(Jurassic), Pranhita-Godavari Valley (A.P.), India

CONTINENTAL MICROFAUNA FROM KOTA FORMATION (JURASSIC), PRANHITA-GODAVARI VALLEY (A.P.), INDIA

A THESIS

Submitted in fulfilment of the requirements for the award of the degree of DOCTOR OF PHILOSOPHY

in EARTH SCIENCES

By

BRIJESH KUMAR

DEPARTMENT OF EARTH SCIENCES UNIVERSITY OF ROORKEE ROORKEE-247 667 (INDIA)

JANUARY, 2001 CANDIDATE'S DECLARATION

I hereby, certify that the work which is being presented in this thesis entitled CONTINENTAL MICROFAUNA FROM KOTA FORMATION (JURASSIC), PRANHITA-GODAVARI VALLEY (A.P.), INDIA" in fulfillment of the requirement of the degree of Doctor of Philosophy, submitted in the Department of Earth Sciences of the University, is an authentic record of my own work carried out during the period from July, 1998 to January, 2001 under the supervision ofDr. Sunil Bajpai.

The matter embodied in this thesis has not been submitted by me for the award of any other degree.

BRIJESH KUMAR

This is to certify that the above statement made by the candidate is correct to the best of my knowledge. /t^_^ d^y/J—- Dr. Sunil Bajpai

Assistant Professor Department of Earth Sciences University ofRoorkee

Roorkee-247 667 Date: 3y//>^/ Uttranchaljndia

The Ph.D. viva-voce examination of Mr. Brijesh Kumar, Research Scholar has been held on %.:.Z/.:..£<%?. I

Signature ofSupervisor Signature ofH.O.D. Signature ofExternal Examiner ABSTRACT

Continental Jurassic sediments are of global significance from the standpoint of vertebrate paleontology, particularly because of their importance in understanding the evolutionary history of early mammals. However, our knowledge of continental vertebrates ofJurassic age in the Gondwanaland continents, still remains inadequate. This is particularly true in the case of Jurassic mammals which at present are mainly

documented from the Laurasian continents. The Kota Formation, which is an integral part ofthe upper Gondwana sequence in the Pranhita-Godavari valley in the south Indian State of Andhra Pradesh, provides an excellent opportunity to document a Jurassic terrestrial ecosystem from India. The Kota Formation, which is largely a fluvio-lacustrine sequence has long been known to yield fish and reptilian faunas. However, microvertebrates from the Kota Formation continue to be poorly known and the present investigation was undertaken to fill this major gap,

with special emphasis on micromammals. During the three field seasons between 1998-2000, the microbiota was recovered mainly by screenwashing techniques. The five investigated sections which form part of

the Godavari subbasin of the Pranhita-Godavari valley, are exposed near Paikasigudem, Kadamba, Metpalli, Manganpalli (District Adilabad) and Kota (District Chandrapur). Microvertebrates recovered during the present investigation comprise over 3500 identifiable elements of fish, rhynchocephalians, lizards, crocodiles, sauropods, ornithischians, theropods and mammals. These elements include isolated teeth, fragmentary dentaries, maxillae, premaxillae, scales, dermal denticles and phalanges. Associated fauna includes ostracods and trace fossils. The vertebrate assemblage comprises 25 genera and 25 species. Fish constitute the most dominant group with 8 genera and 8 species representing holosteans and elasmobranchs. The semonotids are the most common fish. Among the reptiles, theropods and ornithischians are recorded for the first time from this formation. Theropods are known mainly by isolated teeth grouped into 4 morphotypes and ornithischians into two. These finds clearly indicate that the dinosaur fauna was much more diverse than hitherto believed. Another important group in the collection are the rhynchocephalians (sphenodontids) which are known by 2 taxa. Crocodiles and lizards are each represented by a single taxon. Significantly, the acrodont iguanid lizards reported in this work form the first record from the Kota Formation and also the oldest record of this group anywhere in the world. Mammals are the most important component of the presently described Kota vertebrate assemblage. They are represented by 2 orders, Docodonta and Triconodonta. The present docodont material forms the first Gondwanan occurrence of this group. Their discovery from the Indian subcontinent suggests aPangean distribution for this group in the Jurassic. Triconodonts form the most diversified group among the Kota mammals, represented by Dyskritodon indicus sp. nov., Paikasigudodon yadagirii nov. comb.,

Indotherium pranhitai and Triconodonta indet. Invertebrate fauna is represented by a single ostracod genus with two species.

Ichno fossils include Planolites and Monocraterion. Significantly, the new data suggest, based on mammals, that an Upper Jurassic- Lower Cretaceous age is more likely for the Kota Formation than the traditionally held Lower Jurassic (=Liassic) age. The mammalian data is also indicative of a land-locked position for India in the Jurassic, in agreement with geophysical models. Further, the Kota community, overall, represents an admixture ofaquatic, semi-aquatic, terrestrial and aerial elements that thrived in and around a shallow freshwater lake.

in Acknowledgement

The work embraced in this thesis was carried out in the supervision of Dr. Sunil Bajpai, Assistant Professor, Department ofEarth Sciences, University ofRoorkee, and it has been a great opportunity for me to work with him. I further wish to place on record a deep sense ofindebtedness and gratitude for going through the manuscript critically and giving valuable suggestions, which has immensely improved the quality of the present work.

I am greatly indebted to Dr. S.S. Srivastava, Professor, Department of Earth Sciences, University of Roorkee, for his help in many ways.

I thank Dr. A.K. Awasthi, Professor and Head, Department of Earth Sciences for extending all necessary laboratory and infrastructural facilities. I also thank Dr. S.K. Upadhyay, Professor and Former Head, under whose headship the present work was started.

I am thankful to all the faculty members of the department for their help at various occasions, especially Drs. R.M. Manickavasagam, D.K. Mukhopadhyay. I thank Professor R. Chander, Department ofEarth Sciences, University of Roorkee for various encouraging discussions.

I would also like to thank all the non-teaching members for their unstinting support at all stages of thiswork. I am highly thankful to Prof. G.V.R. Prasad, University ofJammu, for providing access to his microvertebrate collections from the KotaFormation, for allowing me to use some of his own collection in the present study and for his generous loan of literature. Discussion with Prof. Prasad proved greatly helpful in improving this thesis.

I thank Dr. Kailash Chandra, Director, U.S.I.C, University of Roorkee, for allowing me to usethe Scanning Electron Microscope.

I thank Drs. C. S. Sudan, Reader and Umesh K. Sharma, R. A., Department of Geology, University ofJammu, Jammu, for their help in identification oftrace fossils. I also thank Dr. B.N Tiwari (WIHG, Dehradun) for helping me in several ways. I am also thankful to Dr. Vijaya (BSIP, Lucknow) for sharing her palynological data with me.

I am also thankful to Dr. P. J. Currei, Royal Tyrell Museum of Paleontology, Alberta, Canada, for his expert comments on the theropod dental remains and sending relevant literature from his personal collection. I am thankful to scores of scientists who have sent me the required literatures.

I express my heartfelt gratitude to my friends, especially Mr. Premanand Mishra Drs. J. Sahoo, J. Devaraju, Sk.R. Basir, R.S. Sambyal, Anil K. Sharma, Chanchal Kumar and Mr. Rajeev Kumar and R.K. Singal for their constant help and encouragement during the course ofthis work. Iam highly indebted to Mr. Syed Latif and Sk. Baba, the chowkidars (caretakers) of the P.W.D inspection bunglows at Rebbena and Chinnur (Andhra Pradesh), who made my stay in the field comfortable. I dedicate this work to my maternal grandmother (Hasanti Devi) who was constant source of inspiration for me. I wish she could have lived longer to see me complete this work.

Last but not least, Iam thankful to my parents, sisters Neelam and Shilpa brother Narinder and the nieces Tanisha, Sonia &Mannu, Sonu, my maternal uncles and Aunt and also my friend Meenu for standing by me and encouraging me to complete the work

VI CONTENTS

±

Page No.

ABSTRACT i

ACKNOWLEDGEMENTS v

CONTENTS vii

LIST OF FIGURES xii

LIST OF TABLES xii Chapter 1 : INTRODUCTION 1 Chapter 2 : PREVIOUS WORK 13 2.1 Geology 13 2.2 Paleontology 19 2.2.1 Fish and Reptiles 19

2.2.2 Mammals 21

2.2.3 Invertebrates 22

2.2.3.1 Ostracods 22

2.2.3.2 Estheriids 23

2.2.3.3 Insects 23

2.2.4 Flora 23

2.2.5 Stromatolites 25

2.2.6 Trace Fossils 25 Chapter 3 : GEOLOGY AND STRATIGRAPHY 27

3.1 Introduction 27 3.2 Pranhita-Godavari Valley 30 3.2.1 Precambrian Basement Complex 31 3.2.2 Pakhal Group 32 3.2.3 Sullavai Group 33

3.2.4 Talchir Formation 34

3.2.5 Barakar Formation 36 3.2.6 Barren Measures 36 3.2.7 Kamthi Formation 37 3.2.8 Yerrapalli Foramtion 39 3.2.9 Bhimaram Sandstone 40 3.2.10 Maleri Formation 41 3.2.11 Dharmaram Formation 42 3.2.12 Kota Formation 43 3.2.13 Gangapur Formation 49 3.2.14 Deccan Traps 50 3.3 Geology ofMeasured Sections 50 3.3.1 Paikasigudem Section 50 3.3.2 Metpalli Section 52 3.3.3 Kadamba Section 52 3.3.4 Manganpalli Section 53 3.3.5 Kota Section 54 Chapter - 4:SYSTEMATIC PALEONTOLOGY 75 Faunal List 75 Pisces 75 Lepidotes deccanensis 78 Paradapedium egertoni 78 Tetragonolepis oldhami 82 Semionotidae indet.1 83 Semionotidae indet.2 84 Semionotidae indet.3 85 Lissodus indicus nov. comb. 87 Elasmobranchii indet. 90 Reptiles 91 Rhynchocephalian 91 Gen. et sp. indet. "A" 92 Gen et sp. indet. "B" 95 Lizards „„ Gen et sp. indet. no Crocodiles 100

?Teleosauridae 100

Dinosaurs 101 Sauropoda indet. 101 Ornithischia Type A 103 Ornithischia Type A 107 Theropoda"A" 108 Theropoda"B" 110 Theropoda "C" 112 Theropoda"D" 113

Mammals 113 Deniseodon godavariensis gen. et sp. nov. 115 Gondtherium dattai gen. et sp. nov. 126 Dyskritodon indicus sp. nov. 132 Paikasigudodon yadagiri nov. comb 138. a Indotherium pranhitai 144

Triconodonta indet. 149

Mammalia indet. 150

Ostracods 151 Darwinula sarytirmensis 151 Darwinulasp. 152

Trace Fossils 153 -T Palnolites sp. 153 Monocraterion sp. 153 Chapter 5: DISCUSSION 159 5.1 Tectonic and Geologic Setting 159 5.2 Community Structure and Palaeoecology 163 5.3 Biogeographic Affinities 172 5.4 Age Consideration 179 Chapter 6 : SUMMARY AND CONCLUSIONS 191

REFERENCES 197 LIST OF FIGURES

Figure No. Page no. 1.1 Generalised map of Pranhita-Godavari valley. 9 1.2 Map showing location ofstudy area. 11

3.1 Distribution of continental Gondwana basins in India. 55 3.2 Geological map of the northern part of Pranhita-Godavari valley. 57 3.3 Location map ofPaikasigudem, Metpalli and Kadamba. 59 3.4 Stratigraphic section exposed at Paikasigudem. 61 3.5 Stratigraphic section exposed at Metpalli. 63 3.6 Stratigraphic section exposed at Kadamba. 65 3.7 Location map ofManganpalli section. 67 3.8 Stratigraphic section exposed at Manganpalli. 69 3.9 Location map ofKota section. 71 3.10 Stratigraphic section exposed at Kota. 73 4.1 Line drawings ofrhynchocephalians (Taxon A). 155 4.2 Line drawings ofrhynchocephalians (Taxon B). 157 5.1 Map showing configuration ofNarmada-Son and

Pranhita-Godavari basins. 181 5.2 Relative composition ofKota Formation fauna. 183 5.3 Taxonomic diversity of Kota reptiles. 185 5.4 Reconstruction ofPangea during Jurassic showing position ofIndia. 187 5.5 Distribution ofMiddle and Upper Jurassic Docodonts. 189 LIST OF TABLES

Table No. Page No. 3.1 Comparative Stratigraphic Classification of rocks exposed in Pranhita-Godavari Valley. 38 3.2 Comparative lithostratigraphic classifications ofthe

Kota Formation. 46 4.1 Measurements ofthyreophoran (Type A) teeth. 105 4.2 Measurements ofTheropod "A" teeth. 109

4.3 Measurements of Theropod "B" teeth. 111 4.4 Measurements ofTheropod "C" teeth. 112

5.1 Distribution of microfauna in the investigated sections. 164

5.2 Biotic composition ofthe Kota Formation. 165

+ Chapter 1

* INTRODUCTION

Mesozoic terrestrial ecosystems receive considerable attention the world over because oftheir importance in understanding the origin and early evolutionary history of much of the modern biota including mammals, birds and flowering plants. Ofparticular significance is the Jurassic period, during which mammals began to diversify. However, continental Jurassic sequences have a restricted occurrence in both the northern and southern hemispheres and our knowledge ofJurassic vertebrate fauna is based largely on data from the northern, Laurasian continents. In recent years, concerted efforts have been made by some workers to correct this underrepresentation in the southern continents (Prasad et al, 1994; Sigogneau-Russel, 1995; Rich et al, 1995; Krause et al, 1997;

Flynne/or/., 1999). The Pranhita-Godavari valley in southcentral peninsular India (Text Fig. 1.1) preserves an almost complete sequence of Gondwana rocks ranging in age from Early Permian to Early Cretaceous, resting over the supracrustal rocks. This sequence, exposed

in a NW-SE linear belt, has attracted the attention of geologists and paleontologists for the past 150 years. Subsequent to the pioneering contributions of Egerton (1852-1878) and King (1881), geological studies in this basin have been carried out by a number of workers (Jain et al, 1964; Sengupta, 1966; 1970; Kutty, 1969; Yadagiri, 1979; Ray,

1997).

The Kota Formation of Pranhita-Godavari valley, Adilabad district, Andhra Pradesh, provides an excellent opportunity to investigate acontinental Jurassic ecosystem in India. This formation, which is the focus of the present study, was named after the

village Kota (18° 55'N: 80° 02'E) situated on the eastern bank of Pranhita river

approximately 8 km north ofits confluence with Godavari river. The formation is fluvio-

lacustrine, composed mainly ofsandstone, clays and limestone. Of the three members of 4 the Kota Formation, the Middle Member, which consists of limestone and intercalated

clays, is the main fossiliferous horizon.

Following the early descriptions of fossil fish in the 19th century (Egerton, 1851-

1878), aprolific megavertebrate assemblage was reported from the Kota Formation in the second half of the 20th century. Amajor portion of this work on megavertebrate fossils > was carried out by geologists ofthe Indian Statistical Institute, Calcutta, in collaboration with University College, London and the Geological Survey of India. However, except for a few sporadic contributions (Datta et al, 1978; Datta, 1981; Yadagiri, 1984; 1985;

1986, Prasad, 1986), no detailed investigations have yet been carried out on the

* microvertebrate assemblages from the Kota Formation. The present investigation was undertaken to supplement the existing palaeontological database by studying the microfaunas of the Kota Formation with special emphasis on mammals. The objectives of

the present work can be listed as follows:

> To delineate fossiliferous sections of the continental Jurassic sediments of the Kota

Formation.

> To recover microvertebrates and associated fauna by applying the various maceration

techniques.

> To systematically describe the recovered assemblage.

+

> To work out the age, biogeographic and palaeoecological implications of the

recovered biota.

Three field trips were undertaken during the years 1998 - 2000 to a number of

fossiliferous localities of the Kota Formation. During these field seasons, five sections, 1 namely Paikasigudem, Kadamba, Metpalli, Manganpalli and Kota (Text Fig. 1.2, 3.3, 3.7,

3.9) were investigated. The area investigated forms northern part of Andhra Pradesh State

(Adilabad District) and falls under Survey of India toposheet numbers 56 M/l 1, 56 M/12,

56 M/16 and 56 N/13. All the sections are accessible by metalled roads to the

neighbouring villages. Microfossils described in this thesis were recovered mainly by screenwashing techniques employed both in the field and laboratory. Atotal of approximately 3tons of matrix was screenwashed. While the soft sediments were directly screenwashed in water, the harder sediments were broken into 1-2 cm size fragments and dried in the sunlight (in field) or in oven (in laboratory) for about a day to eliminate moisture. These were then kept immersed in kerosene for two to six hours. After this the kerosene was decanted and replaced with water. This technique causes the kerosene to force out ofthe rock mass and be replaced with water, resulting in the disintegration of sediment into a mudslurry. The mudslurry was then diluted by adding more water and screenwashed with different sets of sieves. The harder sediments, which did not disintegrate with kerosene, were boiled with NaOH/KOH solution for 1/2 to 1hour. Sediments which could not be disintegrated with 4 kerosene and NaOH/KOH, were treated with mild acetic acid (upto 5%) for upto 10 days. For screening, sieves of 8 to 60 A. S. T. M. were used in the present study. The concentrate so obtained was dried and then examined under microscope and the microfossils recovered from the concentrate were cleaned ultrasonically.

The most productive section is exposed along a stream channel on the western side ofthe village Paikasigudem (79° 30' 07"N: 19° 15' 08"E, PI. 1 fig. a, Text Fig. 1.2,

3.3). Lithologically, the Paikasigudem section consists of about 15m thick succession of sandstone, clay, mudstone and limestone. This section has yielded a diverse assemblage of fish (semionotids and elasmobranchs), sphenodontids (two new taxa), crocodiles, sauropods, theropods, ornithischians and mammals. Mammals include docodonts ~* {Deniseodon godavariensis gen. et sp. nov., Gondtherium dattai gen. et sp. nov.) and triconodonts (Dyskritodon indicus sp. nov, Paikasigudodon yadagirii nov. comb.,

4 Indotherium pranhitai and Triconodonta indet.). Associated biota includes ostracods

(Darwinula sarytirmensis and Darwinulla sp.). In addition to the body fossils this section

has also yielded trace fossils including Planolites and Monocraterion.

The Manganpalli section is exposed 0.75 km northwest of Manganpalli village

(79° 49' 30"N: 19° 06' 13"E; PL 2 fig. b, c, Text Fig. 1.2, 3.7). The section was measured

in a pit excavated by the Geological Survey of India for the recovery of a sauropod

Kotasaurus yamanpallensis. The excavated pit is 4.5m thick and consists of sandstone

and three limestone bands separated by clay beds. Microfossils recovered from the

section include semionotid fish (Lepidotes, Paradepadium and Tetragonolepis), theropod

teeth, fragmentary mammalian bones and ostracods.

£ The Metpalli section is exposed in a creek southwest of the village Metpalli (79°

44' 00"N: 19° 11' 00"E; PI. 1 fig. c and PI. 2 fig. a, Text Fig. 1.2, 3.3). Here, the

composite section is 15m thick and is composed of two dominant lithologies namely clay

and limestone. This section has yielded semionotid fish, fragmentary mammalian bones

and ostracods. In addition, trace fossils represented by Planolites sp. and Monocraterion

sp. were recovered.

The Kadamba section is exposed 2 km south of Kadamba (19° 22' 30"N: 79° 39'

00"E, Text Fig. 1.2, 3.3). This section is composed of clays and limestones. The section is

2.5m thick and has yielded a large number of semionotid fish remains (scales and teeth)

and ostracods.

The Kota section forms the type section of the Kota Formation. It is exposed on

the western side of Kota village, on the eastern bank of the river Pranhita. The section

5 comprises alternating clays and limestones. The limestone has yielded fish, whereas the clays have produced a microfauna comprising fish (semionotids and elasmobranchs),

sphenodontids, crocodiles and ostracods.

One of the most significant aspects of the present work is that it clearly demonstrates that the Jurassic mammals in the Indian subcontinent are much more diverse than hitherto believed. The present mammalian fauna includes triconodonts and docodonts, the latter being the first definite record from the Gondwanaland. The Kota docodonts, which include Deniseodon godavariensis gen. et sp. nov. and Gondtherium dattai gen. et sp. nov., show close morphological similarities to Laurasian taxa (known from Portugal). APangean distribution is thus advocated for these mammals contrary to the earlier notion of only Laurasian distribution. The triconodonts, especially Dyskritodon indicus sp. nov. resembles the Lower Cretaceous species Dyskritodon amazighi from Anoual, Morocco. Its occurrence in the Kota sediments suggests a younger age (Upper

Jurassic - Lower Cretaceous) for the formation.

Another significant find reported in this thesis is the occurrence oftheropods and ornithischians from the Kota Formation. The theropods are known mainly by isolated teeth that can be grouped into four morphotypes. The recognition ofornithischians is also based on isolated teeth, classified into two morphotypes. The discovery of these dental remains demonstrates that the Kota dinosaurs were much more diverse than the already known sauropod and hypsilophodontid fauna. 4 The agamid lizards described in the thesis constitute the first report from the Kota

Formation. It also constitutes the oldest fossil record of agamids in the world. The

sphenodontids recovered represent two taxa, one of which (Taxon A) shows primitive

dental features akin to the Late Triassic and Lower Jurassic sphenodontids whereas the

second taxon (Taxon B) shows advanced dental features akin to the Lower Cretaceous

sphenodontids.

ABBREVIATIONS

A.S.T.M. American Society for Testing Materials

B.M.N.H. British Museum ofNatural History

BW Tooth basal width

FABL Tooth fore-aft basal length

GSI Geological Survey ofIndia

RUBK Roorkee University Collection, Brijesh Kumar

TCH Tooth crown height

VPL/JU/KM Vertebrate Palaeontology Laboratory / University Of Jammu / Kota

Mammal

VPL/JU/KR Vertebrate Palaeontology Laboratory / University Of Jammu /

Kota Reptiles REPOSITORY OF MATERIAL

The assemblage recovered during the present investigation is catalogued as

RUBK numbers and deposited in the Vertebrate Palaeontology Laboratory, Department of Earth Sciences, University of Roorkee, Roorkee.

i 4r

>

Fig. 1.1 Generalised geological map ofPranhita-Godavari valley (after Murti and Lakshminarayana, 1994) 800km

Fig. 1.2 Map showing the location of studied area. Chapter 2

PREVIOUS WORK

This chapter highlights some of the important contributions made by various workers in the past on the Kota Formation of Pranhita-Godavari valley, Andhra

Pradesh. The chapter has been divided into two sections, Geology and Paleontology.

2.1 GEOLOGY

Geological investigations in the Pranhita-Godavari valley started as early as in the second quarter of the 19th century but, largely due to inaccessibility, the area received little attention until the second half ofthe 20th century. The oldest geological account of the Pranhita-Godavari valley goes to the credit of Voysey (1833, in King,

1881). This was followed by Walker (1841) who reported the presence of vertebrate skeletal elements from the Kota Formation in his "Memoir on Coalfield ofKotah".

Huges (1876) for the first time mapped the area and grouped the Kota and the underlying Maleri beds as one unit. He opined that these two beds could not be differentiated on the basis of lithology and, if not classified together, they should be treated as members ofthe same series.

Subsequently, King (1881) gave a detailed account of the geology of the area together with a geological map. It is important to note that King (1881) mapped the Kota and Maleri beds as independent stratigraphic units, unlike Huges (1876). He divided the rocks of the Pranhita-Godavari valley into Lower and Upper Gondwanas and his Upper Gondwana sequence consisted of the following succession:

GROUP LITHOLOGY FOSSIL(S) AGE

Chikiala Sandstone andconglomerate None U. Jurassic

Limestone, sandstone and shale Fish fauna L. Jurassic Kota

Sandstone and shale

Kota flora U. Jurassic

Red clays, sandstone and rubbly Rhynchosaurs, Maleri beds phytosaurs, U. Triassic amphibians

King (1881) was of the view that contacts within the Upper Gondwana group are unconformable. Further, King (1881) defined the Kota Group as "dominantly a sandstone series, with subordinate red clay bands, characterised by three bands of limestone". The limestone bands were named Metpalli, Kota and Bangarani zones. After King's (1881) pioneering work, geological studies ofPranhita-Godavari valley remained neglected for nearly a century when Kutty (1969) provided a modified geological map for the area. Kutty (1969) undertook remapping of the area around Dharmaram and redefined the stratigraphy of the Pranhita-Godavari valley. The Gangapur beds, which were considered by King (1881) to underlie the Kota Formation, were shown to overlie the Kota Formation with an unconformity. This formation was given a formal name, the Gangapur Formation. The recovery of plateosaurid and thecodontosaurid prosauropods of Upper Norian to Rhaetic age

14 helped Kutty (1969) to carve out another formation (Dharmaram Formation) for the topmost part ofMaleri beds ofearlier workers.

The revised geological succession of the Pranhita-Godavari valley given by

Kutty (1969) is as follows:

FORMATION MAIN LITHOLOGIES CHARACTERISTIC AGE FOSSIL(S)

Mudstones, siltstones, sandstones Ptillophyllum flora (? ? Lower

Gangapur (? with pebbly beds, and 'Kota flora) Cretaceous. =Chikiala) conglomerates

Limestones, sandstones, Fish, sauropod Lr. Jurassic

Kota mudstones and red clays, with dinosaurs, crocodiles (?and early pebbly sandstone at base M. Jurassic)

Dharmaram Sandstones with red clays Prosauropod late U.

dinosaurs Triassic

Sandstones, red clays and lime Rhyncosaurs,

Maleri pellet rocks metaposaurs, early U.

phytosaurs, aetosaurs Triassic

Bhimaram Sandstone with intercalated clays None unplaced

Sandstone

Large dicynodonts, late Lr. or Yerrapalli Red clays ?capitosaurs, Early M.

?brachyopids Triassic

Subsequently, Rudra (1972) mapped the area around Vemanapalli and estimated the total thickness ofthe Upper Gondwana sediments at 3800 ft. Later, in a significant paper, Rudra (1982) who mapped the area around Metpalli and Lingal divided the Kota Formation into two members. The lithostratigraphic division of the

Kota Formation proposed by Rudra (1982) is as follows:

15 Upper Sandstone: calcareous with developing concretionary limestone x within it and intercalated red clays. UPPER Lower Sandstone: Argillaceous & ferruginous sandstone with mud MEMBER stone fragment atbase &small patches offerrugineous mudstone. Red clays: with ferrugenous mudstone &finegrained sandstone. Alternating limestone and calcareous clays and small sandstone layer. Red clay: withsandstone lenses and calcareous concreations. LOWER MEMBER Basal Sandstone: Calcareous sandstone, often pebbly, contains limestone conglomerates and red clay lenses.

Rudra (1982) also proposed freshwater depositional conditions for the Kota Formation on the basis of sedimentological studies. He proposed that sandstone was deposited in the fluvial conditions while the limestone was deposited in the playa-type lake.

Yadagiri (1979) mapped the area between Vemanapalli and Mukelpet in the

Pranhita-Godavari valley with emphasis on contact relations of the Kota Formation with the overlying and underlying formations. He concluded that there was only one band oflimestone in the Kota Formation and that the repetition was due to repeated 4 faulting. Significantly, Yadagiri (1979) separated the Gangapur Formation from the

Chikiala Formation unlike Kutty (1969).

Bhattacharya (1980) gave a detailed account of depositional patterns, and petrological characteristics of the Kota limestone. According to him the limestones are well bedded with gentle dips, fine-grained texture, and contain high Mg-calcite, chert, dolomite, clay minerals, ostracods and coccoliths. Bhattacharya (1980) also carried out chemical analysis of the limestone and clays of the Kota Formation.

16 According to him, the Kota sediments were deposited in marine inter-tidal flats, which received abundant terrigenous material brought in by a river estuary. Based on the presence of high boron content and low gallium content in these limestones, he

envisaged a marine transgression from the Indo-Australian gulf in the Jurassic times.

Yadagiri and Rao (1987) gave an account of depositional environments on the

basis of sedimentological and geochemical data and faunal evidences. They favoured

a lacustrine environment for the Kota Limestone, with salinities somewhat more than that ofthe normal lacustrine environment.

Raiverman et al. (1985) worked out the geology of the Pranhita-Godavari

valley from Chandrapur in the northwest to Ashwaraopet in the southeast. Based on

photogeological information along with detailed field mapping, these authors

formalised many formations in addition to the existing ones in the Gondwana

sequence of the Pranhita-Godavari valley. Structurally, according to Raiverman et al.

(1985), Pranhita-Godavari valley is a composite graben, with a number of half and

full grabens, longitudinally divided into three sectors by two major basement ridges,

one near Asifabad and the other at Bhadrachalam. It is important to note that the

classification proposed by these workers has not receivedwide acceptance.

In an important work, Jain and Roychowdhury (1987) attempted stratigraphic

correlation of the Indian Gondwana rocks with their counterparts in various other

parts of the world on the basis of vertebrate fauna. The Yerrapalli Fauna was

correlated with the Middle Triassic Manda Beds of Tanzania. The Maleri fauna was

correlated with Upper Triassic Kueper of Europe and Upper Triassic Chinle and

related sediments of N. America, Africa and South America. The Dharmaram fauna

was found to be intermediate between Keuper and Knokenmergel and Rhatsandstein

17 horizons of the German-type Triassic sequences and provisionally assigned to late Norian and Rhaetian ages. The Kota fish fauna was correlated with European Lias and 1 the Kota pterosaurs with Liassic Holzmaden deposits ofGermany. Based on the Kota vertebrates, they proposed that the position of India was land locked between

Antarctica and Australia. Lakshminarayana and Murti (1990) mapped the southeastern part of the Pranhita-Godavari valley and reported the presence of Upper Gondwana formations along with the Lower Gondwanas in the Chintalaudi sub-basin. The rocks of this basin belong to Talchir, Barakar, Kamthi formations of the Lower Gondwana and Kota and Gangapur Formations ofthe Upper Gondwana. Subsequently, Murti and Lakshminarayana (1994), in an important contribution, proposed that the Jurassic Kota Formation was deposited in the rift x valley. They divided the Kota Formation into three members namely, Lower, Middle and Upper. According to them, the Lower Member is dominantly a sandstone unit, which yields plant fossil of Upper Gondwana affinities. The Middle Member is dominated by fossiliferous limestone interbedded with marls, occasional chert and grey shale containing abundant remains offish, reptiles, and invertebrates. Phosphatic nodules ranging in size from 1-4 cm in radius also occur sporadically in the limestones and marls. The Upper Member consists ofsandstone grossly similar to the Lower Member but lacks large scale cross-bedding.

Significantly, Murti and Lakshminarayana (1994) proposed that the sandstone of the Kota Formation was deposited in braided streams and clays as overbank •i deposits. According to them, the Middle Member was deposited under marine

18 conditions as a result of marine transgression in the Jurassic times along the Son-

Narmada rift. The Upper Member was deposited by a meandering river system.

Lakshinarayana (1994; 1995) studied the stratigraphy and structural framework of the Pranhita-Godavari valley, Andhra Pradesh and divided it into four sub-basins namely Godavari, Kothagudem, Chintalpudi and Krishna-Godavari. The first three of these supported continental sedimentation where as the fourth contained marine sediments. Lakshminarayana (1995) further opined that the Kota Formation appears to be overstepping the underlying Kamthi Formation and that the exposed basal portion of theKotaFormation is similar to the Maleri Formation.

Bandyopadhyay and Roychowdhury (1996) discussed the initiation of the

Jurassic continental sedimentation in India on paleontologicalgrounds. According to them the upper part of the Dharmaram Formation, which yields prosauropods, plateosaurians and sphenosuchians, may extend into the Early Jurassic, signalling the beginning of the continental Jurassic sedimentation in India.

2.2 PALEONTOLOGY

The Pranhita-Godavari valley has attracted the attention of a number of palaeontologists since Egerton (1851; 1854; 1878). What follows is an overview of

paleontological work so far done inthePranhita-Godavari valley.

2.2.1 Fish and Reptiles

In his pioneering contributions, Egerton (1851-1878) described the fossil fish

collected by Walker (1841) from the Kota Formation. The entire collection was

described under three genera: Lepidotes, Tetragonolepis, andDapedium.

19 Subsequently, after a gap of over 75 years, Jain and his co-workers described a prolific vertebrate fauna from the Kota Formation. This included well preserved

holostean fish Paradapedium egertoni (Jain, 1973), a coelacanth Indocoelacanthus robustus (Jain, 1974a), and the semionotid Lepidotes deccannensis (Jain, 1983); a pterosaur Campylognathoides indicus (Jain, 1974b) and the well known sauropod

Barapasaurus tagorie (Jain, et al, 1975; 1977). The last named dinosaur was discussed at length by Jain et al. (1977). According to these workers, B. tagorei is the earliest known sauropod. Later, Jain (1980) in an important contribution suggested the presence of an ornithischian dinosaur in the Kota Formation. He also discussed the palaeoecology ofthe Kota Formation and the role of the Kota fauna in reconstructing the palaeoposition of India during the Jurassic.

More recently, Jain (1996) gave an account of the entirevertebrate fauna from the Gondwana sequences ofthe Pranhita-Godavari valley with emphasis on dinosaur fauna. He also mentioned the occurrence of crocodilian fossils consisting of skulls and other postcranial remains recovered by the geologists ofthe Geological Studies Unit, Indian Statistical Institute, Calcutta. It is important to note that the vertebrate data from the Kota Formation, particularly fish, has been interpreted by Jain (1973; * 1974a; 1983) as being indicative ofa Lower Jurassic (Liassic) age.

Yadagiri and Prasad (1977), for the first time, described pholidophorid fish (Pholidophorus indicus and P. kingii) from the Kota limestones exposed at Nagaram and Gorlapalli, Adilabad district. A Lower Jurassic age was also advocated by these workers. Subsequently, a detailed account of piscean fauna from the Kota Formation 1 was given by Yadagiri et al. (1980). The fish discussed included Lepidotes,

Paradapedium and Tetragonolepis. In addition, a number of lower vertebrates

20 including hybodontid fish, pelobatid amphibians, sphenodontids and varonoids were described by Yadagiri (1986).

Regarding Kota dinosaurs, Yadagiri (1988) gave a detailed account of the sauropod Kotasaurus yamanapalliensis recovered near Vemanapalli village, Andhra

Pradesh. According to him, K. Yamanapalliensis, known by a number of postcranial skeletal elements, is intermediate between sauropods and prosauropods and that the prosauropodian characteristics of K yamanapalliensis outweigh the sauropodian characteristics.

Among other workers, mention may be made of Prasad (1986) who reported ontheKota Formation vertebrates recovered near Gorlapalli village, Adilabad district,

A. P. The new finds included frogs, sphenodontids, and hypsilophodontid dinosaurs along with crocodilian remains. Prasad (1986) concluded that the presence of sphenodontids and hypsilophodontids indicates that India was in close contact with other Gondwanaland continents until the beginning of the Jurassic. Prasad (1986) also favoured a Lower Jurassic age for the Kota Formation.

2.2.2 Mammals

The discovery ofthe mammals from the Kota Formation is credited to Datta et al. (1978). These mammals are known by teeth, mandibles, limb bones, vertebrae, pelvic and pectoral girdles and skull fragments from the marly clay unit of the Kota

Formation near Vemanapalli in the Pranhita-Godavari valley. The fauna included a symmetrodont Kotatherium hadanei (Datta, 1981).

Subsequently, Yadagiri (1984) described two additional symmetrodont molars

(Trishulotherium kotaensis and Indotherium pranhitai) from the Paikasigudem

21 section, 6 km east of Asifabad Road railway station. Yadagiri (1984) was of the

opinion that Indotherium may represent a new family of symmetrodonts. Another X taxon (Nakunodon paikasiensis, family Amphidontidae), akin to amphodontid symmetrodonts of North America and Manchuria, was described by Yadagiri (1985). It is characterised by a large paracone and ahighly reduced metastyle and parastyle which imparts a monocuspid appearance to Nakunodon. Prasad and Manhas (1997) described a new symmetrodont mammal Kotatherium yadagirii from the Kota Formation exposed near Paikasigudum village, Adilabad district. K. yadagirii exhibits a number of characters diagnostic of the Family Tinodontidae. Besides, these authors (Prasad and Manhas 1997) also discussed a previously known genus Indotherium in detail and transferred it to Order Triconodonta from Symmetrodonta.

2.2.3 Invertebrates

2.2.3.1 Ostracods

Govindan (1975), for the first time, described a fresh water ostracod faunule from the limestones and clays of Kota Formation from many localities (Metpalli, * Kunchelli, Daroghapalli) in the Pranhita-Godavari valley. The recovered ostracods were assigned to Darwinula, Limnocythere and Timiriasevia and, based on these forms, a freshwater lacustrine depositional environment was inferred. Further, Govindan (1975) proposed a Middle Jurassic age for the Kota Formation based on

Darwinula, the dominant species.

Mishra and Satsangi (1979) described an ostracod fauna from the limestone of the Kota type area and from clays in the Vemanapalli area. Their assemblage is more

22 diverse than that described by Govindan (1975) and included Darwinula,

± Limnocythere, Timiriasevia, Cypridea, Chinopsis, Candona, Eucandona and

Stenocypris.

2.2.3.2 Estheriids

In an important paper, an estheriid (conchostracan) fauna has been described

by Tasch et al, (1973). The important forms include Estheriina, Palaeolimnadia,

Cyzicus (Euestheria) and Cyzicus (Lioestheria).

2.2.3.3 Insects

Rao and Shah (1959) and Tasch et al. (1973) have reported the occurrence of

insects at several levels in the Kota limestone. Blattids dominate the assemblage,

^ followed by Coleoptera.

2.2.4 Flora

Shah et al. (1973) studied the post-Triassic Gondwana rocks of India and

published a comprehensive account of the flora of these rocks. Based on the plant

fossils, they divided the Upper Gondwana flora into three zones, Zone-A, Zone-B and

Zone-C. Of these, Zones A and B fall in the Kota Formation whereas Zone-C forms

an integral part ofthe overlying Gangapur Formation.

Prabhakar (1986) gave an account of the spores and pollen grains from the

limestone and fine-grained sandstone ofthe Kota Formation. The spores were referred

to pteridophytes represented by Cyathidites, Osmundacidites and Classopollis;

gymnosperms represented by Araucariacites, Calliasporites, Podocarpidites,

Cedripites Cycadopites, Gliscopollis, Granuloperculatipollis Classopollis. Prabhakar

23 (1986) concluded that the Circumpollis group is dominant in the Kota beds, and based thereupon, advocated a Lower Jurassic age and brackish-swampy environment of deposition for the Kota Formation. On the other hand, Rajnikanth and Sukh Dev (1989) who studied the megaplant remains from the Kota Formation, favoured a Middle Jurassic age. According to these authors the floral assemblage is dominated by the conifers followed by pteridophytes, cycadophytes and ginkgophytes. Fiest et al. (1991) gave an account offresh water charophytes from the Kota Formation and assigned them to family Characae- Aclistochara off. A. jonesi. Prior to this find the genus Aclistochara was reported only from the Upper Jurassic and Lower Cretaceous sediments of North America and China (Peck, 1957; Liu, 1982). Fiest et al. (1991) supported aLower Jurassic age for the Kota Formation. Another interesting observation made by Fiest et al. (1991) was the presence of xerophytic structures in Aclistochara, which was interpreted as an adaptation for aridity. Bhattacharya et al. (1994) gave an account of fossil charophytes from the limestone and underlying calcareous marls of the Kota Formation. The specimens were assigned to Preachara symmetrica of the family Characeae. They endorsed the Liassic age ofthe Kota Formation proposed by earlier workers. More recently, Vijaya and Prasad (1999) have proposed an Upper Jurassic - Early Cretaceous age for the Kota Formation on the basis of palynoflora. The palynoflora includes Callialasporites, Contignisporites cooksoniae, Murospora florida, Crybelosporites stylosus, Aequitririadites sp. Coptospora microgranulosa and

Crybelosporites punctatus.

24 2.2.5 Stromatolites

^ Gururaja and Yadagiri (1987) gave the first account of stromatolites from the

Kota limestone exposed between Gorlapalli and Nagaram. These authors did not

comment on the systematic affinities ofthese stromatolites.

Rudra and Maulik (1987) described stromatolites from the Kota Limestone

and grouped them into three morphologic types- domal stromatolites, oncolites and

^ cryptalgal lamites. They inferred fresh water, lacustrine habitat for the stromatolitesof

the Kota limestone. On the basis of lithological, petrological and paleontological

evidences, they suggested that the Kota Limestone was deposited in a widespread

shallow water lakein association with proximal peidmont alluvial sediments.

2.2.6 Trace Fossils ^ Maulik and Rudra (1986) gave an account of trace fossils from the Kota

limestone exposed at Kota. These included full relief burrows divisible into horizontal

non-branching burrows, slightly inclined or straight burrows and vertical burrows

generally straight or slightly sinuous. On the basis of occurrence of burrows in some

limestone beds and their absence in others, Maulik and Rudra (1986) inferred a highly

fluctuating sedimentation rates for the Kota limestone, at times almost negligible.

25 Chapter 3 x GEOLOGY AND STRATIGRAPHY

3.1 INTRODUCTION

In 1872 H. B. Midlecott introduced the term "Gondwana" (after the ancient tribe t "Gond") for rocks exposed in parts of Madhya Pradesh, Central India. The term

"Gondwana" has since been variously used by different workers. To some it implies

essentially terrestrial sedimentary sequences ranging in age from Lower Permian to

Lower Cretaceous, occurring widespread in different continental segments of the

Southern Hemisphere. In geodynamics, the term "Gondwana" implies the dynamic

behaviour of crustal plates, which separated and drifted away from the composite mosaic

ofplates forming the continental superplate, the Gondwanaland.

In the Indian context, the term Gondwana signifies not only terrestrial sediments

ofPermian to Early Cretaceous age deposited in inland basins, but also the coastal marine

sequences fringing eastern and western margins of the peninsular India. The Indian

Gondwana sequences are unique in the world because of their relatively uninterrupted

sedimentation. The Gondwana basins in Indian peninsular craton occupy well-defined

linear belts. These include the well known E-W trending Damodar-Koel basin, NW-SE trending Son-Mahanadi basin and Pranhita-Godavari basin and the E-W trending Satpura and the Rajmahal basins (Text Figure 3.1).

The Rajmahal basin, which is the largest of the Indian Gondwana basins, has a regional stretch ofover 10,000sq km and is partly concealed under the Gangetic alluvium (Datta et al, 1983; Mitra and Raja Rao, 1987). The stratigraphic succession and extension has been studied with the help of boreholes drilled for the exploration of oil and coal. Here, the Gondwana sedimentation was most extensive during the phase represented by the Barakar Formation. Subsequently, the basin area became static, probably due to nominal deposition and was exposed to weathering till the end of the Permian. The onset of Triassic was marked by the deposition of a thick sequence predominantly consisting of chocolate clays, mottled green sandy clays and brownish sandstone. Later, the Rajmahal basin witnessed widespread volcanism. Intercalated sedimentary sequences found in the Rajmahal Volcanics (Rajmahal Traps) have yielded Ptilophyllum flora, dated as Early Jurassic to Early Cretaceous (Sastri et al, 1977). However, the K-Ar dates restrict the age ofRajmahal Traps to 100-106 Ma (McDougall and McElhinny, 1970).

The Damodar-Koel basin is the most intensively studied basin because of its rich potential for coal. This basin is characterised by the classical development of Permian coal measures resting over the Talchir Formation. The Triassic was marked by the deposition of thick cyclic sequences of greenish shale and sandstone, followed by red shale and arkosic sandstone of Middle Triassic Panchet Formation. The latter has received the attention of a number of workers because of its fossil content (Cotter, 1917;

28 Fox, 1937; Krishnan, 1982; Chatterjee and Roy Chowdhury, 1974; Sastri et al, 1977 i etc.). The Panchet Formation is succeeded with an unconformable contact, by a sequence

of coarse-grained sandstone, conglomerate and red shale belonging to Mahadeva

Formation (Supra Panchet).

The Mahanadi-Son basin extends between Talchir in the Mahanadi valley to

Mahendragarh and Hasdo-Arand basin in the southeastern part of the Son valley. The X succession of rocks in this basin comprises Talchir, Karharbari, Barakar and Raniganj

Formations of Permian age, succeeded unconformably bythe Kamthi Formation (Datta et

al, 1983). This basin lacks the record of Middle to Upper Triassic sedimentary

sequences.

In the Satpura basin, the Talchir, Barakar, Motur and Bijori formations represent

the Permian sequences. The Bijori Formation is characterised by the presence of

Gondwanasaurus bijoriensis, an Upper Permian amphibian (Chatterjee and Roy

Chowdhury, 1974). The Bijori Formation is overlain by a thick succession of coarse,

pebbly sandstone of Pachmarhi Formation exposed in the Mahadeva Hills. The

Pachmarhi Formation grades conformably into the Denwa Formation (Denwa Clays)

which is characterised by Metaposaurus -Paratosaurus fauna of Carnian to Norian age

(Chatterjee and Roy Chowdhury, 1974). The Denwa Formation is succeeded by the

Bagra Conglomerates, possibly of Rhaetian age. The Jurassic sediments are not

represented in this basin and the Bagra Conglomerate is unconformably overlain by the

Jabalpur Formation, characterised by a flora rich in conifers and pteridosperms ofLower

Cretaceous age.

29 3.2 PRANHITA-GODAVARI VALLEY I

The Pranhita-Godavari valley, which is the focus of the present investigation, is a

NNW-SSE trending basin exposed in the northeastern part of the southern Indian state of Andhra Pradesh. It is 350 km long and 45 km wide basin. The Pranhita-Godavari valley is an intracratonic rift basin with an aggregate thickness of 3000m of sediments ranging in age from Early Permian to Lower Cretaceous, deposited under continental conditions (Text Fig. 3.2). This highly asymmetric rift basin (Quereshy et, al, 1968; Mishra et al,

1987) is flanked on both sides by Precambrian basement complex rocks. Given below is the generalised stratigraphic successionof the area:

late Up. Cretaceous Deccan Traps unconformity- ~~~ ~ *t Lr. Cretaceous Gangapur (=?Chikiala) Formation unconformity— ~ Lr. Jurassic Kota Formation late Up. Triassic Dharmaram Formation early Up. Triassic Maleri Formation ? Bheemaram Formation late Lr./Early M. Triassic Yerrapalli Formation unconformity Up. Permian to Lr. Triassic Kamthi Formation

? Barren Measures Lr. Permian Barakar Formation

Lr. Permian Talchir Formation unconformity ~ ~ Up. Proterozoic Sullavai Group (Vindhyan) M. Proterozoic Pakhal Group (Cuddapah) Early Proterozoic and Archean(?) Precambrian Basement Complex

30 The entire Upper Gondwana succession in the Pranhita-Godavari valley is characterised by piscean and reptilian fauna. Furthermore, this Gondwana basin is unique in that it has yielded Jurassic mammalian remains (Datta et al, 1978; Datta, 1981; Yadagiri, 1984; 1985; Prasad, 1986; Prasad and Manhas, 1997). What follows is a brief description ofthe various formations exposed in the area under investigation.

X 3.2.1 Precambrian Basement Complex

The basement rocks ofthe area are classified as Peninsular Gneisses which range in age between 3000 Ma and 2000 Ma (Ramam and Murty, 1997). King (1881) classified

these rocks as Gneissic Series and divided them as under:

Micaceous, talcose and hornblendic schist's, with few quartz schist or quartz rocks Schistose gneisses Foliated Gneisses, with frequent quartz schists or quartz

rocks. Grey Gneisses (sometime porphyroitoid)

Massive Gneisses Red Granitoid Gneisses

There is a general consensus among the later workers about the gneisses forming the Archaean basement but the precise relationship between schists and gneisses is not clear in the Pranhita-Godavari valley (Radhakrishna and Vaidyanathan, 1994). The gneisses have been subdivided into 'Older Gneissic Complex' (OGC) older than 3000 Ma and mainly tonalitic and trondhjamitic in composition, and the 'Younger Gneissic

Complex' (YGC) composed of reworked and remobilised gneisses, younger than 2000

Ma (Radhakrishna and Vaidyanathan, 1994).

31 3.2.2 Pakhal Group ^ The Pakhal Group of Proterozoic rocks trend in NW-SE direction along the Pranhita-Godavari valley. The sediments of this group occur in two mutually parallel belts separated from each other by the younger Sullavai Sandstone and Godwana rocks.

The rocks of the Pakhal Group have low to moderate northeasterly dips, and the deformation intensity increases from northwest to southeast (King, 1881; Ramam and Murty, 1997). In the southeastern portion ofPranhita-Godavari valley, around Singareni, the rocks are highly crushed, altered, and sharply folded (King, 1881; Krishnan, 1982;

Ramam and Murty, 1997). The Pakhal Group of rocks is composed of basal conglomerates resting over the gneisses, overlain by the siliceous limestone and shale (King, 1881; Krishnan, 1982; Ramam and Murty, 1997). Chowdhury (1985) divided the Pakhal group into Mallampalli and Mulung Subgroups. The Mallampalli Subgroup consists ofJonalarasi Bodu Formation and Padaikunta Limestone. The basal part (about 2m) ofthe Jonalarasi Bodu Formation is coarse-grained arkosic and the remaining part comprises quartzose sandstone and dolomitic limestone. The Padaikunta Limestone is composed of heterogenous lithologies dominated by carbonates, both limestone and dolomite, with subordinate sandstone, shale and nodular chert. Glauconites from within the limestone have yielded the K-Ar ages ofthe order of 1330 + 53 Ma (Chowdhury and

Howard, 1985).

The Mulung Subgroup consists of Damala Gutta Conglomerates, Ramagundum

Sandstone and Rajaram Limestone in this order of superposition. The Damala Gutta

32 Conglomerate consists of conglomerate to conglomeratic sandstone with subordinate ± arkose. Overlying it conformably is the Ramagundum Sandstone. The basal part of the

Ramagundum Sandstone is arkosic to sub-arkosic, medium grained sandstone showing

wave ripples, mega-ripple bedding and wavy bedding with a few glauconitic beds

(Chaudhury, 1985). The upper part of the Ramagundum Sandstone is an alternation of

fine-grained sub-arkosic sandstone and mudstone. The Rajaram Limestone gradationally

overlies the Ramagundum sandstone. It is micritic and contains algal stromatolites.

3.2.3 Sullavai Group (Sullavai Sandstone)

The Sullavai Group was described as "Sullavai Sandstone" by King (1881) and

Sreenivasa Rao (1987). It overlies the Pakhal Group of rocks with an unconformable

contact. The Sullavai Group dips northward at low angles. The basal portion is made up

of varying thickness of massive quartzitic sandstone and conglomerate, with a few slaty

beds. This unit is overlain by chocolate brown coloured sandstone, which is fine grained

and has streaks of white and buff colour (King 1881). Chaudhury (1985) accorded a Group status to Sullavai Sandstone and divided it into three formations namely,

Encharani Quartzite, Ramgiri Formation and Venkatpur Sandstone. He was of the opinion that Encharani Quartzite and Ramgiri Formation are the lateral facies variants constituting the base ofthe Sullavai group. The Encharani Quartzite consists of quartzose sandstone varying in thickness from 15-90m, with small discontinuous bodies of conglomerate at the base. The quartzose sandstone is coarse to very coarse-grained, gritty at places, cross-bedded and highly ferruginous. The Ramgiri Formation consists of

33 medium-grained, dominantly red, arkosic sandstone with subordinate shale, siltstone and pebbly horizon. It intertongues with the underlying Encharani Quartzite. The Venkatpur

Sandstone is medium to fine-grained, cross-bedded clayey sandstone red in colour

(Chaudhury 1985). The upper part of the Sullavai Group has yielded K-Ar dates of 871

±14 Ma (Chaudhury and Howard, 1985).

3.2.4 Talchir Formation

The Talchir Formation, which is the oldest member of the Gcndwana rocks resting unconformably over the eroded Precambrian rocks, consists of conglomerate sandstone and shale. This formation, named by Blandford et al. (1856) in the Talchir

Coalfield (Orissa), has been investigated by a number of workers (King, 1881;

Raiverman, et al, 1985; Kutty et al, 1987; Murti and Lakshminarayana, 1994;

Lakshminarayan, 1994; 1995). In the Pranhita-Godavari valley, the Talc ur Formation occurs mainly on the western fringes of the basin and crops out as narrow strips. It comprises diamictites, rhythmites and green sandstone. At places polymic tite clasts of granite, quarzite and limestone set in a fabric of mixed grains also occur Kutty et al,

1987). Diamictites occur as thin beds measuring 2m to 3m in thickness in the basal part of the Talchir Formation. They are light green to greenish grey, striated and containing ill-sorted angular clasts of khondalite, basic rocks, granite, gneiss and quartz mica schist in the sandy matrix. Rhythmite facies succeeds the diamictites and consists of alternating siltstone and shale varying in thickness between 10cm to 6m. The shale displays varves represented by alternating lamination of grey and white colours. The siltstone (claystone

34 of Raiverman et al, 1985) is micaceous and laminated and breaks up into thin needles, X- thus gaining the name 'needle shale'. The rhythmite sequence grades upward into green

sandstone, which is made up of quartz, feldspar, mica and lithic fragments. The origin of

the diamictite sequence has received considerable attention, with opinions divided

between fluvioglacial and glacial (Blandford et al, 1856; Fedden, 1885; Smith 1963;

Datta et al, 1983). The Talchir Formation till date has only yielded plant fossils from the

upper part of the formation. Fossils include Pteridosperms: Glossopteris indica, G.

communis; Chordatales: Neoggerathiopsis hislopi and indeterminate seeds: Samaropsis

sp.

In addition to megaflora, spores and pollen have also been recovered from the

Talchir Formation (Potonie and Lele, 1960; Lele, 1964; Bharadwaj, 1970; Surange, 1973;

Lakshminarayana, 1995). These include:

Spores:- Leiotrilete, Granulatesporites, Cyclogranisporites, Plainisporites,

Quadrisporites, Collumnispora

Pollen:- Plicatiopollenites, Virkkipollenita, Protnicisporites, Parasaceites,

Ginkocycadophyta, Crucioacietes.

Sastry and Shah (1974) and Sastry et al. (1977), based on their study of fossil

flora from peninsular India and Western Australia, advocated a Lower Permian

(Assilian) age for the Talchir Formation. More recently, Lakshminarayana (1995) has

favoured a late Carboniferous to Early Permian age based on palynofossils.

35 3.2.5 Barakar Formation 4.

The Barakar Formation was named by Oldham (1861) for the lower coal-bearing

sequences ofthe Damuda Group (Lower Damuda ofBlandford et al, 1856). In Pranhita-

Godavari valley, King (1881) used Barakar Formation for the coal-bearing group ofrocks

overlying the Talchir Formation. The Barakar Formation succeeds the Talchir Formation

with a gradational contact (Kutty et al, 1987; Lakshminarayana, 1994; 1995).

Lithologically, this formation is divided into two members namely, Lower and Upper

(Lakshminarayana, 1994; 1995). The Lower member ranges in thickness from 50m to

200m and is characterised by a fining upward sequence. It consists of pebbly sandstone

and feldspathic sandstone, siltstone and occasional coal laminae. The Upper member

ranges in thickness from 200m to 260m and is characterised by coal bearing cyclothems.

Each cyclothem comprises a coarse sandstone at the base to grey shale / carbonaceous

shale / coal at the top. There is an alternation of coal and shale in each coal seam. Much

of the available information on the Barakar Formation is based on borehole data

(Raiverman et al, 1985; Kutty et al, 1987).

Lakshminarayana (1994) reported a micro and megafloral assemblage from this formation, which included Glossopteris, Gangmopteris, Schizoneura, and Vertebraria and a number of pollen and spores. The Talchir Formation is believed to be late Permian in age as indicated by pollen and spores (Lakshminarayana, 1994; 1995).

3.2.6 Barren Measures

Fox (1930) named the thick sedimentary sequence overlying the Barakar

Formation as the Barren Measures, which lacks workable coal seams. This sequence is well developed in the northeastern part of the Pranhita-Godavari valley (Godavari sub-

36 basin) and tapers towards the southeastern part (Lakshminarayana and Murti, 1990;

Lakshminarayana 1994; 1995). The sequence consists of white to light yellow sandstone,

siltstone, grey shale, carbonaceous shale and thin bands of coal. Raiverman et al. (1985)

favoured the nameBellampalli Formation instead of BarrenMeasures. Kutty et al. (1987)

described it as Infra-Kamthi (Table 3.1). They divided it into four lithozones: Lithozone-

1 consists of coarse sandstone and interbedded shale; Lithozone-2, consists of sandstone,

* shale and carbonaceous and coaly shale; Lithozone-3, consists of feldspathic sandstone

with lenses of mudstone and is devoid of carbonaceous and coaly shale; and Lithozone-4 consists of feldspathic sandstone, with lenses of mudstone and brown shale. Recently, Ray (1999) reported the occurrence of a rich reptilian fauna in the uppermost part of the Barakar Formation and lower part of the Kamthi Formation. The fauna predominantly consists of dycynodonts Endothiodon, Cisticephalus, Pristerodon, Oudenodon and an

Emydops like form, aswellas captorhinid reptiles (Ray, 1999).

3.2.7 Kamthi Formation

The name Kamthi Formation was coined by Blandford (1868) for a sandstone sequence exposed near the erstwhile military station Kamthi, near Nagpur. The Kamthi Formation unconformably overlies the Barren Measures and also shows overlapping relationship with the older Talchir and Barakar formations in the southwestern part ofthe Pranhita-Godavari valley. In the northeastern part of the valley the Kamthi Formation rests directly over the basement rocks (Lakshminarayana and Murti, 1990; Lakshminarayana 1994; 1995). The Kamthi Formation shows a coarsening upward sequence with shale, siltstone and sandstone atthe base and conglomeratic sandstone and r conglomerate at the top.

37 Different stratigraphic classifications have been proposed for the Kamthi Formation. A comparison of these classifications is given in Table 3.1

Table 3.1 Comparative Stratigraphic Classification of rocks exposed in Pranhita-Godavari Valley (after King, 1881*, Raiverman, et al. 1985; Kutty etal., 1987).

King (1881) Raiverman et al. (1985) Kutty et al. (1987) Traps of Deccan Traps Deccan Traps Janagaom Valley Lameta Formation Chikiala Group Peddavagu Chikiala Formation Chikiala Formation Group Gangapur Formation Gangapur Formation

Kota Group Kota Formation Kota Formation Taravai Formation Dharmaram Fm. Maleri Group Sironcha Group Maleri Formation Maleri Formation Bhimaram Sandstone Yerrapalli Formation Kamthi Group Kuderpalli Fm

Maimer Fm Kamthi Group Kamthi Formation

Khanapur Fm. Jaipuram Fm.

Potamagudu Fm. Singareni Bellampalli Fm. Infra-Kamthi Barakar Group Barakar Formation Barakar Formation Formation Talchir Talchir Formation Talchir Formation Formation Sullavai Sandstone Precambrian Precambrian Pakhal Series Gneisses

38 3.2.8 Yerrapalli Formation

The recovery of characteristic Middle Triassic vertebrate fauna from the

lowermost part of the Maleri Group (of King 1881) led to the delineation of the

Yerrapalli Formation (Jain et al. 1964; Chatterjee 1967; Sengupta 1967; 1970). The type

area of the Yerrapalli Formation was defined between Yerrapalli (18°48'N: 70°41'E) and

Meddakellu (18° 47'N: 79° 43'E Sengupta 1967; 1970; Chatterjee,1967). The Yerrapalli 4 Formation has a conformable contact with the underlying Kamthi Formation in the

northern part of the Pranhita-Godavari valley but the contacts in the extreme south are

obscured (Dasgupta, 1993). The Yerrapalli Formation is essentially a clay / mudstone

dominated horizon having a general dip of8° to 12°towards northeast, with an estimated

thickness of 450mto 600m in the vicinity of the Yerrapalli village (Dasgupta, 1993). The

sequence is variegated but the dominant colour is red and violet; the latter is particularly

characteristic of this formation. Associated sediments are lime pellet rocks, fine grained

whitish calcareous sandstone, medium to coarse grained white feldspathic calcareous

sandstone and black calcareous sandstone occurring as lenses of varying dimensions.

Dasgupta (1993) divided the sandstone bodies into two categories namely, lensoid and * sheet like; the smaller lenses are structureless, whereas the larger ones show planar or

trough cross-bedding. The Yerrapalli Formation has yielded diverse vertebrates which include fish:

Ceratodus (Chatterjee, 1967), Saurichthys (Jain, 1984); labrinthodontid amphibians

(capitosaurids): Pratasaurus rajareddyi (RoyChowdhury, 1970; 1970a); reptiles: rhyncosaur Mesodapedon kuttyi (Chatterjee, 1980), tracodontid cynodont Wadiasaurus

39 indicus dicynodont Rechnisaurus cristarhynchus (RoyChowdhury, 1970b), archosaurs

and a prolecertid (Jain et al, 1964). The Yerrapalli fauna is equated with the

Cynognathus Zone of South Africa, of Lower Triassic age (Jain et al, 1964; Colbert,

1977). However, the tetrapod assemblage of the Yerrapalli Formation suggests that the

fauna may be younger than the Cynognathus Zone and is probably of early Middle

Triassic age (Chatterjee and RoyChowdhury, 1974; Chatterjee, 1980a; Colbert, 1984).

Recently, RoyChowdhury et al. (1999) favoured a Middle Anisian age for this formation

based on correlation with other Middle Triassic faunas ofworld.

3.2.9 Bhimaram (Bheemaram) Sandstone

A number of workers (Jain et al, 1964; Sengupta 1966; 1970; Chatterjee 1967) differentiated Bhimaram Sandstone from the 'Maleri Group' of King (1881) on the basis of lithology and absence of fossils. The Bhimaram Sandstone is primarily a sandstone dominated horizon with intercalated red clays. It shows vertical and lateral facies variation. The lower portion is characterised by chocolate to purple coloured ferruginous, feldspathic, medium to coarse grained sandstone and the upper portion is coarse grained, highly calcareous and cross-bedded sandstone. In the southeastern area of the Pranhita-

Godavari valley, grey, hard and calcareous siltstone with numerous greenish clasts are also found. The upper part of the sandstone body has intercalations of red mudstone

(Sengupta, 1970; Kutty et al, 1987; Kutty and Sengupta, 1989; Dasgupta, 1993).

40 3.2.10 Maleri Formation

The fossiliferous red soft clays with the patches of green were first noticed by

Hislop (1864). Subsequently, Huges (1876) grouped them as the "Kota-Maleri" beds.

Blandford (1878) and King (1881) differentiated them on the basis of lithological and

palaeontological evidences. The Maleri Formation got its name from the village Maleri

(or Malledi, 19° 14'N: 79° 38'E) where this formation is well developed and has yielded a 4 large number ofvertebrate remains including fish, amphibians and reptiles.

Lithologically, the Maleri Formation is composed of three main units: clays, lime

pellet rock and sandstone. Various intermediate types, such as, siltstone, siltyclay and

pellet rich sandstone are also quite common. The clays, which are dominant in the Maleri

Formation, are soft, vermilion or red in colour with irregular patches of green at places.

The lime pellet rocks usually occur as lenses of varying thickness and lateral extent

(Robinson, 1964). They are composed of pellets varying in size from a few cm to a few

mm and made up mostly of calcium carbonate with occasional silt fraction. The lime

pellet rocks are pale grey to greenish in colour, but may be ferruginous or red. The

sandstone is usually fine to medium grained, white or grey in colour. Variants include

hard, grey sandstone with calcite cement. The clays normally form low grounds whereas,

the sandstone and lime pellet rocks form mounds and ridges trending parallel to the

general strike direction.

The Maleri Fauna is essentially a vertebrate fauna with the exception of a unionid

Tikhia (Sahni and Tiwari, 1958). The vertebrates include fish: dipnoan, Ceratodus (Oldham, 1859; Miall, 1878; Jain, 1968), an unnamed subholostean and the pleuroacanth

41 shark Xenacanthus indicus (Jain, 1984a); a solitary labyrinthodont amphibian,

Metoposaurus maleriensis (Lydekker, 1882; Huene, 1940; Roychowdhury, 1965); chigutisaurid amphibian Kuttycephalus triangularis (Kutty and Sengupta, 1989;

Sengupta, 1995). Reptiles are represented by the cynodont Exaeretodon statisticea

(Chatterjee, 1980), phytosaur Parasuchus hislopi (Chatterjee, 1978), theropods, rhynchosaur Paradepedon huxleyi (Chatterjee, 1974), and the saurischian Walkeria > maleriensis (Chatterjee, 1987).

3.2.11 Dharmaram Formation

After detailed mapping, Kutty (1969) redefined the Kishnapur sandstone of King

(1881) up to the base of the Kota Formation as the Dharmaram Formation, named after the village Dharmaram (56° 32'N: 23° 86'E). The Dharmaram Formation is essentially a sandstone dominated horizon with subordinate clay, predominantly red in colour. The sandstone is generally pale grey, buff or reddish in colour, coarse grained, gritty and / or pebbly. Fine-grained sandstone is also present, but white sandstone characteristic of the

Maleri Formation is not common (Kutty, 1969). The Dharmaram Formation is made up > of three bands of sandstone and clay. The lime pellet rock, so conspicuous in the Maleri

Formation, is absent in the Dharmaram Formation. The sandstone in the west shows repeated fining upwards sequence and is mostly arkosic and cross-bedded (Rudra, 1982).

The clays are mostly red in colour, tend to be silty and are devoid of lime pellets . These clays form low ground in the area.

42 Kutty (1969) and Roychowdhury (1970) reported the presence of two dinosaur

faunas in the Dharmaram Formation, plateosaurids and thecodontosaurid prosauropods.

The plateosaurids have been reported to be represented well in the collection. Kutty

(1969) also mentioned the presence of two more archosaurs in the fauna but details have not been published as yet.

The Dharmaram Formation has also yielded plant fossils that include Thinnfeldia

hugesi, Dicrodium hugesi, D. odentopteroids, Noegarathiopeis cf. hugesi (Shah, et al,

1973).

On the basis of the above fauna, the Dharmaram Formation has been

provisionally assigned a late Upper Triassic age i.e., Upper Norian and Rhaetic (Kutty,

1969; Roychowdhury 1970). This age assignment is in agreement with the floral

evidences (Raha, et al, 1977). Bandhyopadhyay and Roychowdhury (1996) and

Roychowdhury et al. (1999) are of the opinion that the Dharmaram Formation contains

both Late Triassic and Early Jurassic vertebrates and hence ranges in age from late Upper

Triassic to early Lower Jurassic.

3.2.12 Kota Formation

The Kota Formation, which is the focus ofthe present study, was named after the

village Kota (79° 58' 00"N: 18° 55' 00"E) situated onthe eastern bank of Pranhita river 8

km north of its confluence with the river Godavari. Huges (1876) grouped the Kota

Formation with the Maleri Formation as "Kota-Maleri" stage. King (1881) and Blandford

43 (1876) separated the Kota beds from the Maleri beds on the basis of stratigraphic as well as paleontological grounds.

Lithologically, the Kota Formation consists of sandstone, limestone and clays.

Rudra(1982) divided the Kota Formation into two members: Lower and Upper members.

The Lower member is composed of sandstone and lenticular red clays, which has yielded most of the fossils. The Upper Member is composed of limestone and unconsolidated calcareous beds. Murti and Lakshminarayana (1994) subdivided the Kota Formation into three members, Lower, Middle, and Upper. Their Lower Member comprises trough cross-stratified sandstone, clays and clay-clast bearing sandstone yielding plant fossils.

The Middle Member consists of limestone and the Upper Member is largely a sandstone and variegated clay sequence. The Lower Member of both Rudra (1982) and Murti and

Lakshminarayana (1994) is same, whereas the Upper Member of Rudra (1982) includes both the Middle and Upper members of Murti and Lakshminaraya (1994). Table 3.2 gives the schemes proposed by these authors.

The base of the Kota Formation is marked by sandstone, which is medium to coarse grained and calcareous. It is cross-bedded, poorly to moderately sorted. At places it also encloses lenticular red clays. The basal portion of this sandstone is pebbly. The pebbles vary in size between 1cm to 12cm. The long axis of the pebbles is. generally oriented along the general dip direction. The frequency of the pebbles decreases towards the top of the bed. The pebbles are generally of banded chert, quartz and quartzite. This unit grades into fine grained white sandstone. In the eastern part of the valley, this sandstone is much thicker and its base is marked by a conglomerate with limestone

44 pebbles. The limestone pebbles become rarer towards the northern part of the valley. The

conglomerate-bearing sandstone grades upward through laminated fine-grained

calcareous sandstone and siltstone, into unconsolidated fossiliferous clays, which are

mostly red in colour but occasionally green and grey. These clays are of variable

thickness and have yielded a large number of vertebrate remains. The clays are mostly

unconsolidated, soft and friable, containing calcareous concretions and thin lenses of < cross-bedded calcareous, pebbly sandstone. Five lithofacies have been identified in the

Lower member ofthe Kota Formation (Murti and Lakshminarayana, 1994). These are:

1. Clay clast-bearing sandstone.

2. Trough cross-stratified sandstone

3. Planar cross-stratified sandstone.

4. Ripple cross-stratified sandstone.

5. Micaceous siltstone, indurated red siltstone and white claystone.

The Lower Member is overlain by the Middle Member with a sharp contact

defined by a limestone bed. This limestone varies in thickness from 5m to 20m, being

thinnest in the southeast and thickest in the northwest. The sequence consists of

alternating creamish, pinkish or greyish coloured micritic limestone and unconsolidated

calcareous clays, marls and occasional chert and grey shale. Both limestone and clays are

thinly bedded with varying thickness (7cm to 1.5m). The limestone is mostly hard, partly

porous, micritic and shows parallel laminations. Locally, the laminated limestone

contains cone-in-cone structures. Occasionally, the limestone contains replacement chert,

parallel to bedding plane. Desiccation cracks are common with varying frequency. Some

45 of the desiccation cracks penetrate the entire thickness of beds. Angular limestone

intraclasts are common and are lithologically similar to the enclosing limestone. Pore

spaces occur as intraparticle, fenestral, vugs, channel and fracture porosity. Most of the

pores are filled with clear calcite cement.

Table 3.2 Comparative chart of lithostratigraphic classifications of the Kota Formation proposed by Rudra, (1982) and Murti and Lakshminarayana, (1994).

Rudra (1982) Murty & Lakshminarayana (1994) Upper sandstone: calcareous with <* developing limestone with it. w Upper most part has red clays intercalated with sandstone Sandstone and variegated clay w w Lower sandstone: Argellaceous & E sequence. pq 1 ferruginous sandstone with mud -stone 5 fragment at base & small patches of

W ferruginous mudstone. D Red clays with ferruginous mudstone & 1 g u Limestone interbedded with finegrained sandstone. s marl occasional chert and grey Alternating limestone and calcareous shale. clays. H

Red clay with sandstone lenses and u C calcareous concretions. S3 Trough cross-stratified Clay 1 1 u S3 clast bearing sandstone s s Basal sandstone: Calcareous sandstone, 0 U

o pebbly, contain limestone conglomerates Sandstone: Large scale trough 5 and red clay lenses. cross-stratified sandstone

The interbedded clays are white (rarely red) and commonly contain abundant white calcareous concretions. Angular to subangular limestone intraclasts are also seen in

46 these clays. These clays are highly calcareous and occur as thin to medium bedded units

of varying thickness. The clays generally have sharp and undulatory contacts with the

underlying and overlying limestones.

Phosphatic nodules occur scantily in both limestone and clays. These phosphatic

nodules are ovate, spherical or oblong in shape, white to light pink, massive with

concentric rings. The radius ofthese nodules varies from 1cm to 4cm. 4 The unconsolidated red or grey / greenish clay, overlies the limestone with an

intertonguing relationship. The thickness of this clay horizon decreases towards the

northern part of the valley. The clays are profusely desiccated and in some cases contain

highly ferruginous mudstone pebbles.

The uppermost part of the Upper Member of Rudra (1982) corresponds to the

Upper Member of Murti and Lakshminarayana (1994). It consists of a thick (500m)

sequence of sandstone having a normal contact with the clays. The lower part of this

member is profusely cross-bedded and highly ferruginous. The sandstone is medium to

coarse-grained and contains abundant mudstone pebbles. According to Murti and

Lakshminarayana (1994) five lithofacies can be differentiated in this Upper Member as

follows:

1. Clay clast-bearing sandstone, 2. Trough cross-stratified sandstone, 3. Planar cross-stratified sandstone, 4. Laminated sandstone, 5. Micaceous siltstone and variegated claystone.

47 Lithofacies analyses (Rudra, 1982; Murti and Lakshminarayana, 1994) indicate that the Lower Member of the Kota Formation, which shows repeated fining upwards, was probably deposited by a meandering river system.

The Middle Member represents deposition in distal lacustrine system. The intertonguing relationship between limestone-clay sequence and the overlying red clays may be the result of close genetic interrelationship possibly representing the distal fine grained component of a braided-cum-fan depositional system (Rudra, 1982). In contrast to widely accepted lacustrine depositional environments for the limestones and intercalated clays, some workers have proposed a marine depositional environment for this unit (Bhattacharya, 1980; Murti and Lakshminarayana, 1994; Lakshminarayana,

1995). Bhattacharya (1980) argued for marine depositional environments on the basis of coccoliths and geochemical evidences. Murti and Lakshminarayana (1994) envisaged a marine transgression based on marl rhythm, tidal and flaser bedding, stromatolites, intraclast-bearing limestone, occurrence ofphosphatic nodules and coccoliths. During the present study, no evidence for marine influence was found and the data are in agreement with interpretations favouring lacustrine environments.

The Upper Member of the Kota Formation shows coarsening upwards suggesting that it may have been deposited by a braided river system (Rudra, 1982).

As discussed in chapter 2, a rich vertebrate fauna is known from the Kota

Formation. The limestone has yielded fossil fish whereas dinosaurs are known from clays intercalated with limestones. These clays have also yielded fish, amphibians, sphenodontids, crocodiles, theropod and ornithischian dinosaurs and mammals. In

48 addition, insects, ostracods and estheriids have also been reported (Rao and Shah, 1959;

Tasch et al, 1973; Govindan, 1975; Mishra and Satsangi, 1979). The flora consists of equisetales, cycads, and conifers (Rajanikanth and Sukh Dev, 1989; Prabhakar, 1986).

The floral remains recovered are both mega and microscopic. In addition, trace fossils have also been reported from this formation (Maulik and Rudra, 1986).

3.2.13 Gangapur (=Chikiala) Formation

The Gangapur Formation was named by Kutty (1969), after the village Gangapur

(19° 16"N: 79° 26'E), for a succession of sandstone and clays. This unit was previously groupedwith the Kota Formation (King, 1881). The formation consists of a succession of mudstone, siltstone, sandstone with pebbly bands, which may be locally conglomeratic.

The base of this formation is composed of coarse to very coarse-grained sandstone. The sandstone is mostly pale grey in colour but sometimes it may be red. The basal unit is overlain byup to 3m thick hard siliceous pebbly sandstone which, inturn, is overlain by a coarser sandstone and a series of well bedded, pale grey or whitish mudstone with intercalated bands offine or coarse sandstone (Kutty, 1969).

The Gangapur Formation has yielded ganoid fish scales (Kutty, 1969). The flora consists ofPtilophyllum acutifolium, Taeniopteris, Cladophlebis, Otozamites, Nilssonia,

Elatocladus, Araucarixylon, Brachyphyllum, Equisetites (Feismental, 1879; Rao and

Shah, 1959; Rao, et al, 1983; Prabhakar, 1989). Palynofossils include Callialasporites,

Araucariasporites, Microchryidites, Classopollis, Podocarpidites (Prabhakar, 1989).

49 3.2.14 Deccan Traps M

The Deccan Traps are exposed in the northwestern part of the Pranhita-Godavari

, valley. King (1881) named them as Traps of Janagaom Valley and classified them as Lower Deccan Traps. In the 3-fold geochemical classification of the Traps (Ramam and Murty, 1997), these volcanics correspond to the lower division (Wai Subgroup). There are five basalt flows in the area with intertrappean beds. The individual traps vary in x

thickness from less than a meter or so to as much as 50m.

3.3 GEOLOGY OF MEASURED SECTIONS

The presently investigated area falls in the Godavari subbasin of the Pranhita-

Godavari valley. Current lithostratigraphic classifications of the Kota Formation ^ recognise two (Rudra, 1982) and three (Murti and Lakshminarayana, 1994) members. The Lower Member in both the classifications is the same, but the Upper member of Rudra (1982) was further subdivided into two members (Middle and Upper) by Murti and Lakshminarayana (1994). In the latter, tripartite classification of the Kota Formation, the investigated sections mainly represent the uppermost part of the Lower Member and the +

Middle Member.

3.3.1 Paikasigudem Section

This section is exposed along a stream channel on the western side of the village

Paikasigudem (79° 30' 07"N: 19° 15' 08"E; Plate 1 fig. a, Text Fig. 3.3; 3.4), Adilabad * district, Andhra Pradesh. The section is made up of sandstone, clays, mudstone and

50 limestone. The base of the section is made up of coarse-grained sandstone strewn profusely with pebbles ranging in size between 1cm to 12cm. The sandstone is creamish- white in colour, cross-bedded. The basal portion of this sandstone is buff coloured, coarse-grained and contains numerous pebbles of sandstone, chert, limestone, mudstone etc. The long axis ofthese pebbles is oriented in general dip direction. The upper part of this sandstone is brownish-red and medium-grained. The pebbles are less frequent inthis portion.

The sandstone is overlain by a number of clayey levels. The contact between the sandstone and clays is erosional. The clays and mudstone beds are generally dirty white but the colour may vary between greyish, greenish-grey or at times pinkish. These beds are generally calcareous but the lime content increases upwards in the section. At times the clay beds show mottling of colours. All clay and mudstone horizons are fossiliferous, but the more calcareous ones are generally richer.

The clay and mudstone horizons are overlain by limestone. The limestone is generally dirty white in colour when fresh and weathers to pale-yellow. There are four bands of limestone in this section. Desiccation cracks are seen in all ofthese bands (Plate 1fig. b). With the exception of sandstone and basal clays, all units in this section contain abundant microvertebrates along with ostracods. Vertebrates recovered from the section include fish, amphibians, sphenodontids, acrodont iguanid lizards, crocodiles, sauropods, ornithischians, theropods and most importantly, mammals.

51 3.3.2 Metpalli Section

This section is exposed near the creek to the southwest of the village Metpalli (79° 44' 00"N: 19° 11' 00"E; PI. 1, fig. c; PI. 2, fig. a; Text Fig. 3.3; 3.5). The section is composed of two dominant lithologies namely, clays and limestone. The clay horizons are mostly yellowish in colour but the colour may range between various shades of yellow and grey. The clay units are at times laminated and contain pebbles oflimestone and mudstone. The topmost clay unit is highly calcareous and contains thin layers of limestone. Most ofthe clays are fossiliferous.

The limestones are hard and massive and vary in colour between whitish, dirty- white, pale yellow and grey. Some ofthe limestone also shows desiccation cracks on the upper surface. Stringers of dark grey limestone and pebbles and veins of chert are also ^

common. These limestones have yielded fish and trace fossils.

This section also shows interbedded limestone and clays. The clays in these units are yellowish, laminated, soft and friable, and limestone is greyish-yellow in colour. At places the limestone shows clay partings also. The limestone is generally hard and massive but at places it is spongy. In a few instances, the limestone contains veins and pebbles ofchert.

3.2.3 Kadamba Section

This section is exposed 2 km south of the village Kadamba (79° 39' 00"N: 19° 22'

30"E; Text Fig. 3.3; 3.6). Thesection comprises limestone, clays and claystone. A portion of this section is lost due to soil slump. The base of this section is composed of greenish

52 clays which are generally greenish and are often massive. Majority of the fossils from

this section came from these clays.

The limestone is generally dirty white to yellowish-white in colour and is

massive. The basal limestone is pebbly in nature. The claystone is yellowish-grey in

colour and is massive. This section has yielded fish scales, teeth, ostracods and some

± indeterminate fragmentary bones.

3.3.4 Manganpalli Section

This section is exposed in an excavation pit 0.75 km northwest of Manganpalli village (79° 49' 30"N: 19° 06' 13"E, PI. 2, fig. b, c; Text Fig. 3.7; 3.8). The excavation was undertaken by the Geological Survey of India for the recovery of the dinosaur Kotasaurus yamanapalliensis. The section is composed of sandstone, three limestone bands separated from each other by four clay beds. The base consists of medium-grained,

creamish-white sandstone. The sandstone also shows cross bedding.

The limestone bands exposed in this section are mostly massive, hard and vary in * colour from dark yellow in the basal portion to pale yellow in the uppermost part. The limestone shows irregular fractures filled with siliceous matter. The middle limestone

band shows fine greyish-black laminations.

The clay horizons are generally yellowish in colour. The clays are soft, friable and gradually become harder upwards. Most of the fossils from this section were recovered

from the basal clay unit.

53 3.2.5 Kota Section

This is the type section ofthe Kota Formation, named after the village Kota (79° 58' 00"N: 18° 55' 00"E; Plate 2 fig. d, Text Fig. 3.9, 3.10) on the eastern bank of the Pranhita River 8 km north of Sironcha in Maharashtra. The section, exposed on the western side of village, consists of an alternation of limestone, clay and marl. The limestone is mostly cream coloured, hard and massive and occasionally nodular with desiccation cracks (mud cracks) up to 2.5 cm deep. Most of the limestones in this section contain cone-in-cone structures. In some instances, the limestones are finely laminated with intercalations of marl. These limestones have yielded fish scales.

The clays vary in colour between green, yellowish-green to whitish-yellow. These clays also show mottling ofcolours between brown to yellow. The clays are occasionally calcareous.

The marl varies in colour between various shades of yellow. Most of the marl is soft. Some of the marl units are laminated and pebbly. Both the clays and marls have yielded fish scales, teeth, crocodilian teeth and fragmentary mammalian bones.

54 *

Figure 31Map showing distribution of continental Gondwana basins in Peninsular India (modified after Sastri et al., 1977)

55 * f

1^1 -J

Fig.3.2Geologicalmapofthe northernPart ofPranhita-Godavarivalley(afterKuttyetal., 1987) I '79° 40' 79° 35' Kadamba Kadamba Reserved Forest

To Kagaznagar

1 sr — = & * = = *

19° 20'

Pedda Vagu s*

«

> > % Paikasigudem 19° -19° 15' v Forest^/Z-^^Ny 15'" » \ Cover V*»\n i

^~^fiNarlapur ** Rebbna »»S^^kv""^/)

'% _j5"~**,-",*n"- ^^VHr okm 2km To Mancherial * sjf Metpalli , , i 70° IS' ^79°'40'J Fig 33Map showing the location of the investigated sections of the Kota Formation exposed

near Paikasigudem, Kadamba and Metpalli villages. Fossil locality is indicated by •.

59 15m- vi *"Y'T~ vy vy Soil cover vy vy 14m rS5I Hard white limestone

TT •'•'•'•'•'••••*i'T'•' '•' ' ' ' ' ' ' Hard creamish limestone * Yellow clays

* White clays 12m- White limestonewith mudcracks SOBCOS * Greenish-yellow clays

*Dirty-white mudstone 10m — * Greenish-yellow clays * Grey mudstone * Hard grey mudstone * Greyish-yellow clays ^^srji^jis^^ *Calcareous clays 8m—

v i.v - AVA V * Calcareous greenish-grey clays — A — * •V — V ——

Nodular grey clays

6m— % Unexposed (6.5 m)

4m — Green clays (mottled)

2m

Buff sandstone

Stream bed Fig. 3.4 Measured stratigraphic section at Paikasigudem village, *denotes vertebrate-bearing levels 61 20 m- TTT r~ Blocky yellow limestone xzxzxzx_x F.r •*,*,*! T'T'I •LJLXTX X 18m- * White clays Hard grey limestone

Greyish-yellow mudstone 16m Yellowish-white hard massive limestone

Layered white limestone with vugs and scours at top

Clays

Pebbly white limestone

Light yellow soft clays White hard massive limestone

* Laminated clays

Limestone clay alternation

* Pale-yellow clays

* Hard mudstone * Whitish-yellow clays Yellowish-white hard limestone White hard limestone (with Trace fossils)

* Yellowish-white soft clays

TTTT Greyish-yellow limestone

4m * Greenish-yellow clays

•,.,,, i i i'i'i' Greyish-white limestone

* Yellowish clays 2m -

Pale yellow limestone

Yellowish-white clays Creek base Fig. 3. 5Measured stratigraphic section at Metpalli village, *denotes vertebrate-bearing levels

63 i I l Yellowish-white Limestone S (massive) 2m- * Green clays

• WBIBIII^IW—W" * Claystone * Green clays HTTT, •••••••••••• Yellowish-white Limestone s° lm- ^ Unexposed >

White Limestone

* Green Clays

Fig. 3.6 Measured stratigraphic section at Kadamba Village. * denotes vertebrate-bearing levels

65 >

V

Fig. 3.7 Map showing the location of the investigated section exposed near Manganpalli village

67 5m -i

4m — —""—•"•,' Yellowish white clays

3 m — JZL T7T7T Hard yellow limestone i r

* Greyish-yellow clays

2m O Dark yellow limestone > wwm * Creamish clays ote Massive dark yellow limestone umjjj

lm- * Green Clays

Buff sandstone

Fig. 3.8 Measured stratigraphic section near Manganapalli village(excavation pit). * denotes vertebrate-bearing levels

69 >

Fig. 3.9 Map showing the location of the investigated section exposed near Kota village.

71 Yellow limestone

* Creamish clays •#

* Marl (Hard)

6m— Massive pale-yellowlimestone Pinkish-yellow limestone (with dessication racks)

* Marl (soft)

* Mottled clays

5m— Grey limestone

* Yellowish laminated marl

4m— * Yellow clays * Yellowish-white marl (massive, hard)

* Yellowish-white marl

3m •

Yellow limestone (massive)

* Yellowish marl (soft) Creamish-green limestone * Greenish clays(hard, laminated) 2m — * Greenish clays (mottled) Creamish-yellow limesone (massive, mudcracks)

* Greenish-yellow marl

lm-

Creamish limestone +

.Riverbed Fig. 3.10 Measured stratigraphic section at Kota Village (Type section) ♦denotes vertebrate4)earing levels 73 Chapter 4

SYSTEMATIC PALEONTOLOGY

Checklist ofthe recovered fauna:

PISCES

Order Semionotidei

Family Semionotidae

Lepidotes cf L. deccanensis

Paradepedium egertoni

Tetragonolepis oldhami

Family Indeterminate

Gen. et sp indet. 1

Gen. et sp indet. 2

Gen. et sp indet. 3

Order Hybodontiformes

Family Hybodontidae

Lissodus indicus nov. comb.

Elasmobranchii indet. REPTILIA

Order: Rhynchocephalia

Family: Sphenodontidae

Gen. et sp. indet. A

Gen. et sp. indet. B

Order Squamata

Infraorder Iguania

Gen. et sp. indet.

Order Crocodilia

Family ?Teleosauridae A Gen. et sp. indet.

Suborder Sauropoda

Indet.

Suborder Thyreophora

TYPE A -*

TYPEB

Suborder Theropoda

Theropoda A

Theropoda B

Theropoda C

Theropoda D

76 MAMMALIA

Order Docodonta

Family Docodontidae

Deniseodon godavariensis gen. et sp. nov.

Gondtherium dattai gen. et sp. nov.

Order Triconodonta

Family Incertae sedis

Dyskritodon indicus sp. nov.

Paikasigudodon yadagirii nov. comb.

Family ?Morganucodontidae

Indotherium pranhitai

Triconodonta indet.

INVERTEBRATES

Ostracodes

Order Podocopida

Family Darwinulidae

Darwinula cf. D. sarytirmensis

Darwinula sp.

Trace Fossils

Planolites

Monocraterion

11 Pisces >

Class: Osteichthyes

Subclass: Actinopterygii

Infraclass: Holostei

Order: Semionotidei

Family: Semionotidae

Genus: Lepidotes Sykes, 1851

Lepidotes cf. L. deccanensis Sykes, 1851

(PI. 3, fig. a-v; PI. 4, fig. a-o)

Referred Material: Isolated teeth RUBK/1001 - 1021 and scales RUBK/1022 - 1037.

Horizon and Locality: Clays and mudstones intercalated with limestone bands of Kota

Formation exposed near Paikasigudem, Kadamba and Metpalli Villages, clays underlying

the limestone bands of Kota Formation exposed near Manganpalli village, Adilabad

District, A. P. and clays intercalated with limestone bands exposed near Kota village,

Chandrapur District, Maharashtra.

A Description:

Teeth: During the present investigations four types of teeth attributable to Lepidotes were recovered.

The dome-shaped teeth (RUBK/1001 - 1006) are styliform, smooth and robust.

The occlusal surface is convex, crown is enamelloid and the pulp cavity is distinct. The basal section is circular. These teeth probably belong to palatal series ofdentition.

78 The second type of teeth probably represent the anterior marginal dentition

(RUBK/1007 - 1012). They are slender, acutely conical in shape and recurved posteriorly. The pulp cavity is distinct and the basal section is circular in outline. The enamel ofthe tip is transparent to translucent.

The third type of teeth (RUBK71013 - 1016) are broader at base than higher, conical in outline, with tip acutely pointed and recurved. The crown is enamelloid and smooth. The basal section is circular in outline and the pulp cavity is distinct.

The fourth type of teeth (RUBK71017 - 1021) are sickle-shaped and laterally compressed pharyngeal teeth. The terminal cusp is in the form of a hook and is pointed.

The crown is enamelloid, and the hook-shaped cusp is made up of transparent enamel.

Fine striations are present on the basal part. The basal section is elliptical. The teeth vary greatly in shape and size(0.5 mm to 1.5 mm).

Scales: In the present collection, scales from all over the body are present. They vary in shape from rhombic, sub-rectangular to oval depending on their position on the body.

The surface ofthe scales is covered with thick ganoine. The dorsal ridge scales (RUBK71022 - 1025) are rounded on the anterior margin and possess a slight notch, whereas the posterior margin is narrow and possesses a spur. The dorsal ridge scales are broad, almost circular and symmetrical in form. The shape of the dorsal ridge scale is distinctive. On the external surface, concentric growth lines are visible on larger (older) scales. These growth lines merge on the posterior margin of the scale. A small ridge is developed on the posterior margin, which stands on the spur and does not protrude on the main body ofthe scales. The internal surface ofthe dorsal ridge scales is produced into a raised area on the anterior margin. In some scales, the internal

79 surface is concave towards the body ofthe fish and bears two peg-like projections on the -r anterior margin, whereas the posterior margin isacutely pointed. The scales bordering the dorsal ridge scales (RUBK71026 - 1027) have curved antero-dorsal margin to fit against the sides of the dorsal ridge scales. These scales also show the development of spur on the ventro-dorsal margin. The surface is covered with thick ganoine and the thickness ofthis ganoine layer is greater in the larger scales. There is an opening possibly for the lateral line canal on the anterior margin. Concentric growth lines are visible in the larger (older) scales. The internal surface bears a ridge, which roughly follows the long axis of the scale, but does not reach the anterior margin. It becomes prominent in the central portion of the scales.

The lateral line scales (RUBK71028 - 1031) are rhombic in shape and posses a -x double spur on the posterior margin. The external surface of the scale is covered with a thick layer of ganoine whose thickness increases in the large (older) scales. The concentric growth lines are visible in these scales. These scales also show the development of opening for the lateral line canal on the anterior margin. The internal surface ofthese scales israised onthe anterior margin. The lateral line canal opens onthe A posterior side ofthe internal surface.

The ventral flank scales (RUBK/1032 - 1033) posses denticles on the posterior margin. The number ofdenticles varies from scale to scale and range between two to four denticles. These scales are rhombic in shape and show the opening for the lateral line canal on the anterior margin of the scales. These scales also show the development of a feeble ridge running from anterior to posterior margin.

80 The anal scales (RUBK/1034 - 1037) in external view are convex and are covered v with ganoine. They do not show growth lines. The ganoine covering is roughly oval in

shape. In some of the scales a spine is seen on the dorsal surface. The external shape of

these scales varies from oval to sub-rectangular. The internal surface of these scales is

concave. In some ofthe scales the sides are chisel-shaped with a depression between the

two processes.

Remarks: In the present collection there are more than 1000 teeth and over 2000 scales

which show close similarities to those ofL. deccanensis described first by Sykes (1851)

and subsequently by Jain (1983) and Prasad (1986) from the Kota Formation.

In India, besides Kota Formation, Lepidotes has also been reported from + intertrappean beds of Nagpur (Gayet et al., 1984), Asifabad (Prasad and Sahni, 1987) Kachchh (Bajpai, 1990) and Yennagundi, northern Karnataka (Srinivasan, 1991). Lepidotes ranges in age from Lower Jurassic to Upper Cretaceous. Lepidotes is fairly well distributed in the Lower Cretaceous of Spain (Estes and Sanchiz, 1982) and

Late Cretaceous of England (Woodward, 1895) Zaire, Congo and Bolivia (Gayet., 1982;

A DeMuzuion etal, 1983) and Cameroon (Flynn etal, 1987).

Genus.Paradapedium egertoni (Sykes,1851) Jain, 1973

(PI. 4. Fig. p-r; PI. 5, fig. a-c)

Referred Material: Isolated scales RUBK/1101 - 1106. Horizon and Locality: Clays and mudstones intercalated with limestone bands of the

Kota Formation exposed near Paikasigudem village and clays underlying the limestone

bands exposed nearManganpalli village, Adilabad District, A. P.

81 Description: The scales are rectangular to sub-rectangular in shape, some approaching rhombic shape. External surface is covered with a thin ganoine layer surrounded by peripheral internal layer. The external ganoine layer is thinner than the internal layer. The

external surface in a majority of the scales is convex. The internal surface is concave and has a ridge at the center along the longer axis. The margins ofthe scales are thinner than the actual body. The scales are devoid of any ornamentation. There is no development of prongs or spurs except for a small denticle, which is visible on one ofthe edges ofthe

internal surface.

Remarks: The scales in the present collection show morphological features similar to Paradapedium egertoni (Jain, 1973). These scales are quite distinct from those of Lepidotes in having athinner ganoine. Also, unlike the present scales, the majority of the lepidotes scales are rhombic to oval in shape.

Genus: Tetragonolepis oldhami Egerton, 1851

(PI. 5, fig. d-k) Referred Material: Isolated teeth RUBK/1201 - 1206 and a few fragmentary jaws

RUBK/1207- 1208.

Horizon and Locality: Clays and mudstones intercalated with limestone bands of the Kota Formation exposed near Paikasigudem village and clays underlying the limestone bands exposed near Manganpalli village, Adilabad District, A. P.

Description: Teeth are slender, conical in shape and acutely pointed. The crown is enamelloid with transparent to translucent tip. The teeth show a constriction at the basal part of the crown (development of the neck just above the basal portion). The crown is ornamented with small longitudinal ribs. These teeth belong to the marginal series of the

82 dentition. The pulp cavity is clearly visible. RUBK7 1207 is a jaw fragment 1.6mm long,

which preserves two marginal teeth. RUBK/1208 is 1.7 mm long and has one preserved

tooth along with bases ofthree broken teeth.

Remarks: These teeth show morphological characters similar to Tetragonolepis (Jain,

1973). The teeth are quite distinct from those of the Lepidotes. The teeth are straight and

posses a neck at the basal portion of the crown, unlike the recurved teeth of Lepidotes.

Moreover, unlike in Lepidotes, the crown is not smooth and bears very fine vertical ribs,

which are visible only at very high magnifications (Plate 3 fig. 13).

Order Semionotidei

Indeterminate

A (PL 5, fig. 1-q; PI. 6, fig. a-d)

Referred Material: Isolated teeth RUBK/l301 - 1310 and many unnumbered specimens.

Horizon and Locality: Clays and mudstones intercalated with limestone bands of the

Kota Formation exposed near Paikasigudem village and clays underlying the limestone

bands exposed near Manganpalli village, Adilabad District, A. P.

Description: The teeth are conical in shape and are slightly recurved. Each tooth is

divisible into apical crown and the basal part. The crown is separated from the base by a

well-developed ring-shaped suture or collar. The surface of the crown is smooth and is

capped with a translucent to transparent enamelloid layer. On both the lateral margins,

the crown possesses sharp edges forming a flange laterally. In some of the specimens, the

flange reaches the base ofthe teeth while in others it dies out before reaching the base of

the teeth. The apex of the teeth is pointed and sharp. The base ofthe teeth is ornamented

with fine longitudinal striations.

83 Remarks: The present teeth show general similarities to those of Lepisosteus indicus, originally described by Woodward (1908) from the Late Cretaceous Lameta Formation, Dongargoan, central India and by Rana (1984), Prasad and Sahni (1987) and Bajpai (1990) from the intertrappean beds of Nagpur, Asifabad and Kachchh (Kutch), respectively. However, unlike L. indicus, the Kota specimens possess a lateral flange on both the lateral margins. Also, in contrast to L. Indicus, the crown portion in the Kota specimens is shorter than the basal part. Further, the teeth of Lepisosteus indicus are larger (almost double) than the present teeth.

Order Semionotidei

Indeterminate

(PI. 7, fig. e-o; PI. 5, fig. 1-5) Referred Material: Fragmentary jaws RUBK/1401 - RUBK/1411 and many unnumbered specimens.

Horizon and Locality: Clays and mudstones intercalated with limestone bands of the

Kota Formation exposed near Paikasigudem village and clays underlying the limestone bands of the Kota Formation exposed near Manganpalli village, Adilabad District, A. P. -*- and the clays intercalated with the limestone bands of the Kota Formation exposed near

Kota Village, Chandrapur District, Maharashtra.

Description: All of the recovered jaw fragments are edentulous. In most of the specimens the sockets are present in two parallel rows. Some specimens (RIBK/1403,

RUBK71406, RUBK/1409 and RUBK71411) also show sockets in a single row.

Remarks: More precise taxonomic assignment must await recovery of additional material.

84 Order Semionotidei

Indeterminate

(PI. 6, fig. e-t; PI. 7, fig. a-d)

Referred Material: Isolated scales RUBK71501 - 1520 and many unnumbered specimens.

Horizon and Locality: Clays and mudstones intercalated with limestone bands of the

Kota Formation exposed near Paikasigudem village and clays underlying the limestone bands of the Kota Formation exposed nearManganpalli villages, Adilabad District, A. P.

Description: The scales are very small (up to 1.5 mm) and vary in shape from rectangular to rhombic. In RUBK/1503 - 1504, the shape is more or less rectangular with one of the ends produced into a beak-like projection. The external surface of the scales is ornamented with ridges and furrows. The ridges are fine, whereas the furrows are wide and deep. The ridges and furrows follow the long axis ofthe scales. The ridges start from one end of the scale where they are very weakly developed and become progressively more prominent as they reach the other end. The ridges also show irregular branching and in some cases are interwoven or anatomising. The internal surface of the scales is a concave basin. The borders of the scales are raised to form a rim. This surface of the rim is finely crenulated. RUBK7 1501-1502 are rectangular scales ornamented with branching ribs onthe external surface and the ribs follow the long axis of the scales. On one of the margins a notch is developed on one side ofthe scale. The internal surface is uneven and basin like with raised margins forming the rim. The surface ofthe rim is finely crenulated.

85 In some scales (RUBK/ 1505 - 1506), the ribs are of uniform thickness throughout the scale and are arranged breadth-wise on the scale. The ribs do not show branching pattern. The internal surface of these scales is concave and uneven with raised margins forming the rim. The surface ofthe rim is finely crenulated. RUBK7 1507 - 1512 are rectangular in shape and show anatomosing arrangement of ribs and furrows on the external surface. The internal surface is almost rectangular and concave. The borders on the internal side are raised and form a rim. The surface of the rim is finely crenulated.

RUBK/ 1513 - 1516 are the clusters of the scales. The external surface is ornamented with the anatomising ribs and furrows. The internal surface ofthese scales is similar to other scales with a raised rim and the enclosing basin. The junction ofthree scales is clearly visible on the internal surface.

RUBK/ 1517 - 1520 are rectangular in outline. The external surface of these scales is ornamented with spines instead ofribs. The spines appear to be arranged in a linear pattern, unlike RUBK/ 1517 and RUBK/ 1519. The internal surface ofthese scales

(RUBK/ 1517 - 1520) has a peripheral raised rim and enclosed basin. -*- There are a large number of scales in the present collection which are broken, have ribs and furrows on the external surface arranged in dendritic pattern. Others are ornamented with tubercles. Because of the fragmentary nature of these scales, it is not possible to ascertain the nature of the rim and ornamentation on the internal surface.

Remarks: Lack of comparative material does not permit a detailed study at present.

86 Class Chondrichthyes

Subclass: Elasmobranchii

Order: Hybodontiformes

Family: Hybodontidae

Genus: Lissodus Brough, 1935

Lissodus indicus (Yadagiri, 1986) nov. comb.

(PI. 8, fig. a-c)

Referred Material: Isolated teeth RUBK/1601 - 1603 and a few unnumbered specimen.

Horizon and locality: Clays and mudstones intercalated with the limestone bands of the

Kota Formation exposednear Paikasigudem village, Adilabad District, A.P.

Description: The teeth arevery small in size, measuring only 2.30 mm anteroposteriorly.

The surface is smooth and covered with a uniform layer of enamel. In occlusal view, the lateral margins of the crown are slightly curved lingually. Aprominent occlusal crest runs along the entire length of the tooth. The central crest possesses undulations and at the lateral margins small accessory cuspules are present. The central/occlusal cusp is well developed and has a diamond-shaped base. There is a well-developed labial or falcate cusp, which is curved on the labial margin and a moderately developed cusp on the lingual margin. The lingual cusp is much smaller than the labial cusp. A crest extends from the labial cusp through the central cusp onto the lingual cusp. The posterior side of the lingual cusp is ornamented with a few striations. A prominent crest runs along the entire lingual margin ofthe crown and divides it into two equal portions, apical and basal, each of which slopes away from this lingual crest. The labial crest is not as sharp as the lingual crest but it still divides the crown into two portions.

87 Roots are not preserved in any of the recovered specimens. A prominent

constriction is presentat thejunctionof the crownand root. Remarks: The present teeth closely resembles Lonchidion indicus described by Yadagiri, (1986) from the Kota Formation. Both the specimens share the presence ofa prominent apical cusp, a well-developed prominent labial cusp and a lingual cusp. In addition to these characters, the two specimen share the presence ofa convex, undulating occlusal crest, labial curvature of the lateral margins of the tooth. Yadagiri (1986) has not taken into account the priority of Lissodus over Lonchidion (see Dufin, 1984) and erected a new species for the specimens from the Kota Formation, Lonchidion indicus. Here, the new specimens of the present collection along with those described by Yadagiri (1986) are referred to Lissodus indicus in strict adherence to the Code of Zoological

Nomenclature.

The present teeth differ from Lonchidion selachos, Estes, 1964, in having a more strongly developed labial cusp. Moreover, the Indian species lacks the accessory cusps and possess a lingual cusp which is absent in L. selachos.

Patterson (1966) reported six taxa of Lonchidion from Wealden (Lower

Cretaceous), with Lonchidion breve breve dominating the whole assemblage. The

Wealden species is smaller than the Indian species and the crown overhangs the root.

Case and Cappetta (1975) reported Lonchidion babulskii from the Maastrichtian

Monmouth Group ofNew Jersey. It is similar to the Kota species in having a lingual tilt of the lateral margins of the crown and the swollen lingual face, but differ in having larger teeth (3-7 mm) and a straight rather than curved labial cusp.

88 Murry (1981) described Lonchidion humblii from the Triassic Dockum Group of

Texas. It shares many characters with the Indian species, such as smooth crown and well- developed labial cusp. But the presence of a falcate labial cusp, and a lingual cusp, a constriction between the root and the crown and the better development of the occlusal cusp with an undulating crest differentiate the Indian species from L. humblii.

Estes and Sanchiz (1982) described a new species Lonchidion microselachos, which shares many characters with the Indian species such as a prominent labial cusp, high occlusal cusp, and the convex occlusal crest. But the undulating occlusal crest and the lingual tilt of the lateral margins and relatively larger size of the Indian species differentiate it from Lonchidion microselachos. The possession of the lingual cusp in

Indian species also differentiates it from theLonchidion microselachos.

Case (1987) described Lissodus griffisi from the Campanian Teapot Sandstone Member, Mesaverda Formation, Wyoming. Lissodus griffisi possesses well-developed lateral accessory cusps, has a triagular aspect ofthe crown in the occlusal view and does not possess the lingual cusp. These characters amply differentiate itfrom/,, indicus.

Lissodus is known from the Triassic to Late Cretaceous, both from the freshwater and marine deposits all over the world (Brough, 1935; Estes, 1964; Patterson, 1966; Case and Cappetta, 1975; Murry, 1981; Estes and Sanchiz, 1982; Case, 1987).

Estes and Sanchiz (1982) classified the genus Lissodus {Lonchidion) into three evolutionary stages: primitive, intermediate and derived, according to the possession of certain characters including heterodonty, accessory cusps, labial processes on the anterior

89 teeth, striations, lateral cusps, crenulations, postulae, bulge on occlusal crest and

constriction between crown and root. These characters were numbered from 1-9. The Indian species falls in the derived evolutionary stage with the possession of characters like absence ofthe accessory cusps (2"), tooth striations (4") and the presence ofa strong falcate labial cusp (5'), crenulations on the occlusal crest (6') and constriction between root and crown (9'). It is clear thatthe Indian species shares the most advanced characters with/,, microselachos (Estes and Sanchiz, 1982).

Elasmobranchii indet.

(PI. 8, fig. d-p)

Referred Material: TYPE-I: Isolated dermal denticles RUBK71701-1707 and TYPE-II

RUBK/1801-1806.

Horizon and locality: Clays and mudstones intercalated with limestone bands of the

Kota Formation exposed near Paikasigudem village, Adilabad District, A. P. and Kota village, Chandrapur district, Maharashtra, and the clays underlying the limestone bands exposed near Manganpalli village, Adilabad district, A. P.

Description:

TYPE I: The dermal denticles are conical in shape and are ornamented with longitudinal striations. Some are straight, while others (RUBK/1704 to RUBK71706) are recurved.

Striations are absent on the basal part of the denticles. These striations coalesce at the tip of the denticle. The whole surface is covered by enamel. The tip is acutelypointed. At the base a prominent thickening is present. The denticles are bulbous at the base. A

TYPE II: There are a few specimens in the microvertebrate collection of the Kota

Formation, which resemble the dermal denticles of elasmobranchs. These specimens

90 differ from those described as TYPE-I in having a number of dome-shaped denticles occurring on a broad platform. These denticles show striations, radiating from the tip. In some specimens, these denticles are conical in outline rather than dome-shaped.

Remarks: Identification at generic or evenfamilial level is not possible at present.

Reptiles

The reptilian fauna recovered from the Kota Formation during the present investigation includes rhynchocephalians (sphenodontians), acrodont iguanid (agamid) lizards, sauropods, ornithischians and theropods. Of these, theropods are the most diverse, represented by at least four different forms, followed by the ornithischians (two morphotypes) and sphenodontids (two taxa). The sauropods, crocodile and lizards are represented by one taxon each.

Rhynchocephalians

In marked contrast to its present restricted occurrence (only one genus in islands off the coast of New Zealand), the fossil record shows a Pangean distribution for this group in the Mesozoic. In the Late Triassic and Early Jurassic they were present in both

Gondwanan and Laurasian continents. However, this group is believed to have disappeared from Asia by Early Jurassic (Susan Evans, pers.com.) and from Europe (Barbara and Macuglia, 1988) and North America (Throckmorton et al. 1981; Reynoso, 1998) by Middle Cretaceous. In the southern continents, they are known only by fragmentary remains from the Early Jurassic (Gow and Raath, 1977) and Early

91 Cretaceous (Rich et al. 1983; Sues and Reisz, 1985; Ross et al. 1999) of South Africa and the Early Cretaceous ofMorocco (Evans and Sigogneau-Russell, 1997).

In this section, a new rhynchocephalian fauna recovered from the Kota Formation is described. The new Kota material is represented by two sphenodontian taxa based on dental remains. Prior to this work, presence of sphenodonts in the Kota Formation was mentioned (Yadagiri, 1986; Prasad, 1986), but no detailed study was made.

Besides dental elements, the Kota rhynchocephalian fauna also includes a few isolated amphicoelous vertebrae and humeri. However, these are not described here. Despite the fact that the Kota sphenodontids are quite distinct from all known genera, formal assignment to newgenera is deferred here for wantof additional material.

Subclass: Lepidosauria

Order: Rhynchocephalia

Suborder: Sphenodontia

Family: Sphenodontidae

Gen. et sp. indet. A

(PI. 9, Fig. a-e, Text Fig. 5.1) Referred Material: About 75 numbered and unnumbered specimens representing premaxillae (VPL/JU/KR17-20), maxillary fragments (VPL/JU/KR/24-35), dentary fragments (VPL/JU/KR/1-5, 9, 12-15), and a palatine (VPL/JU/KR/21).

Horizon and Locality: Clays and mudstones intercalated with limestone bands of the

Kota Formation exposed near Paikasigudem village, Adilabad district, A.P.

92 Description: The paired premaxillae have three fully acrodont teeth, which are

anteroposteriorly compressed and bear vertical striations (VPL/JU/KR/17). Each

premaxilla has a broad but shallow dental ramus, slender nasal process, and narrow

maxillary facet.

The anterior, central and posterior regions of the maxillae are preserved. The

maxillary teeth are acrodont in nature. The anterior maxillary teeth are four in number,

slightly recurved, and are more coarsely striated than those following them. The posterior

maxillary teeth are broad-based, striated, and bear small posterior flanges oriented parallel to the long axis of the maxillary bone (VPL/JU/KR/24). The medial surface of

the maxillae exhibits premaxillary facet. A deep concave facet on the medial face for the

maxillary process of palatine is present (VPL/JU/KR/31). The dentary fragments represent the anterior and middle parts of the bone. Specimens representing the anterior symphyseal region (VPL/JU/KR/1-2) bear five small, laterally compressed teeth. The first three of these are relatively smaller than the

last two. Behind these successional teeth are the conical hatchling teeth without flanges or striae. A deep notch separates the alveolar margin from the symphyseal region. Thus the symphyseal surface is restricted dorsally and is oriented anteroventrally. The subdental shelf is deep, restricting the Meckelian fossa to the ventral border. The posterior additional teeth are preserved only in a few specimens (VPL/JU/KM/12). These

teeth are conical, broad-based, and have posterior striae and anterior facetting. Asingle specimen (VPL/JU/KR/21) represents the left palatine. The palatine teeth A- are pyramidal and bear coarse striae. The outer row ofteeth is slightly curved and has six teeth ofnearly same size. Medial to the outer row, a shorter tooth row bearing three teeth

93 are present on a narrow but prominent ridge. Although the maxillary process is broken

anteriorly, it was deep and matches the facet on maxilla.

Remarks: The taxon A differs from the basal rhynchocephalians (Late Triassic Diphydontosaurus, Whiteside, 1986 and Gephyrosaurus, Evans, 1980) and in having

fully acrodont teeth. It is also distinct from Clevosaurus, Pleurosaurus, Homoeosaurus, Opisthias, Kallimodon, pleurosaurs, Tingitana in possessing more than one row of

palatine teeth and by lacking strong overlapping flanges onposterior additional teeth. The shape ofmandibular symphysis oftaxon A is also different from that ofCynosphenodon (Reynoso, 1996), Pamizinsaurus (Reynoso, 1997), Toxolophosaurus (Throckmorton et al. 1981), and Eilenodon (Rasmussen and Callison, 1981). It can also be distinguished from the Late Triassic Brachyrhinodon of Scotland and Polysphenodon of Germany

(Fraser and Benton, 1989) in having two rows of palatine teeth and less robust premaxillae. Although taxon A compares well with Late Triassic Planocephalosaurus in bearing strongly striated anterior teeth and more than one row of palatine teeth, it differs from the latter in its shorter lateral palatine tooth row, a short medial tooth row with only three teeth, slender nasal process of premaxilla, narrow terminal dentary symphysis, spatulate anterior dentary teeth, facetted dentary teeth and small flanges on maxillary teeth. These morphologic differences are suggestive of a separate generic status for the

Indian species.

-»L

94 Subclass: Lepidosauria

Order: Rhynchocephalia

Suborder: Sphenodontia

Family: Sphenodontidae

Gen. et sp. indet. B

(PI. 9, Fig. f-o; Text Fig. 5.2)

Referred Material: Many numbered and unnumbered specimens of premaxilla

(VPL/JU/KR/45), fragments of maxillae (VPL/JU/KR/40-44, 49-52), anterior parts of dentaries (VPL/JU/KR/37-38, 47, 48, 65), more posterior fragment of dentary

(VPL/JU/KR/39), partial left palatine (VPL/JU/KR/46).

Horizon and Locality: Clays and mudstones intercalated with limestone bands of the

Kota Formation exposed near Paikasigudem village, Adilabad district, A. P.

Description: Premaxilla, known by a single specimen, is broad, U-shaped and has a broad alveolar margin bearing four small teeth of equal size (VPL/JU/KR/45). The nasal process is much shorter than the lateral process and is without facets for nasal bones. The teeth are blunt, unstriated and anteroposteriorly compressed. The lateral margin of the premaxillary bone is produced into a long maxillary process.

The anterior part of the maxilla (VPL/JU/KR/49) bears several compressed acrodont teeth and has a very thin and nearly vertical edge. The maxillary teeth are conical and slightly recurved anteriorly with a small posteromedial flange

(VPL/JU/LR/40). There is no palatal shelf. A large elongated surface is present for the palatine.

95 The anterior symphyseal part ofdentary (VPL/JU/KR/37-38) has broad-based and spatulate four fully acrodont teeth coarsely striated lingually and smooth labially. The dentary symphysis is deep and terminal. The symphyseal surface is long, vertical and is separated from the alveolar margin by a small notch. The subdental shelf is deep below the first few teeth and then becomes shallow posteriorly. The middle part of the dentary (VPL/JU/KR/39) represents ajuvenile and carries six small triangular teeth of hatchling dentition. The additional teeth are pyramidal with strong anteromedial facet, incipient anterolateral flanges, and posterior carinae, but they lack striations. VPL/JU/KR/46 is the posteromedial part of a left palatine and is attributed to Taxon Bbased on the similarity of its teeth to that of maxillae and the shape of maxillary facet. It has a single, straight lateral tooth row carrying four non-striated teeth similar to those of maxilla and small posterolateral flanges. It has a broad but shallow maxillary

process. Remarks: Taxon Bis distinguishable from most of the known sphenodontians in having a deep, U-shaped premaxilla with a small nasal process and a large lateral process which would have almost excluded the maxilla from the narial margin. Sues and Reisz (1995) considered this type of premaxilla as characteristic of the genus Clevosaurus. But Reynoso (1997) observed that similar type of premaxilla might have been present in Pamizinsaurus. On the other hand, the rest of the dental elements disagree with the inclusion ofpresent specimen in Clevosaurus. In contrast to strong flanges on maxillary teeth of Clevosaurus, the Kota specimens bear weak flanges. The additional teeth of the dentary are also pyramidal, facetted, and incipiently flanged unlike the broad-based and strongly flanged teeth of Clevosaurus. The palatine teeth are laterally compressed and

96 subdental shelf anteriorly. A diastema formed by the erosion of small teeth

(VPL/JU/KR/70) separates the anterior pleurodont teeth from the hatchling dentition. The

hatchling dentition has 11 teeth, which anterior in position, triangular and acrodont in

young individuals (VPL/JU/KR/68). In VPL/JU/KR/83, only posterior teeth of hatchling

dentition occur as a ridge of fused or partially acrodont denticles. The jaw bone

underlying hatchling dentition is tubular in shape. The posterior additional dentition

consists of 2-4 blade-like laterally compressed acrodont teeth with carinate margins (VPL/JU/KR/66). The subdental shelf is moderately deep. In young individuals, the lower margin of the dentary bears a long narrow facet for long and slender angular bone

which extends anteriorly to the level of hatchling dentition, but in adults the angular gets fused to the ventral margin of the dentary. There is no splenial facet. The postdental part of the dentary is mostly incomplete and extends into a small rounded coronoid process (VPL/JU/KR/76) with lingual but no labial facet for coronoid bone. A facet for

surangular is present posteroventrally behind the coronoid facet. Remarks: These specimens differs from rhynchocephalians in having oval medial dentary symphysis, anterior dentary with subpleurodont teeth, and a few blade-like, unflanged pleuroacrodont posterior dentary teeth. They also differ from living acrodont lizards in the presence of five pleurodont teeth on the anterior dentary, a weak medial maxillary flange, an angular bone fused to the dentary in adults, and only 2-4 additional teeth in each jaw ramus. Although Kota species shares the last named feature and blade like posterior teeth with pleuroacrodont implantation with Albian and Maastrichtian A priscagamids of Asia (Alifanov, 1989; Borsuk-Bialynicka and Moody, 1984; Gao and Hou, 1996; Borsuk-Bialynicka, 1996), it differ from the latter in having no labial flange

99 of coronoid, in possessing a reduced or absent splenial, a much longer angular fused to the dentary in adults and a coronoid process.

Crocodiles

Subclass: Archosauria

Order: Crocodilia

Family: ?Teleosauridae

(PI. 12, fig. a-1) Material Referred: Isolated teeth (RUBK7 3001 - RUBK/ 3012).

Horizon and locality: Clays and mudstones intercalated with the limestone bands of Kota Formation exposed near Paikasigudem village Adilabad District, A. P. Kota village Chandrapur district, Maharashtra. Description: The teeth (RUBK/3001 - RUBK/2006) are conical in shape, laterally compressed and gradually taper towards the apex. The apex is sharp and pointed. The lateral edges ofthe teeth are sharp, non-serrated and form a flange on both the lateral margins running from the apex to the base of the crown. The base is bulbous. The teeth are ornamented with longitudinal striations. In the cross-section the teeth appear nearly > circular. These teethprobably belong to the anterior series of dentition.

RUBK/3007 - RUBK/3012 are broader at the base than those described above. In the cross section these are elliptical in outline. The base is distinct and bulbous. These teeth probably belong to the posterior seriesofdentition. Remarks: In the absence of other skeletal elements (cranial and post-cranials) the familial and generic identification of these isolated teeth is not possible. Prior to the present find, a femur and dermal scutes (Owens, 1852) and teeth (Prasad, 1986) were

100 reported from the Kota Formation. Owens (1852) considered the femur and the dermal

scutes to have the affinities to Family Teleosauridae. Prasad (1986) also opined that teeth

might belong to the Family Teleosauridae. The present specimens are morphologically

similar to ones described by Prasad (1986) and are tentatively referred to the

Teleosairidae.

However, it must be pointed out that recurved and longitudinal striated teeth are

also found in the genus Hsisosuchus ofthe family Goniopholidae

Recently Jain(1996) has indicated the presence of good fossil teleosaurid material

from the Kota Formation but no account ofthis material is published as yet.

Dinosaurs

*^ Infraclass: Archosauromorpha

Subclass: Archosauria

Order: Saurischia

Infraorder: Sauropoda

Indet.

A (PI.11, Fig. a-b)

Referred Material: Isolated dentary/ maxillary teeth, RUBK/5501 andRUBK/5502.

Horizon and Locality: Clays and mudstones intercalated with the limestone bands ofthe

Kota Formation exposed nearPaikasigudem village, Adilabad district, A. P.

Description: The teeth are spatulate, labiolingually flattened and spoon-shaped. The

crown is higher than the anterior-posterior length (h= 2.25mm, 1= 1.7mm, l/h= 0.75mm).

The crown of RUBK/5501 bears a dominant apical cusp, with a median ridge extending

from the base to the top of the crown. The apical cusp seems to be offset posteriorly. It 101 also bears two marginal cusps onthe anterior margin. The posterior margin is broken but suggests the presence of marginal cusps as well. The crown is uniformly enamelled and has feeble longitudinal striations. The lingual face of the crown is concave and the labial face convex. A bulge is also present at the basal portion of the crown. The root is not preserved in the present specimens.

RUBK/5502 is spatulate tooth, asymmetrical in outline and is devoid of marginal cusps. The tooth is longer than high (h=0.95mm, 1=1.05mm, l/h=1.10mm). The crown is labiolingually compressed and covered by uniform enamel layer. The tooth bears a large apical cusp that forms a ridge extending tothe base ofthe crown where it merges with the basal bulge.

Remarks: The present specimens are very similar to the sauropod teeth in having a spatulate crown and are thus distinct from philliform ornithopod teeth. They appear to be similar to those of Barapasaurus tagorei known from the Kota Formation (Jain et al,

1975), in having spoon-shaped teeth with lateral cusps. Further comparison with

Barapasaurus can not be made, as theteeth are notillustrated bythese authors.

The present teeth also differ from those of Neosodon praecursor (Late Jurassic of

France, Buffetaut and Martin, 1993) in that the latter are relatively larger in size than

RUBK/5501. In shape also, the two taxa are distinct from each other. Neosodon teeth are heart-shaped, whereas the Kota specimens are spoon-shaped. Further, RUBK/5501 has marginal cusps which are absent in the Neosodon teeth. The labial curvature and lingual tilt of the Neosodon teeth is morepronounced than in presentspecimen (RUBK/5501).

102 The new specimens from India can be differentiated from Camarasaurus (Osborn

and Mook, 1921; Gilmore, 1925; White, 1958) in several features. In Camarasaurus, the

teeth are relatively broad, labio-lingually compressed, heart-shaped and sometimes also

have a ridge on the lingual surface.

Order: Ornithischia A, Suborder: Thyreophora

Family: Incertae sedis

Type"A"

(PLll.Fig.c-j)

Referred Material: Isolated dentary/maxillary teeth (RUBK/5601-RUBK/5608.

Horizon and locality: Clays and mudstones intercalated with limestone bands of the

Kota Formation exposed nearPaikasigudem village, Adilabad District, A. P.

Description: The teeth are labio-lingually compressed, philliform and asymmetrical in shape. The apical cusp is the largest, highest and most dominant cusp ofthe crown and is offset posteriorly. The tip of the apical cusp is acutely pointed. A median ridge extends from the tip of the apical cusp to the base ofthe crown. In addition to the apical cusp, the

crown also bears marginal cusps onthe anterior and posterior crests. The anterior and the posterior margins bear four and three marginal cusps, respectively. The tips of the marginal cusps are pointed and radiate away (outwards) from the apical cusp (at an angle of 19° to 20°). The flutings between the marginal cusp onthe lingual side do not extend + onto the main body of the crown. The labial side of the crown in RUBK/5602 is abraded

and notwell preserved. Onthe labial side, the fluting between the marginal cusp extends

103 slightly onto the crown. It imparts a faint ornamentation in the form of faint grooves to

the apical portionof the crown, but the basalportionof the crownis not ornamented. The

posterior margin of the crown is slightly flattened, whereas the anterior margin is less

flattened. Although the root is not preserved, a constriction is present at the junction of

crown with the root.

RUBK/5604 is a highly rolled specimen and all the apices of the cusps i.e. marginal as well as the apical are abraded. It possesses four anterior marginal cusps and three posterior marginal cusps. The marginal cusps radiate outwards from the apical cusp

(17° to 20°).

RUBK75601 is a labio-lingually compressed philliform tooth possessing a large

apical cusp. The apical cusp is recurved and offset posteriorly. Both the anterior and posterior margins bear three cusps each. The apices ofall the cusps (apical and marginal)

are pointed (but in worn teeth, the marginal cusps are rounded). The crown is not

ornamented and the flutings between the marginal cusps are not prominent and do not

extend on to the crown. Both the lingual and the labial faces of the crown are devoid of ornamentation. The lingual face is concave whereas the labial face is convex. The apical margin of the crown is tilted towards the lingual side. The tooth is broken at the base, but appears to have had a constriction at its base.

The crown of RUBK/5603 is labilo-lingually compressed and philliform. The crown bears apical and marginal cusps. The apical cusp is large, offset and recurved posteriorly. The tip of the cusp is chisel-shaped. The margin anterior to the apical cusp bears four marginal cusps. The posterior crest also bears four marginal cusps. The cusps and the posterior marginal cusps radiate away from the center of the tooth (at an angle of

104 18° to 21°). The tip of the marginal cusps is similar to the tip of the apical cusp. The * fluting between the marginal cusps extends on to the crown as faint grooves, which forms

the only ornamentation of the crown. On the posterior margin of the lingual face of the

crown, a cuspule is developed below the last marginal cusp. The labial side of the crown

is smooth without any fluting. A median ridge is present which extends from the tip of

the apical cusp to the base of the crown and merges with the basal ridge. The basal ridge

runs from the anterior to the posterior side of the crown. The basal ridge is ornamented

with faint flutings. Although the root is not preserved, the preserved portion of the crown

showsthe presence of a distinct constriction between the crown and root.

Table 4.1 Measurement ofthyreophoran (Type A) teeth.

Length (1) Height (h) 1/h

RUKB/5601 1.6mm 1.25 mm 1.28 mm

RUKB/5602 1.5 mm 1.75 mm 0.86 mm

RUKB/5603 1.25 mm 1.4 mm 0:89 mm

RUKB/5604 2.35 mm 2.25 mm 1.04 mm

RUKB/5505 1.6 mm 1.03 mm 1.55 mm

RUKB/5606 1.78 mm 1.07 mm 1.6 mm

RUKB/5607 2 mm 1.45 mm 1.37 mm

RUKB/5608 2 mm 1.5 mm 1.33 mm

Remarks: The labiolingually compressed crown, asymmetrical philliform shape and a

constriction separating the crown from the root are features that favour the inclusion of

the present teeth in the Order Ornithischia. These teeth can be differentiated from the

prosauropod teeth and from the spatulate sauropod teeth by their triangular philliform A shape, bulbous and inclined crowns.

105 The new specimens from India also differ from the fabrosaurid teeth in lacking a

cingulum. Further, the fabrosaurid teeth are antero-posteriorly expanded and the crown

varies in shape from triangular to rhomboidal (Galton, 1986), whereas the crown in the

present teeth is more triangular in aspect and crown height and antero-posterior length are

almost equal. The recurved marginal cusps of the present teeth also differentiate them

from those ofFabrosaurus australis (Thulborn, 1971), which has straight marginal cusps.

Furthermore, Fabrosaurus has up to 7 marginal cusps, while there are only 4 marginal

cusps in the Kota specimens.

The Kota specimens can also be differentiated from the teeth ofAlocodon kuehnei

(Thulborn, 1973) in overall shape of the crown and the lack of cingulum in the former.

The marginal cusps in Alocodon are straight, whereas in the present collection, the

marginal cusps diverge away from the apical cusp. The ornamentation of the lingual face

of the crown of Alocodon also distinguishes it from the non-ornamented nature of the

Kota teeth.

Trimucrodon cuneatus recovered from the Upper Jurassic of the Portugal

(Thulborn, 1973) is quite distinct from the Indian specimens. The crowns of the

Trimucrodon teeth are higher than long and bear straight marginal cusps. The present

teeth bear fewer marginal cusps than Trimucrodon.

Scutellosaurus has teeth that resemble closely those of fabrosaurids (Galton,

1986). The crowns of Scutellosaurus teeth are symmetrical and straight in anterior and

posterior view, whereas the present teeth are asymmetrical with diverging marginal cusps. ...

106 The Kota teeth do not show similarity to any of the known ornithischian genera. A comparative study of dental characters of the teeth in question (RUBK/5601-5608) was made with the various known genera. It was found RUBK/5015-5022 share the outward

radiating marginal cusps and the pointed tip of cusps with Palaeoscinus costatus,

Edmontonia rugosidens and Sauropelta edwardsi (Coombs, 1990). However, the presence of cingulum, and ornamented crowns of Palaeoscinus, Edmontonia and Sauropelta differentiate these from the Kota specimens. The marginal cusps are also

fewer in the Kota specimens than in the above mentioned genera. The size of the crown

ofthe present teeth is also smaller than inthe above mentioned genera.

Order: Ornithischia

Suborder: Thyreophora

Family: Incertae sedis

"B"

(PI. ll.Fig.k.1)

Referred Material: Isolated dentary/maxillary tooth (RUBK75701). Horizon and locality: Clays and mudstones intercalated with limestone bands of the

Kota Formation exposed near Paikasigudem village, Adilabad District, A. P. Description: The tooth is labiolingually compressed and asymmetrical in appearance. The length and height of the tooth are nearly equal. (1=1.3mm, h=1.25mm). The apical cusp of the crown dominates the major part of the crown and is acutely pointed. The anterior lateral margin bears one smaller accessory cusp. Both the anterior and the posterior lateral margins bear small denticles. The tip of the apical cusp is blunt. The

entire tooth crown is covered with uniform enamel layer. Both the labial and lingual faces

107 ofthe crown are ornamented with fine longitudinal striations. The labial face ofthe tooth A- is more convex than the lingual face. The basal portion of the crown is bulbous. Root is not preserved, but a prominent constriction is present at the level of the root / crown junction.

Remarks: The present tooth (RUBK/5701) can be distinguished from the teeth described as Type "A" (RUBK/ 5601-5608), in having fine denticles rather than typical marginal J* cusps on both the lateral margins seen in the latter. Moreover, the philliform shape ofthe latter also differentiates thetwotypes of teeth.

RUBK75701 compares well with the dentary/maxillary teeth of theLucianosaurus wildi reported from the Upper Triassic Bull Canyon Formation (North America, Hunt and

Lucas, 1994). In both Lucianosaurus and the present dentary/ maxillary tooth, the crown is constricted below the crown. Both these teeth also share the presence ofaccessory cusp on the anterior lateral margin. Other common features include longitudinal striations on both the labial and lingual faces and marginal fine denticles.

Order: Saurischia

Suborder: Theropoda

Theropoda "A"

(PI. 12, Fig. m-t, PI. 13, fig. a-f)

Material Referred: Isolated maxillary RUBK/6501-6502 and premaxillary teeth

RUBK/6503- RUBK/6507.

Horizon and locality: Clays and mudstones intercalated with the limestone bands of

Kota Formation exposed near Paikasigudem village Adilabad District, A. P.

108 Description: The teeth are conical in shape, gradually tapering towards the apex and recurved posteriorly. The tip is slightly bent towards the lingual side. Denticles are present on both the anterior and posterior carinae. The anterior and posterior carinae bearing denticles are displaced towards the lingual side ofthe teeth. The basal section of

theteeth is almost circular. Most of theteeth in the present collection do notpreserve the

denticles on the entire carina. The number of denticles on the posterior carina is nearly 30 in RUBK/6501. In comparison to the premaxillary teeth the maxillary teeth are more recurved and the TCH is approximately double the FABL. The individual denticles are chisel-shaped. No grooves are seen in between two adjacent denticles.

Table 4.2 Measurement ofTheropod "A" teeth.

Specimens TCH(mm) FABL (mm) BW(mm)

RUKB/6501 2.85 1.34 0.86

RUKB/6502 1.42 0.57 0.40

RUKB/6503 1.6 0.63 0.48

RUKB/6504 1.6 0.63 0.48

RUKB/6505 1.25 0.42 0.39

RUKB/6507 1.57 0.57 0.42

< RUKB/6506 1.77 ~ ~

Remarks: The maxillary (RUBK/6501-6502) and premaxillary (RUBK/6503-6507) teeth

described here show close resemblance to the corresponding teeth of Dromaeosaurus albertensis (Currie, 1987; Currie et al, 1990; Fiorillo and Currie, 1994). Currie et al. (1990) considered the lingual twists ofthe anterior carina to be a characteristic feature of the maxillary teeth of Dromaeosaurus albertensis. The present specimens show the

characteristic twists ofthe anterior carinae. This feature, and the presence of denticles on

109 both anterior and posterior carinae, favour the inclusion ofthe present teeth in the family

Dromasauridae. However, this assignment is deferred for want of more diagnostic material.

Although dinosaurian remains belonging to early sauropods and hypsilophodontids have been known from the Kota Formation for a long time, theropods are being recorded for the first time. Besides the Kota Formation theropods have also been reported from Late Cretaceous Lameta Formation (Lydekkar, 1880; Vainey-Liaud et al, 1987) and from the intertrappean beds (Rao and Yadagiri, 1981; Prasad and Sahni,

1987; Vainey-Liaud et al, 1987, Ghevaariya, 1988; Bajpai, 1990, Mohabey and Udhoji,

1996). The present specimens differ from all these megalosaurid teeth in having the characteristic lingual twist ofthe anterior carina and in the shape and size ofdenticles on the carinae.

Theropoda "B"

(PI. 13, Fig. g-n)

Material Referred: Isolated maxillary/ dentary teeth, RUBK/6601 and RUBK/6603.

Horizon and locality: Clays and mudstones intercalated with the limestone bands of

Kota Formation exposed near Paikasigudem village Adilabad District, A. P.

Description: The teeth are very small (1.3 and 1.4 mm) from base to apex, conical in outline, recurved posteriorly and strongly compressed labiolingually. RUBK/6601 is broken at the apex and the portion bearing anterior carina is abraded. The posterior T margin of the teeth is concave and the anterior margin is convex. The broken anterior carina in RUBK/6601 shows indications ofdenticles on it. The posterior carina preserves

110 10 denticles. In RUBK/6602 10 denticles are preserved on the posterior carina and 14 denticles are preserved on the anterior carina. The labial side ofthe teeth is more convex than the lingual side. Both the anterior and the posterior carinae are present close to the longitudinal midline of the teeth.. The denticles on the basal part are larger and are pointed towards the apex. In general, the size ofthe denticles decreases towards the apex. The individual denticles are higher than wide. A distinct groove is present at the base of adjacent denticles. The blood grooves which are typically found in tyrranosaurids between the denticles, are present. Thebasal section is elliptical.

Table 4.3 Measurement ofTheropod "B" teeth.

Specimens Tooth crown Fore-aft basal Basal Width height(mm) length (mm) (mm)

RUKB/6601 1.28 0.74 0.28

RUKB/6602 1.14 0.71 0.28

RUKB/6603 2.35 1.6 0.71

Remarks: Theropod "B" does not show characters similar to any ofthe known theropod taxa. It differs from Theropod "A" in having a more labiolingually compressed crown and the denticle-bearing carinae along the longitudinal midline. Moreover, the denticles are conical and pointed, unlike Theropod "A". Also, Theropod "B" lacks the lingual tilt seen in Theropod "C". The denticles in the latter arearcuate-shaped.

111 Theropoda "C" A- (PI. 13, Fig. o-r)

Material Referred: Isolated teeth, RUBK76701and 6702.

Horizon and locality: Clays and mudstones intercalated with the limestone bands of

Kota Formation exposed near Paikasigudem village, Adilabad District, A. P.

Description: The teeth are small in size (1.1mm and 1.17mm), conical in shape, tip of the teeth is slightly tilted lingually, recurved and gradually tapering towards the apex.

Apex is sharp. Denticles are present upto the apex. The denticles on the anterior carina do not reach the distal end. The denticles are arc-shaped and longer than high. The denticles on the posterior carina form an angle of about 45° with the vertical axis. The labial margin is more convex than the lingual margin. The basal section is elliptical.

Table 4.4 Measurement ofTheropod "C" teeth.

Specimens TCH(mm) FABL (mm) BW(mm)

RUKB/6701 1.1 0.82 0.57

RUKB/6702 1.17 0.60 0.51

Remarks: The teeth described here do not show any resemblance to any known theropod teeth. They differ from the Theropod "A" in lacking the lingually displaced anterior carina and in the shape of the denticles. They also differ from Theropod "B" and

Theropod "D" teeth in having a lingually tilted apex and arc-shaped denticles.

y

112 Theropoda "D"

(PI. 13, Fig. s, t)

Referred material: Isolated tooth RUBK/ 6801 Horizon and locality: Clays underlying the limestone bands of the Kota Formation exposed near Manganpalli village, Adilabad District, A. P. Description: The preserved part of the tooth is 2 mm in height and the fore-aft basal length of the preserved part is also 2mm. The tooth is conical in shape, with the convex anterior and concave posterior carinae. The posterior carina bears 11 preserved denticles. The tip of the denticle is acutely rounded. The tooth is ornamented with longitudinal

striations. The root is not preserved.

Remarks: Additional material is required to identify this taxon.

Mammals

The study of Mesozoic mammals is significant for gaining insight into the origin and the evolution ofearly mammals. Mesozoic mammalian history is poorly understood at present (Clemens et al, 1979) mainly because of the paucity of continental deposits yielding the Mesozoic mammalian remains coupled with the sampling bias. The sampling bias has been corrected with the application ofthe screenwashing techniques for recovery

ofthe micromammalian remains from the scarce Mesozoic continental deposits theworld over. Secondly, early mammals have been studied extensively in the Laurasian continents, whereas such studies in the Gondwanan continents have been undertaken only in the last decade. Significantly, the recent discoveries ofmammals from the Gondwanan

113 continents (Rich et al, 1997; Flynn et al, 1999; Sigogneau-Russel, 1995) have disputed the earlier notions that the tribospenic, placental and marsupial mammals essentially evolved in the Laurasian landmasses (Bonaparte, 1994).

In India, the earliest Mesozoic mammals are known from the Late Triassic Tiki

Formation of central India where Datta and Das (1996) have described an isolated molariform tooth of morganucodontid mammal. This mammal, named Gondwanodon tapani, is represented by a solitary molar which has been referred to Family

Morganucodontidae. According to these authors Gondwanodon tapani is the oldest mammal known at present.

The Jurassic mammals from India are better known as compared to the Triassic.

These included, prior to the present study, symmetrodonts and the triconodonts (Datta,

1981; Yadagiri, 1984; 1985; Prasad and Manhas, 1997). The symmetrodonts from the

Indian sub-continent belong to Tinodontidae {Kotatherium haldanei), Amphidontidae

{Nakunodon paikasiensis) and an uncertain family {Trishulotherium kotaensis). The

Order Triconodonta is represented byIndotherium pranhitai (Prasad and Manhas, 1997).

The Cretaceous mammals of the Indian sub-continent are reported mainly from the Deccan intertrappean beds of Andhra Pradesh (Prasad and Sahni, 1988; Prasad etal,

1994; Prasad and Godinot, 1994; Godinot and Prasad, 1994; Das Sarma, et al, 1995;

Krause et al, 1997). These mammals are represented by the Palaeoryctidae and

Sudamericidae. The Palaeoryctidae includes Deccanolestes hislopi, and Deccanolestes robustus (Prasad and Sahni, 1988; Prasad et al, 1994). These taxa have been considered morphologically close to North American palaeoryctids in certain derived characters (but see Thewissen, 1990; Thewissen and McKenna, 1992). The second group of Late

114 Cretaceous mammals of the Indian sub-continent includes the highly specialised sudamericids (Sudamericidae, Order Gondwanatheria; Krause et al, 1997). The sudamericids are multituberculate or multituberculate-like mammals previously known only from the Late Cretaceous and Paleocene of Argentina (Bonaparte, 1990). These mammals have also been documented from the late Cretaceous ofMadagascar (Krause et al, 1997). During the present study, triconodontid and docodontid mammals were recovered from the Kota Formation. The docodontids have added yet another mammalian component to the already known symmetrodonts and triconodonts from this formation. Recovery of docodont mammals from the Kota Formation is significant as it has established a Pangean distribution for this group contrary to the earlier views (Kron, 1979). The recovery of additional triconodont material during the present study has led to a substantial improvement in our knowledge ofthe diversity ofthe Kota mammals.

Class Mammalia

Order Docodonta

Family Docodontidae

Genus Deniseodon gen. nov.

(PI. 14, Fig. a-e)

Type species: Deniseodon godavariensis sp. nov.

Holorype: Left upperpremolar, (VPL/JU/KM/12).

Horizon and locality: Clays and mudstones intercalated with the limestone bands of the

Kota Formation exposed near Paikasigudem village, Adilabad district, A. P.

115 Generic Diagnosis: Crown is asymmetrical in outline, with a cleft on the posterior margin and a slight indentation on the anterior margin; the labial cingulum is almost absent; small posterolabial cusp (cusp C) at the posterolabial corner of the tooth and is separated from cusp A by a broad notch and the tip of cusp C diverging away from the vertically oriented cusp A. A vertical flat facet is present anterior to cuspule E

(protuberance of anterolabial margin) and cuspule E' (? Parastyle); wide talon basin posterior to the crest from the lingual tip of A to its base; anteroposteriorly long lingual cusp 'A" higher than cusp C, but lower than CuspA.

Specific Diagnosis: Same as for genus.

Description: The holotype is an upper premolar with asymmetrical occlusal outline.

There are three principal cusps on the crown: one on the lingual margin and two on the labial margin of the tooth. Cusp A is the highest cusp and stands in the middle of the labial margin. Posteriorly, an angulated crest connects cusp A to a small posterolabial cusp C. The cusp C has a curved posterior face. A very broad notch separates the two labial cusps from each other. The tip of cusp A points ventrally, whereas cusp C points posteroventrally. A crest extends from the anterior tip of A, first anteriorly and then

making a slight anterolabial turn at its base to merge with a small cuspule occuring as a

small protuberance of anterolabial margin. This reduced cuspule possibly represents cusp E. A small worn cuspule E' occurs atthe anterolabial margin slightly lingual to cusp E. In size, cuspule £' is equal to cusp E, but is present slightly at lower level than cusp E and is projecting anteriorly. An anterolingually and posterolabially oriented crest connects the cusp E and E1. The two labial cusps have nearly flat (cusp C) or slightly convex (middle part ofA) labial faces but the crown has a vertical concave face labially because ofthe

116 pronounced concavity between cusps A and C and between the former and the * anterolabial end of the tooth. The labial projections of the anterolabial and posterolabial

ends of the crown causes this pronounced concavity between A and C. At the level of

labial cingulum, the labial face is broken and from the preserved part it appears that a

very narrow labial cingulum might have existed. A vertical flat face is present between

cusp E and E' on the anterolabial corner of the tooth possibly for recieving posteriorly

projecting small cusp C of the preceeding tooth.

A distinct talon is present, which is lingually extended, large and stout with

anteroposteriorly wide lingual cusp, lower than A but higher than cusp C. A deep talon

basin separates this robust cusp from cusp A. A completely worn crest descends lingually

from the tip of cusp A to the middle of its base and might have extended to the lingual

cusp in the unworn condition. As the enamel is spalled off from the surface of the crown,

the presence of the lingual crest connecting cusp A with the lingual cusp is difficult to

establish. Although, a weak trace of this crest is present lingual to the base of A, it is

difficult to ascertain whether it was a true crest or not, in the present state ofpreservation.

The talon basin lies posterior to this crest and occupies the place between the Ungual

junction of the labial cusps and the labial base of the lingual cusp. The labial face of the

lingual cusp steeply slopes posterolabially. A cingular crest, which is highly worn,

extends from the posterolabial tip of the lingual cusp to the lingual base of C. Another

crest extends from the anterolabial tip of lingual cusp with gentle anterolabial slope and

terminates at the lingual base of the cuspule E'. This crest is at an higher level than the

posterior one. The anterolingual face of the lingual cusp is rounded, convex at the base,

but becomes flat above the base and has a relatively large area than the posterolingual

117 face, which is rounded. Because of this, the tooth shows a projection on the posterolingual margin in occlusal view. The lingual face of the crown is also convex.

There is some enamel chipping on the posterolingual face of the lingual cusp. The posterior face of the tooth is nearly at right angle to the labial face, whereas the anterior face is obliquely oriented to it. The tooth is indented at the lingual base of the labial cusps, which is more pronounced on the posterior face. The study of the wear facets is not possible as the enamel is spalled off the crown. The roots are also not preserved, but the tooth possibly possessed three roots.

Remarks: The new specimen approaches the morphology of docodonts in having an assymetrical occlusal outline and double indentation lingual to labial cusps. Like in the upper molars of docodonts, the ectoflexux is absent; cusp E occurs as reduced cingular elavation rather than as a distinct cusp; cuspule E' is small cuspule; labial placement of cusp A and C; cusp C is placed on posterolabial corner of the tooth with a curved face.

Haldanodon (Kuhne and Krusat, 1972; Krusat, 1980), Docodon (Simpson, 1929),

Simpsonodon (Kermack etal, 1987), Borealestes (Waldman and Savage, 1972), Delsatia

(Sigogneau-Russel and Godifroit, 1997) and Peraicynodon (Kermack etal, 1987) arethe known taxa of the Family Docodontidae. Among these, the first five taxa are known by both upper and lower dentitions, whereas, Peraicynodon is known by lower dentition only.

In the development of individualised labial cusps, lingual extension and the talon basin, VPL/JU/KM/12 is just like any upper molar of docodonts. But the transverse posterior face with median indentation and obliquely straight anterior face only with slight indentation, asymmetrical triangular outline, and a deep talon basin posterior to

118 central crest from A to the lingual cusp, recalls the premolar morphology of the docodonts, such as Haldanodon, and Docodon. VPL/JU/KM/12 shares some features with P3 ofDocodon superus (Simpson, 1929) Both have asymmetrical triangular crown outline, development of cingular crest from the lingual cusp anteriorly and posteriorly, the posterior position of talon basin and lingual cusp higher than cusp C. P3 of D. superus differs from VPL/JU/KM/12 in possessing cusp Awhich occupies more than 75% ofthe crown and extends almost to the lingual margin of the crown, cusp C incompletely individualised, incipient cuspules E and E' and complete absence of a definitive labial cingulum. Moreover, P3 of D. superus has already achieved the doubling of the lingual cusps. Thus, D. superus has the accessory lingual cusp Y, split from the posterior part of the X, and the lingual part of the crown is less extensive than in VPL/JU/KM/12. Ifsuch a cusp is subjected to prolonged rolling, as in VPL/JU/KM/12, it is not expected to remain as a separate cusp. Therefore, it is inferred that the absence of this cusp in VPL/JU/KM/12 might be related to the rolled nature ofthis specimen. The present specimen compares well with the upper dentition of Haldanodon exspectatus (Krusat, 1980) in many morphological features. The P3 of Haldanodon has a narrow .labial cingulum, well individualised posterolabial cusp and a posteriorly protruding lingual part similar to that of VPL/JU/KM/12, but the lingual extension is less prominent than in VPL/JU/KM/12 and has already achieved the splitting of lingual cusps

into X and Y. The large lingual extension of the crown and its strong posterior protrusion in VPL/JU/KM/12 are unlike in P3 of Haldanodon. However, the two are similar in having an asymmetrical triangular crown and a distinct cusp C. Further, in Haldanodon, the

119 transverse width of the molar is more than the labial length and in premolars the reverse is true. In VPL/JU/KM/12, the labial length is greater than the transverse width, as in the premolars ofHaldanodon.

The position of tooth on the maxilla, and its orientationwith respect to labial face, may account for the dissimilar indentation ofanterior and posterior margins of the crown.

For example, in Haldanodon, as one proceeds from posterior upper molar to anterior

ones, the anterior indentation becomes progressively less pronounced and the anterior marginbecomes oblique to the labial face of the ultimate premolars (Krusat, 1980; fig. 20

A). By analogy with Haldanodon upper dentition, the present tooth is considered to be the ultimate upper premolar.

The upper molars of Haldanodon are indented on the anterior and posterior borders lingual to the labial cusps and the crown is rather asymmetrical triangular in outline. The crown is also asymmetrically triangular and similarly indented in

VPL/JU/KM/12, but indentation is more on the posterior border than on the anterior one.

In Haldanodon, the anterior and posterior borders are nearly at right angles to labial face, but, in VPL/JU/KM/12, the posterior face is at right angle to the labial face, whereas the anterior face is obliquely oriented to labial face due to more posterior position of the lingual cusp. The labial cingulum is narrow in the upper molars of Haldanodon.

Although the crown is not well preserved in this area in VPL/JU/KM/12, it appears to be very narrow. In both these taxa, the labial face oflabial cusps is flat and the lingual faces are convex, A is the largest cusp, C is smaller than A (almost half the height of cusp A).

However, a V-shaped valley separates these cusps close to their tip and the long axes of the two cusps is almost parallel to each other in Haldanodon. In marked contrast to

120 Haldanodon, in VPL/JU/KM/12, avery broad notch separates the two cusps and their tip X are diverging away from each other. In M1 of Haldanodon, a very small cingular cuspule V is present at the posterolabial base of Cand this cuspule is relatively larger in M2. No such cuspule is seen in the premolars of Haldanodon as well as on VPL/JU/KM/12. In both, Haldanodon and VPL/JU/KM/12, cusp Ais connected anterolabially to a labial cingular cusp £ by a crest; the lingual base ofAis not far lingual of the lingual base of C; and the cusp Cis located at the posterolabial corner of tooth. In Haldanodon, a crest decends from the lingual tip ofA and extends to the tip oflingual cusp. In VPL/JU/KM/12 also, a similar but worn crest is present from the lingual tip ofAto its lingual base; but there is only atrace of its extension to the lingual cusp. In both Haldanodon and VPL/JU/KM/12, the lingual crest is large, lower than A, higher than C, anteroposterior^ wide and projecting posteriorly with convex posterior and lingual faces, flat to slightly convex anterior face less steeper than posterior face and a steep labial face sloping posterolabially. In Simpsonodon also, the lingual cusp Xis larger, but it is not projecting posteriorly. But in VPL/JU/KM/12, the labial face of the lingual cusp is less steeper than in Haldanodon. In Haldanodon, an additional lingual cusp Y is present lingual to the principal lingual cusp X. In VPL/JU/KM/12, the enamel is chipped off in the usual position of cusp Y. In both the taxa the talon basin is deep, (although, in VPL/JU/KM/12, it is slightly wider), a cingular crest extends from the tip ofthe lingual cusp to cuspule E\ In Haldanodon, the second crest decends from the posterior tip oflingual cusp and reaches posterolabial base ofthe cusp C. But in VPL/JU/KM/12, this crest merges with C at its lingual base. In Haldanodon upper molars, an anterior shallow sulcus is present between the cusp Eand

121 the cuspule E\ possibly for recieving the cusp Cofthe preceeding tooth. Such sulcus is absent in VPL/JU/KM/12, instead a vertically flat facet occurs between cusp E and the cuspule E'. In both thetaxa, teeth arenearly of the same size. VPL/JU/KM/12 differs from Docodon and Simpsonodon in crown shape which is hour glass-like in Docodon and trapezoidal in Simpsonodon. In both these taxa, there is extensive development ofbasins both anteriorly and posteriorly to the central crest from Ato X. IBorealestes known from Middle Jurassic Mammal beds, Oxfordshire, England, also has a stout trapezoidal upper molar (Freeman, 1979).

1Woutersia mirabilis, which isreported from the Upper Triassic Saint-Nicolas-de-

Port locality, France was considered tentatively, as a primitive docodont based on the comparison of the upper molars with P3 ofHaldanodon (Sigogneau-Russel and Hahn, X 1995). They have interpreted Woutersia as a symmetrodont because the lower molar in 1W. mirabilis bears an additional cusp {g) occuring lingual to cusp a, and (cusp g) was homologised with cusp c. Butler (1997) contradicted this interpretation and homologised the metaconid of the docodonts with cusp c rather than with cusp g, and suggested that the additional lingual cusp g of Woutersia should correspond to the more anterior lingual

cusp of the docodonts, which is designated as h. Butler (1997) further elaborated that the

upper molars of Woutersia with cusp X might represent the earliest member of the

docodont clade. VPL/JU/KM/12, share some docodont features with 1Woutersia mirabilis, such as the more labial occurence of the labial cusps, a posteriorly placed lingual cusp with respect to A, and talon basin occupying the posterior part of the tooth.

But the taxa differ from each other in the following features. Cusp E of Woutersia is stouter and more labially displaced than in VPL/JU/KM/12. Likewise, in Woutersia

122 parastylar cusp is absent and labial cingulum unlike in VPL/JU/KM/12 is confined to the anterior and posterior corners ofthe tooth. Furthermore, the crown in Woutersia is stouter and regularly symmetrical with unequal but twinned labial cusps, a crest connecting cusp A with the lingual cusp X as in docodonts, and a wide roughly triangular basin on the anterior face of the crown lingual to A. These characters are not in favour of any taxonomic relationship betweenVPL/JU/KM/12 and Woutersia. An upper premolar from the Upper Triassic (Lower Rhaetian) Saint-Nicolas-de-

Port locality, France has been described under a new taxon Delsatia rhupotopi (Sigogneau-Russel and Godifroit, 1997), with close affinities to Middle Jurassic docodont genus Borealestes (Waldman and Savage, 1972; Freeman, 1979). These authors were of the opinion that the lower dentition of D. rhupotopi recalls the lower dental morphology

of Woutersia mirabilis, and is closely allied to the symmetrodonts (Sigogneau-Russel and Hahn, 1995), while the upper teeth of Woutersia with docodont affinity may actually belong to Delsatia. VPL/JU/KM/12 can be distinguished from the upper premolar of Delsatia, which possesses a transversely narrow crown, a distinct medially interrupted labial cingulum and no lingual extension of the crown. These two taxa exhibit similarity

inthe presence of cusp E and a detached cuspule E'. Shuotherium shilongi, a pseudotribosphenic upper molar described from the Upper Jurassic (Oxfordian-Kimmeridgian) Upper Shaximiao Formation, Sichaun, China, (Wang et al, 1998) show some resemblances in overall morphology with

VPL/JU/KM/12. In both S. shilongi and VPL/JU/KM/12, the teeth are relatively small, cusp A larger and higher than cusp C, cusp E reduced to small cuspule at the labial margin of the tooth, absence of the metastylar cusp, presence of a small cuspule E', and

123 rounded lingual faces of the lingual cusp. But the metacrista is not very marked and cusp C lies at the posterolabial corner of the tooth in VPL/JU/KM/12. These two taxa can be further distinguished by a number ofmorphological characters. In S. shilongi the crown is equilateral triangle, whereas in VPL/JU/KM/12, it is an asymmetrical triangle. The distinct double pinching of crown lingual to labial cusps of VPL/JU/KM/12 is absent in S. shilongii and the talon basin is equally distributed on both anterior and posterior faces of the crown. The cusp Cof S. shilongi is only slightly smaller than cusp A, more closely placed with their long axes parallel to each other, whereas in VPL/JU/KM/12, these two are broadly separated and their long axes make an open angle with each other and the tip ofthe cusp C is directed posteroventrally. In VPL/JU/KM/12, the lingual cusp is larger than cusp C and anteroposteriorly wide, whereas it is smaller than pseudometacone in S. shilongi. Moreover, in VPL/JU/KM/12, the lingual region ofthe tooth is pushed towards the posterior end.

Sigogneou-Russel (1998) documented an upper molar of a second species of Shoutherium, S. kermacki, from the Bathonian Kirlington Quarry of Oxfordshire, England. Like VPL/JU/KM/12, £ kermacki possesses a better developed narrow cingulum, labially placed labial cusps, a small pseudo metacone, nearly half the height of paracone and oriented slightly at an angle to the paracone, with diverging tips, parastyle as modest anterior extension, and post-protocrista extending from the lingual cusp to the posterolingual base of the metacone. But there are some major differences between the crown morphology of these taxa. S. kermacki differs from VPL/JU/KM/12 in possessing symmetrical crown, concave labial face of the labial cusps, more lingually placed labial cusps, which occupy the major part of the crown, presence of small metastyle at the end

124 of postmetacrista, presence of faint bulge on the postmetacrista possibly representing cuspule C, a very small and much lower, labiolingually short lingual cusp smaller than pseudo metacone not projecting posteriorly, small trigon basin and stepped protocrista. From the above discussion, it is apparent that VPL/JU/KM/12 is closer to Haldanodon among all the known docodonts. The tooth profile with its doubly indented asymmetrical crown, anteroposteriorly wide lingual cusp, lingual portion of the tooth pushed towards the posterior end of the tooth, more labially placed labial cusps, narrow ectocingulum, small cusp Econnected to cusp Aby a crest and asmall cuspule E' joined to the E, perfectly agrees with the upper molar morphology in general and premolar morphlogy in particular, of//, exspectatus (Krusat, 1980; fig. 20 A-E). The absence of a distinct crest connecting cusp Awith lingual cusp Xand additional lingual cusp Fare the * characters which might nullify the inclusion ofVPL/JU/KM/12 in Family Docodontidae. M5 of the Haldanodon also lacks cusp Y (Krusat, 1980), but in contrast to VPL/JU/KM/12, M5 of Haldanodon also lacks cusp Cand its labial part is compact and smaller than the lingual part. P3 of Docodon, on the other hand, has already developed an accessory cusp in anticipation to cusp Yof the molar, whereas Haldanodon has an individualised posterolabial cusp C as in VPL/JU/KM/12 along with accessory lingual cusp Y. Since the development of the accessory lingual cusp Yposterior to Xhas already taken place in P3 of Haldanodon and Docodon, as in the upper molars, its absence in the VPL/JU/KM/12 can be attributed to the chipping of enamel in this area and the rolled nature ofthe tooth. The differences in the crown morphology ofVPL/JU/KM/12 and all known genera ofFamily Docodontidae are sufficient for erecting a new genus.

125 Genus Gondtherium gen. nov. A (PI. 14, Fig. f-h) Gondtherium dattai sp. nov.

Holotype: Right lower molar, (VPL/JU/KM/14).

Horizon and locality: Clays and mudstones intercalated with the limestone bands ofthe Kota Formation exposed near the Paikasigudem village, Adilabad district, A. P. Generic Diagnosis: The small size of the present molar differentiates it from all the known taxa ofFamily Docodontidae. It differs from Peraiocynodon and Haldanodon in the lack of distinct crest connecting anterolingual cusp with cusp b, incipient development of the posterior basin, and flat anterior crown; differs from Docodon and Simpsonodon in possessing an incipient anterolingual cusp, flat anterior crown and incipient basin posteriorly. The absence of ridges and furrows on the enamel fur'her differentiate it from Docodon, Peraiocynodon and Simpsonodon; and the absence of cingulum between cusp g and d, presence ofincipient anterolingual cusp, cuspule e, ;;nd flat anterior crown differentiates it from Borealestes. The presence of incipient anterolingual cusp, absence of transverse crest at the right angle to a, and presence of incipient posterior basin differentiate it from Delsatia.

Specific Diagnosis: Same as for the genus Description: The present specimen is a fragmentary right lower molar (maximum lengt'i - 0.79mm, maximum width =0.509mm). The anterior and labial face and tip of cusp a is broken, but the preserved part of this cusp is nearly equal in height to that of posterolingual cusp g. From the broken tip of cusp a and the labial base, it appears thai the cusp a is the highest cusp of the molar. Cusp a is labiolingually elongated and

126 occupies the middle portion ofthe labial margin. Cusp g is placed on the lingual margin ofthe crown slightly posterior to the base ofthe cusp a, and is the second highest cusp of the crown. A sharp crest starts from the lingual tip of cusp a and terminates at its lingual

base. A similar crest descends from the labial tip of cusp g and terminates at its labial base, thus leaving a notch between these two crests. The lingual face of cusp g is rounded. On the posterior side, cusp g is connected to a relatively very small * posterolabially placed cusp d by a crest. An obscure crest joins cusp d with a small posterolingual cuspule/. The tip ofcusp d is directed labiodorsally. Afaint crest extends

from the mid-height of anterolabial face of a and terminates before reaching the crest

linking cusp g with d. The lingual cingulum starts from the anterior base of accessory cuspule /, and X encircles cusp g and gently climbs up posteriorly from the posterior base of cusp g and ends in a small anterolingual cingular cuspule hwhich is in the form ofcingular swelling. Cuspule e, which is slightly larger than h, occurs as a cingular cusp slightly anterolabial to the cuspule h. The crown is broken labial to the cuspule e in the supposed position of cusp balong with the part bearing the labial part ofcusp a. Due to the incomplete nature ofthe tooth, the shape and size ofthe cusp b and its relation with cusp a is not known. The anterior base of cusp a is more anterior than that of cusp g. Cusp a has a flat and broad face posteriorly. Cusp g is hollowed between its posterolabial crest to cusp d and

the labial crest to cusp a. The present specimen seems to bear two roots, one supporting the anterior half

and the other supporting the posterior half.

127 Remarks: VPL/JU/KM/14 exhibits several characters such as the arrangement of cusps ^k in two rows, high labial cusp a, cusp g posterolingual to cusp a and these two cusps connected by a transverse crest, hollowed cusp g, crest linking cusp g with cusp d and cusp of with cuspule/, and the mid-posterolabial face of cusp awith afeeble crest, and the presence of anterolingual cuspule h, which support its inclusion in the Family

Docodontidae.

The crown morphology ofVPL/JU/KM/14 is similar to a great extent to that of Haldandon exspectatus lower molar (Krusat, 1980). In both VPL/JU/KM/14 and Haldanodon, the posterolingual cusp g is connected to cusp i by a straight anterolingually and posterolabially oriented crest, and the latter cusp is joined to posterolingual cuspule/by an indistinct crest. However, these two crests are very well developed in Haldanodon and enclose a deep talon basin. Contrary to it, the talon basin in VPL/JU/KM/14 is shallow and incipient. Moreover, in Haldanodon, the crest from cusp a to the middle ofthe crest joining g with d is well developed and a small bud is present at their junction. In Haldanodon, the cusp a is broadly hollowed on its posterior face. In VPL/JU/KM/14, no such fluting is present. Likewise, in Haldanodon, cusp g is hollowed on its posterior face in contrast to the labial face in VPL/JU/KM/14. In Haldanodon, the cusp g, hand/occur as cingular cusps, whereas, in VPL/JU/KM/14, cusp g is encircled by the lingual cingulum. Although the anterolingual cusp h and e are present in VPL/JU/KM/14, a crest linking cusp hwith cusp band bifurcating the anterior crown into two lingually sloping shelves, a feature characteristic of Haldanodon, Simpsonodon and Docodon is not seen. It is difficult to comment on the presence ofthe crest connecting cusp bwith e, as the anterolabial face ofthe crown is not preserved. In

128 marked contrast to the deep anterior basin of Haldanodon, Simpsonodon and Docodon,

anterior basin in VPL/JU/KM/14 is nearly flat and support small cuspules h and e on it.

On the whole, the anterior part of the crown is more complexly developed and the

posterior crests are more accentuated inHaldanodon than inVPL/JU/KM/14.

The lower molar morphology ofDocodon differs from VPL/JU/KM/14 in having

more labiolingually wider crown, larger size, relatively large anterolingual cusps, deeper * anterior and posterior crown basins, anterolingual shelf, complex furrow and ridge pattern on the posterior and anterior faces of the cusp a and the manner inwhich cusp g

and d are connected. However, a notch separates cusp d from cusp a in bothDocodon and

VPL/JU/KM/14. But in VPL/JU/KM/14, the notch is broader than that of Docodon.

Secondly, the notch is developed onthe crest extending from the posterolabial tip of cusp +- a to d in Docodon. No such crest is present in VPL/JU/KM/14. Further, Docodon lacks the crests typical of posterior crown ofHaldanodon and VPL/JU/KM/14, rather have a

different set offurrows and ridges. VPL/JU/KM/14 can be distinguished from Simpsonodon (Kermack et al, 1987) in lacking an anterolingual shelf, large anterolingual cusp, a posterolabial crest from a to

1994). The lower molars of Delsatia rhupotopi posses angulated crests between cusp a and posterolingual cusps, whereas Haldanodon and VPL/JU/KM/14 have the angulated crest between cusp d and posterolingual cusp. But the anterolingual cusp in D. ruphotopi is as large as the posterolingual cusp and is connected to cusp a by an angulated crest. In

129 both Haldanodon and VPL/JU/KM/14, cusp gis bigger than the anterolingual cusp hand is not connected to aby an angulated crest. This angulated crest is not fully developed in Haldanodon. Although the anterolingual cusp is as large as the posterolingual cusp in Simpsonodon, the transverse crests are not at right angle to cusp aas in D. rhupotopi. D. rhupotopi has also retained the anterior indentation characteristics of triconodonts and early symmetrodonts. Since D. rhupotopi shows the features of both docodonts and symmetrodonts (lingual position of the cusp aand anterior indentation), it may represent the primitive stage of docodonty. D. rhupotopi lacks the posterior basin and the enamel crests of Haldanodon, Simpsonodon, Docodon and VPL/JU/KM/14. Thus VPL/JU/KM/14 appears to be more advanced than D. rhupotopi in having an incipiently developed posterior basin, although the enamel crest is not developed on the anterior crown.

Peraiocynodon was considered to be a juvenile of Docodon (Butler, 1939; Patterson, 1956; Kermack et al. 1987). Peraiocynodon and VPL/JU/KM/14 shares some features, such as cusp hoccuring as a tiny swelling of the lingual cingulum anterior to cusp g and anteriorly connected to e by a weak and curved crest, the anterolingual position ofewith respect to cusp b, rounded lingual face ofg, a small cuspule /posterior tog connected tod by a crest and the separation of cusp a from d by a notch at its base. But the presence of ridges and furrows on cusp a, crest connecting cusp b with h, and relatively deep basins anteriorly and posteriorly distinguish Peraiocynodon from VPL/JU/KM/14. In Peraiocynodon the posterior basin slopes from the posterior base of cusp a forming a notch on the crests extending lingually from d and posterolabially from cuspule / located at the base of g. This is absent in VPL/JU/KM/14. Besides,

130 Paraiocynodon also posses an anterior cingular shelf formed by crest joining cusp e with J± cusp b and h.

Borealestes serendipitus (Waldman and Savage, 1972, Middle Bathonian, Isle of

Skye, Scotland) differ from VPL/JU/KM/14 in possesing a cingulum following the crown

border between cusp g and d, in the absence of cusp e and in the presence of a well

defined cusp h and anterior basin between cusp a, h and b. A In comparison to Cyrtlatherium canei (Freeman, 1979), cuspa is not elongated in

VPL/JU/KM/14, rather it is transverse. The lingual cingulum is strongly curved upwards

beneath cusp a in C. canei in contrast to horizontal lingual cingulum in VPL/JU/KM/14.

In VPL/JU/KM/14, cuspg is substantially large in size and only slightly posteriorto cusp

a; a is connected to g by a transverse crest; there is no labial crest joining a to d; the crest X from g to d is oriented posterolabially and anterolingually; a crest extends from d to/ a

well developed lingual cingulum encircles g; no anterolingual crest is present from the

apex of a to h; a small anterolingual cuspule is present. These features distinguish it from

C. canei.

If Delsatia is accepted as an early stage of docodonty, VPL/JU/KM/14 appears to

be more derived stage than the former in having a crested posterior basin. In this respect it closely approaches Haldanodon. On the other hand, it is less derived than Haldanodon, Simpsonodon, Peraiocynodon, Borealestes and Docodon in the development of

anterolingual and anterolabial cusps, crests in anterior crown basin and complex enamel

crests and furrows.

131 Order Triconodonta

Family Incertae Sedis.

Genus Dyskritodon Sigogneau-Russel, 1995 Type species: Dyskritodon amazighi Sigogneau-Russel, 1995 Dyskritodon indicus sp. nov. (PI. 15, Fig. a-j)

Holotype: VPL/JU/KM/13, Lower left molar.

Referred Material: A fragmentary lower right molar, RUBK798013.

Horizon and locality: Clay and mudstones intercalated with the limestone bands of the Kota Formation exposed near the Paikasigudem village, Adilabad district, A. P. Emended Generic Diagnosis: Lower molar with high and narrow crown, cusps a, c, d decreasing regularly in height posteriorly. The tips of cusp a and c slightly recurved posteriorly. The anterior crest ofa and c slightly shorter than the posterior one and cusps a and c with angulated lingual and labial bases, cusp b reduced to very small cingular cusp and cusp d transverse in position. Specific Diagnosis: Dyskritodon indicus sp. nov. can be differentiated from the type species Dyskritodon amazighi, Sigogneau-Russel, 1995, by its smaller size; possession of cusp bin line with a and c, cusp bonly slightly smaller than d, almost equally developed cusps e and f enclosing a well defined anterior notch, a well developed but faintly crenulated lingual cingulum and labial thickening at the base of the tooth.

Description: The tooth is well preserved except for the broken tips of the cusp a and c.

The crown is transversely narrow and high with three principal cusps in line. The cusps apparently decrease in height posteriorly. The cusp formula for this tooth is a>c>d>b.

The largest cusp of the crown is anteriorly placed cusp a which is connected to small

132 cusp b at its anterior base. Although the tips of cusp a and c are broken, it appears that

they had posterior crests slightly longer than the anterior ones. Cusp d has flat anterior

face and a convex posterior face, smaller than cusp c, and is placed perpendicular to the

line of cusp a and c. The posterior face is separated from the anterior one by a crest

ascending on to this cusp from the lingual cingulum. The cusp a and c have angulated

labial faces, clearly seen in the occlusal view. Cusp a, c and d are separated from each -\ other by V-shaped notches. Cusps a and b are closely appressed and separated from each

other probably very close to the tip of b. A vertical accessory cuspule is present at the

anterolingual base of cusp b. The slightly crenulated cingulum is equally prominent all

along the lingual margin and terminate posteriorly as a vertical crest on cusp d. In

between the lingual cingulum and the main cusps a narrow shelf is present. The labial

faces of the cusps a and c are strongly convex and the labial face of a is more convex

than that of the cusp c. These cusps are swollen at their labial base, but the labial

cingulum is absent. There is a small vertical, columnar cuspule/at the labial base of cusp

b. Cuspule e and/ are nearly equal in size. In labial view, a narrow sulcus separates

cuspule / from cusp a. Anteriorly, cuspule e and / enclose a well-developed sulcus.

Labially, cusps a, c and d are separated from each other by a broad vertical sulci . The

labial face of cusp d is separated from the posterior face by a ridge. This ridge bears a

very small cuspule at its mid-height. The crown overhangs therooton all sides.

A narrow wear facet is present at the posterolabial border of the cusps a and c.

Another sub-spherical wear facet is present on the posterolabial base of cusp a and might

extend on to the median labial face ofthe same cusp.

133 The tooth bears two well preserved roots. The anterior root is cylindrical in X outline and short anteroposteriorly, and sub-spherical in cross section. The posterior root originates at the posterior base of the cusp a and is relatively broader anteroposteriorly,

, labiolingually flattened and possess a rounded posterior face. The roots taper ventrally.

RUBK/98013 is a fragmentary right lower molar. The anterior face of the crown

and the tips of the cusp a and c are broken. The preserved part of the crown bears a

complete cusp d, cusp c with broken tip and posterior portion of cusp a. The. V-shaped

notch separating cusp c and d is clearly visible, but the notch separating the a and c is not

seen. Labially, on the preserved part of the crown, labial portion of cusp c is better

preserved than cusp a. The labial portion of cusp a is broken. Lingually, the enamel is

spalled off at two places, though the crenulated lingual cingulum is fairly well preserved.

The labial portion of the crown is not well preserved. The posterior root originates at the

posterior base ofcusp a, is anterioposteriorly long and ventrally tapering.

Remarks: VPL/JU/KM/13 shows a typical lower molar morphology of triconodonts,

with the linear arrangement of cusps b, a, c, d in an anteroposterior direction, well

developed lingual cingulum and an anterior sulcus for recieving the cusp d of the

preceding molar. At present the Order Triconodonta includes four families,

Morganucodontidae, Amphilestidae, Austrotriconodontidae and Triconodontidae along

with four unnamed families represented by Jeholodens jenkinsi (Qiang et al. 1999)

Tendagurodon janenschi (Heinrich, 1998) and Dyskritodon amazighi and Icthyoconodon

jaworoskorum (Sigogneau-Russel, 1995). Morganocodontids differ from VPL/JU/KM/13

in following features: a highly reduced cusp b (lingual cingular cusp); cusp a occupies a

major part ofthe crown; presence ofa prominent lingual cingular cusp g (kuhneocone).

134 Further unlike in VPL/JU/KM/13, the main cusp a in amphilestines, x gobiconodontines, and austrotriconodontids is much larger than the adjacent cusps band c which are nearly equal in size. Awell developed faintly crenulated lingual cingulum in

VPL/JU/KM/13 further differentiates it from the centrally arched lingual cingulum of some amphilestines. Moreover, unlike in VPL/JU/KM/13, the amphilestine lower molars

have a well developed labial cingulum at the anterior and posterior ends ofthe crown.

Triconodontids differ from VPL/JU/KM/13 in possessing sub-equal cusps b, a,

and c with slight posterior inclination.

VPL/JU/KM/13 differs from Jeholodens in having a well developed, faintly

crenulated lingual cingulum which is discontinuous in the latter. Tendagurodon does not

even have the trace of the lingual cingulum. The crown inIcthyoconodon is high, narrow,

and trenchant blade-like with sub-equal posteriorly inclined cusps b, a, and c and a very

faint cingulum, unlike VPL/JU/KM/13.

VPL/JU/KM/13 also differs from morganucodontids, amphilestids, triconodontids

and Jeholodens in the molar interlocking mechanism. The broad posterior margin of the

lower molar crown of the morganucodontids fits into the shallow embayment between b and c. The cingular cuspules e and /are absent in Jeholodens. The crescent shaped cusp of the preceding molar fits into the concave anteromedial margin of the cusp b ofthe succeeding molar, thus it lacks the molar interlocking mechanism of the morganucodontids and also VPL/JU/KM/13. Cuspules e and / though present in + amphilestids, are mostly prominent in the posterior molars and hence interlocking is not

evident in the anterior molars. In a fragmentary genus Triconolestes, the interlocking

mechanism is absent. A triconodontid of uncertain familial status, Dinnetherium (Lr.

135 Jurassic, Kayenta Formation, Arizona, USA, Jenkins et al, 1983) shows interlocking by means of anterior cuspules e and / and overhanging of the crown over the roots as in VPL/JU/KM/13. Asimilar interlocking system also characterises some gobiconodontids. The interlocking mechanism in all Jurassic triconodontids is restricted to juxtaposing of accessory cuspules or cingular cuspules of adjacent teeth, whereas, tight interlocking between adjacent teeth through a tongue and groove mechanism that extends well down to the molar root between e and / is characteristic of Cretaceous triconodontids. In Tendagurodon, there is no/cuspule and no anterior indentation for the reception of cusp dof the preceding tooth. Similarly, Icthyoconodon also lacks the anterior interlocking

mechanism ofthe lower molars.

Chow and Rich (1984) documented Klamelia zhaopengi from the Jurassic Shishagou Formation of Zunggar Basin, China. VPL/JU/KM/13, shares a number of feature with Klamelia such as, possesion of four cusp a, b, c, and don the crown, cusp a and c are the main cusps of the crown and cusp a bigger of the two, having a lingual cingulum and lack ofthe cuspule g. But, VPL/JU/KM/13 differs from Klamelia in having cusp dlarger than b, whereas the reverse is true for Klamelia. Awell developed cingulum is present in Klamelia on the lingual side of the crown. The labial cingulum is well developed on the anteroir and posterior ends of the crown only. In VPL/JU/KM/13, the lingual cingulum is crenulated and the labial cingulum is compeletely missing. An unusual mammalian species, Dyskritodon amazighi (Sigogneau-Russel, 1995) was reported from the lower Cretaceous Anoual Syncline littoral sediments of Morocco.

After discussing at length the molar morphology in different families of Triconodonta (Morganucodontidae, amphilestidae, Austrotriconodontidae, Triconodontidae)

136 Sigogneau-Russel (1995) arrived at the conclusion that D. amazighi possibly represents a

new family ofTriconodonta.

VPL/JU/KM/13 shares a large number of characters with Dyskritodon amazighi.

In both the specimens, the crown is high, labiolingually narrow with cusps a, c, and d

decreasing in height posteriorly, cusp a and c are the more dominant cusps than others and the posterior crest is slightly longer than the anterior crest. The cusp d is A' perpendicularly placed with respect to the a-c line with flat anterior face and convex posterior face, and a ridge separating short labial face from the posterior face. Cusps a and c have angulated lingual and labial faces and swollen labial bases separated by broad sulci. In both, cuspules e and / are present anterior to cusp b. Furthermore, both the specimens have anteroposteriorly short anterior root, subcircular in cross section and an A anteroposteriorly long posterior root, which is labiolingually flattened and starts below the cusp a. The crown overhangs the roots on all sides in both the specimen. The above mentioned similarities between Dyskritodon amazighi and VPL/JU/KM/13 favour the

inclusion oflatter in the genus Dyskritodon. However, at specific level the two specimens show some differences.

VPL/JU/KM/13 is smaller in sizethanD. amazighi. The cusp b in VPL/JU/KM/13 is not displaced lingually as in D. amazighi. In VPL/JU/KM/13, cuspules e and/are equally developed and occur at the anterolingual and anterolabial bases ofcusp band enclose a well developed vertical sulcus between them, whereas in D. amazighi, cuspule e occurs only in the form ofa small bump at the anterior base ofcusp band the anterior sulcus is also very shallow. In VPL/JU/KM/13, cuspule / occurs at the anterolabial base ofa and

137 extends obliquely on the anterior part of a in the latter, while it is more vertical in the

former.

In VPL/JU/KM/13, the lingual cingulum is more developed than in D. amazighi, hence a narrow and better developed shelf occurs between the main cusps and the cingulum. In VPL/JU/KM/13, the posterior root is not as long anteroposteriorly as in D. amazighi. However, this difference can be attributed to the positional variation of teeth on the mandible. The molar ofD. amazighi has been considered as the ultimate molar,

whereas VPL/JU/KM/13 might represent the penultimate molar. The above citied differences between D. amazighi and VPL/JU/KM/13, necessitates the placement of the latter specimen in a new species.

Family: Incertae sedis

Genus: Paikasigudodon gen. nov.

Paikasigudodon yadagirii nov comb.

{Kotatherium yadagirii, Prasad and Manhas, 1997)

(PI. 16, Fig.a-h)

Holotype: Right upper molar, (VPL/JU/KMIO).

Horizon and locality: Clays and mudstones intercalated with the limestone bands of the

Kota Formation exposed near the Paikasigudem village, Adilabad district, A. P.

Generic Diagnosis: Upper molar crown bearing a high and symmetrical central cusp with a flat labial face and convex lingual face. Cusp B is higher than C. A large anterolabial cusp is present, which is connected to B by a sharp crest. Presence of small anterior and posterior lingual cingular cuspules. Lingual cingulum rudimentary between

138 A and B. Differs from all known triconodont genera in the transverse arrangement of cusp

B, presence of an anterolabial cusp and anterolingual cingular cusp.

Specific Diagnosis: Same as for genus. Description: The tooth is bean-shaped, double rooted, excellently preserved right upper

molar. In occlusal view, the principal and accessory cusps form an obtuse angled triangle.

Cusp A is the largest and highest cusp with vertically oriented long axis and a nearly flat

A or slightly convex labial face. Cusp A is strongly convex on the lingual side and the

lingual bases of cusps B and C are also convex. The next highest cusp on the crown, cusp B is separated from cusp ,4 at slightly higher level than cusp C by a V-shaped notch. The

anterolingual face of cusp B is convex and is connected to A by a sharp crest, whilst the

labial face is flat, slightly obliquely oriented relative to labial face of A. A sharp

A transverse crest connects B with relatively large anterolabial cusp E which is less than

half the size of cusp B, with a labially projecting tip. The posterolingual face of anterolabial cusp is flat and is oriented at right angle to the labial face of cusp B and the

anterior face is rounded. Avery small cuspule also occur at the anterolingual base of cusp B. The two small anterior cusps (anterolabial and anterolingual cusps) together are placed transversely to the long axis ofthe tooth. Cusp C is slightly smaller than cusp B, but is larger than the anterolabial cusp Eand is labial to A-B line in occlusal view. Anterolabial and anterolingual faces of this cusp are moderately convex and are separated by a crest and the posterior face is almost rounded. At the anterolabial base of cusp C, a small cingular cusp is present and another slightly large cuspule is present on the anterolingual base of this cusp. Labial cingulum is weakly developed and is beaded with tiny cuspules

connecting cusp C with the anterolabial cusp E. The cingular cusps are tiny, more or less

139 of same size and a narrow shelf is present anteriorly. In occlusal view, the labial

cingulum describes a slight ectoflexus because of labial projection of cusp C and the

anterolabial cusp. Distinct lingual cingulum is absent, but the lingual margin between A

and B is thickened and whole of the lingual base of the crown is swollen, and small

cingular cusps are also present anterolingually and posterolingually. In the anterior view,

the crownis transverse and only the posterior crests of B and A are in line. The crown is

supported by two cylinderical roots.

Wear facets are weakly developed in the present tooth. A weakly developed wear

facet extends lingually from the posterior tip of cusp A to its base and continues aross the

notch between A and C to just below the tip of C. Another very faint wear facet can be

seen on the anterolingual face of cusp A extending from the notch between B and A. This

wear facet is broad at the base of A and gradually narrows towards its tip to disappear before reaching the tip. The posterolingual face ofB appears to be fresh without any wear

facets.

Remarks: VPL/JU/KM/10 was earlier assigned to a new species of Kotatherium, K yadagiri, Family Tinodontidae, Order Symmetrodonta, by Prasad and Manhas (1997),

based on the literature available to them at that time. Comparison of this specimen with the casts of the Mesozoic mammals helped to redefine the taxonomic status of

VPL/JU/KM/10. The comparison leads to the conclusion that VPL/JU/KM/10 is not a symmetrodont but a triconodont. The general construction of the principal and accessory cusps of the VPL/JU/KM/10 differentiates it from the upper molars of symmetrodonts such as, Kuehneotherium, Eurylambda, Woutersia, and Kotatherium. The principal cusp in VPL/JU/KM/10 is stocky, symmetrical, occupying the major part of the tooth and the

140 accessory cusps are well individualised. On the contrary, the cusps in Eurylambda are

slender and closely appresed to a narrow principal cusp and are separated from the latter

very close to their tips. Similarly, in Kuehneotherium, Woutersia and Kotatherium, the

cusps are not individualised.

VPL/JU/KM/10 can be differentiated from Kotatherium haldani (Datta, 1981) by

its bean-shaped crown, vertically oriented symmetrical cusp A with no labial tilt and the

pronounced lingual swelling which imparts a lingual tilt, absence of an anterolingual shelf, prominent cusp B slightly larger than C, presence of posterolingual cuspule and a large posterolingual accessory cusp. Moreover, the transverse arrangement of the accessory cusps at the anterior and posterior ends of the crown and a large anterolabial

cusp are not known in any of the symmetrodont genera and as such negates the inclusion

of VPL/JU/KM/10 in Kotatherium. In Kuehneotherium, Eurylambda and Woutersia, the

cusps are symmetrical, the crests connecting the apices of the three main cusps are anterioposteriorly oriented. In these taxa the two lateral cusps B and Care more or less in line with cusp A. The lateral cusps in Kuehneotherium, Eurylambda and Woutersia are

not individualised from the main cusp. In VPL/JU/KM/10, the cusps are asymmetrical

'' and well individualised. Further, anteriolabial cusp isjoinedwith cusp B by a sharp crest. Although the lingual face of the symmetrodonts is convex, it lacks the strongly swollen lingual base and the antero- and postero-lingual cuspules ofVPL/JU/KM/10. Among the various groups of early mammals the crown morphology of

VPL/JU/KM/10 is diagnostic of triconodonts. Within Triconodonta, the family

Gobiconodontidae is characterised by molars with central cusp taller and larger than the

adjacent accessory cusps which are nearly equal in size, as in the present tooth. A

141 distinctive, strongly symmetrical outline of the principal cusp is characteristic of amphilestid molars. The subfamily Amphilestinae is known by lower molars referred to

Amphilestes, Phascolotherium (Middle Jurassic of Europe, Owen, 1871), Phascolodon,

Aploconodon and Triconolestes (Upper Jurassic of USA, Simpson. 1925; 1926). As these genera are only known by the lower molars, no comparison is possible with

VPL/JU/KM/10.

The upper molar of Family Gobiconodontinae {Gobiconodon borissiaki, G. hoburensis, G. ostromi) are characterised by incipient triangular arrangement ofthe cusps and the degree of triangular arrangement increases posteriorly (Kielan-Joworowska and Dashzeveg, 1998) reaching an angle of 145°-158° on M3 and M4. The shape of upper molars too, changes from oval to subrectangular anteriorly to rectangular crown posteriorly. As in VPL/JU/KM/10, they show labial indentation but lingual indentation is also present on the posterior teeth. In both VPL/JU/KM/10 and Gobiconodon, the labial cingulum is beaded but the lingual cingulum is strongly developed and is wider at anterior and posterior ends than in the middle in the latter. In VPL/JU/KM/10, the lingual cingulum is incipiently developed on the anterior portion of the crown and bears a small cusp anteriorly as well as posteriorly. However, VPL/JU/KM/10 strongly differs from

Gobiconodon in having cusp B, C as well as anterior and posterior accessory cuspule arranged transversely to the long axis of tooth. Presence of a crest connecting cusp B with anterolabial accessory cusp, absence of distinct lingual cingulum, lingual indentation of crown and interlocking mechanism. The transverse arrangement of cusps at the anterior and posterior ends of the crown is unique to VPL/JU/KM/10. Furthermore, cusp A of

142 Gobiconodon, though largest on the crown, is only slightly higher than B and C in

X contrast to the high central cusp of VPL/JU/KM/10.

Another triconodont Jeholodens jenkinsi (Upper Jurassic-Lower Cretaceous of

Liaoning, China; Qiang et al. 1999) is known which shows a high central cusp and small

lateral cusps. The upper molars lack the interlocking mechanism as in VPL/JU/KM/10.

But, in Jeholodens the cusps are arranged in straight line. The cingulum on both the lingual and labial sides of M1 is absent, but a faint or weak cingulum is present on the

labial side of M2 and M3, no cingular cuspules are seen on the labial as well as lingual

side of cuspB on the exposed molar of Jeholodens. VPL/JU/KM/10 is closest in crown morphology to the M1 of Megazostrodon

rudnerae known from the Late Triassic of Lesotho, Southern Africa (Crompton, 1974).

In both VPL/JU/KM/10 andM. rudnerae, the crown is bean-shaped, dominated by main

symmetrical cusp with median labial indentation, anterior border more broader than the posterior border, a large cusp E is present labial to B and the three main cusp form an obtuse angled triangle in occlusal view. In M. rudnerae, cusp Abecomes less dominant in M2 and onwards. By this analogy, VPL/JU/KM/10 can be considered as M1. But unlike the present specimen, the main cusp A in M. rudnerae, is elongated and extends to the labial margin in the middle of the crown. Besides, in VPL/JU/KM/10, the height of the main cusp is greater than the width, whereas in M. rudnerae it is nearly equal. In M. rudnerae, cusp B is smaller than cusp C, whereas it is slightly larger than C in

VPL/JU/KM/10. In this respect, VPL/JU/KM/10 is similar to Austrotriconodon

(Bonaparte, 1992), but in the upper molars of the Austrotriconodon, cusp B is the largest of all cusps and the crown is quite distinct from VPL/JU/KM/10. Unlike M. rudnerae, the

143 labial cingulum in the present molar is interrupted in the middle and does not bear lingual

cingulum. The difference in the configuration and arrangement of cusps on the crown between the two taxa, particularly in the transverse arrangement of the cusps posteriorly

is also seen in all triconodontids. In view of the morphological distinctiveness of the

present specimen, it isplaced under a new genus ofuncertain famlial affinities.

Family: ?Morganocodontidae

Genus: Indotherium Yadagiri, 1984

Indotherium pranhitai Yadagiri, 1984

(PI. 17, Fig. a-d)

Referred material: Right upper molar (VPL/JU/KM/11).

Horizon and locality: Clays and mudstones intercalated with the limestone bands of the

Kota Formation exposed near the Paikasigudem village, Adilabad district, A. P.

Emended Generic Diagnosis: Crown oval in occlusal view, cusp A and C nearly equal in size and in line, cusp B very small and occur as a cingular cusp. A deep groove separates cusp A from cusp C. labial faces of cusp A and C steeply sloping labially. A smooth crest extends from the anterior tip of cusp A tothe lingual cingular cuspule

144 dividing the anterolingual shelf into two parts. It differs from Morganucodon in having labiolingually compressed Aand Cand a broad and deep notch separating the two halves; in the absence ofa deep notch between A and B and the presence ofa horizontal lingual cingular border anteriorly. Differs from Megazostrodon and Erythrotherium in having equally developed cusps A and C, in possessing the main cusps arranged in more or less

straight line rather than ina triangle and in lacking a large cingular cusp. Description: The tooth is an eroded right upper molar and the enamel on the labial surface of the crown is completely spalled off. The crests joining A with B and C are completely abraded. The tooth is roughly oval in outline (in occlusal view) with a slight

indentation on both labial and lingual faces opposite the posterior limit of A. There are two major and one minor cusp on the crown. Cusp A is the principal cusp, located

X anterior tothe mid-point ofthe tooth. Cusp C occurs posterior to it and is about the same size. Cusp A is nearly vertical whereas the cusp C is reclined and the two are separated from each other by broad and deep groove which runs about the halfway to the gum margin. The anterior cusp Bis small, vestigial and is slightly offset from the line ofthe^4 and C. The cusp Barises from the labial cingulum and occurs at the anterolabial corner of the crown. The labial faces of cusps A and C are flat and steeply labially sloping. The labial cingulum arises from the mid-height of cusp C, slopes down anteriorly and joins the cuspule B at a lower level. Opposite cusp A, this cingulum appears narrow but is relatively wide and swollen opposite the groove separating cusp A from C. There is no evidence for cingular cuspules possibly due to the highly abraded nature ofthe cingulum. Awide shelf is present anterior to A on both labial and lingual sides. Cusp A is encircled

anteriorly by the labial cingulum which continues lingually and posteriorly as a narrow

145 worn ridge to the anterior base of C. At the anterolabial base ofA, the lingual cingulum

bears cingular cuspule. The cingular cuspules are connected to cusp A by a crest which

extends from the anterior tip ofA and turns lingually at its anterior base. The posterior

labial cingular bulge suggests the presence ofat least two cingular cuspules posteriorly.

The tooth is double-rooted. The posterior root appears to be transversly oriented

to the long axis of the crown and is dilated at the distal end in the labial view. The

anterior root is not well preserved.

Wear facets are observed on the lingual face of the crown. A broad wear facet

extends from the posterolingual base of.4 and narrows opposite the middle part ofA. In

addition to this, another broad wear facet present from the mid-height from anterolingual

face of A and is limited anteriorly by the lingual cingular cuspule. Another elongated,

narrow wear facet is observed between the anterolingual margin of the crown and the

crest from the tip ofA to lingual cingular cuspules.

Remarks: A mammalian molar was described by Yadagiri (1984, GSI Type No.

SR/PAL/11) from the Paikasigudem section of Kota Formation. He considered this

specimen to be a lower molar and made it a type of Indotherium pranhitai gen. et sp.

nov., family Incertae sedis of order Symmetrodonta. Subsequently, Prasad and Manhas

(1997) described a new molar VPL/JU/KM/11 from the same section and referred it to

Indotherium pranhitai. They transferred /. pranhitai to the order Triconodonta from order

Symmetrodonta because its molar morphology which shows the three main cusps more or less in a straight line. However, like Yadagiri (1984), they also mistook it for a lower molar.

146 VPL/JU/KM/11 is assigned to an upper molar because of the presence of both labial and lingual cingula and by comparison with the maxillary teeth of morganucodontids. Austrotriconodontids and amphilestids differ from VPL/JU/KM/11 in the cusp formula and arrangement of cusps on the crown. Any relationship with the family Triconodontidae can also be ruled out for VPL/JU/KM/11, because in all known taxa ofthis family, cusps B, A, and C of the upper molar are subequal in size. It is only in the family Morganucodontidae that the cusp B is very reduced and occurs anterior to cusp

Aor slightly labial to the A-C line but cusps A and Care equal or nearly equal in size.

VPL/JU/KM/11 shares with morganocodontids the presence of anterior root, which is circular or oval in cross-section with an anteroposterior long axis and a transversely elongated posterior root, projection of crown over the posterior root, cusp B occuring as a small cusp more or less in line with A-C line, anterolingual cingular cuspule slightly smaller than cusp B, labial cingulum widening posteriorly and absence of posterior cusp D.

Among all the morganucodontid teeth known so far, the morphology of the present specimen is closest to that of BMNH No. M26014 (recovered from the Middle

Jurassic, Kirlington quarry), a maxillary fragment bearing possibly the penultimate and ultimate molars. In both VPL/JU/KM/11 and M26014, the crowns are oval in outline, cusp A and C nearly equal in size, (cusp A slightly larger). As in the Indian specimens

(VPL/JU/KM/11 and SR/PAL/11) the cusp C is reclined. Also in both VPL/JU/KM/11 and M26014, cusps A and C have flat labial faces, cusp B very small and occur in line with/4 and C or slightly labial to this line. The labial cingulum in M26014 is broad, but it becomes narrow at the base ofA, and bears a cuspule opposite the groove between A and

147 C and another behind this. The labial cingulum in VPL/JU/KM/11 occurs opposite the

groove between v4 and C, and though, highly abraded, is swollen. In both VPL/JU/KM/11

and M26014, the labial cingulum climbs on to the distal margin of C and a broad shelf is

present anteriorly between labial cingulum and the main cusps. In both the specimens the

labial cingulum is at the lower levels than the lingual cingulum and latter is narrower.

The last molar of M26014 shows the overhanging of the posterior crown over the root

like a balcony and lacks an anterior sulcus for recieving the cusp 'D' as in

VPL/JU/KM/11.

In M26014, however, the groove between A and C is not as broad as in

VPL/JU/KM/11. Broader groove between^ and C and the anterior crown morphology of

VPL/JU/KMl 1 differentiate it from the members of family Morganucodontidae. But, the groove between cuspA and C shows the same degree of development as in M26014 and

SR/PAL/11. In M26014, a small accessory cuspule occurs posterior to C, both are separated from each other at the tip of former. Also, the cusp B is slightly larger than in

VPL/JU/KM/11. In VPL/JU/KM/11, the cusp C is stubby in appearance and cusp D is absent, which may be a reflection of taphonomic processes. In M26014, the lingual cingulum extends from the anterior base ofA to the anterior base of C in the last molar, but to the mid-base of cusp C in the penultimate molar as in VPL/JU/KM/11. In

VPL/JU/KM/11, the labial faces ofthe cusps are steeply sloping labially, unlike M26014.

In the anterior crown morphology lies the major difference between

VPL/JU/KM/11 and M26014. In M26014, the broad transverse notch separating the cusp

A and B imparts a dorsal slope to lingual cingulum from the anterolingual base ofcusp A.

In VPL/JU/KM/11 this margin is horizontal and bears a small cingular cuspule at the

148 anterolingual base of cusp A. This cingular cuspule is absent in M26014 but a bulge occurs lingual to cusp B.

The configuration and size difference of cusps of VPL/JU/KM/11 is not seen in any other group of triconodonts. These characters along with the anterior crown morphology are sufficient for distinguishing the Indian specimens from Morganucodon or for that matter any member of Morganocodontidae at the generic level. Although the morphologic differences cited above are enough for the erection of a new family for the Indian specimens, it is premature to do so with poorly preserved fossil material in hand.

Tentatively, the Indian specimens are reffered to the family Morganucodontidae.

Triconodonta indet.

(PI. 14, Fig. d-e)

Referred material: Fragmentary left lower molar, (VPL/JU/KM/15,).

Horizon and locality: Clays intercalated with the limestone bands of the Kota Formation exposed nearPaikasigudem village, Adilabad district, A. P. Description: The specimen is a partially preserved left lower molar. The anterior part consisting of the anterior cusp and the anterior root is broken. The main cusp a is only partially preserved. Among the preserved cusps, cusp a is the largest and highest with a flat lingual face. Aposterior crest connects the cusp a tothe small posterior cusp c, which is less than the halfthe height of the cusp a. The cusp a is vertical in the orientation of its long axis, whereas cusp c is slightly reclined posteriorly making an acute angle with the cusp a. A shallow V-shaped notch separates cusp c from cusp a. The lingual face of cusp c is also flat. The posterior cusp occurs as a small cingular cusp and is prolonged anterolingually by lingual cingulum, which bear two incipient cingularcuspules. Anterior

149 to these cingular cuspules, the cingulum becomes reduced and indistinct at the middle of cusp a. The labial face of cusp a is acutely angulated. A slight swelling is present between the cusp a, c and d. The labial face of cusp c is convex but the convexity is less than that of cusp a. The enamel ofthe crown is poorly preserved, which makes it difficult to comment on the nature of wear facet, although there appears an indistinct U-shaped wear facet on the labial face of the cusp c and d. The posterior root is long and supports the entire preserved part of the crown. The root tapers ventrally and is moderately flattened labiolingually, with rounded anterior and posterior faces. A very shallow sulcus extends from the base of the crown, below the junction of cusp a and c, to the mid-length ofthe root.

Remarks: Definite comments on the taxonomic position of this specimen are not possible at present because of its incomplete preservation. However, the presence of a high central cusp with its long axis vertically oriented and an accessory cusp c with its long axis, diverging away from that of cusp a is seen in some amphilestids, gobiconodontids and Jeholodens. If the wear facets observed in VPL/JU/KM/15 are correct, then the occlusion pattern for the present tooth can be considered to be similar to that ofamphilestids and gobiconodontids.

Mammalia indet.

(PI. 17, Fig. e-h.)

-The present collection also includes a large number ofpostcranial remains and a few incisors showing affinities to the class Mammalia. It is not possible to ascertain their taxonomic status. The specimens include phalanges and a heavily worn pectoral girdle.

150 Ostracods

Subclass: Ostracoda

Order: Podocopida

Family: Darwinulidae

Gen\xs:Darwinula Brady and Robertson, 1885

Darwinula cf. D. sarytirmensis Sharapova, 1947

(PI. 18, Fig. a-d)

Referred Material: RUBK/11001 - RUBK/11004.

Horizon and Locality: Clays and mudstones intercalated with limestone bands of Kota

Formation exposed near Paikasigudem, Kadamba and Metpalli Villages and clays underlying the limestone bands of Kota Formation exposed near Manganpalli village,

Adilabad District A. P.

Description: The carapace is elongate-oval in lateral view. The shell is thin and the surface is smooth. The valves are large, reniform, tapering anteriorly. The dorsal margin is evenly rounded, ventral margin is concave and the anterior and posterior margins are evenly rounded. The left valve is larger than the right valve, overlapping it completely.

This overlapping is more pronounced in the ventral and anterior margins and least on the dorsal margin. The maximum height of the carapace is in the posterior third and the greatest length passes slightly below the mid-point. The anterior margin is narrower than the posterior margin. Internal details not known. Remarks: In the present collection there are more than 2000 specimens, which can be attributed to Darwinula sarytirmenensis. The specimens includes juveniles, males and females. They show close resemblance to Darwinula sarytirmenensis Sharapova, 1947,

151 described from the Kota Formation by Govindan (1975) and subsequently by Mishra and

Satsangi (1979).

Darwinula sarytirmenensis is widely distributed in the Middle Jurassic faunas of the Mangishlaka Peninsula on the eastern shore of the Caspian Sea (Sharapova, 1947), China (Hao et al., 1983; Meizhen, 1984; Xu, 1988) and United states of America (Kietzhe and Lucas, 1994; Kayenta Formation Arizona). The most complete range ofthis ostracod is reported in China, where it occurs from upper Middle Jurassic to Upper Jurassic (Meizhen, 1984; Hao et al, 1983). Darwinula sarytirmenensis is most abundant in the Middle Jurassic ofChina. In the Kota Formation also, Darwinula sarytirmenensis

is the most abundant species.

Darwinula sp.

(PI. 18, Fig. e-h)

Referred Material: RUBK/11005 - RUBK/11008

Horizon and Locality: Clays and mudstones intercalated with limestone bands of Kota Formation exposed near Paikasigudem, Kadamba and Metpalli Villages and clays underlying the limestone bands of Kota Formation exposed near Manganpalli village,

Adilabad District A. P.

Description: The carapace is elliptical elongate in lateral view. Right valve is larger than the left valve. The right valve overlaps the left valve on all sides. The overlap is more pronounced onthe posterior side. The surface is devoid of any ornamentation. The valves are large, reniform, tapering anteriorly, with their dorsal margin almost straight.

Remarks: It is not possible to erect a new species for these ostracods for want of comparative material.

152 Trace Fossils

lchnogenus: Planolites Nicholson, 1873

Planolites sp.

(PI. 2, fig. d)

Referred Material: RUBK7 9901-RUBK9902.

Horizon and Locality: Calcareous sandstone overlying the limestone bands exposed

near Paikasigudem village.

Description: Unbranched, unornamented, straight to slightly curved sand infilled tubes

of variable lengths, occasionally crossing each other. The diameter of the burrows varies

from 4mm to 12mm. ± Remarks: The burrows ascribed to the lchnogenus Planolites is thought to be produced

by the worm or 'worm-like' animal (Hantzschel, 1975). Planolites ranges in age from

Precambrian to Recent.

lchnogenus: Monocraterion Torell, 1870

Monocraterion sp.

(PI. 19, fig. c )

Referred material: RUBK/9911 and RUBK/9912

Horizon and Locality: Limestoneband overlying clays exposed near Metpalli village

Description: Funnel-shaped specimens perforated centrally by a straight to slightly

curved plugged tube which consists of closely spaced vertical pipes lying perpendicular

153 to the bedding. The maximum diameter and the depth of the traces is up to 21mm and

27mm respectively. The tubes are abundant but not crowded as in Skolithos.

Remarks: The dwelling burrow probably belongs to gregarious, suspension feeding worm-like- organisms. The funnel shape of the trace is constructed by upward migration of the animal inhabiting the tube as suggested by downward warping of surrounding bedding planes towards the central tube.

-A

154 4s

Pal-f

X-

f-sy

Sphenodontid Taxon B Fig. 4.2

155 Fig. 4.1 Sphenodontid Taxon A (rhynchocephalians)

la. JU/KM/KR/17, left premaxilla, posterior view, bar=800um (Np.r=Nasal process, Mp.r-maxillary process) lb JU/KM/KR/17, left premaxilla, anterior view, bar=800um 2a. JU/KM/KR/24, left maxillary fragment, medial view, bar=920um (J.f= Jugal facet, Ec.f .= facet for ectopterygoid) 2b. JU/KM/KR/24, left maxillary fragment, lateral view, bar=920um (J.pr. = Jugal process) 3a. JU/KM/KR/21, left palatine, dorsal view, bar=550um 3b. JU/KM/KR/21, left palatine, ventral view, bar=550um 3c. JU/KM/KR/21, left palatine, lateral view, bar=550um

4a. JU/KM/KR/1, symphyseal region of left dentary, medial view, bar=895p;m (s. tt. A = hatchling dentition) 4b. JU/KM/KR/1, leftsymphyseal region of leftdentary, lateral view, bar=895um 5a. JU/KM/KR/5, right dentary fragment, medial view, bar=950um (sds. = subdental shelf) 5b. JU/KM/KR/5, right dentary fragment, lateral view, bar=950um, (Mk.f= Mackelian fossa) 6a JU/KM/KR/12, posterior region of left dentary medial view, bar=950um ((Mk.f= Mackelian fossa) 6b. JU/KM/KR/12, posterior region ofdentary, lateral view, bar=950u,m 7a. JU/KM/KR/13, left dentary fragment, medial view, bar=925um (Mk.f= Mackelian fossa) 7b JU/KM/KR/13, left dentary fragment, lateral view, bar=925um (wf = wear facet)

156 Mxf

*s Jt

F'g- 4.1 Sphenodontid Taxon A

157 & / V*;:?. roo^ Fig. 4.2 Sphenodontid Taxon B (rhynchocephalians)

la. JU/KM/KR/45, right premaxilla, anterior view, bar=800um (Mx. f. = Maxillary facet) lb. JU/KM/KR/45, right premaxilla, posterior view, bar=800um (N.Pr.= Nasal process) 2a JU/KM/KR/24, partial left palatine, ventral view, bar=840um (Mx. pr. = Maxillary process) 2b. JU/KM/KR/24, partial left palatine, lateral view, bar=840ixm 2c. JU/KM/KR/24, partial left palatine, medial view, bar=840um 3a. JU/KM/KR/40, central part ofleft maxilla, medial view, bar=430um ( pal.f and f.5 = Foraman for entry ofmaxillary nerve and blood vessel) 3b. JU/KM/KR/40, central partof leftmaxilla, lateral view, bar=430um 4a JU/KM/KR/37, symphyseal region of right dentary, medial view, bar=865um 4b. JU/KM/KR/37, symphyseal region of right dentary, lateral view, bar=865um 5a. JU/KM/KR/44, central part of right maxilla, lateral view, bar=860um 5b. JU/KM/KR/44, central part of right maxilla, medial view, bar=860u.m 6a. JU/KM/KR/47, partial right dentary, medial view, bar=850iam (Mk. f. - Makelian fossa) 6b JU/KM/KR/13, partial right dentary, lateral view, bar=850um 7a JU/KM/KR/38, symphyseal region of left dentary, medial view, bar=830um (Sy= Symphysis) 7b JU/KM/KR/38, symphyseal region of left dentary, lateral view, bar=830um

[58 Chapter 5

DISCUSSION

5.1 TECTONIC AND GEOLOGIC SETTING

The Gondwana basins of peninsular India occupy well-defined linear belts occurring in interconnected intracatonic rifts. The NW-SE trending Pranhita-Godavari valley is a rift valley basin in the southeastern peninsular India, about 45 -50 Km wide and 450 Km long. Together with the Narmada-Son rift valleys to the north, the Pranhita-

Godavari valley forms a roughly Y-shaped structure, whose, all sides are bounded by

Precambrian protocontinents. (Aravalli to the north, Singhbhum to the east, Eastern Ghats to the south and Dharwar to the west) (Naqvi et al, 1974; Biswas, 1999; Mamtani et al,

1999; Text Fig. 5.1). The Gondwana intercratonic rift basins are constrained within the

Early / Mid Proterozoic orogenic belts. These Proterozoic mobile belts mark the collision zones of the protoplates, representing preferred locales for rifting by basement reactivation during crustal distention (Daly et al, 1989). The Pranhita-Godavari valley occurs along such a zone sandwiched between the Dharwar and Singhbhum protocontinents (Text Fig. 5.1). The valley is bounded by two convergent dip-slip faults with the development of grabens and half-grabens (Raiverman et al, 1985). The fault activity is variously considered to be pre- to syn-depositional (Fox, 1934; Chaterji and Ghosh, 1970; Lakshminarayana, 1994; Murti and Lakshminarayana, 1994) or post-

depositional (Ahmed and Ahmed, 1974; Raiverman et al, 1985).

The Pranhita-Godavari valley has undergone three distinct phases of basin

development during the Palaeozoic- Mesozoic times (Lakshminarayana, 1994). The first

major episode of NNW-SSE faulting commenced in the beginning of Triassic, which

imparted linearity to the basin. The presence of conglomerates in the Lower Gondwana

(Kamthi Formation) indicates that this phase of faulting was syndepositional. The

reactivation of Narmada-Son lineament at the same time limited the northward

propagation of this rift (Biswas, 1999). This phase ofrifting was terminated following the

breakup of the Gondwanaland in the Upper Triassic (Lakshminarayana, 1994; Biswas,

1999).

The second phase of rifting commenced at the beginning of Jurassic with faults trending in NW-SE direction. This is supported by the absence of Upper Gondwana sediments over "Mailaram High" and Kamavarpukota Ridge. These ridges are believed to have been uplifted during this phase oftectonic activity (Lakshminarayana, 1994).

'The third and the final phase of tectonic activity in the Pranhita-Godavari basin resumed in the Late Jurassic-Early Cretaceous, prior to the separation of Madagascar and

Antarctica (Biswas, 1999). During this phase the sediments were deposited as syn- to post-rift basin fill. This phase of tectonic activity coincided with the breakup of the

Indian plate from the Gondwanaland continents, which caused major uplift in the Eastern

160 Ghats. It is believed that the outpouring of the Deccan flood basalts caused the cessation

of the Gondwana sedimentation in this valley (Lakshminarayana, 1994).

The Pranhita-Godavari valley is unique among the Gondwana basins of

peninsular India as it preserves about 3000m thick relatively uninterrupted lithic fill

deposited in a timespan of 200 m.y., i.e., from Lower Permian to Lower Cretaceous. The

basin is divisible in to four subbasins namely, the Godavari, the Kothagudem, the A. Chintalapudi and the Krishna-Godavari (Lakshminarayana, 1994). The first three of these

subbasins preserve the continental Gondwana sequences and constitute the NW-SE

trending linear tracts of the Pranhita-Godavari valley. The fourth subbasin, the Krishna-

Godavari coastal belt, is situated in the southeastern part of the valley and preserves

mainly coastal Upper Gondwana sequences.

Another significant feature of the Pranhita-Godavari valley is that it lacks the igneous intrusions unlike other Gondwana basins along the Narmada-Son-Damodar

lineaments. The absence of igneous activity in this basin is attributed to its passive rift nature (Olsen and Morgan, 1995). It is believed that the passive rifts were formed due to custal stretching in response to far field stress unaccompanied by mantle uparching

(Biswas, 1999).

Recent field studies aided by geophysical data has revealed that the Lower

Gondwana sediments form the bulk of the sediments (about 75%) and the Upper

Gondwana sediments form only a small portion (about 25%) of the total sediments •4. deposited in this valley (Sastry and Rao, 1987; Keshavmani et al, 1990). Accumulation

161 of thick pile of sediments of the Lower Gondwana was possible only due to the active

subsidence of the basin along NW-SE axis.

The Upper Gondwana sediments of the Pranhita-Godavari valley consists of Yerrapalli Formation, Bhimaram Sandstone, Maleri, Dharmaram, Kota and Gangapur (=Chikiala) formations in this order ofsuperposition. The Kota Formation holds a unique

position in several respects: relatively uninterrupted sedimentation; occurrence of phosphatic limestone underlain and overlain by plant {Ptillophylum flora) bearing

sandstones. The strike continuity of the Kota Formation has been established over a

length of about 250 km from Sirpur in the Godavari subbasin to Kumarapukota in the Chintalapudi subbasin. This formation has been divided in to three members namely,

Lower, Middle and Upper (Murti and Lakshminarayana, 1994). The lower Member A. consists of large scale, trough cross-stratified and clay-clast bearing sandstone. The

Middle Member consists mainly of limestone but also intercalated clays. The limestone

contains sporadic phosphatic nodules, fish, reptiles and ostracods. The clays intercalated

with these limestones have yielded mammals, dinosaurs, lizards, sphenodontids, fish and

ostracods. The Upper member consists mainly of sandstone and clays.

Lithofacies analysis and palaeocurrent data form the Lower and Upper members of the Kota Formation indicate deposition in northwesterly flowing fluvial system (Murti and Lakshminarayana, 1994). The intervening limestone with intercalated clays represents a shallow, inland lake (Robinson, 1970; Rudra, 1972; 1982).

162 5.2 COMMUNITY STRUCTURE AND PALAEOECOLOGY

The present investigation was undertaken with the objectives of analysing the

microfaunal assemblage including mammalian fauna of the Kota Formation exposed in

the Pranhita-Godavari valley. The investigated sections (Paikasigudem, Metpalli,

Manganpalli Kadamba and Kota) have yielded a rich fossil assemblage comprising

mainly vertebrates, but also ostracods. Text Fig. 5.2 gives the taxonomic diversity of the

A- major biotic groups based on the minimum number of species. The vertebrates comprise fish (27.6%), sphenodontids (6.9%), lizards (3.44%) crocodiles (3.44%), sauropods (3.44%), ornithischians (6.9%), theropods (13.8%), mammals (20.7%), and ostracods

(6.9%) and trace fossils (6.9%). In terms of taxonomic diversity, fish dominate the

vertebrate fauna followed by mammals and theropod dinosaurs.

The biotic composition ofthe Kota Formation is given in Table 5.2, Text Fig. 5.2

and Table 5.1 gives the faunal list from various localities of the Kota Formation investigated during the present work. The relative abundance of various taxa in percentage is not given here because of great uncertainty involved in the estimation of

numbers of individuals on the basis of isolated remains, especially teeth. This problem is further compounded by the fact that a number ofteeth may have been shed during growth

of an individual, which is true particularly in the case of reptiles. The palaeoecology of the Kota fish, reptiles, mammals and ostracods is inferred on the basis of ecological niches in which their present day relatives exist. In instances

where the taxa are not found today, a generalised ecological condition is inferred on the

basis ofits nearest related taxon or the group.

163 Table 5.1 Distribution of microfauna in the investigated sections.

Paikasigudem Menganapalli Kota Metpalli Kadamba Fish

L. deccanensis + + + + +

P. egertoni + + + + +

T. oldhami +

Semionotidae indet. 1 + + + + +

Semionotidae indet. 2 + + + + +

Semionotidae indet. 3 +

Lissodus indicus nov. comb. + +

Elasmobranchii indet. + Reptiles Sphenodontids

Taxon A +

'Taxon B +

Lizards (Gen.et sp. indet) +

Crocodile (?Teleosauridae) + + + + + Theropods

Theropoda "A" +

Theropoda "B" +

Theropoda "C" +

Theropoda "D" +

Ornithischians

Type A +

TypeB +

Mammals Deneisodon godavariansis gen. et

sp. nov. + Gondtherium .dattai gen. et sp.

nov. + -* Dyskritodon indicus. sp. nov. + Paikasigudodon. Yadagirii nov.

comb +

Indotherium pranhitai +

Triconodonta indet. +

Ostracods

D. sarytirmensis + + + + +

Darwinula sp. + + + + +

164 Table 5.2 Biotic composition of the Kota Formation.

TERRESTRIAL COMMUNITY AQUATIC And SEMI-AQUATIC COMMUNITIES

Reptiles Fish 1. Sphenodontids Semionotidae a) Taxon A a) Lepidotesdeccanensis b) Taxon B b) Paradapedium egertoni

2. Lizards c) Tetragonolepis oldhami a) Gen. et sp. indet. d) Semionotidae indet. 1 X 3. Sauropoda e) Semionotidaeindet. 2

indet. f) Semionotidae indet. 3

4. Ornithischia Elasmobranchii a) Type A a) Lissodus indicus b) Type B b) Elasmobranchii indet. 5. Theropoda Ostracods a) Theropod "A" a) Darwinulasarytirmensis b) Theropod "B" b) Darwinula sp. c) Theropod "C" d) Theropod "D" Crocodiles

6. Mammals ?Teleosauridae A) Docodonts a) Deniseodon godavarensis gen. et sp.

nov. b) Gondtherium dattai gen. et sp. nov. B) Triconodonts a) Dyskritodon indicus sp. nov. b) Paikasigudodon yadagirii nov'. comb. c) Indotherium pranhitai d) Triconodonta indet.

I) Fish: Fish in the present collection are known mainly by isolated teeth, scales and a few fragmentary jaws. The fish fauna is dominated by semionotids represented by Lepidotes, Paradapedium and Tetragonolepis and three

165 indeterminate forms. Also present in the fauna are a hybodont shark Lissodus and

an indeterminate elasmobranch.

In terms of frequency of occurrence, Lepidotes is the most abundant fish

in the Kota Formation. The genus Lepidotes became extinct at the end of the

Cretaceous. Most of the known occurrences of Lepidotes are from fresh or

brackish water deposits. These include the freshwater Wealdean and Cenomanian -deposits of Britain and Brazil (Jain, 1984, 1996), freshwater Berremian-Aptian deposits of Galve (Tereul, Spain, Estes and Sanchiz, 1982). Lepidotes also occurs in brackish to freshwater Rheatic, Oxfordian and Kimmerridgian, Purbeckian and marine upper Liassic and Cenomanian deposits of Britain (Jain, 1984, 1996). Based on the global records, it is inferred that the Kota species {Lepidotes

deccanensis) inhabited relatively shallow lakes with clearwater.

Paradapedium egertoni and Tetragonolepis oldhami are the other semionotid fish found in the Kota Formation. Paradapedium resembles Dapedium

(Jain, 1973), the latter occurring in the marine Liassic deposits of Europe and marine Upper Triassic of Lombardy, northern Italy (Tintori, 1982).

Tetragonolepis is known only from the Upper Liassic marine sediments of

Europe. It appears very likely, as pointed out by Jain (1973) and Chatterjee et al.

(1987), that P. egertoni and T. oldhami are freshwater counterparts of Dapedium and T. elvensis, respectively.

166 In addition to semionotid fish, some dental material of the freshwater

elasmobranch (hybodont shark) Lissodus indicus is also present in the collection.

The genus Lissodus is known from freshwater Lower Triassic rocks of South

Africa (Brough, 1935), Upper Triassic ofTexas (Murry, 1981), Lower Cretaceous

of Spain, Texas and Wyoming, England (Estes and Sanchiz, 1982; Thurmond,

1971; Patterson, 1966), Upper Cretaceous Monmouth Group, New Jersey

X (Cappetta and Case, 1975); marine Late Triassic sediments of Syren, Belgium

(Godifroit et al, 1998) and estuarine Maseverde Formation, Wyoming (Case,

1987). Thus, Lissodus appears to be a euryhaline form, having been reported from

both freshwater and marine sediments.

The Kota fish fauna also includes: a coelocanth Indocoelacanthus

robustus (Jain, 1974a) and pholodophorids Pholidophorus kingii and P. indicus

(Yadagiri and Prasad, 1977). Indocoelacanthus was a large toothless fish

inhabiting the bottom of the shallow lakes (Jain, 1974a). The Indian coelacanth

and the one known from the Belgian Congo possibly represent the only survivors

in the Jurassic freshwater habitats (Chatterjeeet al, 1987). The pholidophorid fish

are euryhaline forms inhabiting bothfresh and marine habitats (see Jain, 1980).

Thus, the fish fauna from the Kota Formation consists mainly euryhaline

forms that suggest freshwater lacustrine environment forthe Kota Formation.

II) Reptiles: Reptiles in the present collection are represented by

"#• rhynchocephalians, lizards, crocodiles and dinosaurs (Text Fig. 5.3).

167 a) Rhynchocephalians: At present rhynchocephalians are represented by two species

of the genus Sphenodon {S. punctatus and & guntheri), which inhabit approximately

30 small, relatively inaccessible, islands offthe coast ofNew Zealand. The islands are

generally cliff- bound, often exposed to strong winds, and support a natural,

frequently stunted, vegetation of salt and wind tolerant species.

b) Lizards: The agamids are the Old World counterpart of the New World iguanids.

The agamids (acrodont iguanids) are at present found in North America, Australia,

New Zealand, New Guinea, East Indies, Caribbean Islands and Asia. The agamids

have undergone extensive adaptive radiation in terrestrial and arboreal habitats. They

inhabit sandy biotopes (on or near rocks, walls or stem of the trees), and some are true

desert lizards.

c) Crocodiles: In the present collection, crocodiles are represented by isolated teeth.

The crocodiles are presently found in varying environments such as marine, coastal

lagoons, estuaries, lakes, streams and swamps. The present Indian species C.palustris

occurs in freshwater estuarine condition and is unable to tolerate marine

environments. At this moment, it can only be surmised that crocodiles inhabited the

lake and lake margins and fed on abundant fish in the lake. d) Dinosaurs: Dinosaurs represent the megaterrestrial community in the Kota

Formation. They are known in the assemblage by isolated teeth pertaining to three suborders: Sauropoda, Theropoda and Thyreopora.

168 Inaddition to theropods, thyreophorans and sauropods, hypsilophodontids and pterosaurs are also known from the Kota Formation (Jain, 1974b; Jain et al, 1975; 1977; Yadagiri and Prasad, 1979; Prasad, 1986; Yadagiri, 1988). The sauropods Barapasaurus tagorei (Jain et al, 1975, 1977) and Kotasaurus yamanapallensis (Yadagiri, 1988) share many characters with prosauropods. It appears likely that the Kota sauropods, like ornithischians, might have inhabited the land around the lake

and fed on the succulent vegetation around it. The palynological data from the Kota

Formation indicates that the flora consisted of pteridophytes, bryophytes, filicales, sphenospids and lycopods. The pteridophytes form the dominant group in this flora

(Dr. Vijaya, BSIP, pers. com.).

That the Kota lake may also have supported a pterosaur fauna is indicated by

the occurrence of Campyloganolhoides indicus reported byJain (1974b).

Ill) Mammals: Mammals represent microterrestrial community in the Kota fauna.

They are known mainly by isolated dental remains and a few post-cranial remains

that are not identifiable. The teeth are referable to the orders Triconodonta (3

genera and 3 species and one indeterminate taxon) and Docodonta (2 genera and 2

species). During the present study, no articulated skeleton was found, and this

makes interpretation onthe body sizes of these mammals very difficult. However,

the recovered skeletal material from other parts of the world indicates that these

mammals hardly exceeded the size of the mice. The dentition of the

morganucodontids (earliest triconodonts) indicates that it was adapted for an

insectivorous diet, whereas the dentition of other triconodonts was essentially a

169 shearing device suitable for carnivorous diet (Jenkins and Crompton, 1979). The

docodont molars on the other hand, may have achieved a greater shearing

capability due to the expansion of the internal cingulum accompanied by the

addition of ridges and crenulations. At present it is generally believed that the

docodont dentition was adapted to an omnivorous diet and that these mammals

enjoyed a more flexible food habits than their contemporary and peer mammals

whichwere mostly insectivorous (Kron, 1979). X

The Kota mammals also include the symmetrodonts: Kotatherium

haldanei (Datta, 1981) Trishulotherium kotaensis and Nakunodon paikaisensis

(Yadagiri, 1984, 1985). Kotatherium is a tinodontid symmetrodont known from

upper molar. The familial status of Trishulotherium is unknown and Nakunodon

represents the Family Amphidontidae.

IV) Invertebrates: The only invertebrates in the present collection are represented

by ostracods. Although the frequency of occurrence is very high, the taxonomic

diversity is low with only one genus Darwinula and two species. Darwinula is

very conservative in its morphology, and is known to occur from the

Mississippian onwards. The living members of the genus Darwinula inhabit

permanent, relatively large fluvio/lacustrine environments with a preference for

depths less than 6 meters. A similar lacustrine environment is inferred for the

Kota Formation.

Besides ostracods, a diverse assemblage of estheriids has also been

described from the Kota Formation (Tasch et al, 1973). Fossil insects have also

170 been reported to occur and the assemblage includes blattids, coleopterans and

hemipetrans (Rao and Shah, 1959; also See Jain, 1996).

V) Trace Fossils: The presently recovered ichno taxa are Planolites sp. and

Monocraterion sp. Planolites is facies independent and is known from a number

of facies from Precambrian to Recent. Monocraterion is confined to the littoral

zone and indicates a high-energy environment. The present ichno assemblage is ♦ too meager to allow any meaningful palaeoecological inferences.

The above data clearly show that the Kota Fauna includes an interesting

admixture of aquatic, semi-aquatic, terrestrial and aerial vertebrates and invertebrates.

It is interesting to consider ecological relations of the Kota fauna (Chatterjee et al.,

1987). The fauna suggests a shallow freshwater lake inhabited by a variety of deep-

bodied and lanceolate fish (particularly semionotids), some fast swimming

phohdophorids as well as a few coelacanths. The ostracods and estheriids may have

formed the main food of the fish, but much larger forms including the freshwater

sharks may have fed on smaller fish. Crocodiles inhabited the lake margins and also

fed on fish. The theropods may have led an active life in the pursuit of the prey. They,

like all the modern carnivore mammals, might have frequented around the Kota lake

for easy availability of prey. The sauropods and ornithischians probably also

inhabited the land around the lake and fed on the succulent vegetation around it. The

pterosaurs may also have depended on fish in the lake. Small mammals as well as

lizards may have fed (atieast partly) on a variety of insects which inhabited the land

around the Kota lake.

171 5.3 BIOGEOGRAPHIC AFFINITIES

As seen above, the Kota Formation fauna consists almost exclusively of non-

marine elements. The assemblage includes the largest mammalian fauna known so far

from the Mesozoic strata of the Indian subcontinent. Docodontid mammals are recorded

for the first time from the Kota Formation along with a number of triconodontids. The

non-mammalian component is represented by a diverse assemblage including

sphenodontids, lizards, crocodiles, ornithischians, theropods and sauropods. Of these,

ornithischians and theropods are recorded for the first time from the Kota Formation. The

non-marine nature of the Kota fauna makes it interesting to examine it in the context of

India's position in the Gondwanaland during the Jurassic.

Fish: Fusiform semionotid fish Lepidotes deccanensis is the most common taxon in the

Kota fauna. Lepidotes is represented by isolated teeth and scales. In addition to Kota

Formation, the genus Lepidotes is known to occur in the Deccan intertrappean beds of peninsularIndia (Gayet etal, 1984; Prasad, 1985; Prasad and Sahni, 1987; Bajpai, 1990;

Srinivasan, 1991). Elsewhere in the world, Lepidotes has been reported from the Jurassic

(Lower Liasssic) of England (Gardiner, 1960), Solenhofen Limestone of Germany, (Jain,

1984) and from Lower Cretaceous of Spain (Estes and Sanchiz, 1982) and France (Saint-

Seine, 1949). It is also known from the Upper Cretaceous ofEngland (Woodward, 1895),

Zaire, Congo and Bolivia (Gayet, 1982; De Muzion et al, 1983) and Cameroon (Flynn et al, 1987).

In addition to Lepidotes, the hypsisomid semionotid fish Paradapedium and

Tetragonolepis have also been recovered during the present investigation. Paradapedium is represented only by isolated scales, whereas Tetragonolepis is known by isolated teeth and a few fragmentary jaws. In India, the occurrence of these fish taxa is limited to the

172 Lower Jurassic Kota Formation (Jain, 1973) and there is no report of its occurence in any other formation in India. Both these genera are known to occur in the Liassic marine deposits of Europe. Recently, Godefroit et al (1998) has doubtfully assigned isolated teeth from the Upper Triassic ofSyren, Luxembourg to Dapedium. Jain (1973) concluded that Paradapedium is more closely allied to Dapedium and is the freshwater substitute of

Dapedium.

The elasmobranch Lissodus indicus in the present collection is represented by isolated teeth. In addition to India, the genus Lissodus is known from the Lower Triassic to Upper Cretaceous (Maastrichtian) rocks throughout the world. Lissodus africanus (Brough, 1935) is known from the freshwater sediments of Lower Triassic Beaufort

Series South Africa. L. minimus and L. lepagi (Godefroit et al, 1998) is known from the Upper Triassic (Rhaetian) of Syren, Luxembourg. Lonchidion breve breve (Patterson 1966) is known from freshwater Lower Cretaceous of Wealden. Lonchidion microselachos (Estes and Sanchiz, 1982) is known from the freshwater Lower Cretaceous ofGalve, Spain. Lonchidion selachos (Estes 1964) is known from the Upper Cretaceous (Maastrichtian) Lance Formation of Wyoming and Lonchidion babulskii (Cappetta and Case, 1975) from the Upper Cretaceous (Maastrichtian) Monmouth Group, New Jersey. Lissodus is thus a long ranging genus which thrived in both marine and freshwater environment. The Indian species shows close similarity to the Lower Cretaceous Lonchiodon microselachos (Estes and Sanchiz, 1982) in the possession ofa falcate labial cusp. Estes and Sanchiz (1982) considered that the Lonchiodon microselachos is

173 intermediate between L. b. breve and L. selachos. As the Indian species is closer to L.

microselachos, a similar evolutionary position is proposed for it.

From the above discussion it is clear that the Kota fish fauna is cosmopolitan in

nature.

Reptiles: The rhynchocephalians, lizards, crocodiles, sauropods, ornithischians and

theropods represent the reptilian fauna in the present collection from the Kota Formation.

Rhynchocephalians: At present, there are very few records of fossil rhynchocephalians

from the Gondwanan continents and these include the occurrences in the Late Triassic of

Madagascar (Flynn et al. 1997, 1999a) and Brazil (Ferigolo, 1999); Early Jurassic of

Zimbabwe (Gow and Raath, 1977) and South Africa (Sues and Reisz, 1995); and the Late

Jurassic and Early Cretaceous of Morocco (Evans and Sigogneau-Russell, 1997) and

4 South Africa (Ross et al, 1998). The new finds from the Indian subcontinent indicate a

wider Mesozoic distribution for rhynchocephalians in the southern continents. From the

palaeobiogeographic point of view, the presence of rhynchocephalians in the Indian

subcontinent is not surprising because at the time of deposition of the Kota Formation

India-Madagascar-Seychelles block was in close contact with Africa on the west and

Antarctica- Australia block in the south (Text Fig. 5.4).

Lizards: All living squamates are grouped into two important clades: 1) Iguania represented by pleurodont iguanids, acrodont agamids and chameleons and 2)

Scleroglossa that includes all the remaining lizards, snakes and amphisbaenians. The pleurodont lizards are distributed in the western hemisphere, Madagascar, and the islands of Fiji and Tonga, whereas agamids are confined to southern Europe, Africa, Australia,

174 and South East Asia. Prior to recent investigations in Central Asia, China and North

<*- America (Alifanov, 1989; 1993; Gao and Nessov, 1998; Borsuk-Bialynicka, 1996; Borsuk-Bialynicka and Moody, 1984, Gao and Fox, 1996), it was assumed that iguanian lizards originated in the Gondwanaland and subsequently reached Laurasia when land connections were established (Estes, 1983). A single record of the Mesozoic iguanian {Prisciguana; Estes and Price, 1973) in the Late Cretaceous of Brazil and the absence of Jurassic iguanians in Laurasia together with the current distribution of this group was cited in favour of the above hypothesis. However, recent discoveries of iguanids and agamids in the Mesozoic ofAsia and North America have disputed this hypothesis. Both pleurodont and acrodont iguanians have been reported from the Aptian-Albian strata of Central Asia (Gao and Nessov, 1998; Nessov, 1988; Alifanov, 1993), from the Campanian and Maastrichtian deposits of Mongolia (Alifanov, 1989; Borsuk-Bialynicka and Alifanov, 1991; Borsuk-Bialynicka and Moody, 1984), China (Gao and Hou, 1996) and Canada (Gao and Fox, 1996). Since these finds represent the oldest known iguanians (both pleurodont and acrodont), most of these authors favoured Asia as the centre of origin for iguanians from where they radiated into the former Gondwanaland (Alifanov,

1993; Gao and Hou, 1996). According to the current palaeogeographic scenarios (Text Fig. 5.4), India was still part of the Gondwanaland at the time of deposition of Kota sediments and possibly got separated from Africa at about 165 m.y. and from Antarctica-Australia around 120 m.y. (Powell, 1979). If we accept the Early/Middle Jurassic age for the Kota Formation, the agamid lizards recovered from this formation can be considered to be the earliest

175 known record ofthis group. Even if the Kota Formation is considered slightly younger (Late Jurassic or earliest Cretaceous) than the long held Early/Middle Jurassic age, the present record is the oldest. However, a better documentation of iguanian fossils from various continents is required before any definite conclusion can be drawn regarding the centre oforigin for iguanians.

Crocodiles: As the generic identification of the crocodile material from the Kota Formation must await the recovery of additional material, nothing definite can be said about their affinities at present. Dinosaurs: As the Kota theropods and ornithischians are not identifiable at the generic or even familial level, it is difficult to comment on their affinities at present. However,

Theropod A teeth are morphologically similar to those of Dromeaesaurus known from the Judith River Formation, Alberta, Canada (Currie, 1987; Currie et al, 1990; Fiorillo and Currie, 1994). The ornithischian Type A teeth do not show close morphological similarities to any of the known ornithischians, but are broadly similar to Trimucrodon known from the Upper Jurassic ofPortugal (Thulborne, 1973). The ornithischian Type B tooth is closest to Lucianosaurus wildi known from Upper Triassic of North America (Lucas and Hunt, 1994). The sauropod teeth show close similarity to the already known

Barapasaurus tagorie from the Kota Formation (Jain etal, 1975; 1977).

Mammals: Among the mammals, the triconodonts - Dyskritodon indicus sp. nov. and

Indotherium pranhitai Yadagiri, 1984, and the docodonts Deniseodon godavariensis gen. et sp. nov. and Gondtherium dattai gen. et sp. nov. are important from palaeobiogeographic point of view. Dyskritodon amazighi, the type species of

176 Dyskritodon was originally described from the Lower Cretaceous (?Berriasian) deposits of Anoual Syncline, Morocco (Sigogneau-Russell, 1995). Except for minor differences,

D. indicus is very similar to D. amazighi. Likewise, Indotherium pranhitai closely approaches the upper molar morphology of morganucodontids, particularly those from the Kirlington Quarry (Middle Jurassic), England.

Prior to the present work, docodonts have been documented from the Middle

Jurassic beds of Isle of Skye, Scotland {Borealestes serendipitus, Waldman and Savage,

1972), Middle Jurassic Kirlington beds, England {Simpsonodon oxfordensis, Kermack et al. 1987), Upper Jurassic Lulworth Beds of Durlstone Bay, England {Peraiocynodon inexpectatus, Simpson, 1928), Upper Jurassic of Portugal {Haldanodon exspectatus, Krusat, 1980) and Upper Jurassic Morrison Formation, U.S.A. (various species of

Docodon; Kron, 1979 and references therein, Text Fig. 5.5). The Kota docodont,

Deniseodon godavariensis gen. et sp. nov., compares well with Haldanodon exspectatus from Portugal (Krusat, 1980). The second docodont, Gondtherium dattai gen. el sp. nov., although resembling Haldanodon exspectatus in the lower molar morphology, appears to be more primitive than the latter as well as Simpsonodon (Kermack et al. 1987J and Docodon (Simpson, 1929). From the fossil record, it is clear that docodonts had an exclusively Laurasian distribution in the Middle and Upper Jurassic. The presence of

docodonts in the Kota fauna is highly significant because it is the first Gondwanan docodont of typical Laurasian affinity. Although Reigitherium from the Late Cretaceous

of South America has been considered as a docodont, it appears to be highly derived with respect to Laurasian taxa and has been placed in a family of its own with sister-group

177 relationship to the Family Docodontidae (Pascual et al. in press). Therefore, the new finds

from India suggest a Pangean distribution for docodont mammals in the Jurassic. Similar

views have been expressed by Colbert (1977; 1979) according to whom "during the

opening phases of Jurassic history India was still a land-locked part of Gondwanaland".

The evidence of estheriids (Tasch et al, 1973) also suggests close proximity of Indian

plate to both Antarctica and Australia.

Ostracods: Ostracods inthe present collection occur abundantly but are represented by

only one genus Darwinula with two species, Darwinula sarytirmensis and Darwinula sp.

Darwinula sarytirmensis is reported from freshwater Middle Jurassic deposits of Former

USSR and China. It has also been reported from the Lower Jurassic Kayenta Formation of Arizona, United States (Kietzke and Lucas, 1994). In China, this genus is also known from the early and late Middle Jurassic (Pang and Watley, 1990).

It is clear that the microbiota recovered from the Kota Formation does not show any-evidence of significant endemism. The paleontological data agrees well with the current geophysical models, based on marine magnetic anomalies, which suggest that dispersal of the major continental areas and separation by ocean basins probably did not occur throughout most of the Jurassic. In the absence of impassable barriers to dispersal

Jurassic fauna and flora included numerous cosmopolitan elements. In general

Gondwanan and Laurasian biotas were less distinctive in Jurassic than they had been in

Triassic.

178 5.4 AGE CONSIDERATION

Traditionally, the Kota Formation has been dated as Lower Jurassic (Liassic or Oolitic), primarily on the basis of the fish and reptilian fauna (Jain, 1973; 1974; 1983; 1996; Jain et al, 1975; 1977; Yadagiri et al, 1979; Prasad, 1986; Yadagiri, 1986) and palynofossils (Prabhakar, 1986). However, some workers have suggested a younger age

for the Kota Formation based on ostracods (Middle Jurassic, Govindan, 1975; Mishra and Satsangi, 1979), floral evidences (Middle Jurassic or younger, Rajnikanth and Sukh Dev, 1989) and palynological data (Upper Jurassic - Lower Cretaceous Vijaya and Prasad, W B Ia*' 1999, in press) The mammalian component of the presently studied biota has important implications for the age ofthe Kota Formation. This assemblage includes two genera and two species of docodont mammals and three genera and three species of triconodontid mammals. Prior to the present record, docodonts were only known from the Middle and Upper Jurassic deposits ofEurope and North America (Kron, 1979). The present record

of definite docodont mammals from the Kota Formation further extends the geographic distribution ofthis group to Gondwanan continents. Based on this record, it is tempting to lower the stratigraphic range ofthis group to Lower Jurassic. However, the evolutionary grade of atieast one of the Kota docodonts {Deniseodon godavariensis) appears to approximate that of the Upper Jurassic docodont H exspectatus and therefore this possibility appears unlikely. A more likely explanation is that the Kota Formation is younger in age (i. e., Upper Jurassic or even younger) than the current estimates.

179 The presence of a Lower Cretaceous (?Berriasian) north African genus in the

Kota Formation {Dyskritodon) is also significant biostratigraphically. If the current age assignment (Lower Jurassic) of the Kota Formation is accepted, it leaves a gap of 45 - 50 m. y. between the Indian and the Moroccan Dyskrilodon-yielding sites. At the known rates of mammalian evolution, no mammalian genus is expected to survive for such a long period. The longest ranging genus of the Mesozoic Era is a triconodont mammal Gobiconodon spanning about 20 m. y. from Berriassian (Morocco) to ?Aptian / ?Albanian (Mongolia, USA, Trofimov, 1978, 1981; Jenkins, 1984). This implies that the dates of one of the two Dyskritodon-yield'mg sites (Anoual and Kota) is not correct, and leads to the following two alternatives:

> Anoual mammal yielding site may be older than the presently accepted Lower

Cretaceous age. •4. > The Kota Formation may be younger than the presently accepted Lower Jurassic

age.

Because the Anoual mammal yielding site has been precisely dated on the basis of nannofossils {Po/ycostella, Micrantholithus, and Nannocus, Sigogneau-Russel et al,

1991), thefirst ofthe above alternatives is unlikely. Thus, in the view of the above discussion, it is concluded that the mammalian fauna of the Kota Formation is more in agreement with an Upper Jurassic - Lower

Cretaceous rather than Lower Jurassic age. This conclusion is also supported by independent palynological (Vijaya and Prasad, 1999; in press) and ostracod (Mallikarjuna etal, manuscript) datafrom the Kota Formation.

180 Mumbai /

460 Km —i

5.1 Map showing the configuration of Narmada-Son and Pranhita-Godavari basins.

181 BUnBJUOJJEULIOjJBJO^ 3qj JOUOIJISOdlUOO3A1JBPHrS '§!J

sjmirurejAi cc

SpOOBJlSQ

SrtSSOJ 33SJ1 u

t e o

o

«

o

-C

^- o c o

o

o u I

PS

185 5.4 Reconstruction of Pangea in Jurassic showing position of India (ornamented) in a) Lower Jurassic and, b) Upper Jurassic (after Smith and Bridden, 1979; Dewey, 1989).

187 Fig. 5.5KnownMiddleand UpperJurassic docodont-yieldingsitesinthe world Chapter 6

SUMMARY AND CONCLUSIONS

1) This thesis deals with the detailed description of microvertebrates and associated

fauna from the Continental Jurassic sediments (Kota Formation) of the Pranhita-

Godavari valley in the southcentral peninsular India (Andhra Pradesh state). The

study was undertaken with the objectives of a) documenting the microfauna with emphasis on micromammals and b) working out palaeoecological, biochronological

and palaeobiogeographical implications of the recovered fauna. 2) Five sections ofthe Kota Formation were investigated for the recovery of microbiota.

These sections are located near the villages Paikasiguden, Kadamba, Metpalli, Manganpalli (District Adilabad) and Kota (District Chandrapur). Lithologically, these

sections comprise mainly sandstone, limestone and clays. 3) For the recovery ofmicrofossils, bulk screening techniques were employed mainly in

the field but also in the laboratory. This method yielded a taxonomically diverse

assemblage of microvertebrates. Associated fauna includes ostracods. 4) Microvertebrates comprise over 3500 identifiable elements of fish, sphenodontids,

lizards, crocodiles, sauropods, ornithischians, theropods and mammals. These elements include isolated teeth, fragmentary maxillae, premaxillae dentaries, scales,

dermal denticles, and phalanges. The vertebrate assemblage comprises 25 species

assigned to 25 genera.

5) Fish constitute the dominant group with 8 genera and 8 species representing

holosteans and elasmobranchs. Holosteans include freshwater taxa Lepidotes

deccannensis, Paradepadium egertoni, Tetragonolepis oldhami and three

indeterminate forms. Lepidotes deccannensis is the most common fish in the Kota

Formation recorded by nearly complete dentition including palatal, anterior and

pharyngeal series. Elasmobranchs are represented by freshwater hybodont shark

Lissodus indicus nov. comb, and an indeterminate form.

6) The present work is the first detailed account of sphenodontids from the Kota

Formation. Atieast two taxa are present in the collection. Taxon A is characterised

mainly by fully acrodont teeth, in having two rows ofpalatine teeth and in having less

robust premaxillae than in most other sphenodontids. Taxon B is distinguishable from

most of the known sphenodontians in having a deep, U-shaped premaxilla with a

small nasal process and a large lateral process.

7) Acrodont iguanid lizards are recorded for the first time from the Kota Formation,

based on the maxillary and dentary fragments. The present find is the oldest record of

acrodont iguanid lizards in the world.

8) Crocodiles are known only by isolated teeth and their generic identification is not

possible at present. These dental remains are referred tentatively to the family

Teleosauridae.

[92 9) Dinosaurs in the present assemblage are known by isolated teeth belonging to three

suborders: Sauropoda, Thyreophora and Theropoda. Significantly, theropods and

thyreophorans are recorded for the first time from the formation. Theropods are the

most dominant group represented by four morphotypes distinguished on the basis of

tooth shape and denticles. Thyreophorans and sauropods are represented by two and

one morphotype, respectively. The thyreophoran morphotypes are also distinguished

on the basis of the shape of maxillary/dentary teeth and the nature of accessory cusps

and denticles on lateral margins.

10) Mammals form the most important component of the presently described

microvertebrate assemblage. They are represented by two orders namely, Docodonta

and Triconodonta.

Docodonts are documented for the first time not only from India but also from

the Jurassic of any Gondwanaland continent. These taxa recorded are Deniseodon godavariensis gen. et sp. nov. and Gondtherium dattai gen. et sp. nov. In its evolutionary grade Deniseodon godavariensis approaches Haldanodon exspectatus known from the Upper Jurassic sediments of Portugal. On the other hand, Gondtherium dattai appears to be primitive relative to several known docodonts {H. exspectatus, Docodon and Simpsonodon) known from the Middle and Upper Jurassic

of North America and Europe, but is relatively more advanced over Delsatia known from the Upper Triassic of France. The discovery of docodonts from the Kota Formation clearly indicates a Pangean distribution for this group in the Jurassic.

Triconodonts from the Kota Formation are taxanomically more diverse comprising atieast 4 species. They include a new species Dyskritodon indicus

193 characterised by lower molars with high and narrow crowns, cusps a, c, d decreasing

regularly in height posteriorly and the tips of cusps a and c slightly recurved

posteriorly.

A known speciesKotatherium yadagirii Prasad and Manhas, 1997 which was

previously described as a symmetrodont, is here transferred to a new triconodont

genus Paikasigudodon yadagirii of uncertain familial affinities. Important characters

of these species include: upper molar crown bearing a high and symmetrical central

cusp with a flat labial face and convex lingual face; cusp B higher than C; presence of small anterior and posterior lingual cingular cuspules; presence of a rudimentary

lingual cingulum between A and B. The present investigation has revealed that

Paikasogudodon yadagirii is close to Megazostrodon rudnerae known from the Late

Triassic ofLesotho, Southern Africa.

Athird triconodont taxon which is clearly distinct from above two species but whose affinities are not clear at present, is characterised by a high and large central cusp-a and a small cusp c, the latter being half the size ofcusp a and making an acute

angle with it. These two cusps are separated from each other by a V-shaped notch. A fourth taxon, Indotherium pranhitai Yadagiri, 1984 which was previously considered to be a symmetrodont, is here transferred tentatively to the family

Morganucodontidae in the order Triconodonta. This is based on the presence of two subequal cusps (A and Q and a highly reduced cusp B. Among all the morganucodontid teeth known so far, the morphology of the present specimen is closest to that of BMNH No. M26014 known from the Middle Jurassic, Kirlington quarry, U.K.

194 11) Associated fauna includes freshwater ostracods. These are represented by a single

genusDarwinula with two species (D. sarytirmensis and Darwinula sp). Trace fossils

are represented by Planolites and Monocraterion.

12) In contrast to the widely held Lower Jurassic age, an Upper Jurassic - Lower

Cretaceous age is suggested for the Kota Formation based on the mammalian

evidence, particularly the presence of docodonts and the triconodont Dyskritodon.

Prior to the present find, the genus Dyskritodon was known from Anoual, Morocco

where it is precisely dated at Lower Cretaceouson the basis of nannofossils.

13)All the major groups described in this thesis (fish, sphenodontids, lizards, sauropods,

thyreophorans, theropods, docodont and triconodont mammals) are cosmopolitan in

distribution and do not show any marked endemism. Although the docodonts include

^ two new genera, they bear close affinities to contemporary mammals {Haldanodon

exspectatus) known from the Upper Jurassic of Portugal. The present data clearly

supports the current notion that India was a land-locked part of Gondwanaland in the

Jurassic.

14) Overall, the Kota fauna comprises an admixture of aquatic, semi-aquatic and

terrestrial vertebrate and invertebrate communities. The assemblage, especially fish

and ostracods, points to a freshwater shallow lacustrine depositional environment for

the Kota Formation.

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X

220 Explanation of Plate 1

a) Panoramic view of the Kota Formation exposed on the western side of the village

Paikasigudem, Adilabad District, Andhra Pradesh.

b) Mud cracks in limestone exposures near Paikasigudem village. c) KotaFormation exposures nearthe village Metpalli.

Explanation of Plate 2

a) Clays intercalated with limestone near the village Metpalli. b) Close up view ofthe Manganpalli excavation pit showing clays and limestone. c) Kota Formation exposures at type locality (Kota village). d) RUBK/99011, limestone block showing Monocraterion e) RUBK/99001, limestone block showing Plan olites • V*

• Explanation ofPlate 3 (Bar length in all cases =200 p., or otherwise specified) Lepidotesdeccanensis a) RUBK/1001, isolated palatal tooth, lateral view b) RUBK/ 1002, isolated palatal tooth, lateral view c) RUBK/ 1003, isolated palatal tooth, lateral view d) RUBK/ 1004, isolated palatal tooth, lateral view e) RUBK/ 1005, isolated palatal tooth, lateral view f) RUBK/ 1006, isolated palatal tooth, lateral view g) RUBK/ 1007, isolated anterior marginal tooth, lateral view h) RUBK/ 1008, isolated anterior marginal tooth, lateral view i) RUBK/ 1009, isolated anterior marginal tooth, lateral view j) RUBK/ 1010, isolated anterior marginal tooth, lateral view k) RUBK/1011, isolated anterior marginal tooth, lateral view 1) RUBK/1012, isolated anterior marginal tooth, lateral view m) RUBK/ 1013, isolated tooth, lateral view n) RUBK/1014, isolated tooth, lateral view o) RUBK/1015, isolated tooth, lateral view p) RUBK/ 1016, isolated tooth, lateral view q) RUBK/ 1017, isolated pharyngeal tooth, lateral view r) RUBK/ 1018, isolated pharyngeal tooth, lateral view s) RUBK/1019, isolated pharyngeal tooth, lateral view t) RUBK/ 1020, isolated pharyngeal tooth, lateral view u) RUBK/ 1021, isolated pharyngeal tooth, lateral view v) RUBK/1022, isolated dorsal ridge scale, dorsal view

Explanation ofPlate 4 (Bar length in all cases - 200 p., or otherwise specified) Lepidotes deccanensis a) RUBK/ 1023, isolated dorsal ridge scale, dorsal view b) RUBK/ 1024, isolated dorsal ridge scale, ventral view c) RUBK/ 1025, isolated dorsal ridge scale, ventral view d) RUBK/1026, isolated scale bordering dorsal ridge scale, dorsal view e) RUBK/ 1027, isolated scale bordering dorsal ridge scale, ventral view f) RUBK/1029, isolated lateral line scales, dorsal view g) RUBK/1030, isolated lateral line scales, dorsal view h) RUBK/1031, isolated lateral line scales, ventral view i) RUBK/1031, isolated lateral line scales, ventral view j) RUBK/1032, isolated ventral flank scale, dorsal view k) RUBK/1033, isolated ventral flank scale, ventral view 1) RUBK/1034, isolated anal scale, dorsal view m) RUBK/1035, isolated anal scale, dorsal view n) RUBK/103 6, isolated anal scale, dorsal view o) RUBK/1037, isolated anal scale, lateral view

Paradapedium egertoni p) RUBK/1101, isolated scale, dorsal view q) RUBK/1102, isolated scale, dorsal view r) RUBK/1103, isolated scale, dorsal view

Explanation of Plate 5 (Bar length in all cases = 200 p, or otherwise specified) Paradepedium egertoni a) RUBK/1104, isolated scale, ventral view b) RUBK/1105, isolated scale, ventral view c) RUBK/1106, isolated scale, ventral view Tetragonolepis oldhami d) RUBK/1201, isolated tooth, lateral view e) RUBK/1202, isolated tooth, lateral view f) RUBK/1207, jaw fragment with teeth, lateral view g) RUBK/1203, isolated tooth, lateral view h) RUBK/1204, isolated tooth, lateral view i) RUBK/1207, jaw fragment with tooth, lateral view j) RUBK/1205, isolated tooth, lateral view k) RUBK/1206, isolated tooth, lateral view

Order Semionotidei

Indet. 1 1) RUBK/1301, isolated tooth, lateral view m) RUBK/1302, isolated tooth, lateral view n) RUBK/1303, isolated tooth, lateral view o) RUBK/1304, isolated tooth, lateral view p) RUBK/1305, isolated tooth, lateral view q) RUBK/1306, isolated tooth, lateral view

Explanation of Plate 6 (Bar length in all cases = 200 p, or otherwise specified)

Order Semionotidei

Indet. 1 a) RUBK/1307, isolated tooth, lateral view b) RUBK/1308, isolated tooth, lateral view c) RUBK/1309, isolated tooth, lateral view d) RUBK/1310, isolated tooth, lateral view

Order Semionotidei

Indet. 3 e) RUBK/1501, solated scale, dorsal view f) RUBK/1502, solated scale, ventral view g) RUBK/1503, solated scale, dorsal view h) RUBK/1504, solated scale, ventral view i) RUBK/1505, solated scale, dorsal view j) RUBK/1506, solated scale, ventral view k) RUBK/1507, solated scale, dorsal view 1) RUBK/1508, solated scale, ventral view m) RUBK/1509, solated scale, dorsal view n) RUBK/1510, solated scale, ventral view o) RUBK/1511, solated scale, dorsal view p) RUBK/1512, solated scale, ventral view q) RUBK/1513, solated scale, dorsal view r) RUBK/1514, solated scale, ventral view s) RUBK/1515, solated scale, dorsal view t) RUBK/1516, solated scale, ventral view WWSt X' ^•ff/Zy,:

*r* •^- Explanation of Plate 7 (Barlength in all cases = 200 p, or otherwise specified)

Order Semionotidei

Indet. 3 a) RUBK/1517, isolated scale, dorsal view b) RUBK71518, isolated scale, ventral view c) RUBK/1519, isolated scale, dorsal view d) RUBK/1520, isolated scale, ventral view

Order Semionotidei

Indet. 2 e) RUBK/1401, fragmentary jaw, lateral view f) RUBK/1402, fragmentary jaw, lateral view g) RUBK/1403, fragmentary jaw, lateral view h) RUBK/1404, fragmentary jaw, lateral view i) RUBK/1405, fragmentary jaw, lateral view j) RUBK/1406, fragmentary jaw, lateral view k) RUBK/1407, fragmentary jaw, lateralview 1) RUBK/1408, fragmentary jaw, lateralview m) RUBK/1409, fragmentaryjaw, lateral view n) RUBK/1410, fragmentary jaw, lateralview o) RUBK/1411, fragmentaryjaw, lateral view 4 /

•"*• SBSF

&*W?

iiwiw* . <*?* n Explanation of Plate 8 (Bar length in all cases = 200 p, or otherwise specified)

Lissodus indicus nov. comb. a) RUBK/1601, isolated tooth, lingual view b) RUBK/1602, isolated tooth, occlusal view c) RUBK/1603, isolated tooth, lingual view

Elasmobranchii indet.

TYPE-I d) RUBK/1701, isolated dermal denticle e) RUBK/1702, isolated dermal denticle f) RUBK/1703, isolated dermal denticle -A g) RUBK/1704, isolated dermal denticle h) RUBK/1705, isolated dermal denticle i) RUBK/1706, isolated dermal denticle j) RUBK/1707, isolated dermal denticle

TYPE-II k) RUBK/1801, isolated dermal denticles 1) RUBK/1802, isolated dermal denticles m) RUBK/1803, isolated dermal denticles n) RUBK/1804, isolated dermal denticles o) RUBK/1805, isolated dermal denticles p) RUBK/1806, isolated dermal denticles 8

4 Explanation of Plate 9 (Bar length in all cases = 500 p, orotherwise specified) Sphenodontidae Gen. et sp. indet. A X a) VPL/JU/KR/17, left premaxilla, medial view b) VPL/JU/KR/24, left premaxillary fragment, medial view c) VPL/JU/KR/21, left palatine, ventral view d) VPL/JU/KR/35, left premaxillary fragment, medial view e) VPL/JU/KR/1, left dentary, anterior symphyseal region, medial view

A Gen. et sp. indet. B f) VPL/JU/KR/45, right premaxilla, (inner, posterior). g) VPL/JU/KR/40, left maxillary fragment, lateral view, h) VPL/JU/KR/46, left maxillary fragment, medial view. i) VPL/JU/KR/38, symphyseal region of left dentary, medial view. j) VPL/JU/KR/38, symphyseal region of left dentary, lateral view. k) VPL/JU/KR/3 7, symphyseal region ofleft dentary, medial view. ^ 1) VPL/JU/KR/39, more posterior fragmentary dentary, lateral view. m) VPL/JU/KR/52, right maxillary fragment, medial view. n) VPL/JU/KR/47 partial right dentary, medial view. o) VPL/JU/KR/47, partial right dentary, lateral view.

Explanation of Plate 10 (Bar length in all cases = 500 p, or otherwise specified)

Acrodonta Gen. et sp. indet. a) VPL/JU/KR/88, anterior region of left maxilla, medial view b) VPL/JU/KR/88, anterior region of left maxilla, lateral view c) VPL/JU/KR/91,?posterior end of the left maxilla, lateral view d) VPL/JU/KR/98, anterior symphyseal region of right dentary, medial view view e) VPL/JU/KR/98, anterior symphyseal region of right dentary, lateral view f) RUBK/3001, posterior part of the left dentary, medial view g) RUBK/3001, posterior part of the leftdentary, lateral view h) RUBK/3002, posterior partof the left dentary, medial view i) RUBK/3002, posterior part of the leftdentary, lateral view j) VPL/JU/KR/86, mid region ofright dentary with hatchling dentition, medial view k) VPL/JU/KR/86, mid region ofright dentary with hatchling dentition, lateral view 1) VPL/JU/KR/80, anterior symphyseal region of leftdentary, medial view m) VPL/JU/KR/80, anterior symphyseal region of left dentary, lateral view n) VPL/JU/KR/93, posterior region of left dentary, medial view o) VPL/JU/KR/93, posterior region of left dentary, lateral view

Explanation of Plate 11 (Bar length inall cases = 500 p, orotherwise specified) Sauropoda indet. a) RUBK/5501, isolated tooth, medial view b) RUBK/5502, isolated tooth, medial view Thyreophora Type A c) RUBK/5601, isolated tooth, medial view d) RUBK/5602, isolated tooth, medial view e) RUBK/5603, isolated tooth, medial view f) RUBK/5604, isolated tooth, medial view g) RUBK/5605, isolated tooth, medialview h) RUBK/5606, isolated tooth, medial view i) RUBK/5607, isolated tooth, medial view j) RUBK/5608, isolated tooth, medial view Thyreophora Type B k) RUBK/5701, isolated tooth, medial view 1) RUBK/5701, enlarged part of posterior margin

Explanation of Plate 12 (Bar length inall cases = 200 p, orotherwise specified)

Order crocodilia Family ? Teleosauridae a) RUBK/4001, isolated tooth, lateral view b) RUBK/4002, isolated tooth, lateral view c) RUBK/4003, isolated tooth, lateral view 41 d) RUBK/4004, isolated tooth, lateral view e) RUBK/4005, isolated tooth, lateral view f) RUBK/4006, isolated tooth, lateral view g) RUBK/4007, isolated tooth, lateral view h) RUBK/4008, isolated tooth, lateral view i) RUBK/4009, isolated tooth, lateral view j) RUBK/4010, isolated tooth, lateralview k) RUBK/4011, isolated tooth, lateral view 1) RUBK/4012, isolated tooth, lateral view

Theropoda "A"

m) RUBK/6501, isolated maxillary tooth, lateral view, bar = 606 pm n) RUBK/6501, isolated maxillary tooth, medial view, bar = 570 pm o) RUBK/6501, a portion ofposterior denticles of maxillary tooth, bar=30 pm p) RUBK/6502, isolated maxillary tooth, medial view q) RUBK/6503, isolated premaxillary tooth, lateral view, bar = 400 pm r) RUBK/6503, denticles of premaxillary tooth, lateral view, bar = 40 pm s) RUBK/6504, denticles of premaxillary tooth, lateral view, bar = 40 pm t) RUBK/6504, isolated premaxillary tooth, lateral view, bar= 300 pm 12 Explanation of Plate 13

Theropoda "A"

a) RUBK/6505, anterior denticles ofpremaxillary tooth, scale bar =40 pm b) RUBK/6505, anterior denticles ofpremaxillary tooth, scale bar - 400 pm c) RUBK/6505, anterior denticles ofpremaxillary tooth, scale bar =40 pm d) RUBK/6506, ?posterior denticles of?premaxillary tooth, scale bar =40 pm e) RUBK/6506, isolated ?premaxillary tooth, scale bar =400pm f) RUBK/6507, isolated premaxillary tooth, scale bar = 400pm

Theropoda "B"

g) RUBK/6601, basal denticles ofposterior carinae, scale bar = 40pm h) RUBK/6601, basal denticles ofposterior carinae, scale bar =40pm i) RUBK/6601, isolated tooth, scale bar =400 pm j) RUBK/6602, isolated tooth, scale bar =400 pm k) RUBK/6602, posterior denticles, scale bar = 40 pm 1) RUBK/6603, posterior denticles, scale bar = 60 pm m) RUBK/6603, isolated tooth, scale bar = 400 pm n) RUBK/6603, anterior denticles, scale bar = 80 pm

Theropoda "C" o) RUBK/6701, posterior denticles scale bar = 80 pm p) RUBK/6701, isolated tooth, medial view, scale bar = 400 pm q) RUBK/6702, isolated tooth, lateral view, scale bar = 400 pm r) RUBK/6702, posterior denticles, scale bar = 80 pm

Theropoda "D" s) RUBK/6801, posterior denticles, scale bar = 80 pm t) RUBK/6801, isolated tooth, ?lateral view, scale bar = 400 pm 13 Explanation of Plate 14

(Bar length in all cases = 500 p, or otherwise specified)

Deniseodon godavariensis gen. et sp. nov. a) VPL/JU/KM/12, left upper premolar, occlusal view b) VPL/JU/KM/12, left upper premolar, labial view c) VPL/JU/KM/12, left upper premolar, lingual view d) VPL/JU/KM/12, left upper premolar, posterior view

Gondtherium dattai gen. et sp. nov.

1 e) VPL/JU/KM/14, right lower molar, lingual view. f) VPL/JU/KM/14, right lower molar, occlusolingual view. g) VPL/JU/KM/14, right lower molar, posterior view.

Triconodonta indet. h) VPL/JU/KM/15, fragmentary left lower molar, lingual view, i) VPL/JU/KM/15, fragmentary left lower molar, labial view. 14

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'

0» k

Explanation of Plate 15 (Bar length in all cases = 500 pm, or otherwise specified)

Dyskritodon indicus sp. nov. a) VPL/JU/KM/13, lower left molar, posteriorview. b) VPL/JU/KM/13, lower left molar, anterior view. c) RUBK/980013, fragmentary right lower molar, lingual view. d) RUBK/980013, fragmentary right lower molar, labial view. e) VPL/JU/KM/13, lower left molar, labial view. f) VPL/JU/KM/13, lower left molar, occlusal view. g) VPL/JU/KM/13, lower left molar, lingual view. h) VPL/JU/KM/13, posterior base of cusp a showing wear facet, bar= 55pm. i) VPL/JU/KM/13, middle portion of the crown showing wear facet (w) on the posterolabial border ofcusp a, bar=91pm. j) VPL/JU/KM/13, posterior part of crown showing wear facet (w) on posterolabial face ofcusp c, bar= 108pm. 15

-* *

Explanation of Plate 16 (Bar length in all cases = 500 p, or otherwise specified)

Paikasigudodon yadagirii sp. nov. a) VPL/JU/KM/10, right upper molar, lingual view. b) VPL/JU/KM/10, right upper molar, labial view. c) VPL/JU/KM/10, right upper molar, posterior view. d) VPL/JU/KM/10, right upper molar, anterior view. e) VPL/JU/KM/10, right upper molar, occlusal view. f) VPL/JU/KM/10, right uppermolar, lingual view. g) VPL/JU/KM/10, anterior part of the crown showing anterolingual wear facet on between cusps A and B. h) VPL/JU/KM/10, posterior part of the crown showing wear facet (w) on the posterolingual part ofthe cusp A and C. i) posterior part of the crown showing wear facet (w) on the posterolingual part of the cusp A and C 16 Explanation of Plate 17 (Bar length in all cases =500 p, or otherwise specified)

Indotherium pranhitai

a) VPL/JU/KM/11, right upper molar, lingual view. b) VPL/JU/KM/11, right upper molar, anterior view. c) VPL/JU/KM/11, right upper molar, occlusal view. d) VPL/JU/KM/11, right upper molar, labial view.

Mammalia indet. e) RUBK/980014, fragmentary phalange. f) RUBK/980015, fragmentary phalange. g) RUBK/980016, incisor, labial view, h) RUBK/980016, incisor, lingual view. 17 Explanation of Plate 18 (Bar length in all cases =500 p, or otherwise specified) Darwinula sarytirmensis a) RUBK/11001, left valve b) RUBK/11002, right valve c) RUBK/11003, dorsal view. d) RUBK/11004, ventral view.

Darwinula sp.

e) RUBK/11005, left valve. f) RUBK/11006, right valve. g) RUBK/11007, dorsal view, h) RUBK/11008, ventral view. 18