple trophic levels and have the potential to provide an insight to the condition of soil food web. They contribute much in maintaining the structure and function of the soil food web (Ferris, 2010). Their occurrence across multiple trophic levels is vitally important in the soil environment. Yeates et al. (1993) categorized nematodes into five trophic groups: herbivores/plant parasites, bacterivores, fungivores, predators and omnivores. Bongers (1990) classified nematodes along a colonizer-persister (c-p) range of 1-5 based on their life strategies depending upon their r-selective or k-selective nature. Another parameter, the maturity index (MI), is a weighted mean frequency of c-p scaling across the entire nematode community and provides the information about the condition of the soil environment (Bongers, 1990). The development of MI represents a significant advancement in interpreting the relationships between the ecology of nematode communities and functions of the soil (Neher et al., 2005) and to measure the successional status of a soil community. They are based on the principle that different taxa have different sensitivities to stress because of their characteristic life histories. Ruess (2003) and Ruess & Ferris (2004) studied faunal analysis of soil

261 nematodes and the successional changes in decomposition pathways in different ecosystems. The community status after common agricultural practices such as cultivation, application of fertilizers, pesticides (Ferris & Ferris, 1974; Wasilewska, 1979) may reflect the history of disturbance. Therefore, smaller MI values indicate more disturbed environment and larger values indicate less disturbed environment (Freckman & Ettema, 1993). The indices are useful for interpretation of the quantitative levels of disturbance, ecosystem types (Neher, 2001) in major land resource regions (Neher et al., 1995; 1998; Neher & Campbell, 1996). Therefore, each soil sample has high intrinsic information value (Yeates et al., 1993; Bongers & Ferris, 1999) giving the abundance and composition of species. Although Bongers (1990) and Yeates (1970, 1984) applied Diversity indices and Maturity Index (MI) for the terrestrial nematodes, the application of the MI was later extended successfully to marine and brackish ecosystems (Bongers et al., 1991). Ferris et al. (2001) assigned weights to indicator nematode guilds representing basal, enriched and structured conditions of the food web and proposed food web indices including enrichment index (EI) and structure index (SI). EI is based on the expected responsiveness of the opportunistic guilds (bacterivore nematodes with c-p value 1) to organic resources enrichment and indicates towards nutrient enriched (high EI) or depleted (low EI) soil environment. SI represents an aggregation of functional guilds with c-p values ranging from 3-5 and describes structured soil ecosystem with greater trophic links (high SI) or degraded (low SI) one with fewer trophic links. Plotting of EI and SI provide a model framework of nematode faunal analysis as an indicator of the likely conditions of the soil food web. The nematode taxa, under stressed conditions were of c-p value 2, while the cp-1 nematodes are important indicators of soil fertility (De Goede et al., 1993) and enrichment. Moens et al. (2004) gave the statement that nematodes can be act as useful model system for ecological studies on the interactions between biodiversity and ecosystem functioning. Besides the environmental factors like soil texture and pH (de Goede, 1993; Korthals et al., 1996; Neher et al., 1999), the nematode community composition is affected by the anthropogenic activities like land management practices such as cultivation (Neher & Campbell, 1994), mineral fertilizers (Beare, 1997), pesticides (Ettema & Bongers, 1993), heavy metals (Weiss & Larink, 1991; Korthals et al.,

262 1996a, 1996b, 1998) or petroleum products (Blakely, 1999). Thus the interpretation of the abundance and function of their faunal assemblages or community structure offers an in situ assessment of the disruptive factors (Bongers & Ferris, 1999). Soil health is a fundamental necessity for the integrity of terrestrial ecosystem. Several bioindicators of soil health and quality have been developed and reviewed (Trasar- Cepeda et al., 2000; Van Bruggen & Semenov, 2000). Among them, microorganisms, due to their capability to respond quickly to environmental changes, are expected to be efficient bioindicators. Soil ecosystem services are benefits derived from ecosystems that are necessary to maintain soil health and productivity; they are delivered by the ecosystem functions of soil organisms (Brussaard, 2012). Sanchez-Moreno & Navas (2007); Zhang et al. (2007); Pen-Mouratov et al. (2008); Chen et al. (2009); Li et al. (2011); Park et al. (2011) and Šalamún et al. (2012) studied the nematode responses in the soil with heavy metal stress. Later, Pen-Mouratov et al. (2010) studied the effect of both industrial pollution and livestock activity on the free-living nematodes in Central Asia while Šalamún et al. (2014) studied the diversity and food web structure of nematode communities with soil having high alkaline pH and salinity. The use of nematodes in detecting environmental change, pollution and other anthropogenic impacts has taken great progress in the recent past (Neher, 2001; Wilson & Kakouli-Duarte, 2009; Ferris and Tuomisto, 2015). Steel & Ferris (2016) studied the soil nematode assemblages for regulation of pest species. The main characteristics of the nematode fauna that make them a good bioindicator have been well documented, i.e. they are abundant, they live in very high numbers in small areas, have high diversity, have limited mobility so that they can easily be exposed to what is in their immediate environment, have short life cycles, occupy key positions at most trophic levels in soil food webs, can be extracted by standardized procedures and are easily identified from morphological and anatomical characters. Since their feeding habits are directly related to oral structure, their trophic roles can be easily inferred. Nematodes have been used as environmental bioindicators in aquatic systems too. Raffaelli & Mason (1981) used the nematode:copepod ratio in monitoring the conditions of aquatic ecosystem due to differing in their sensitivities to stress. Generally, nematodes are less sensitive to environmental stress as compared to copepods (Warwick et al., 1988). Therefore, a high ratio indicates pollution, such as

263 oil spills, sewage and increasing organic enrichment. Coull et al. (1981) contest the validity of the use of nematode:copepod ratio as a biomonitoring tool since errors can be introduced by natural fluctuations in population size. Amjad & Gray (1983) used the nematode:copepod ratio along a known gradient of organic pollution and found that copepod numbers decreased and nematode numbers increased along the gradient of increasing organic enrichment. Besides working on the aquatic nematodes, the scientists increased their interest in terrestrial nematodes by using the nematode communities as indicators for monitoring the environmental conditions (Freckman, 1988; Bongers, 1990). Panagrellus redivivus, which has wide applicability in a biomonitoring system, has been used to detect the toxicity of complex environmental samples and chemical fractions of such samples. Šály & Rágala (1984) and Wasilewska (1979, 1989) worked on bioindicative properties of nematodes with respect to soil microfauna taken into account, the permeability of the nematode’s cuticle. It allows these organisms to respond with a range of reactions to pollutants and correspond with the restorative capacity of soil ecosystems. Hashmi et al. (1997) gave information about the highly conserved heat shock proteins in nematodes. Expression of these proteins is enhanced when exposed to stress such as heat, metal ions or organic toxins (Kammenga et al., 1998, 2000). A study on nematode Monhystera disjuncta by Warwick et al. (1988) shows its rapid response more than other nematode species. The nematode genus Pontonema and Bulbamphiascus, both shows much dominance in organically enriched sediments (Moore & Bett, 1989). Nematodes of the families Rhabditidae and Diplogasteridae commonly exhibit zonation in the filter beds of wastewater plants, with the first group found in areas of raw waste and the second group in the later treatment stages (Zullini, 1976; Hánĕl, 2004). Members of family Dorylaimidae may also act as a good bioindicators for monitoring the disturbed environmental conditions as they do not have any resistant stages to cope with the disturbances and under stress conditions, this makes them more sensitive to environmental changes and makes them good bioindicator (Bongers, 1999). Wetlands are the productive ecosystems that provide many important services to mankind. In wetlands, water is the primary factor controlling the environment as well as associated fauna and flora. The wetlands can be of various types due to their genesis, geographical location, water regime and chemistry, species composition and

264 substrate characteristics. The total area of wetlands of the world has been estimated by different workers from 917 million hectares (m ha) to more than 1275 m ha. Wetlands represent a variety of habitat types viz., rivers and lakes, coastal lagoons, mangroves, peat lands, coral reefs, human-made ponds, farm ponds, irrigated agricultural lands, salt pans, reservoirs, gravel pits, sewage farms and canals. The wetlands occur where the water table is at or near the surface of the land or where the land is covered by shallow water. An international treaty for conservation and sustainable use of wetlands was signed at Ramsar, a city in Iran, in 1971. This convention is known as the Ramsar Convention that takes care of the Ramsar sites- wetlands of international importance. According to Ramsar convention (1971), wetlands are defined as: “Areas of marsh, fen, peat land whether natural or artificial, permanent or temporary, covered with water that is static or flowing, fresh, brackish or salty, including areas of marine water, the depth of which at low tide does not exceed six metres”. The goal of the Convention is the conservation and wise use of all wetlands through national and international cooperation for their sustainable development, worldwide. The Convention has World Conservation Union with member countries as Contracting Parties and UNESCO serving as Depositary for the Convention and an entrusted secretariat known as the "Ramsar Bureau". India joined the Convention as a contracting party on 1st February 1982 and registered 19 wetland sites of international importance covering a surface area of 648,507 hectares. Now there are 26 sites designated as Wetlands of International Importance (Ramsar Sites), with a surface area of 689,131 hectares. Wetlands in India are distributed in different geographical regions ranging from Himalayas to Deccan plateau and have a significant contribution to local livelihoods. A regulatory framework for wetlands was introduced in the form of wetland (Conservation and Management) Rules, 2010 under the provisions of the Environment (Protection) Act, 1986. The rules stipulate prohibition and regulation of a range of developmental activities within a wetland notified under its provision by the State/ UT Governments. The National Water Policy (2012) refers to conservation of wetlands considering their role in buffering floods, as well as groundwater recharge.

265 DESCRIPTION OF THE SELECTED WETLAND,

KEETHAM LAKE

The work in the present thesis envisages the taxonomy and community analysis of the nematodes of a nationally conserved wetland, Keetham Lake, Agra.

Wetlands are the ecosystems, which are currently facing continuous threat from mankind and are losing their biodiversity at an alarming rate. Wetlands in India are distributed in different geographical regions ranging from Himalayas to Deccan plateau and have a significant contribution to local livelihoods. A regulatory framework for wetlands was introduced in the form of wetland (Conservation and Management) Rules, 2010 under the provisions of the Environment (Protection) Act, 1986. The rules stipulate prohibition and regulation of a range of developmental activities within a wetland notified under its provision by the State/ UT Governments. The National Water Policy (2012) refers to conservation of wetlands considering their role in buffering floods, as well as groundwater recharge. For conservation of lakes and wetlands, the Ministry of Environment and Forests introduced two separate Centrally Sponsored Schemes (CSS), namely the National Wetlands Conservation Programme (NWCP) and the National Lake Conservation Plan (NLCP). On February 7 of 2013, the Cabinet Committee on Economic Affairs approved the merger of both into a new scheme called the 'National Plan for Conservation of Aquatic Eco-systems' (NPCA). Ministry has also commissioned research projects on economic valuation of wetlands for developmental planning and decision making. So far 115 wetlands have been identified under the national conservation plan.

The Directory of Indian wetlands, first prepared by International Union of Conservation of Nature and Natural Resources (IUCN) as a part of the Asian Wetland Directory, and recently revised by World Wildlife Fund (WWF) India, is the only source of useful information on 170 wetlands and wetland complexes in the country. Keetham lake is the 8th wetland of importance out of 16 wetlands in the state of Uttar Pradesh listed for holistic conservation of lakes and wetlands (Table 24).

266 Table 24. Wetlands of Uttar Pradesh under National Wetland Conservation & Management Programme (NWCMP)

S.No. Name of Wetland City/District Area Coordinates 1. Shahid Chandra Unnao 2.24 km2 26°34’60”N & 80°40’00”E Shekhar Azad Bird Sanctuary (Nawabganj) 2. Sandi Bird Hardoi 3.08 km2 27°15’00”N & 79°55’00”E Sanctuary 3. Lakh-Bahoshi Bird Kannauj 80.24 km2 27°30’00”N & 79°30’00”E Sanctuary 4. Samaspur Bird Rae Bareilly 7.99 km2 26°00’00”N & 81°25’00”E Sanctuary 5. Alwara Wetland Kaushambi 7.00 km2 25°25’10”N & 81°11’39”E 6. Semarai Lake Lakhimpur 0.77 km2 28°01’14”N & 80°30’47”E Kheri 7. Nagaria Lake Lakhimpur 0.77 km2 28°22’41”N & 80°29’27”E Kheri 8. Keetham Lake Agra 7.83 km2 27°00’00” N & 77°45’00” E 9. Shekha Wetland Aligarh 1.50 km2 27°49’00”N & 78°10’00”E 10. Saman Bird Mainpuri 5.25 km2 27°04’60”N & 79°00’00”E Sanctuary 11. Sarsai Nawar Etawah 1.61 km2 26°96’00” N & 79°23’38”E Wetland 12. Patna Bird Etah 1.09 km2 27°34’60”N & 78°45’00”E Sanctuary 13. Chando Wetland Basti 20.00 km2 26°43’11”N 82°38’37”E 14. Taal Bhaghel Bahraich 14.00 km 27°23’53”N & 81°44’50”E 15. Taal Gambhirvan & Azamgarh 4.04 km2 26°09’54”N 88°22’47”E Taal Salona 16. Aadi Jal Jeev Jheel Hathras --* 27°35’51”N & 78°03’00”E *Data not available.

267 BASELINE INFORMATION

Originally called Keetham lake, the wetland was declared as Sur Sarovar National Bird Sanctuary on 27 March 1991 by U.P. Forest Department. It has been named Sur Sarovar as the great poet Sur Das penned a devotional poem ‘Bhakti Kavya’ on its banks. The riverine belt of Yamuna surrounds the area of Sur-Sarovar Bird Sanctuary, this shallow water reservoir in Agra, Uttar Pradesh which was developed by the British, more than 100 years ago. It is a scenic lake that falls at coordinates 27°14’25” N and 27°15’57” N along the latitudes and 77°49’41” E and 77°51’37” E along the longitudes. The lake is located on the Agra-Delhi highway (NH 2) about 20 km from Agra and 12 km from Sikandra and is pentagonal in shape sprung in 7.13 sq km area with artificially created islands serving as breeding grounds of the migratory birds.

Water management. The raw water for Keetham Lake is obtained from Agra canal originating from Okhla barrage on River Yamuna in Delhi. The lake water of Keetham is also used as raw water intake for Mathura Refinery Water Treatment Plant located in vicinity of Keetham Lake.

Edaphic and climatic characteristics. The soil tends to be predominantly loam dominated with sandy patches in terrestrial areas with pH ranging from 6.5-7.4. The climatic conditions of the lake area is typical of Uttar Pradesh plains with hot windy summers and extremely cold winters. The winters extend from October to February followed by summers between March and June and the monsoon season between July and September. The average temperature ranges between 1.5°C to 49°C.

Keetham lake has always been a favourite spot for picnickers and nature lovers as it is home to over 100 species of migratory and native birds, more than 18 species of reptiles and 12 species of mammals.

268 Fig. 60. The entry gate of the wetland Keetham Lake also called as Sur Sarovar Bird Sanctuary

(Photo: Malka Mustaqim)

Fig. 61. Candidate standing next to a hoarding of Sur Sarovar Bird Sanctuary

269 Fig. 62. Map of India showing position of Keetham Lake (Photo: www.googlemaps.com)

Fig. 63. Map of Uttar Pradesh showing position of Keetham Lake.

(Photo: www.googlemaps.com)

270 Zone A Zone B Zone C Fig. 64. Map of Keetham Lake area showing study zones and samping sites. (Photo: www.googlemaps.com)

Fig. 65 (Left & Right). Types of plants constituting the vegetation of Keetham Lake. (Photo: Malka Mustaqim)

271 Vegetation Type. Large area of the wetland is surrounded by woodland. The woodland is largely dominated by Acacia nilotica. Other plants include Azadirachta indica, Phoenix sylvestris, Ficus bengalansis, Prosopis juliflora, Albizia lebbeck. Aquatic plants include Eichhornia crassipes, Hydrilla, Nymphaea, Vallisneria and Typha. During summers, the lake area gets largely covered by profuse growth of macrophytes especially Eichornia sp. and Potamogeton sp.

Common animals. The water quality of Keetham lake supports wide range of avifauna during winter season. The important aquatic birds inhabiting Keetham lake are: Little Gerbs, Cormorants, Darter, Paddy Bird, Cattle Egrets, Indian Reef Heron, Black necked Stork, white Ibis, Spoon Bill, Greying Goose, Bar headed Goose, Lesser Whistling Teal, Ruddy Shelduck, Pintail, Common Teal, Spot Billed Duck, Gadwall, Wigeon, Shoveler and Comb Duck.

Fig. 66. Open water area of Zone A of Keetham Lake. (Photo: Malka Mustaqim)

Sampling sites. The present work focuses on the taxonomic diversity and community structure of nematodes of Keetham Lake. For convenience to cover the maximum area for sampling of all possible habitats, the area is divided into three different zones. These sampling zones identified are given hereunder-

272 Zone A: It comprised of the open water areas, the areas submerged under water and the nearby coastal areas.

The samples collected were mainly water samples, mud samples and samples from soil adjacent to coasts covered by the mollusc shells.

Fig. 67. Coastal region of Zone A of Keetham Lake covered with univalve and bivalve shells. (Photo: Malka Mustaqim)

Fig. 68. Coastal region adjacent to the submerged area of Zone A of Keetham Lake. (Photo: Malka Mustaqim)

273 Zone B: The area represents a woodland, covered profusely mainly with tremendous Acacia nilotica plants far away from the water zone.

Fig. 69 (Left & Right). Vegetation and substrate condition at the sampling sites of Zone B at Keetham Lake (Photo: Malka Mustaqim)

Fig. 70. Vegetation and substrate condition at the sampling sites of Zone B at Keetham Lake (Photo: Malka Mustaqim)

274 Zone C: It is the most interior and undisturbed area of the wetland without any human intervention. It is also the restricted entry zone of the bird sanctuary and the place for many pythons which can be seen easily in the below photograph.

Fig. 71(Left). A signboard of the restricted access zone (Zone C) at the wetland, Keetham Lake Fig. 71(Right). Vegetation and substrate condition at the sampling sites of Zone C of Keetham Lake (Photo: Malka Mustaqim)

Fig. 72. A python moving along at one of the sampling sites of Zone C of Keetham Lake (Photo: Malka Mustaqim)

275 Fig. 73. A python basking at one of the sampling sites of Zone C of Keetham Lake (Photo: Malka Mustaqim)

276 PROTOCOL AND THE PARAMETERS USED FOR NEMATODE COMMUNITY ANALYSIS

The methodology and protocol followed for the community analysis of nematodes have been discussed here under.

The present study formed a part of the three-year project funded by Ministry of Environment and Forests, New Delhi. For a thorough survey and extensive sampling the wetland area was divided into three zones A, B and C and samples were collected from identified (Fig. 64) sampling stations of three zones. The division of the wetland area into these zones was on the basis of dominant vegetation/ substrate conditions (Fig. 66-73) and also on anthropogenic involvement.

Nematode Counting:

The nematodes from the collected samples of Keetham Lake were extracted using sieving and decantation and modified Baerman’s funnel techniques. The inactive nematodes in the coarse sieve residue that failed to move into the funnel water were also isolated through centrifugation technique and added to the extracted bulk. The suspension of extracted nematodes was later observed under Stereoscopic Zoom Microscope (Olympus SZ-61) for generic identification.

Water was added to the extracted nematode suspension to make its volume 100 ml. The suspension was stirred thoroughly and then 5ml volume was sucked by a pipette to pour in a Syracause dish. Counting was done thrice for each sample and finally the mean was calculated. The counting was made separately of individuals belonging to a genus/ species to assign them taxonomic or trophic categories. At the same time representative nematodes from each taxon were processed for dehydration and were mounted on master slides. The master slide represented the variety of taxa present in each sample. In view of a good number of juveniles in the samples, which could not be assigned the correct species status.

Final population of nematodes in each sample was obtained by the following formula

= Total volume of nematode suspension (100 ml) x Mean of counted nematode / Quantity of suspension used for counting (5 ml)

277 Community attributes: The following attributes were studied for community analysis of various nematode taxa encountered from the region using techniques of Norton (1978).

1. Frequency (N): It shows how often a taxon occurs in the collected samples. The frequency of a nematode genus represents the number of samples in which it is found.

2.

3. Relative Frequency

4. Mean Density

5. Relative Density

6. Prominence Value

PV=

7. Relative Prominence Value

8. Biomass (G) was calculated by using the method of Norton (1978) in µg

Where, a = greatest body width; b =body length and 16 X 1,00,000 (pre determined empirical value).

278 9. Total Biomass (TG) - Number of nematodes of the species present in the sample x Biomass of a nematode of respective species.

10. Mean Biomass

11. Importance Value

IV= R.F. of the species + R.D. of the species + R.G. of the species

12. Relative Importance Value

13. Species richness SR = (s- 1) ln N

Where, s= number of taxa in sample and N= total number of nematodes identified in the sample.

Trophic and Food web indices

The feeding (trophic) groups were determined according to classification scheme of Yeates et al. (1993) as phytophagous/ herbivores (plant parasites), bacteriophagous/ bacterivores (bacterial feeders), mycophagous/ fungivores (fungal feeders), predators/ predaceous (carnivore), and omnivores while allocation of c-p values was made after Bongers (1990). Maturity index was calculated to estimate the relative state of the substrata of the three zones. Trophic diversity was calculated by the trophic diversity index (TDI) (Heip et al., 1988). The channel index (CI) was calculated to indicate predominant decomposition pathways (Ferris et al., 2001). Enrichment index (EI), Basal Index (BI) and Structure Index (SI) were calculated to determine the comparative stability of the ecosystem studied (Ferris et al., 2001).

a. Shannon’s diversity (H′) = −Σ (pi ln pi)

Where pi = proportion of individuals of taxon i in the total population.

b. Maturity Index

Where v(i)= c-p value of the ith taxon.

279 f(i) the frequency of that taxon in a sample

* Maturity index (MI) is calculated as the weighted mean of the individual c-p value.

c. Plant Parasitic Index (PPI)

PPI= Σ PPiXi / Σ Xi

Where, PPi = PP value assigned to taxon i according to Bongers (1990).

Xi = abundance of taxon i in the sample.

d. Nematode Channel Ratio (NCR)/ Channel Index

NCR=

Where, B = Total abundance of Bacterial feeding nematodes

F = Total abundance of Fungal feeding nematodes.

e. Enrichment Index (EI) = (e/e+b) x 100

f. Structure Index (SI) = (s/s+b) x 100

g. Basal Index (BI) = (b/s+e) x 100

where e, b & s are sum products of assigned weights and number of individuals of all species

h. Trophic Diversity Index (TDI) = 1 ⁄ Σpi²

where pi² is the proportional contribution of ith trophic group.

Energy Dispersive X-Ray Analysis (EDX): The elemental composition of soil from the different zones of Keetham Lake was determined by processing the soil for viewing under the scanning electron microscope with EDX attachment. The data generated included spectra showing peaks corresponding to the elements making up the true composition of the sample being analysed.

Data Analysis: Nematode diversity was described using the univariate measures of the Shanon Diversity index at species level (H’) calculated using SPECDIVE. Other food web indices, community parameters and correlation coefficient were calculated using MS-Excel. ANOVA (Analysis of Variance) was performed using statistical programme SPSS to check the significance of the results obtained.

280 RESULTS

The present work envisaged the studies on the nematode faunal diversity of the nationally conserved wetland, Keetham Lake with information on their community structure, their species diversity, the relative dominance of feeding guilds in the three selected zones of the wetland in order to have an overall assessment of the environment quality.

The values of parameter used for community analysis with respect to individual trophic group, have been given in table 26-40, while table 41 represents the calculated values of the various community and food web indices. The pie charts indicates the comparative analysis of values between trophic groups. The regression lines with coefficient of correlation ‘r’ represent the relationship between the three zones of the lake, on account of the parameters analysed.

Summation and updating information on sampling site: Though much information regarding the status, topography and ecology of a sampling site can be obtained from early records. However, on the spot baseline information of the sampling site was obligatory for a sound analysis. Besides, the ecological conditions of an ecosystem change due to the changes in climate and the process of succession which is a dynamic attribute. The following preliminary information about the terrestrial or aquatic sampling site was obtained. The chemical analysis of samples was also done of the three sampling zones of the sampling site.

The following information regarding individual sampling station will be obtained.

1. Location of sampling station State: Uttar Pradesh / District: Agra

2. Nature of site Natural

3. Size of sampling site 7.83 km2

4. Geographical coordinates 27°00’00” N & 77°45’00” E

5. Agroclimatic characteristics a) Temperature range: 1.5°C to 49° C

b) Rainfall: 1300 mm

c) Soil type: Alluvium

d) Vegetation type: woodland, shrubs, submerged plants and macrophytes

281 6. Hydrological features- Source of water: Originating from Okhla barrage on River Yamuna in Delhi

Minimum and maximum depth of water: 2-8 m

7. Physical characteristics of water a) Transparency: low

b) Temperature: 4°C to 39°C

c) Colour: Deep green

d) pH: 7.39-8.21

8. Sediment characteristics i) Temperature: 1.5°C to 49°C

ii) pH: 6.5-7.4

Energy Dispersive X-ray analysis

Soil was analysed for the presence of elements or heavy metals in the three selected zones of the Keetham Lake. Besides the usual elements some heavy/ toxic metals viz., Lead, Arsenic, Cadmium, Zinc were found in traces but their relative concentration and occurrence varied ( Table 25 & Fig. 74-76).

Table 25. Selected elements in the soil of three zones of Keetham Lake as analysed by Energy Dispersive X-ray (EDX) technique.

Element Zone A Zone B Zone C (Weight%) Oxygen 58.04 66.08 50.13 Carbon 5.34 11.93 4.66 Nitrogen 0.00 0.00 2.03 Potassium 0.00 1.32 2.25 Calcium 0.37 2.51 0.79 Magnesium 0.75 1.80 0.00 Silica 16.86 15.62 27.00 Copper 0.19 0.09 1.09 Zinc 0.16 0.21 0.70 Cadmium 0.00 0.01 0.00 Arsenic 0.08 0.15 0.48 Lead 0.14 0.03 0.13

282 283 284 285 Taxonomic attributes

Species abundance per sample: The samples collected from different regions of the lake showed variation in the number of species as well as nematode densities. The number of species varied from 15 to 26 per sample in Zone A; in Zone B, the number of species ranged from 17 to 23 per sample. The number of species varied from 14 to 20 per sample in Zone C.

Individual abundance per sample: The number of nematodes in a sample ranged from 438 to 1041 individuals with mean value of 721.2±239.6 per 100 cc of soil in Zone A. The number of individuals varied from 540 to 1030 with mean value of 946.43±126.6 individuals per 100 cc of soil in Zone B whereas in terms of abundance, the number of individuals varied from 300 to 900 with mean value of 496.93±168.36 individuals per 100 cc of soil in Zone C.

Ordinal abundance in the samples of three zones

The Dorylaimida (22%) represented the most abundant order (Fig. 77) with representation of maximum number of individuals in Zone A, followed by Rhabditida (19%), Plectida (16%), Tylenchida (14%), Triplonchida (9%), Monhysterida (8%), Mononchida (6%), Chromadorida and Enoplida (3% each). In Zone B (Fig. 77), Rhabditida (27%) was most abundant followed by Dorylaimida (25%), Tylenchida (19%), Plectida (13%). The other orders were represented by less than 10% such as Mononchida (5%), Chromadorida and Triplonchida (4% each) and Enoplida (3%). In Zone C, Rhabditida (35%) represented the most abundant group (Fig. 77), followed by Dorylaimida (26%) Tylenchida (17%), Plectida (10%), Mononchida (7%) and Chromadorida (5%)

286 Zone A

Zone B

Zone C

Fig. 77. Abundance of nematodes of different Orders at three selected zones of Keetham Lake.

287 Ordinal Frequency and Diversity

Zone A

The order Dorylaimida was most frequent (31%) with 17 species from 17 genera under 12 families (Fig. 78), followed by Rhabditida (25%) with 15 species under 14 genera from five families, Tylenchida (16%) with nine species belonging to nine genera under six families, Plectida (7%) with four species under 4 genera from 3 families, Monhysterida (6%) with 3 species under 3 genera from one family, Triplonchida (5%) with 3 species under 3 genera from 3 families, Mononchida and Enoplida (4% each) with 2 species under 2 genera from 2 families each, Chromadorida (2%) with one species under one genus from 1 family.

Zone B

The order Rhabditida was most frequent (39%) with 23 species under 21 genera from nine families (Fig. 78), followed by Dorylaimida (29%) with 16 species under 16 genera from 10 families, Tylenchida (17%) with nine species under nine genera from six families; Plectida (7%) with five species under four genera from two families; Chromadorida, Enoplida, Mononchida and Triplonchida (2% each) were represented by one species under one genus from one family each.

Zone C

Rhabditida was most frequent (46%) with 21 species under 20 genera from 7 families (Fig. 78), followed by Dorylaimida (25%) with 11 species under 11 genera from 8 families, Tylenchida (20%) with nine species under nine genera from six families, Plectida (5%) with two species under two genera from one family and Chromadorida and Mononchida (2% each) with one species under one genus and one family each.

288 Zone A

Zone B

Zone C

Fig. 78. Species of nematodes in different Orders at three selected zones of Keetham Lake

289 COMMUNITY/ FOOD WEB ATTRIBUTES

Trophic Abundance

Zone A

Among the feeding guilds, predators (35%) formed the most abundant group (Fig. 79), followed by omnivores (29%), bacteriovores (23%), herbivores (7%) and fungivores (6%).

Zone B

In terms of abundance (Fig. 79) or the number of individuals, bacteriovores (28%) formed the most abundant group, followed by herbivores (24%), predators (21%), omnivores (15%). Fungivores (12 %) represented the least abundant group.

Zone C

The bacteriovores (37%) were (Fig. 79) the most abundant groups, followed by herbivores (23%), predators (19%), fungivores (12%) and omnivores (9%). Trophic diversity (Species)

In Zone A, the bacteriovores (26) constituted the most dominant group (Fig.80 & Tables 26-30) in having maximum species, followed by predators (12), omnivores (7), herbivores (7) and fungivores (4). The trophic diversity index (TDI) of the zone ranged from 1.10-1.85 (1.27 ±0.10). Among bacteriovores, Acrobeloides nanus was the most dominant species while Hemicycliophora dhanachandi, Aphelenchus avenae, Mesodorylaimus subtiloides and Discolaimus similis were most dominant genera among herbivores, fungivores, omnivores and predators respectively. The least dominant species among bacteriovores, herbivores, omnivores, fungivores and predators were Drilocephalobus saprophilus sp. n., Hemicriconemoides brachyurus, Dorylaimus innovatus, Aphelenchoides composticola and Aquatides deconincki respectively.

In Zone B of Keetham Lake, bacteriovores constituted the most dominant group with maximum number (26) of species (Fig. 80 & Tables 31-35) followed by herbivores and predators (11 each), omnivores (5), fungivores (4). The trophic diversity index (TDI) of the zone ranged from 1.67-2.54 (2.10±0.07). Among bacteriovores the species Panagarolaimus hygrophilus was the most dominant while the species, Helicotylenchus dihystera, Aphelenchus avenae, Mesodorylaimus subtiloides and

290 Zone A

Zone B

Zone C Fig. 79. Numerical representation (%) of individuals of different trophic groups in three zones of Keetham Lake

291 Zone A

Zone B

Zone C Fig. 80. Representation of species (No.) in different trophic groups in three zones of Keetham Lake

292 Mylonchulus hawaiiensis were most dominant among herbivores, fungivores, omnivores and predators respectively. The least dominant species among bacteriovores, herbivores, omnivores, fungivores and predators were Wilsonema bangaloreiensis, Hemicriconemoides brachyurus, Thornenema nodicaudatum, Leptonchus buccatus and Ironus dentifurcatus respectively.

In Zone C, bacteriovores (22) constituted the most dominant group of genera in numbers (Fig. 80 & Tables 36-40) followed by herbivores (9), predators (8), fungivores (3) and omnivores (2). The trophic diversity index (TDI) of the zone ranged from 1.02-1.25 (1.12 ± 0.15). Among bacteriovores the species Chiloplacus subtenuis was the most dominant while the species Tylenchorynchus mashhoodi, Aphelenchus avenae, Mesodorylaimus subtiloides and Discolaimus similis were most dominant species among herbivores, fungivores, omnivores and predators respectively. The least dominant species among bacteriovores, herbivores, omnivores, fungivores and predators were Wilsonema bangaloreiensis, Hemicriconmoides brachyurus, Thornenema nodicaudatum, Basirotyleptus basiri and Neoactinolaimus agilis respectively. Prominence Value

Zone A

The data of the wetland revealed the Prominence Value (PV) of bacteriovores to be the greatest among all groups i.e., 52% (Fig. 81), followed by predators (28%), omnivores (14%), fungivores (4%) and herbivores (2%). Among bacteriovores, Acrobeloides nanus dominated all species in terms of Prominence Value (PV) and Relative Prominence Value (RPV), which were calculated to be 310.95 and 13.86% respectively whereas Drilocephalobus saprophilus sp. n., showed lowest Prominence Value (PV) and Relative Prominence Value (RPV), which were calculated to be 0.07 and 0.02% respectively. Among predators, Actinolaimus omercooperi demonstrated maximum Prominence Value (PV) and Relative Prominence Value (RPV) i.e., 512.18 and 23.51% respectively whereas Ironus dentifurctaus showed lowest Prominence Value (PV) and Relative Prominence Value (RPV), which were calculated to be 0.07 and 0.01% respectively. Moshajia sp. was the omnivore with highest Prominence Value (PV) and Relative Prominence Value (RPV) of 26.97 and 1.24% respectively whereas, Dorylaimus innovatus showed lowest Prominence Value (PV) and Relative

293 Table 26. Community analysis and population structure of Bacterivores in Zone A

Bacteriovores N* AF% RF% MD RD% PV RPV% G(µg) TG (µg) MG RG% IV RIV% (µg) Achromadora indica 6.00 35.53 1.85 2.85 1.03 16.99 0.78 0.42 548.00 91.33 0.26 3.14 1.29 Acrobeles complexus 15.00 68.89 3.59 7.95 2.60 65.99 3.03 0.16 400.00 26.67 0.08 6.26 2.57 Acrobeloides nanus 13.00 98.33 5.12 30.45 14.05 301.95 13.86 0.26 348.00 26.77 0.08 19.25 7.89 Alaimus assamensis 8.00 27.78 1.45 1.48 0.67 7.80 0.36 0.35 200.00 25.00 0.07 2.19 0.90 Cephalobus parvus 20.00 90.22 4.70 23.55 10.66 223.69 10.27 0.35 500.00 25.00 0.07 15.43 6.33 Cervidellus vexilliger 10.00 16.67 0.87 0.63 0.28 2.57 0.12 0.08 448.00 44.80 0.13 1.28 0.52 Chiloplacus subtenuis 14.00 83.33 4.34 21.53 9.75 196.54 9.02 0.17 548.00 39.14 0.11 14.20 5.82 Chronogaster glandulata sp. n. 18.00 38.89 2.03 3.05 1.38 19.02 0.87 0.38 900.00 50.00 0.14 3.55 1.46 Diploscapter coronatus 14.00 25.25 1.31 5.06 1.25 25.43 1.17 0.09 1012.00 72.29 0.21 2.77 1.14 Drilocephalobus mustaqimi sp. n. 7.00 5.56 0.29 0.15 0.07 0.35 0.02 0.10 440.00 62.86 0.18 0.54 0.22 Drilocephalobus saprophilus sp. n. 8.00 5.56 0.29 0.15 0.07 0.35 0.02 0.10 548.00 68.50 0.20 0.56 0.23 Eucephalobus oxyuroides 15.00 50.00 2.60 2.83 1.28 20.01 0.92 0.35 300.00 20.00 0.06 3.94 1.62 Geomonhystera villosa 9.00 45.06 2.35 2.45 10.09 16.45 0.75 0.23 238.00 26.44 0.08 12.51 5.13 Mesorhabditis anisospicula sp. n. 25.00 83.33 4.34 5.25 10.38 47.92 2.20 0.18 742.00 29.68 0.09 14.80 6.07 Monhystera paludicola 10.00 22.22 1.16 2.83 1.28 13.34 0.61 0.38 100.00 10.00 0.03 2.47 1.01 Monhystrella dorsicurvata sp. n. 13.00 11.11 0.58 0.13 0.06 0.43 0.02 0.13 345.00 26.54 0.08 0.71 0.29 Oscheius keethamensis sp. n. 19.00 15.06 0.78 0.45 0.89 1.75 0.08 0.56 805.00 42.37 0.12 1.80 0.74 Panagrolaimus hygrophilus 8.00 27.78 1.45 0.50 0.23 2.64 0.12 0.20 912.00 114.00 0.33 2.00 0.82 Plectonchus longevulvus 6.00 15.06 0.78 0.25 0.15 0.97 0.04 0.52 75.00 12.50 0.04 0.97 0.40 Plectus geophilus 27.00 88.89 4.63 3.25 1.47 30.64 1.41 0.07 250.00 9.26 0.03 6.13 2.51 Prismatolaimus intermedius 20.00 66.67 3.47 5.53 2.50 45.15 2.07 2.02 278.00 13.90 0.04 6.01 2.47 Rhabdolaimus terrestris 20.00 64.67 3.37 10.33 4.67 83.07 3.81 0.09 120.00 6.00 0.02 8.05 3.30 Stegellata jaisalmerensis 7.00 22.22 1.16 1.15 0.52 5.42 0.25 0.17 25.00 3.57 0.01 1.69 0.69 Udonchus tenuicaudatus 9.00 20.22 1.05 0.95 0.68 4.27 0.20 0.07 80.00 8.89 0.03 1.76 0.72 Wilsonema bangaloreiensis 5.00 11.11 0.58 0.25 0.11 0.83 0.04 0.08 80.00 16.00 0.05 0.73 0.30 Zeldia punctata 7.00 45.00 2.34 1.10 0.50 7.38 0.34 0.44 50.00 7.14 0.02 2.86 1.17 Mean 12.81 41.71 2.17 5.16 2.95 43.88 2.01 0.31 395.85 33.79 0.10 5.22 2.14 SD 6.17 29.45 1.53 7.91 4.18 77.10 3.54 0.38 290.39 28.06 0.08 5.44 2.23

294 Table 27. Community analysis and population structure of Fungivores in Zone A Fungivores N* AF% RF% MD RD% PV RPV% G(µg) TG (µg) MG (µg) RG% IV RIV Aphelenchoides composticola 22.00 10.00 0.52 10.58 4.79 33.46 1.54 0.08 480.00 21.82 0.06 5.37 2.20 Aphelenchus avenae 14.00 11.11 0.58 11.63 5.26 38.76 1.78 0.08 512.00 36.57 0.10 5.94 2.44 Leptonchus buccatus 8.00 11.11 0.58 0.13 0.06 0.43 0.02 0.31 60.00 7.50 0.02 0.66 0.27 Tylencholaimus ibericus 12.00 38.89 2.03 0.93 0.42 5.80 0.27 0.35 200.00 16.67 0.05 2.49 1.02 Mean 14.00 17.78 0.93 5.82 2.63 19.61 0.90 0.21 313.00 20.64 0.06 3.62 1.48 SD 5.89 14.08 0.73 6.13 2.77 19.30 0.89 0.15 219.29 12.16 0.03 2.48 1.02

Table 28. Community analysis and population structure of Herbivores in Zone A Herbivores N* AF% RF% MD RD% PV RPV% G(µg) TG (µg) MG (µg) RG% IV RIV Basirotyleptus basiri 18.00 61.11 3.18 8.18 3.70 63.95 2.94 0.26 150.00 8.33 0.02 6.91 2.83 Helicotylenchus dihystera 12.00 38.89 2.03 0.88 0.40 5.49 0.25 0.18 200.00 16.67 0.05 2.47 1.01 Hemicriconemoides brachyurus 15.00 5.56 0.29 0.05 0.02 0.12 0.01 0.26 250.00 16.67 0.05 0.36 0.15 Hemicyclophora dhanachandi 28.00 94.44 4.92 8.75 3.96 85.03 3.90 0.27 280.00 10.00 0.03 8.91 3.65 borai 6.00 15.45 0.80 0.13 0.09 0.51 0.02 0.12 120.00 20.00 0.06 0.95 0.39 Tylenchorhynchus mashhoodi 27.00 88.89 4.63 8.80 3.98 82.97 3.81 0.39 370.00 13.70 0.04 8.65 3.55 Tylenchus agricola 22.00 94.44 4.92 7.63 3.45 74.15 3.40 0.68 403.00 18.32 0.05 8.42 3.45 Mean 18.29 56.97 2.97 4.92 2.23 44.60 2.05 0.31 253.29 14.81 0.04 5.24 2.15 SD 8.01 37.72 1.96 4.29 1.94 40.43 1.86 0.18 106.48 4.33 0.01 3.83 1.57

295 Table 29. Community analysis and population structure of Omnivores in Zone A Omnivores N* AF% RF% MD RD% PV RPV% G(µg) TG (µg) MG (µg) RG% IV RIV Dorylaimus innovatus 4.00 4.54 0.24 0.05 0.02 0.11 0.01 1.70 1200.00 300.00 0.86 1.12 0.46 Epidorylaimus andrassyi 8.00 11.11 0.58 0.08 0.03 0.27 0.01 3.17 1745.00 218.13 0.63 1.23 0.51 Latocephalus gracile 5.00 11.11 0.58 0.05 0.02 0.17 0.01 1.07 1300.00 260.00 0.75 1.34 0.55 Mesodorylaimus subtiloides 15.00 44.45 2.31 2.45 8.65 16.33 0.75 0.83 400.00 26.67 0.08 11.04 4.53 Moshajia sp. 32.00 10.56 0.55 8.30 3.76 26.97 1.24 1.04 486.00 15.19 0.04 4.35 1.79 Oriverutus sundarus 6.00 5.56 0.29 0.08 0.03 0.19 0.01 1.24 425.00 70.83 0.20 0.52 0.21 Thornenema nodicaudatum 8.00 5.56 0.29 0.05 0.02 0.12 0.01 1.01 606.00 75.75 0.22 0.53 0.22 Mean 11.14 13.27 0.69 1.58 1.79 6.31 0.29 1.44 880.29 138.08 0.40 2.88 1.18 SD 9.14 13.01 0.68 2.86 3.08 10.11 0.46 0.75 492.05 109.16 0.31 3.55 1.45

296 Table 30. Community analysis and population structure of Predators in Zone A

Predators N* AF% RF% MD RD% PV RPV% G(µg) TG (µg) MG (µg) RG% IV RIV Actinolaimus omercooperi 10.00 30.33 1.58 93.00 0.42 512.18 23.51 2.30 345.00 34.50 0.10 2.10 0.86 Aporcelaimellus tropicus 10.00 33.33 1.74 1.73 0.78 9.99 0.46 2.73 3266.00 326.60 0.94 3.45 1.42 Aquatides deconincki 9.00 16.67 0.87 0.70 0.32 2.86 0.13 1.23 400.00 44.44 0.13 1.32 0.54 Brevitobrilus glandulatus 10.00 15.40 0.80 1.45 12.00 5.69 0.26 1.60 749.00 74.90 0.21 13.02 5.34 Discolaimoides teres 8.00 27.78 1.45 0.93 0.42 4.90 0.22 2.83 648.00 81.00 0.23 2.10 0.86 Discolaimus similis 20.00 66.67 3.47 2.00 0.91 16.33 0.75 3.90 2150.00 107.50 0.31 4.69 1.92 Eudorylaimus vulvastriatus 8.00 27.78 1.45 1.10 0.50 5.80 0.27 3.17 2745.00 343.13 0.98 2.93 1.20 Ironus dentifurcatus 15.00 5.56 0.29 0.03 0.01 0.07 0.01 1.06 645.00 43.00 0.12 0.42 0.17 Mononchus istvani 10.00 4.65 0.24 1.52 1.25 3.28 0.15 1.79 615.00 61.50 0.18 1.67 0.68 Mylonchulus hawaiiensis 10.00 12.45 0.65 2.25 0.98 7.94 0.36 1.35 745.00 74.50 0.21 1.84 0.76 Thonus garhwaliensis 8.00 27.78 1.45 0.63 0.28 3.32 0.15 1.08 545.00 68.13 0.20 1.92 0.79 Tobrilus longus 18.00 10.45 0.54 9.54 1.00 30.84 1.42 1.60 3000.00 166.67 0.48 2.02 0.83 Mean 11.33 23.24 1.21 9.57 1.57 50.27 2.31 2.05 1321.08 118.82 0.34 3.12 1.28 SD 3.88 16.18 0.84 25.26 3.16 139.49 6.40 0.88 1071.89 102.25 0.29 3.16 1.29

297 Table 31. Community analysis and population structure of Bacterivores in Zone B

Bacteriovores N* AF% RF% MD RD% PV RPV% G(µg) TG (µg) MG (µg) RG% IV RIV Acrobeles complexus 20.00 44.55 2.23 20.50 11.10 136.83 7.77 0.16 400.00 20.00 0.06 13.39 6.10 Acrobeloides nanus 35.00 93.33 4.68 35.45 16.05 342.47 19.45 0.26 450.00 12.86 0.04 20.77 9.46 Alaimus assamensis 8.00 27.78 1.39 1.48 0.67 7.80 0.44 0.35 245.00 30.63 0.09 2.15 0.98 Cephalobus parvus 37.00 83.22 4.17 23.55 10.66 214.83 12.20 0.35 845.00 22.84 0.06 14.90 6.78 Cervidellus vexilliger 5.00 16.67 0.84 0.63 0.28 2.57 0.15 0.08 345.00 69.00 0.19 1.31 0.60 Chiloplacus subtenuis 40.00 85.33 4.28 21.53 9.75 198.88 11.29 0.17 450.00 11.25 0.03 14.06 6.40 Achromadora indica 8.00 27.78 1.39 2.03 0.92 10.70 0.61 0.42 525.00 65.63 0.19 2.50 1.14 Chronogaster glandulata sp. n. 12.00 38.89 1.95 3.05 1.38 19.02 1.08 0.38 345.00 28.75 0.08 3.41 1.55 Drilocephalobus mustaqimi sp. n. 3.00 4.26 0.25 0.16 0.10 0.38 0.02 0.38 258.00 86.00 0.24 0.59 0.27 Drilocephalobus saprophilus sp. n 4.00 5.56 0.28 0.15 0.10 0.35 0.02 0.10 100.00 25.00 0.07 0.45 0.20 Eucephalobus oxyuroides 15.00 50.00 2.51 2.83 1.28 20.01 1.14 0.10 212.00 14.13 0.04 3.83 1.74 Mesorhabditis anisospicula sp. n. 25.00 83.33 4.18 5.25 2.38 47.92 2.72 0.18 375.00 15.00 0.04 6.60 3.01 Panagrolaimus hygrophilus 38.00 97.78 4.90 25.50 11.23 252.15 14.32 0.20 545.00 14.34 0.04 16.17 7.36 Plectus geophilus 17.00 58.89 2.95 2.25 0.47 17.27 0.98 0.10 150.00 8.82 0.02 3.45 1.57 Wilsonema bangaloreiensis 3.00 6.50 0.42 0.35 0.15 0.33 0.05 0.03 45.00 15.00 0.04 0.61 0.28 Neotylocephalus annonae 3.00 11.11 0.56 0.25 0.10 0.83 0.05 0.08 250.00 83.33 0.24 0.89 0.41 Tylocephalus aprimitivus sp. n. 6.00 12.50 0.63 1.02 0.29 3.61 0.20 0.03 55.00 9.17 0.03 0.94 0.43 Zeldia punctata 15.00 50.00 2.51 1.10 0.50 7.78 0.44 0.44 75.00 5.00 0.01 3.02 1.38 Rhabditis terricola 8.00 27.78 1.39 0.50 0.23 2.64 0.15 0.78 525.00 65.63 0.19 1.81 0.82 Oscheius keethamensis sp. n. 27.00 88.89 4.46 3.25 1.47 30.64 1.74 0.56 250.00 9.26 0.03 5.95 2.71 Diploscapter coronatus 3.00 11.11 0.56 0.25 0.11 0.83 0.05 0.09 150.00 50.00 0.14 0.81 0.37 Protorhabditis mucronata sp. n. 6.00 12.50 0.63 1.02 0.29 3.61 0.20 0.08 155.00 25.83 0.07 0.99 0.45 Metarhabditis amsactae 14.00 45.00 2.26 1.10 0.25 7.38 0.42 0.56 545.00 38.93 0.11 2.62 1.19 Macrolaimellus iucundus 8.00 27.78 1.39 0.50 0.23 2.64 0.15 0.12 200.00 25.00 0.07 1.69 0.77 Tricephalobus longihystera sp. n. 12.00 18.89 0.95 0.55 1.43 2.39 0.14 0.08 350.00 29.17 0.08 2.46 1.12 Teratorhabditis synpapillata 3.00 11.11 0.56 0.25 0.11 0.83 0.05 0.18 400.00 133.33 0.38 1.04 0.48 Mean 14.42 40.02 2.01 5.94 2.75 51.35 2.92 0.24 317.12 35.15 0.10 4.86 2.21 SD 12.03 31.09 1.55 10.00 4.62 94.10 5.34 0.19 189.43 31.15 0.09 5.80 2.64

298 Table 32. Community analysis and population structure of Fungivores in Zone B

Fungivores N* AF% RF% MD RD% PV RPV% G(µg) TG (µg) MG (µg) RG% IV RIV Aphelenchoides composticola 15.00 50.00 2.51 1.10 0.50 7.78 0.44 0.08 575.00 38.33 0.11 3.11 1.42 Aphelenchus avenae 33.00 78.11 3.92 11.63 5.26 102.79 5.84 0.08 475.00 14.39 0.04 9.22 4.20 Leptonchus buccatus 3.00 11.11 0.56 0.13 0.06 0.43 0.02 0.31 375.00 125.00 0.35 0.97 0.44 Tylencholaimus ibericus 12.00 38.89 1.95 0.93 0.42 5.80 0.33 0.35 250.00 20.83 0.06 2.43 1.11 Mean 15.75 44.53 2.23 3.45 1.56 29.20 1.66 0.21 418.75 49.64 0.14 3.93 1.79 SD 12.58 27.73 1.39 5.47 2.47 49.16 2.79 0.15 139.01 51.25 0.14 3.63 1.66

Table 33. Community analysis and population structure of Herbivores in Zone B

Herbivores N* AF% RF% MD RD% PV RPV% G(µg) TG (µg) MG (µg) RG% IV RIV Dorylaimellus curvatus 20.00 66.67 3.34 6.20 2.81 50.62 2.87 0.54 740.00 37.00 0.10 6.26 2.85 Tylenchus agricola 18.00 74.44 3.73 5.63 2.45 48.57 2.76 0.68 800.00 44.44 0.13 6.31 2.87 Helicotylenchus dihystera 22.00 88.89 4.46 2.88 2.90 27.15 1.54 0.18 545.00 24.77 0.07 7.43 3.38 Hemicriconemoides brachyurus 2.00 5.56 0.28 0.05 0.02 0.12 0.01 0.27 648.00 324.00 0.92 1.21 0.55 Hemicycliophora dhanachandi 22.00 84.44 4.23 6.75 2.76 62.03 3.52 0.33 545.00 24.77 0.07 7.06 3.22 Tylenchorhynchus mushhoodi 18.00 38.89 1.95 4.80 1.98 29.93 1.70 0.39 485.00 26.94 0.08 4.01 1.82 Hoplolaimus indicus 8.00 18.78 0.94 1.50 1.23 6.50 0.37 1.03 398.00 49.75 0.14 2.31 1.05 Basiria graminophila 7.00 15.89 0.80 0.25 0.47 1.00 0.06 0.26 253.00 36.14 0.10 1.37 0.62 Longidorus brevicaudatus 9.00 11.21 0.56 0.25 0.11 0.84 0.05 5.96 1500.00 166.67 0.47 1.14 0.52 Xiphenema brevicola 16.00 12.50 0.63 1.02 0.29 3.61 0.20 0.92 748.00 46.75 0.13 1.05 0.48 Psilenchus hrithiki 15.00 50.00 2.51 1.10 0.50 7.78 0.44 0.28 545.00 36.33 0.10 3.11 1.42 Mean 14.27 42.48 2.13 2.77 1.41 21.65 1.23 0.99 655.18 74.33 0.21 3.75 1.71 SD 6.74 31.78 1.59 2.60 1.18 23.16 1.32 1.67 323.08 91.96 0.26 2.57 1.17

299 Table 34. Community analysis and population structure of Omnivores in Zone B

Omnivores N* AF% RF% MD RD% PV RPV% G(µg) TG (µg) MG (µg) RG% IV RIV Mesodorylaimus subtiloides 3.00 42.30 2.12 42.00 0.12 273.16 15.51 0.83 700.00 233.33 0.66 2.90 1.32 Latocephalus gracile 3.00 11.11 0.56 50.00 0.02 166.66 9.46 1.07 600.00 200.00 0.57 1.14 0.52 Oriverutus sundarus 2.00 5.56 0.28 25.00 0.03 58.95 3.35 1.24 845.00 422.50 1.19 1.50 0.68 Thornenema nodicaudatum 6.00 5.56 0.28 25.00 0.02 58.95 3.35 1.01 840.00 140.00 0.40 0.69 0.32 Oxydirus gigas 5.00 10.00 0.50 0.10 0.05 0.32 0.02 1.24 745.00 149.00 0.42 0.97 0.44 Mean 3.80 14.91 0.75 28.42 0.05 111.61 6.34 1.08 746.00 228.97 0.65 1.44 0.66 SD 1.64 15.52 0.78 19.21 0.04 108.47 6.16 0.17 102.55 114.70 0.32 0.87 0.39

Table 35. Community analysis and population structure of Predators in Zone B

Predators N* AF% RF% MD RD% PV RPV% G(µg) TG (µg) MG (µg) RG% IV RIV Aporcelaimellus tropicus 7.00 23.33 1.17 0.84 0.46 4.06 0.23 2.73 2345.00 335.00 0.95 2.58 1.17 Butlerius butleri 13.00 11.11 0.56 0.25 0.11 0.83 0.05 0.42 315.00 24.23 0.07 0.74 0.33 Discolaimoides teres 8.00 27.78 1.39 0.93 0.42 4.90 0.28 2.83 1012.00 126.50 0.36 2.17 0.99 Discolaimus similis 20.00 66.67 3.34 35.00 0.91 285.78 16.23 3.90 2675.00 133.75 0.38 4.63 2.11 Eudorylaimus vulvastriatus 8.00 27.78 1.39 22.00 0.50 115.95 6.58 3.17 3125.00 390.63 1.10 3.00 1.36 Ironus dentifurcatus 2.00 5.56 0.28 0.03 0.01 0.07 0.01 1.06 1212.00 606.00 1.71 2.00 0.91 Mylonchulus hawaiiensis 25.00 42.22 2.12 3.10 7.45 20.14 1.14 1.35 2100.00 84.00 0.24 9.80 4.46 Oigolaimella paraninae sp. n. 8.00 27.78 1.39 20.00 0.23 105.41 5.99 0.75 543.00 67.88 0.19 1.81 0.83 Oigolaimella indica sp. n. 5 24.25 2.10 0.65 0.25 108.41 6.02 0.85 615.00 75.00 0.22 1.95 1.03 Paroigolaimella bodamica 9.00 16.25 0.81 3.25 1.47 13.10 0.74 0.42 345.00 38.33 0.11 2.39 1.09 Thonus garhwaliensis 8.00 27.78 1.39 0.63 0.28 3.32 0.19 1.08 1366.00 170.75 0.48 2.16 0.98 Mean 10.80 27.63 1.38 8.60 1.18 55.36 3.14 1.77 1503.80 197.71 0.56 3.13 1.42 SD 6.81 17.14 0.86 12.43 2.24 92.02 5.23 1.26 1004.89 187.95 0.53 2.54 1.16

300 Table 36. Community analysis and population structure of Bacterivores in Zone C

Bacteriovores N* AF% RF% MD RD% PV RPV% G(µg) TG (µg) MG (µg) RG% IV RIV Achromadora indica 12.00 12.20 0.78 8.45 0.05 29.51 1.89 0.42 325.00 27.08 0.11 0.94 0.49 Acrobeles complexus 35.00 73.53 4.69 25.45 8.05 218.23 13.99 0.16 525.00 15.00 0.06 12.80 6.72 Acrobeloides nanus 37.00 86.33 5.51 35.45 16.05 329.38 21.12 0.26 845.00 22.84 0.09 21.65 11.36 Caenorhabditis heptalineata sp. n. 22.00 67.65 4.31 2.15 0.98 17.68 1.13 0.35 407.00 18.50 0.08 5.37 2.82 Cephalobus parvus 19.00 72.22 4.61 22.55 10.66 191.64 12.29 0.35 825.00 43.42 0.18 15.45 8.10 Cervidellus vexilliger 15.00 16.67 1.06 5.63 1.28 22.99 1.47 0.08 442.00 29.47 0.12 2.46 1.29 Chiloplacus subtenuis 40.00 83.33 5.31 21.53 9.75 196.54 12.60 0.17 733.00 18.33 0.08 15.14 7.94 Diploscapter coronatus 8.00 22.22 1.42 1.15 0.52 5.42 0.35 0.09 209.00 26.13 0.11 2.04 1.07 Eucephalobus oxyuroides 14.00 50.00 3.19 2.83 1.28 20.01 1.28 0.10 523.00 37.36 0.15 4.62 2.43 Macrolaimellus iucundus 5.00 24.22 1.54 1.85 0.58 9.10 0.58 0.12 160.00 32.00 0.13 2.26 1.18 Mesorhabditis anisospicula sp. n 15.00 83.33 5.31 4.25 2.38 38.80 2.49 0.18 544.00 36.27 0.15 7.84 4.11 Metarhabditis amsactae 19.00 66.67 4.25 5.53 2.50 45.15 2.89 0.56 415.00 21.84 0.09 6.84 3.59 Oscheius keethamensis sp. n. 15.00 46.67 2.98 10.33 4.67 70.57 4.52 0.45 426.00 28.40 0.12 7.76 4.07 Panagrolaimus filiformis 28.00 27.78 1.77 0.50 0.23 2.64 0.17 0.20 398.00 14.21 0.06 2.06 1.08 Panagrolaimus hygrophilus 24.00 24.23 1.55 1.50 0.35 7.38 0.47 0.20 431.00 17.96 0.07 1.97 1.03 Plectus geophilus 15.00 25.20 1.61 6.45 0.89 32.38 2.08 0.10 250.00 16.67 0.07 2.57 1.35 Protorhabditis mucronata sp. n. 13.00 11.11 0.71 0.25 0.11 0.83 0.05 0.08 196.00 15.08 0.06 0.88 0.46 Rhabditis terricola 27.00 78.85 5.03 3.25 1.47 28.86 1.85 0.78 442.00 16.37 0.07 6.57 3.44 Teratorhabditis synpapillata 18.00 11.11 0.71 0.13 0.06 0.43 0.03 0.18 212.00 11.78 0.05 0.82 0.43 Tricephalobus longihystera sp. n. 5.00 50.00 3.19 1.10 0.50 7.78 0.50 0.06 125.00 25.00 0.10 3.79 1.99 Wilsonema bangaloreiensis 5.00 12.23 0.78 4.80 0.09 16.79 1.08 0.08 112.00 22.40 0.09 0.96 0.50 Zeldia punctata 6.00 22.22 1.42 2.83 1.28 13.34 0.86 0.44 175.00 29.17 0.12 2.82 1.48 Mean 18.05 43.99 2.81 7.63 2.90 59.34 3.80 0.25 396.36 23.88 0.10 5.80 3.04 SD 10.31 27.77 1.77 9.65 4.31 89.23 5.72 0.19 213.20 8.41 0.03 5.68 2.98

301 Table 37. Community analysis and population structure of Fungivores in Zone C

Fungivores N* AF% RF% MD RD% PV RPV% G(µg) TG (µg) MG (µg) RG% IV RIV Aphelenchoides composticola 20.00 61.11 3.90 4.63 2.26 36.19 2.32 0.08 325.00 16.25 0.07 6.22 3.27 Aphelenchus avenae 24.00 77.67 4.95 5.54 2.79 48.82 3.13 0.08 385.00 16.04 0.07 7.81 4.10 Basirotyleptus basiri 18.00 53.11 3.39 3.18 1.70 23.17 1.49 0.26 275.00 15.28 0.06 5.15 2.70 Mean 20.67 63.96 4.08 4.45 2.25 36.06 2.31 0.14 328.33 15.86 0.07 6.39 3.35 SD 3.06 12.53 0.80 1.19 0.55 12.83 0.82 0.10 55.08 0.51 0.00 1.34 0.70

Table 38. Community analysis and population structure of Herbivores in Zone C

Herbivores N* AF% RF% MD RD% PV RPV% G(µg) TG (µg) MG (µg) RG% IV RIV Basiria graminophila 9.00 20.54 1.31 0.54 0.75 2.45 0.16 0.26 250.00 27.78 0.11 2.17 1.14 Helicotylenchus dihystera 11.00 28.89 1.84 0.78 0.40 4.19 0.27 0.18 275.00 25.00 0.10 2.35 1.23 Hemicriconemoides brachyurus 6.00 5.56 0.35 2.00 0.04 4.72 0.30 0.27 336.00 56.00 0.23 0.63 0.33 Hoplolaimus indicus 10.00 25.50 1.63 2.25 1.02 11.36 0.73 1.08 1012.00 101.20 0.42 3.06 1.61 Longidorous brevicaudatus 10.00 15.54 0.99 10.00 0.20 39.42 2.53 5.96 1655.00 165.50 0.68 1.87 0.98 Paralongidorous rex 15.00 10.25 0.65 0.89 0.30 2.85 0.18 5.93 1565.00 104.33 0.43 1.38 0.73 Psilenchus hrithiki 12.00 12.50 0.80 5.00 0.35 17.68 1.13 0.28 546.00 45.50 0.19 1.34 0.70 Tylenchorhynchus mashhoodi 22.00 52.35 3.34 12.00 1.98 86.82 5.57 0.39 526.00 23.91 0.10 5.42 2.84 Tylenchus agricola 15.00 24.33 1.55 4.22 0.87 20.82 1.33 0.68 789.00 52.60 0.22 2.64 1.38 Mean 12.22 21.72 1.39 4.19 0.66 21.14 1.36 1.67 772.67 66.87 0.28 2.32 1.22 SD 4.63 13.82 0.88 4.18 0.59 27.38 1.76 2.44 534.74 47.72 0.20 1.38 0.72

302 Table 39. Community analysis and population structure of Omnivores in Zone C

Omnivores N* AF% RF% MD RD% PV RPV% G(µg) TG (µg) MG (µg) RG% IV RIV Thornenema nodicaudatum 2.00 5.56 0.35 2.05 0.02 4.83 0.31 1.01 545.00 272.50 1.12 1.50 0.79 Mesodorylaimus subtiloides 9.00 16.65 1.06 25.00 0.45 102.01 6.54 0.83 825.00 91.67 0.38 1.89 0.99 Mean 5.50 11.11 0.71 13.53 0.24 53.42 3.42 0.92 685.00 182.08 0.75 1.69 0.89 SD 4.95 7.84 0.50 16.23 0.30 68.71 4.41 0.13 197.99 127.87 0.53 0.28 0.15

Table 40. Community analysis and population structure of Predators in Zone C

Predators N* AF% RF% MD RD% PV RPV% G(µg) TG (µg) MG (µg) RG% IV RIV Aporcelaimellus tropicus 8.00 34.05 2.17 25.00 0.42 145.88 9.35 2.73 1819.00 227.38 0.94 3.53 1.85 Butlerius butleri 5.00 18.85 1.20 1.85 0.45 8.03 0.51 0.42 642.00 128.40 0.53 2.18 1.14 Discolaimoides teres 8.00 27.78 1.77 0.93 0.42 4.90 0.31 0.42 546.00 68.25 0.28 2.47 1.30 Discolaimus similis 10.00 46.67 2.98 35.00 0.91 239.10 15.33 3.90 642.00 64.20 0.26 4.15 2.18 Eudorylaimus vulvastriatus 8.00 17.73 1.13 1.10 0.50 4.63 0.30 3.17 1211.00 151.38 0.62 2.26 1.18 Mylonchulus hawaiiensis 12.00 12.24 0.78 45.00 0.54 157.44 10.09 1.35 745.00 62.08 0.26 1.58 0.83 Neoactinolaimus agilis 2.00 11.52 0.73 0.55 0.18 1.87 0.12 2.45 335.00 167.50 0.69 1.61 0.84 Thonus garhwaliensis 8.00 21.77 1.39 25.00 0.28 116.65 7.48 1.08 260.00 32.50 0.13 1.80 0.95 Mean 7.63 23.83 1.52 16.80 0.46 84.81 5.44 1.94 775.00 112.71 0.47 2.45 1.28 SD 3.02 11.92 0.76 17.92 0.22 92.13 5.91 1.31 510.96 66.78 0.28 0.93 0.49

303 Prominence Value (RPV) among omnivores which is 0.11 and 0.01% respectively. Among fungivores, Aphelenchus avenae dominated all genera in terms of Prominence Value (PV) and Relative Prominence Value (RPV), calculated to be 38.76 and 1.78% respectively whereas, Leptonchus buccatus had lowest Prominence Value (PV) andRelative Prominence Value (RPV) i.e., 0.43 and 0.02% respectively. Among herbivores, Hemicycliophora dhanachandi, demonstrated highest Prominence Value (PV) and Relative Prominence Value (RPV), calculated to be 85.03 and 3.90% respectively whereas Hemicriconemoides brachyurus showed lowest Prominence Value (PV) and Relative Prominence Value (RPV) i.e., 0.12 and 0.01% respectively.

Zone B

The Prominence Value (PV) of bacteriovores was found to be the greatest among all groups (Fig. 81) i.e., 41%, followed by predators (24%), omnivores (20%), herbivores (10%) and fungivores (5%). Among bacteriovores, Panagrolaimus hygrophilus dominated all species in terms of Prominence Value (PV) and Relative Prominence Value (RPV), which were calculated to be 252.15 and 14.32% respectively whereas, Wilsonema bangaloreiensis shows lowest Prominence Value (PV) and Relative Prominence Value (RPV) i.e., 0.33 and 0.05% respectively. Discolaimus similis dominated all species of predators in having highest Prominence Value (PV) and Relative Prominence Value (RPV) of 258.78 and 16.23% respectively whereas Ironus dentifurcatus showed least Prominence Value (PV) and Relative Prominence Value (RPV) of 0.07 and 0.01% respectively. Among omnivores, Mesodorylaimus subtiloides demonstrated maximum Prominence Value (PV) and Relative Prominence Value (RPV) of 273.16 and 15.51% respectively whereas Oxydirus gigas showed lowest Prominence Value (PV) and Relative Prominence Value (RPV), which were calculated to be 0.32 and 0.02% respectively. Among fungivores, Aphelenchus avenae surpassed all species on account of Prominence Value (PV) and Relative Prominence Value (RPV) i.e., 102.79 and 5.84% respectively whereas Leptonchus buccatus showed lowest Prominence Value (PV) and Relative Prominence Value (RPV), which were calculated to be 0.43 and 0.02% respectively. Hemicycliophora dhanachandi, dominated among herbivore species in terms of Prominence Value (PV) and Relative Prominence Value (RPV) i.e., 62.03 and 3.52% respectively whereas Longidorus brevicaudatus showed lowest Prominence Value (PV) and Relative Prominence Value (RPV) of 0.84 and 0.05% respectively.

304 Zone C

The Prominence Value (PV) of bacteriovores was found to be greatest (Fig. 81) among all groups i.e., 60%, followed by predators (16%), herbivores (14%), omnivores and fungivores (5% each). Among bacteriovores, Acrobeloides nanus dominated all species in terms of Prominence Value (PV) and Relative Prominence Value (RPV), which were calculated to be 329.38 and 21.12% respectively whereas Teratorhabditis synpapillata showed least Prominence Value (PV) and Relative Prominence Value (RPV) i.e., 0.43 and 0.03% respectively. Discolaimus similis surpassed all predator species in terms of Prominence Value (PV) i.e., 239.10 and Relative Prominence Value (RPV) i.e., 15.33% whereas Neoactinolaimus agilis showed lowest Prominence Value (PV) and Relative Prominence Value (RPV), which were calculated to be 1.87 and 0.12% respectively. Among omnivores, Mesodorylaimus subtiloides dominated all genera in terms of Prominence Value (PV) and Relative Prominence Value (RPV) i.e., 102.01 and 6.54% respectively whereas Thornenema nodicaudatum demonstrated lowest Prominence Value (PV) and Relative Prominence Value (RPV) i.e., 4.83 and 0.31% respectively. Among fungivores, Aphelenchus avenae dominated all genera in terms of Prominence Value (PV) and Relative Prominence Value (RPV), which were calculated to be 48.82 and 3.13% respectively whereas Basirotyleptus basiri showed lowest Prominence Value (PV) and Relative Prominence Value (RPV) i.e., 23.17 and 01.49% respectively. Tylenchorynchus mashhoodi was the herbivore that demonstrated maximum Prominence Value (PV) and Relative Prominence Value (RPV), calculated to be 86.82 and 5.57% respectively whereas Basiria graminophila showed least Prominence Value (PV) and Relative Prominence Values (RPV) i.e., 2.45 and 0.16% respectively.

305 Zone A

Zone B

Zone C Fig. 81. Prominence values (%) of the trophic groups in three selected zones of Keetham Lake

306 Biomass

Zone A

The data of the wetland revealed the biomass of predators to be the greatest (Fig. 82) among all groups i.e., 42%, followed by bacteriovores (30%), omnivores (19%), herbivores (5%) and fungivores (4%). Among predators, Aprocelaimellus tropicus had the greatest total biomass of 3266 µg whereas Aquatides deconincki showed least total biomass of 400 µg. Among bacteriovores, Panagrolaimus hrgrophilus dominated with highest total biomass of 912 µg whereas Stegellata jaisalmerensis had least total biomass value of 25 µg . Among omnivores, Dorylaimus innovatus surpassed all species in terms of total biomass calculated to be 1200 µg whereas Mesodorylaimus subtiloides showed least total biomass value, 400 µg. Tylenchus agricola demostrated maximum total biomass of 403 µg among herbivores whereas Trichodorus borai demonstrated least total biomass of 120 µg. Among fungivores, Aphelenchus avenae had maximum total biomass value of 512 µg whereas Leptonchus buccatus showed least total biomass value of 60 µg.

Zone B

The total biomass of predators was found to be the greatest (Fig. 82) among all groups i.e., 38%, followed by bacteriovores (28%), omnivores (17%), herbivores (11%) and fungivores (6%). Among predators, Eudorylaimus vuvlvastriatus demonstrated greatest total biomass of 3125 µg whereas the total biomass value (315 µg) of Butlerius butleri was least. Among bacteriovores, Cephalobus cubaensis dominated with the total biomass of 845 µg whereas Wilsonema bangaloreiensis showed lowest value of total biomass (45 µg). Oriverutus sundarus was the omnivore representing the highest value of total biomass (845 µg) whereas Mesodorylaimus subtiloides showed least total biomass value (400 µg). Tylenchus agricola surpassed all the herbivore genera on account of total biomass (403 µg) whereas Latocephalus gracilei, showed lowest total biomass value (600 µg). Among fungivores Aphelenchoides composticola surpassed all species on account of total biomass (575 µg) whereas Tylencholaimus ibericus showed lowest total biomass of 250 µg.

307 Zone A

Zone B

Zone C Fig. 82. Total Biomass (%) of trophic groups in three selected zones of Keetham Lake

308 Zone C

The data of the wetland revealed the biomass of bacteriovores to be the greatest (Fig. 82) among all groups i.e., 44%, followed by herbivores (25%), predators (22%), omnivores (5%) and fungivores (4%). Among bacteriovores, Acrobeloides nanus demonstrated maximum total biomass of 845 µg whereas Wilsonema bangaloreiensis showed lowest total biomass value of 112 μg. Hoplolaimus indicus was the herbivore showing highest total biomass of 1012 µg while Basiria graminophila showed lowest total biomass value of 250 µg. Among predators, Aprocelaimellus tropicus surpassed all species on account of total biomass calculated to be 1819 µg while Thonus garhwaliensis, demonstrated lowest total biomass value (260 µg). Mesodorylaimus subtiloides, among omnivores, showed greatest total biomass of 825 µg whereas Thornenema nodicaudatum showed least total biomass (545 µg). Among fungivores, Aphelenchus avenae dominated all species in terms of total biomass calculated to be 385 µg whereas Basirotypletus basiri had the total biomass value to be 275 µg. Importance Value

Zone A

The data of the wetland revealed the Importance Value (IV) of bacteriovores (Fig. 83) to be the greatest among all groups i.e., 47%, followed by predators (23%), herbivores (13%), omnivores (12%), fungivores (5%). Among bacteriovores, Acrobeloides nanus surpassed all species on account of Importance Value (IV) and Relative Importance Value (RIV), which were calculated to be 19.25 and 7.89% respectively whereas Drilocephalobus mustaqimi sp. n., demonstrated lowest Importance Value (IV) and Relative Importance Value (RIV ) i.e., 0.54 and 0.22% respectively. Discolaimus similis was the predator with greatest Importance Value (IV) and Relative Importance Value (RIV) of 4.69 and 1.92% respectively whereas Ironus dentirfurctaus showed lowest Importance Value (IV) and Relative Importance Value (RIV) i.e., 0.42 and 0.17% respectively. Among omnivores Mesodorylaimus subtiloides demonstrated maximum Importance Value (IV) and Relative Importance Value (RIV) i.e., 11.04 and 4.53% respectively whereas, Oriverutus sundarus showed lowest Importance Value (IV) and Relative Importance Value (RIV) i.e., 0.52 and 0.21% respectively. Among fungivores Aphelenchus avenae dominated all species in terms of Importance Value (IV) and Relative Importance Value (RIV), which were

309 calculated to be 5.94 and 2.44% respectively whereas Leptonchus buccatus showed lowest Importance Value (IV) and Relative Importance Value (RIV) i.e., 0.66 and 0.27% respectively. Hemicycliophora dhanachandi, among herbivores, dominated all species in terms of Importance Value (IV) and Relative Importance Value (RIV), which were calculated to be 8.91 and 3.65% respectively whereas Hemicriconemoides brachyurus demonstrated lowest Importance Value (IV) and Relative Importance Value (RIV) i.e., 0.36 and 0.15% respectively.

Zone B

The data of the wetland revealed the Importance Value (IV) of bacteriovores (Fig. 83) to be the greatest among all groups i.e., 43%, followed by predators (24%), omnivores (15%), fungivores (11%) and herbivores (7%). Among bacteriovores, Acrobeloides nanus was the top most species with maximum Importance Value (IV) and Relative Importance Value (RIV) of 20.77 and 9.46% respectively whereas Drilocephalobus saprophilus sp. n., was least important with Importance Value (IV) and Relative Importance Value (RIV) of 0.45 and 0.20% respectively. Mylonchulus hawaiiensis among predators, dominated other species in terms of Importance Value (IV) and Relative Importance Value (RIV) which were calculated to be 9.80 and 4.46% respectively whereas Butlerius butleri demonstrated lowest Importance Value (IV) and Relative Importance Value (RIV) i.e., 0.74 and 0.33% respectively. Among omnivores, Mesodorylaimus subtiloides demonstrated highest Importance Value (IV) and Relative Importance Value (RIV) i.e., 2.90 and 1.32% respectively whereas Thornenema nodicudatum showed lowest Importance Value (IV) and Relative Importance Value (RIV) i.e., 0.69 and 0.32% respectively. The fungivore Aphelenchus avenae dominated other species in terms of Importance Value (IV) i.e., 9.22 and Relative Importance Value (RIV) i.e., 4.20% whereas Leptonchus buccatus showed least Importance Value (IV) and Relative Importance Value (RIV) i.e., 0.97 and 0.44% respectively. Among herbivores, Helicotylenchus dihystera dominated all species in terms of Importance Value (IV) and Relative Importance Value (RIV) i.e., 7.43 and 3.38% respectively whereas Xiphinema brevicola showed lowest Importance Value (IV) and Relative Importance Value (RIV) i.e., 1.05 and 0.48% respectively.

310 Zone A

Zone B

Zone C Fig. 83. Importance Value (%) of trophic groups in three selected zones of Keetham Lake

311 Zone C

The data of the wetland revealed the Importance Value (IV) of bacteriovores (Fig. 83) to be the greatest among all groups i.e., 55%, followed by herbivores (16%), predators (14%), fungivores (11%) and omnivores (4%). Among bacteriovores, Acrobeloides nanus demonstrated the highest Importance Value (IV) and Relative Importance Value (RIV), i.e., 21.65 and 11.36% respectively whereas Teratorhabditis synpapillata showed lowest Importance Value (IV) and Relative Importance Value (RIV) of 0.82 and 0.43 % respectively. Among predators, Discolaimus similis dominated all species in terms of Importance Value (IV) and Relative Importance Value (RIV) i.e., 4.15 and 2.18% respectively whereas Mylonchulus hawaiiensis showed lowest Importance Value (IV) and Relative Importance Value (RIV) i.e., 1.58 and 0.83% respectively. Mesodorylaimus subtiloides was the omnivore with greatest Importance Value (IV) and Relative Importance Value (RIV) i.e., 1.89 and 0.99% respectively whereas Thornenema nodicaudatum demonstrated least Importance Value (IV) and Relative Importance Value (RIV) i.e., 1.50 and 0.79% respectively. Among fungivores, Aphelenchus avenae surpassed all species on account of Importance Value (IV) and Relative Importance Value (RIV) calculated to be 7.81 and 4.10% respectively whereas Basirotyleptus basiri showed lowest Importance Value (IV) and Relative Importance Value (RIV) i.e., 5.15 and 2.70% respectively. Among herbivores Tylenchorynchus mashoodi demonstrated maximum Importance Value (IV) and Relative Importance Value (RIV), which were calculated to be 5.42 and 2.84% respectively whereas Hemicriconemoides brachyurus showed the lowest Importance Value (IV) and Relative Importance Value (RIV) i.e., 0.63 and 0.33% respectively.

Nematode Community Dynamics

Shanon’s Diversity Index (H’)

The Shanon’s Diversity Index (H’) varied from 2.45-3.45 (2.84±0.15) in Zone A; 2.65-3.85 (2.75±0.09) in Zone B and 2.00-2.85 (2.15±0.15) in Zone C.

Species richness/ Margalef Index

Species richness/ Margalef Index was calculated to be 6.62-7.20 (6.96 ± 0.25) in Zone A; 5.15-6.88 (6.36 ± 0.54) in Zone B and 4.43-6.20 (5.46 ± 0.53) in Zone C.

312 Simpson Dominance

Simpson Dominance was found to be 8.20-9.86 (8.70 ± 0.93) in Zone A; 5.10-6.21 (5.88 ± 0.50 ) in Zone B and 5.65-10.5 (6.27 ± 1.45) in Zone C.

Heip Evenness

Heip evenness was found to be 0.35-0.42 (0.39± 0.02) in Zone A; 0.38-0.48 (0.41±0.10 ) in Zone B and 0.42-0.60 (0.52 ± 0.15) in Zone C.

Maturity Index (MI)

The maturity index (MI) ranged from 2.62-3.45 (3.15±0.25) in Zone A; 2.85-3.98 (3.85±0.15) in Zone B and 2.15-3.65 (2.85±0.45) in Zone C.

Plant Parasitic Index (PPI)

The plant parasitic index (PPI) varied from 1.00-3.86 (2.41±0.93) in Zone A; 2.00- 5.00 (3.98±1.04) in Zone B and 2.45-3.15 (2.80±0.26) in Zone C.

PPI/MI

The PPI/MI varied from 0.61-1.87 (1.26±0.35) in Zone A; 0.62-2.05 (1.85±0.35) in Zone B and 0.68-1.36 (1.02±0.19) in Zone C.

Enrichment Index (EI)

The enrichment index (EI) ranged from 41.25-64.45 (31.85±7.50) in Zone A; 23.51- 63.21 (32.51±10.5) in Zone B and 38.45-78.45 (51.48±20.12) in Zone C.

Structure Index (SI)

The structure index (SI) was found to be 55.99-78.75 (68.43±4.05) in Zone A; 79.15- 91.75 (86.15±12.25) in Zone B and 39.32-52.56 (55.82±34.42) in Zone C.

Basal Index (BI)

Basal index (BI) varied from 4.05-16.25 (9.11±4.25) in Zone A; 3.45-16.25 (8.44±2.75) in Zone B and 8.22-36.32 (17.75±7.75) in Zone C.

Nematode Channel Ratio (NCR)

NCR can be powerful tool in analyzing the decomposition pathway prevailing in the ecosystem. Zone A have 0.50-0.62 (0.59±0.18) value; Zone B have 0.62-0.74 (0.66±0.18) value and Zone C have 0.75-0.85 (0.79±0.15) value.

313 Table 41. Ecological indices and characteristic of three zones of Keetham Lake

Ecological indices/ ZONE A ZONE B ZONE C characteristics Mean±SD Mean±SD Mean±SD (Range) (Range) (Range) Shanon Diversity (H') 2.84 ± 0.15 2.75 ± 0.09 2.15 ± 0.15 (2.45-3.45) (2.65-3.85) (2.00-2.85) Species richness 6.96 ± 0.25 6.36 ± 0.54 5.46 ± 0.53 Margalef index (6.62-7.20) (5.15-6.88) (4.43-6.20) Simpson Dominance 8.70 ± 0.93 5.88 ± 0.50 6.27 ± 1.45 (8.20-9.86) (5.10-6.21) (5.65-10.5) Heip Evenness 0.39± 0.02 0.41± 0.10 0.52 ± 0.15 (0.35-0.42) (0.38-0.48) (0.42-0.60) Maturity Index (MI) 3.15 ± 0.25 3.85 ± 0.15 2.85 ± 0.45 (2.62-3.45) (2.85-3.98) (2.15-3.65) Maturity Index (MI25) 2.4 ± 0.18 3.4 ± 0.18 2.2 ± 0.18 (2.06-2.85) (3.02-3.65) (2.0-2.6) Plant parasitic Index (PPI) 2.41 ± 0.93 3.98 ± 1.04 2.80 ± 0.26 (1.00-3.86) (2.00-5.00) (2.45-3.15) PPI/MI 1.26 ± 0.35 1.85 ± 0.35 1.02 ± 0.19 (0.61-1.87) (0.62-2.05) (0.68-1.36) Enrichment Index (EI) 31.85 ± 7.50 32.51 ± 10.5 51.48 ± 20.12 (41.25-64.45) (23.51-63.21) (38.45-78.45) Structure Index (SI) 68.43 ± 4.05 86.15 ± 12.25 55.82± 34.42 (55.99-78.75) (79.15-91.75) (39.32-52.56) Basal Index (BI) 9.11 ± 4.25 8.44 ± 2.75 17.75 ± 7.75 (4.05-16.25) (3.45-16.25) (8.22-36.32) Trophic Diversity Index (TDI) 1.27±0.10 2.10±0.07 1.12±0.15 (1.10-1.85) (1.67-2.54) (1.0-1.25) Nematode Channel Ratio 0.59±0.18 0.66±0.18 0.79±0.15 ((NCR) (0.50-0.62) (0.62-0.74) (0.75-0.85) % Rhabditids 19.2±8.5 27.5±6.4 35.5±15.4 (8-20) (23-40) (8-55) % Tylenchids 14.6±9.8 19.7±9.8 17.7±9.8 (8-22) (15-29) (8-20) % Dorylaims 22.7±6.2 25.3±6.2 26.7±6.2 (20-35) (23-35) (20-31) % Others 43.5±8 27.0±8 20.1±8 (40-75) (25-45) (12-25)

314 Correlation of indices with feeding guilds

Zone A: Population of dorylaims showed very high degree of positive correlation (P < 0.01) with MI and SI and a very significant negative correlation with BI. With all other indices dorylaims showed almost no correlation. Populations of rhabditids showed a very high degree of negative correlation (P < 0.01) with both MI and SI and very high degree of positive correlation (P < 0.01) with BI, while with all other indices, almost no correlation could be found (Fig. 84).

Zone B: The population of dorylaims showed low positive correlation with MI and significant positive correlation (P <0.05) with SI and significant negative correlation with BI while with all other indices population of dorylaims showed almost no correlation. Populations of rhabditids showed very high degree of negative correlation (P < 0.01) with MI and SI and a very high degree of positive correlation (P < 0.01) with BI while, with all other indices, there was almost no correlation (Fig. 85).

Zone C: The populations of dorylaims in showed a very high degree of positive correlation (P < 0.01) with MI and significant positive correlation (P < 0.05) with SI and a very high degree of negative correlation (P < 0.01) with EI and CI and significant negative correlation with BI and PPI/MI. With all other indices there was almost no correlation. Population of rhabditids show high negative correlation with MI and SI Population of tylenchids showed non significant negative correlation with PPI and significant negative correlation with H΄ while with all other indices, they showed almost no correlation (Fig. 86).

Quadrat analysis

The three zones were compared using the Enrichment and Structure indices to determine the quality of the environment in the wetland. Zone A reflected conditions of moderate enrichment to moderate structuredness. Zone B reflected most of the sampling sites showing moderate enrichment but highly structured status. Zone C showed most of the sampling sites indicating high enrichment while few indicated high structured status (Fig. 87).

315 (a)

(b)

(c)

(d) Fig. 84. Correlation between different indices and trophic group of Zone A

316 (a)

(b)

(c)

(d) Fig. 85. Correlation between different indices and trophic group of Zone B

317 (a)

(b)

(C)

(d) Fig. 86. Correlation between different indices and trophic group of Zone C

318 Zone A Zone B Zone C 100

50 Enrichment Index Enrichment

0 0 50 100 Structure Index

Fig. 87. Quadrat analysis [Graph constructed using functional guild approach, after Ferris (2001)] depicting comparative status and stability of three zones of Keetham Lake.

319 DISCUSSION

The present study revealed some interesting findings about the nematode community of the wetland, Keetham Lake. Firstly the taxonomic diversity of the wetland revealed interesting array of species from all orders of soil and aquatic nematodes. About fifty seven species were identified of which twenty three have been reported in the thesis with detailed descriptions. Twelve species have been reported as new to science while two have been reported for the first time from India.

The superficial division of the wetland into zones A, B and C for the sake of making the analysis easy, did not reveal much difference in nematode community characteristics. The overall nematode counts over the sampling sites ranged widely from 300-1041 individuals per 400 ml of soil, showing immense variation in substrate conditions and indicating some sites to be extremely dry and nutritionally deficient for nematode survival. Such sites indicated presence of basal indicators i.e., Cephalobidae. The wide range of nematode numbers i.e., 52 to 9,166 nematodes per 200 cm3 soil has also been reported by Niblack and Bernard (1985).

Despite extreme variability in nematode numbers at different sampling sites the nematode fauna of the wetland was found to be in dynamic equilibrium representing all trophic groups. The total generic diversity of nematodes in the wetland was fairly high with fifty five genera represented by fifty seven species. However, the bacterivores showed the greatest generic and species diversity and constituted 25-46% of the total species of individual zone.

Ten species Acrobeloides nanus, Aphelenchus avenae, Tylenchorhynchus mashhoodi, Mesodorylaimus subtiloides, Discolaimus similis, Chiloplacus subtenuis, Mylonchulus hawaiiensis, Helicotylenchus dihystera, Panagrolaimus hygrophilus and Mesorhabditis anisospicula sp.n. were found to be most important of the total fifty seven species identified and constitute about 35.98-50.70% of total nematode community. The high frequency and dominance of these species also indicated their greater competence in variable environment types hence cosmopolitan occurrence. Similar findings were reported by other workers when six of twenty-two species made up 91% of the nematode populations (Eder & Kirchengast, 1982) while Beier & Traunspurger (2003b) reported seven of seventy-one nematode species to constitute 71% of total nematode population.

320 Although extensive, the list of species may not be complete due the fact that all species may not have been recorded as they could not have been extractable, in a life stage that could not have been sampled due to specialized microhabitats, at densities too low for detection or present at restricted time of the year. In the samples the endoparasites Heterodera and Meloidogyne could not be found largely due to the fact that the samples largely comprised of soil and not plant roots. However, the juvenile of the above pests were not observed in the samples collected from around the roots. Similar reports by Talavera & Navas (2002) also conform to this finding who could not find root knot nematodes in grassland samples.

Among the trophic groups, bacteriovores were the dominant groups responsible for dissemination of bacterial/ microbial populations. The largely aquatic habitat i.e., Zone A and the Core zone (Zone C) showed relatively smaller trophic diversity index (TDI). Rhabditida being highly diverse and competent was the most numerous taxon. Barring the aquatic habitat of zone A, the substrate conditions of the wetland in zone B and C remained dry with low to moderate enrichment hence the other group, dominant and numerous was Dorylaimida indicating towards stability of the wetland ecosystem. Rhabditids in dry substrate were predominantly the Cephalobidae, the basal indicators.

Acrobeloides nanus, Chiloplacus subtenuis of family Cephalobidae and Panagrolaimus hygrophilus of family Panagrolaimidae all represent the smaller c-p values. However the species of family Cephalobidae preferred and tolerated well, an environment with low moisture/ drought conditions (Dmowska, 2000 and Yeates, 2003). On the other hand, presence of Panagrolaimus was correlated with enriched conditions of the substrate.

Some species that were more frequent at the sites of organic enrichment as well as the conditions of low oxygen concentrations were Mesorhabditis anisospicula sp. n., Teratorhabditis synpapillata, Diploscapter coronatus, Butlerius butleri, Oigolaimella paraninae sp. n., Geomonhystera villosa etc. The species exclusively found in anoxic conditions, were Panagrolaimus hygrophilus, Monhystrella dorsicurvata sp. n. and Tobrilus longus. These species were largely absent in samples from open water zone (having plenty of oxygen). The prevalence of these species in the shore samples of Zone A of the wetland indicated some anthropogenic

321 disturbances largely because of the activities of visitors and the conditions of organic enrichment and eutrophication leading to oxygen depletion.

The dominant herbivores/ plant parasites viz., Helicotylechus dihystera, Hemicycliophora dhanachandi and Hemicriconemoides brachyurus indicated towards successful phytoparasitic associations. The presence of woody plants, the Acacia nilotica forest justified fairly well the dominance of plant parasites with pharyngeal overlap. Though largely categorized as ectoparasites they led to compensatory plant growth (Monteiro et al., 2014). The presence of sensitive indicated stability of environment. Furthermore, the abundance of the nematodes with overlapping pharyngeal glands viz., Helicotylenchus dihystera also reflected a stable habitat as reported by Bongers (1990). The ratio of plant parasites/ herbivores to predators showed a unity or close to unity thus, indicating towards a balanced type of ecosystem. The fair representation of the second degree consumers or so called carnivores/ predators, in the soil environment, was detrimental to the population build of the smaller nematodes or plant parasites and a balance was always maintained.

Beside plant parasites, the non parasitic species that preferred the root zone of Acacia nilotica are Eucephalobus oxyuroides. Oigolaimella indica.sp. n. which presumably rely upon the bacterial colonies that grow on the root exudates and root leachates. Some other bacterivores viz., Tylocephalus aprimitivus sp. n., Oscheius keethamensis sp. n. etc. found in the vicinity, showed phoretic association with insects that depend on the plants in one way or other.

Among the predators, the genera Mylonchulus hawaiiensis and Discolaimus similis were the dominant ones and also been reported with absolute abundance in stable and structured ecosystems by Beier and Traunspurger (2003a, b), Jacobs (1987) and Nuss (1984). The numerical strength of predators outnumbering any group in Zone A reflects the abundance of prey and subsequently the food resources. Another species Chronogaster glandulata reflecting inability to propagate in moisture stress was found in large numbers in the Zone A where water was available perinneally.

Although with diverse characteristics of substrate the three zones showed similarity in having low representation of fungivores in the wetland population specifically in Zones B and C. Thus, their low frequency may be attributed to the low moisture levels of the zone, as fungi require significantly warm but humid conditions for growth. Thus, fungivores with their low prevalence and abundance seemed to

322 contribute least to the total nematode community/ food web interactions and also to the decomposition pathway.

The relative abundance of bacterial and fungal feeders (Twinn, 1974; Wasilewska, 1979; Freckman and Ettema, 1993) indicated towards the decomposition pathways or channels in an ecosystem, also an important factor for assessing the productivity of soils (Yeates, 2003). In the present study, bacteria seemed to constitute the major food resources for these subterranean organisms with nematode channel ratio calculated to be >0.50. The bacterial decomposition pathway appears to be the dominant pathway in Zone C followed by Zone B and Zone A. An increased bacteriovores’ diversity probably was due to high diversity of microbes and thus reflected the nature and quality of soil environment (Standing et al., 2006) and was indicative of the fact that Lake habitat showed predominant bacterial-based energy channels of decomposition thus further confirming the results of Bardget et al. (2001).

The various indices calculated during the study also revealed high diversity and species richness, the attributes of a stable and undisturbed environment. The average Plant Parasitic Index (PPI) was found to be >2 reflecting the dominance of the ectoparasites of c-p value 3 or higher. The MI of the wetland was also > 2 in all zones showing the undisturbed status of habitat, which is apparently free from perturbations or pollution (Zullini, 1976). The contribution of the persisters in enhancing the maturity and structuredness of the ecosystem is well evident from the correlation graphs. Colonizers of c-p value 2 are the key components for the resilience and continuity of any ecosystem as they operate in conditions of moderate enrichment often supplemented with moisture stress.

The over all integration of the nematode community structure with the soil elemental composition may give a faint picture of the substrate type. By and large the wetland Keetham Lake was found to be undisturbed and stable habitat. However, presence of negligible concentration of heavy metals only in specific zones cannot be overlooked but should be taken with utmost caution. The heavy metals viz., Lead (Pb), Arsenic (As), Cadmium (Cd) and Zinc (Zn) were largely found to be in relatively greater concentration in Zone C that has been the restricted entry zone. The zone, also called as python zone showed abundance of predators. Hence in such unaltered ecosystem the death and decay of the organisms would add to the soil various elements and compounds. The heavy metals and other toxicants can enter the

323 food chain of the wetland through some migrating species predominantly the aquatic birds of the bird sanctuary that might visit the extremely polluted Yamuna river located close by or some adjoining pollted water bodies (a good number of industrial units around); and the process of biomagnifications could have led to build up of higher concentration of these pollutants in top carnivores/ predators viz., pythons etc. The death of these predators eventually could release these chemicals to soil.

As per quadrat analysis, it can be said that of the three zones, Zone B was found to be most stable/ undisturbed and structured zone with moderate level of food resources and largely dominated by persisters. On the contrary, moderate to high level of enrichment has been reported at most sampling sites of Zone C which happened to be the restricted access zone providing habitat to most birds. It could be largely due to the disturbances caused by the mobile consumers (predominantly birds that are lodged in the zone) which also connected to other polluted habitats and were the causative agents of pollutant entry in the food chain of the wetland and their further bioaccumulation and biomagnifications. Zone A showed an intermediate position with most of the sites undisturbed except those facing excessive human encroachment. The system showed maturity with a shift towards structured status.

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