Silva Balcanica, 17(1)/2016

SOIL OF FAMILY (NEMATODA, ) IN DIFFERENT PLANT COMMUNITIES IN STRANDZHA MOUNTAIN (, TURKEY)

Iliyan Iliev1, Zhenya Ilieva2 1 Faculty of Biology, St. Kliment Ohridski Sofia University 2 Institute of Soil Science, Agrotechnology and Plant Protection – Sofia

Abstract

During 2009-2010, 30 different localities in the region of Strandzha Mountain were sampled for terrestrial nematodes. Sampling plots were located in plant communities typical for the region in the Bulgarian and Turkish part of the mountain. In total, 15 species of order Plectida were identified and data on their distribution, morphology and morphometrics are provided, Plectus cancellatus and Ereptonema arcticum being new geographical records. Fifteen species are reported for first time from the region of Strandzha, comprising 62% of all species of the family reported for Bulgaria. Twelve species are recorded in the Turkish part of the mountain and 11 of them are new for the fauna of Turkey. The representatives of family Plectidae were the most abundant group and had the highest species diversity of all soil nematodes in the studied localities (Iliev, 2014). The most frequently encountered specieswere Anaplectus granulosus, P. acuminatus and P. cirratus. These three species are the most abundant of all plectids identified in the investigated communities. Key words: abundance, Anaplectus, distribution, Ereptonema, morphology, Plectus, Tylocephalus, Wilsonema

INTRODUCTION

Strandzha is a low mountain in Southeastern Bulgaria and Northwestern Turkey. The highest peak is Mahiada (1031 m a.s.l.). The Bulgarian part is protected area that includes 33 natural habitats. Strandzha Mountain belongs to the Euxeinos botanic- geographic province. The region was not greatly influenced by Oligocene glaciations and developed a specific flora now distinguished by 63Tertiary relicts and 55 endemic plants (Gussev, Tzonev, 2014). Data on the nematode fauna of the region are scarce (Katalan-Gateva et al., 1991; Iliev, 1992; Lazarova et al., 1998) and the only study that includes species of Plectidae as a part of the general fauna covers three beech forests (Iliev, Ilieva, 2014). Gadea (1978) studied free-living nematodes of mosses in several habitats in the continental part of Turkey. He reported Plectus cirratus from three locations in Capadokia, Pamukkale and Bursa province. In a more recent study Akyazi et al. (2012, 2014) identified the genera Plectus and Wilsonema in potato crops and hazelnut orchards in the province of Ordu, Northeastern Turkey but no species were reported. To the best our knowledge, no investigations of the family have ever been conducted in the Turkish part of the mountain.

71 The aim of present study is to i) elucidate the composition and distribution of species of family Plectidae in Strandzha Mountain, and ii) provide morphological data about the species recovered.

MATERIAL AND METHODS

Sampling sites. During 2009-2010, 30 different localities in the region of Strandzha Mountain were sampled for nematodes. The plots were located in plant communities typical for the region in the Bulgarian and Turkish part of the mountain. A description of the sampling sites and periods is presented in Table 1. All habitats are distributed in the four Floristic-climatic zones of Strandzha: І. Coastal zone: the eastern low part of the mountain reaching the Black Sea Coast; ІІ. Rhododendron zone: deciduous forest with edificatorFagus orientalis Lipsky and abundant evergreen Tertiary relicts; ІІІ. High zone: Different oak associations; ІV. Northwestern arid zone: mixed forest with much less precipitation during the year, in comparison to the other zones of the mountain (Gussev, Tzonev, 2014). Sampling, extraction and processing. At most sites representing different habitats five bulk samples were collected for faunistic study; ten bulk samples were collected in seven habitats (2, 5, 6, 7, 9, 15, and 16) nine times for the period of investigation in order to describe population dynamics. Habitat 1 was sampled for population dynamics on the first year but at the beginning of the second year it was excluded due to local floods on the first two collection dates. Each sample consisted of 10 soil corers at 20 cm depth. Nematodes were extracted from 100 g of soil after homogenization using a modified Bearman method with 72 h exposition (Bezooijen, 2006), counted alive and gently fixed at 50oC in 4% formaldehyde. Up to 200 nematodes per sample were mounted on temporary slides for quantitative analysis (Paramonov, 1963). The rest of the specimens were mounted on permanent slides in glycerol (Seinhorst, 1959). The mounted specimens were measured and photographs were taken under DIC microscope Olympus BX60 with digital camera DP70 and specialized software Imaging System cell^B (Olympus). Relative densities were calculated on the basis of recovered mature nematodes and morphometric characters were described only from permanently mounted specimens. Terminology of species morphology is after Holovachov (2006). We used the classification of subfamilies and genera of Plectidae proposed by Holovachov, de Ley (2006). Old synonyms used in earlier records for Bulgaria are given for all species.

RESULTS AND DISCUSSION

During the study a total of 15 species of family Plectidae were identified from 363 samples collected in Strandzha region – 15 species in the Bulgarian part and 12 in the Turkish part of the mountain.

72 VII V, VI V, IX, X IX, X IX, X V, VI, V, V, VI, V, V, VI, V, II, VIII II, period** I, III, IV, I, III, IV, I, III, IV, I, III, IV, I, III, IV, I, III, IV, I, III, IV, I, III, IV, VII, VIII, VIII, VII, VII, VIII, VIII, VII, VII, VIII, VIII, VII, Sampling Sampling 5 15 15 15 105 250 m a.s.l. Altitude 3’40” o 57’55” o GIS 27°59’13” 28°01’41” 27°47’35” 27°45’51” 27°45’53” N 42 coordinates E 27 N 41°59’01” E N42°18’24” E N 42°03’23” E N 42°06’42” E N 42°03’10’’ E N 42°03’10’’

Cyclamen coum Mill.) Cyclamen ( Habitat Bulgaria summer snowflake ( Leucojum aestivum pseudocorus L .), summer snowflake Soil type***: Fluvisols Soil Soil type***: Fluvisols Soil Soil type***: Leptosols, Rendzik Soil etc. At the base of the slope meadows are bordered by aged by , etc. trees: the At base of thebordered slope are meadows Typha latifolia L.), etc. bulrush ( Typha Huds.), Description of studied habitats and sampling periods 1. Description Table Haplic Alisols rich and humid Haplic developed, type***: well Soil Molic Gleyisols type***: humid and deep rich organic Molic Soil Stev.) and Cerris oak ( Q. cerris ). oak ( Q. hartwissiana Stev.) Strandzha eastern sowbread sp .), and perennial rush ( Luzula Ephedra distachya L. and gramineous grasses with a dominant species Ephedra Coastal open area sp.), Poacea gen. spp., Fabacea gen spp., and and gen spp., Fabacea gen. spp., Poacea L.), blackberry sp.), ( Rubus regia walnut ( Juglans Willd.), and Black Sea mission bell mission bell Sea and Black Willd.), tauricum ( Symphytum comfrey acutifolius L.), Crimean Smilax excelsa L.), etc. excelsa ( Clematis vitalba L.), Smilax beard woody and herbaceous stems: o ld man’s Rhododendron ponticum L.), of shrubs ( Rhododendron and herbs: pontic rhododendron dense undergrowth common nettle ( U. dioica ) Asparagus aculeatus L.), wild asparagus ( Asparagus ( Ruscus of shrubs:with undergrouth butcher’s-broom Schur.); Schur.); Q. polycarpa durmast ( orientalis Lipsky) and Oriental beech ( Fagus of Oriental Forest sp.), Festuca sp.), of wood-rush ( Luzula undergrowth laevis Pall.), white-elm ( Ulmus and European water flag ( Iris sp.), sedge ( Cyperus sp., Rumex hydrolapathum water dock ( Rumex great sp., dioica L.), Polygonum L.), common nettle ( Urtica sp.), Persian Persian sp.), ( Salix of black alder ( A. glutinosa ), willow in late winter to spring with single trees Meadows near Veleka river (secondary succession of gardens – 20 years ago). Regularly flooded flooded ago). Regularly (secondary – 20 years river succession of gardens Veleka near Meadows (Sm.) Greut.), etc. Greut.), (Sm.) rubra acaulis spp. ( Primula Caucasian primrose Wahlenb.), pontica Fritillaria Alnus glutinosa Gartn.) black alder ( Alnus Willd.), oxycarpa of Caucasian ash ( Fraxinus Longose forest L.) cerris L.) and Cerris oak ( Quercus Ten.) frainetto oak ( Quercus of Hungarian coastal forest Windy Ruscus hypoglossum L.), wood- L.), mouse thorn ( Ruscus pontica daphne ( Daphne single shrubs of Pontic ), climbing plants with ) and black alder ( A. glutinosa ), climbing plants with oxycarpa of Caucasian ash ( F. Longose forest ( area Elijah village reka-1 village village Veleka Locality Protected Protected Protected Protected Protected Protected Estuary of Near Kosti Kosti Near Locality St. Locality St. area Silistar area area Marina Marina area – Butamjata Maslen cape Maslen Near Rezovo Rezovo Near I I I I II II Zone* 2 1 3 4 5 6 N

73 I I II II IX, X IX, X V, VI, V, V, VI, V, II, VII II, period** I, III, IV, I, III, IV, I, III, IV, I, III, IV, VII, VIII, VIII, VII, VII, VIII, VIII, VII, Sampling Sampling 230 278 255 265 270 211 420 m a.s.l. Altitude 05’48” E 06’24” E 39’55” 50’36” GIS o o o o 27°39’09 27 27 25°35’14” 27°45’54” 27°40’53” 27°20’21” coordinates N 42 N 42 N 42°18’60” E N 42°06’58” E N 42°06’02” E N 42°00’17” E N 41°51’40” E

and different ; and different Pontic daphne ), Pontic . ) and herbaceous plants: eastern ontica ) and herbaceous plants: eastern Pontic germanica L.), Pontic , medlar ( Mespilus etc. L.), wild asparagus latifolia ( Phyllyrea e trees , Habitat Table 1. Continued Table Bulgaria D. pontica ) ( gramineous grasses. Soil type***: Alisols Soil Soil type***: Luvisols Soil C. coum ), gramineous grasses, etc. ( ) undergrowth ) undergrowth durmast ( Q. polycarpa оr ientalis ) and Oriental Haplic Alisols type***: Haplic Soil Haplic Alisols type***: Haplic Soil Haplic Alisols type***: Haplic Soil Lithic Leptosols type***: Lithic Soil Chromic Luvisols type***: Chromic Soil Ilex colchica Poj) of Colchis holly ( Ilex L.) incanus ( Cistus of rockrose cover Sedum hispanicum L.), and etc. ( Sedum stonecrop sowbread sp.), perennial: eastern sowbread ( C. coum ) eastern sowbread perennial: blackberry sp.), ( Rubus , (Hedw.) Angstr.) L.) and moss ( Leucobryumarctostaphylos glaucum (Hedw.) Spanish pontica ), Spanish mission bell ( F. Sea acutifolius L.), garmineous grasses, Black Asparagus Prunus of cherry ( Prunus orientalis with dense undergrowth laurel beech – F. of Oriental Forest ( ); single shrubs orientalis of beech ( F. ) and Oriental durmast ( Q. polycarpa of Oriental Forest and dense Q. frainetto) oak ( and Hungarian durmast ( Q. polycarpa) of Oriental trees Single single shrubs ( Rh. ponticum ) of pontic rhododendron ); undergrowth with with ); undergrowth durmast ( Q. polycarpa ) and Oriental orientalis beech ( F. of Oriental Forest Vaccinium of Caucasian whortleberry) with undergrowth orientalis ( Vaccinium beech ( F. of Oriental Forest Ruscus hypoglossum L L.), Colchis holly ( I. colchica ), mouse thorn Ruscus laurocerasus green oliv of green with pioneer vegetation rock Siliceous Mixed forest of Oriental beech ( F. of Oriental forest Mixed ), Pontic daphne ( D. р ( Rh. ponticum ), Pontic pontic rhododendron daphne ( D. pontica ) prast Near Near reka-2 village Under Under reserve Locality Locality Locality Silkosiya Silkosiya Daskalite Protected Protected Protected Protected Indipasha Kondolovo Kondolovo Papiya peak Papiya area Marina Marina area Zone Bjalata Zone II II II II II II III Zone* 9 7 8 N 10 12 11 13

74 I V V V I, IX IX, X IX, X V, VI, V, V, VI, V, V, VIII V, period** I, III, IV, I, III, IV, I, III, IV, I, III, IV, VII, VIII, VIII, VII, VII, VIII, VIII, VII, Sampling Sampling 5 11 20 20 224 385 220 319 m a.s.l. Altitude GIS 27°39’35” 27°29’32” 27°21’44” 27°19’36” 27°57’32” 27°57’31” 27°56’54” 27°56’44” coordinates N 41°58’54” E N 41°57’38” E N 42°09’01” E N 42°11’37” E N 41°51’27” E N 41°49’43” E N 41°51’51” E N 41°51’54” E

Galium C. coum ), woodruff ( Galium ( L.), etc. nivalis Galanthus ( ), etc. Scop . Turkey Habitat Table 1. Continued Table Bulgaria Carpinus betulus of common hornbeam ( Carpinus and single trees

Soil type***: Leptosols Soil odoratum (L.) odoratum Eutric Fluvisols type***: Eutric Soil R. aculeatus butcher’s-broom Rendzik Leptosols type***: Rendzik Soil Chromic Cambisols type***: Chromic Soil F. oxycarpa of field ash – F. Longose forest dioica L.), common snowdrop nettle ( Urtica L. and single Cerris oak trees – Q. cerris L. vulgaris L. and single Cerris oak trees common lilac – Syringa spp., etc. spp., pontica , Geranium mission bell – F. Sea gramineous grasses, Black and Oriental durmast – Q. polycarpa orientalis and Oriental beach – F. of Oriental Forest Gartn.) forest on the bank of Rezovska river with with river on the bank of Rezovska glutinosa Gartn.) forest Alluvial black alder ( Alnus Mill., orientalis Mill., hornbeam – Carpinus of Oriental on karst (<30% canopy cover) Shrubs of D. pontica , eastern sowbread undergrowth L.) and scarce with undergrowth of of and Cerris oak – Q. cerris with undergrowth durmast – Q. polycarpa of Oriental Forest L.), common sanguineum L.), common of gramineous grasses, bloody geranium ( Geranium undergrowth Forest of aged trees of Strandzha oak – Q. hartwissiana and Cerris oak – Q. cerris. with rich of Strandzha of aged trees Forest R. aculeatus of butcher’s-broom with undergrowth oak – Q. frainetto of and Hungarian Forest ) orientalis beech ( F. of Oriental Forest European cornel – Cornus mas L., common – C. orientalis , European hornbeam of Oriental undergrowth L., campestre ornus L., field maple – Acer dogwood – Cornus sanguinea L., manna ash – Fraxinus river river 1**** village close to Locality Locality Propada Locality Slivarovo Slivarovo Protected Protected springs of springs of Shafariica Igneada – – Igneada Above the the Above Mladezhka Igneada – 2 Igneada Igneada – 3 Igneada Igneada – 4 Igneada Zone Bataka Zone I I I I IV III III IV Zone* N 16 15 14 17 18 19 20 21

75 V V V V V V, VIII V, V, VIII V, V, VIII V, V, VIII V, period** Sampling Sampling 22 45 45 52 190 380 655 360 436 m a.s.l. Altitude GIS 28°05’08” 27°59’26” 27°59’26” 27°54’36” 27°48’50” 27°45’30” E27°44’13” E27°33’21” E27°33’24” coordinates N41°47’43” N41°49’56” N 41°50’25” N 41°39’25” E N 41°56’42” E N 41°56’42” E N 41°57’44” E N 41°49’03” E N 41°49’17” E Oriental erris , Oriental and Hungarian oak – Q. erris and Hungarian , rockrose – C. incanus, Thymus spp ., , rockrose Habitat Table 1. Continued Table Bulgaria ponticum L. andrachne undergrowth of gramineous grasses undergrowth Carpinus orientalis, etc. hornbeam – Carpinus F. orientalis beech – F. of Oriental Forest F. orientalis beech – F. of Oriental Forest with undergrowth of gramineous grasses with undergrowth frainetto L. L. betulus of common hornbeam – Carpinus Forest with Q. cerris with and Cerris oak – Wild, pubescens oak – Quercus of downy forest Scarce Greek strawberry – Arbutus tree acutifolius L., Greek of wild asparagus – Asparagus undergrowth Q. с of Cerris oak – syriaca L. and single trees mountain tea – Sideritis Greek Shrubs and grasses on karst above cave – Chrysopogon cave sp . on karst above and grasses Shrubs with undergrowth of pontic rhododendron – Rh. of pontic rhododendron with undergrowth durmast – Q. polycarpa of Oriental Forest with with oak – Q. frainetto and Hungarian durmast – Q. polycarpa of Oriental forest young Scarce with undergrowth of pontic rhododendron – Rh. ponticum of pontic rhododendron orientalis with undergrowth beech – F. of Oriental Forest , Cerris oak – Q. с durmast – Q. polycarpa of Oriental forest Scarce village Kiyikoy Kiyikoy cave – 1 cave – 2 cave village 1 village 2 Locality Dupnica Dupnica Dupnica Region of Region Region of Region Region of Region Region of Region Region of Region Region of Region Region of Region Beigendik Beigendik Beigendik Beigendik Shishlioba Vicinity of Vicinity of Vicinity Demirköy 3 Demirköy Demirköy 2 Demirköy Demirköy 1 Demirköy I II II II II III III III III Zone* N 23 22 24 25 26 28 27 29 30 -Northwestern arid zone ІV -Northwestern zone; ІІІ -High zone; ІІ -Rhododendron І- Coastal zone; of Strandzha: zones *Floristic-climatic VII VI – 3-5.04.2010; V – periods: 28-30.11.2009; I-16-19.04.2009; II – 3-5.05.2009; III -3-6.06.2009; III – 1-4.08.2009; ** IV Sampling – 28.09-4.10.2009; VIII – 31.07-2.08.2010; IX 29-30.11.2010 – 25.05.-1.06.2010; et al., 2009) – Atanasov type (after FAO-UNESCO-ISRIC *** Soil Park National Forests Floodplain Igneada ****The

76 Subfamily Anaplectinae Zell, 1992 Anaplectus granulosus (Bastian, 1865) de Coninck et Schuurmans Stekhoven, 1933 Syn. Plectus g. Bastian, 1865 (Fig. 1i, 3) The species was found in most habitats in all studied periods: in zone I: 1, 2, 3, 18, 19, 20, 21 and 22; in zone II: 5, 7, 8, 9, 10, 24 and 25; in zone III: 13, 14, 15 and 27, 28, 30, and in zone IV: 16, 17. Its relative density was 1-13 individuals per 100 g soil. The species has been reported from natural areas in Bulgaria, in different habitats in coniferous forests and the Subalpine belt of Mountain (Andrássy, 1958, Ilieva, 1998; 2007), in the vicinity of Varna, (Andrássy, 1958) and in a forest of Quercus frainetto Ten. in Prisad village, Burgas region (Alexiev et al., 1998). There are also several records from agricultural lands: in tobacco fields close to Gotse Delchev in the valley of Mesta river, in the vicinity of Razlog, Blagoevgrad region, in Markovo village, Plovdiv region (Katalan-Gateva, Baicheva, 1978; Katalan-Gateva, Stefanov, 1978), and in hop fields in Samokov (Katalan-Gateva, Milkova, 1978). Considering the worldwide distribution of A. granulosus (Andrássy, 1985; Holovachov et al, 2004) the species is probably more widely spread in the country. Subfamily Plectinae Örley, 1880 Plectus andrassyi Timm, 1971 Syn. Chiloplectus a. (Timm, 1971) Andrássy, 1984 (Table 2; Fig. 1g, h and 4) Our specimens are similar to the Ukrainian populations of the species described by Holovochov et al. (2000). Lips are strongly setoff but relatively low in comparison with other close species found in studied area – P. cancellatus. No longitudinal incisures were observed on the cuticle. Different parts of pharynx are not well discernable, cylindrical part of pharynx gradually enlarges into basal bulb. The species was found in zone I: habitat 19, zone II: 5, 6, and 11 and zone III: 14. Its relative density was 1 – 17 individuals per 100 g soil. The most abundant population was in Papija locality (11): 12-17 individuals per 100 g soil counted in April, 2009. In other habitats single females were found in all studied periods. No males were isolated. The species has been reported from Bulgaria in a study of moss on stones in Mountain (Lazarova et al., 2000) but without any data on its morphology. Plectus cancellatus Zullini, 1978 (Table 2; Fig. 1f and 5) Syn. Chiloplectus c. (Zullini, 1978) Holovachov et al. 2000; Chiloplectus loricatus Andrássy, 1985 Our specimens are characterized by a relatively high and strongly setoff lip region and a thick cuticle with longitudinal incisures well visible from the end of pharynx to V-an region of body under light microscopy. The corn-like structure of cuticle can hardly be observed in this region and is better visible at the level of the vulva. Cephalic setae are thick and directed forward. First lateral seta originates 19 annulations after lips in two of Bulgarian specimens and 20 annulations after lips in all others. In 4 specimens the

77 Fig. 1. Habitus of different species: a –P. parietinus; b, c – P. acuminatus; d – P.cirratus; e – P. rhyzophilus; f – P. cancellatus; g, h – P. andrassyi; I – A. granulosus (Scale 200 µm) total number of somatic setae was counted as follows: 7 pairs in pharyngeal region (2 ventral, 2 subventral and 3 subdorsal); 3 pairs in the cardia-vulva region, last pair slightly before vulva level; 3 pairs in vulva-anus region (4 in one of the specimens), and two pairs and spur on tail. Our specimens are with clearly visible wide amphidial apertures with almost regular circular shape but we consider that shape and size could be influenced by the fixation procedure. The apertures are located 17-18 μm from the anterior end

78 Table 2. Morphometric data of Plectus specimens found in the present study. Measurements in the form: mean ± standard deviation (range) Species P. andrassyi P. cancellatus Habitat 11 Habitat 15 Habitat 30 Character (n=16) (n=5) (n=1) 966 ± 37 859 ± 40 L (µm) 1021 (894 – 1012) (821 – 901) 19 ± 2 26 ± 7 a 22 (17 – 22) (18 – 31) 4.2 – 0.1 4.0 – 0.2 b 4.0 (4.1 – 4.4) (3.8 – 4.2) 9.5 ± 0.8 9.8 ± 1.6 c 11.6 (8.6 – 11.2) (8.6 – 11.6) 3.7 ± 0.3 4.2 ± 0.5 c’ 3.4 (3.1 – 4.2) (3.7 – 4.8) 48 ± 1 50 ± 3 V (%) 51 (47 – 49) (47 – 52) 11 ± 0.8 11 ± 1 Body diameter at lip region (µm) 10.5 (11 – 13) (10 – 13) 3.1 ± 0.3 6 ± 1 Lip height (µm) 5 (3 – 4) (5 – 7) 46 ± 5 35 ± 6 Body diameter at base of pharynx (µm) 46 (41 – 56) (30 – 39) 51 ± 6 34 ± 9 Body diameter at mid-body (µm) 47 (44 – 59) (29 – 45) 27 ± 2 Body diameter at anus (µm) 21 26 (23 – 31) 230 ± 8 216 ± 3 Neck (µm) 258 (214 – 242) (214 – 219) 105 ± 16 Corpus (µm) 111 (86 – 114) 60 ± 13 Istmus (µm) 84 (51 – 75) 29 ± 3 Length of basal pharyngeal bulbus (µm) 32 – 34 35 (24 – 33) 11.5 ± 0.8 17 ± 0.8 Length of postbulbal prolongation (µm) 18 (10 – 12) (10 – 12) 13 ± 1 Vagina (µm) 11 – 12 18 (11 – 15) 21 ± 2 24 ± 2 Rectum (µm) 27 (18 – 23) (23 – 26) 102 ± 9 89 ± 11 Tail (µm) 88 (85 – 113) (78 – 100) 144 ± 6 124 ± 5 Distance from anterior end to excretory pore (µm) 160 (134 – 154) (119 – 128) 150 ± 6 134 ± 6 Distance from anterior end to deirids (µm) 168 (140 – 159) (127 – 137)

79 Table 2. Continued Species P. andrassyi P. cancellatus 123 ± 6 100 ± 17 Distance to beginning of nerve ring (µm) (113 – 131) (88 – 112) Annulli at stoma level 1.4 – 1.5 1.7 2.5 Annulli at midbody 1.1 – 1.2 1.5 – 1.7 2 Annulli at tail 1.2 – 1.5 1.3 – 2 2 21 ± 2 23 ± 1 Length of stoma (µm) 28 (20 – 24) (22 – 23) 4.8 ± 0.7 Width of gymnostoma apically (µm) 4.0 4.0 (4 – 6) Gymnostoma length (µm) 2-3 4.0 4.0 3.6 ± 0.2 3.2 ± 0.3 Length of cephalic setae (µm) 4 (3.5 – 4) (3 – 3.5) 2.3 ± 0.6 Origin of cephalic setae – annuli after lips 4 3 (2 – 3) Amphids location – length from anterior end to 12 ± 1 18 16 amphidial orifice (µm) (10 – 13) 3.8 ± 0.4 Amphidial orifice diameter (µm) 3.5 – 4 4 (3.5 – 4) 7.8 ± 0.4 Position of amphidial orifice – annuli from lip base 7 – 8 8 (7 – 8) 463 ± 17 430 ± 17 Distance from anterior end to vulva (µm) 523 (433 – 490) (415 – 449) 400 ± 17 341 ± 50 Distance from vulva to anus (µm) 410 (363 – 425) (307 – 398) 11 ± 4 11 ± 1 Distance from spur to tail tip (without spinneret) (µm) 14 (7 – 16) (10 – 12) 4.3 ± 0.5 Diameter at amphid region /Diameter of amphidial orifice 4.3 – 4.4 4.5 (4 – 5.3) 3.1 ± 0.5 Diameter at lip region /Diameter of amphial orifice 2.8 – 3.0 2.6 (2.8 – 4.0) 4.0 ± 0.6 3.2 ± 1.0 Diameter at base of pharynx / diameter at lip region 4.4 (3.2 – 5.1) (2.5 – 3.9) 3.8 ± 0.7 3.2 ± 0.8 Diameter at mid body/Vagina 2.6 (2.9 – 4.8) (2.6 – 3.8) 4.0 ± 0.4 3.9 ± 1.1 Distance from vulva to anus / Tail 4.7 (3.5 – 4.7) (3.1 – 5.1) 0.8 ± 0.1 Rectum / Body diameter at anus 1.1 – 1.2 1.0 (0.7 – 1.1) Cuticle at stoma (µm) 2.0 2.8 – 3.0 3 Cuticle at midbody (µm) 2.0 3.0 – 5.0 5.5 2.2 ± 0.3 Cuticle at ventral part of the tail (µm) 3.0 – 4.0 3.0 (2 – 2.5) Width of lateral field (µm) 6 – 7 5 – 6 5.5

80 in Bulgarian specimens and 16 μm in Turkish specimen. The Turkish specimen rather resemble the description of C. loricatus by Andrasy (1985) as compared to the data presented by Holovachov et al. (2000). The species was found in zone III: habitats 15 and 30 with relative density 1-5 individuals per 100 g soil. The most abundant population was in Propada locality (15): 5 individuals per 100 g soil observed in November 2009. Plectus cf accuminatus Bastian, 1865 (Table 3; Fig. 1b, c; 6c, d, k; 7c, f, i, l, q and r) Our populations resemble those described by Boström (1995, 1997) but body length is generally smaller. In most specimens the cervical setae are quite thick and directed foreward, but in some outward. Somatic setae are not clearly visible in most of specimens: 8-9 pairs in pharyngeal region, 2 pairs in cardia-vulva region; 1(2) pairs in vulva-anus region and 6-7 setae on cauda. Most of the studied specimens have a C-shaped tail when relaxed with a narrowing before the half of its length. General view of tail is more slender in comparison to P. cirratus (C-form but generally more cylindrical) and P. parietinus (more straight and uniformly conoid). All observed specimens have two sphincters around the vagina and a relatively short rectum between 19 – 24 µm. No males were found. The species was found in most habitats in all studied periods: in zone I: 3 and 22, in zone II: 5, 6, 7, 8, 9, 10, 12, 23 and 26, in zone III: 15, 27, 28, 29 and 30, and in zone IV: 17. Its relative density was 1-88 individuals per 100 g soil. Highest abundance was observed in cooler months. In November and April in habitats 6, 7 and 9 the individuals counted in 100 g soil were 72, 88 and 82, respectively. The species has been reported from natural areas in Bulgaria: in different habitats in the coniferous forest belt and the Subalpine belt in Rila Mountain (Ilieva, 1998; 2007) and in Prisad village, Burgas region (Alexiev et al., 1998). Katalan-Gateva (1985) transferred all records originally concerning P. communis to P. accuminatus (Stoyanov, 1961; Katalan-Gateva, 1961; Katalan-Gateva, Budurova, 1975, 1978; Katalan-Gateva, Baicheva, 1976, Katalan-Gateva et al., 1981). As far as neither permanent slides are currently available, nor descriptions of found specimens have been presented we assume that the records are doubtful and needed further confirmation. Plectus cirratus Bastian, 1865 (Fig. 1b, 6b, e, i, j; 7b, e, h, o and p) The species was found in zone I: habitats 2, 3, 18, 19, 20, 21 and 22; zone II: 5, 6, 7, 8, 9, 10, 11, 12, 23, 24 and 26; zone III: 12 and 30; and zone IV: 17 with relative density 1-94 individuals per 100 g soil. The most abundant populations are in habitats 8, 14, 20, 21, 23 and 24 with relative density between 62 and 94 individuals per 100 g soil. P. cirratus is the most frequently reported species of family Plectidae in Bulgaria. It has been found in many parts in Bulgaria: in the vicinity of Varna, in Balkan, the Rhodopes and Vitosha (Andrassy, 1958), Rila Mountain (Andrássy, 1958; Ilieva, 2007), Mountain (Katalan-Gateva, 1968), and different agricultural fields in Sofia region (Stoyanov, 1961; Katalan-Gateva, Milkova, 1978), Pazardzhik region (Katalan-Gateva,

81 Table 3. Morphometric data of specimens of P. acuminatus found in the present study. Measurements in the form: mean ± standard deviation (range)

Habitat 7 Habitat 9 Habitat 17 Habitat 26 Character (n=20) (n=20) (n=20) (n=12) 659 ± 36 688 ± 16 674 ± 44 750 ± 72 L (µm) (618 – 694) (675 – 706) (602 – 727) (691 – 874) 21 ± 3 18 ± 1 20 ± 2 22 ± 3 a (17.5 – (17 – 18.5) (19 – 23) (19 – 26) 23.5) 3.5 – 0.1 3.8 – 0.2 3.7 – 0.1 3.9 – 0.4 b (3.5 – 3.6) (3.6 – 3.9) (3.5 – 3.9) (3.5 – 4.6) 10 ± 1 9.1 ± 0.8 9.3 ± 0.9 9.3 ± 0.7 c (8.8 – 11.6) (8.3 – 9.9) (7.6 – 10.1) (8.1 – 9.9) 3.3 ± 0.2 3.9 ± 0.5 3.8 ± 0.5 4.4 ± 0.9 c’ (3.0 – 3.5) (3.5 – 4.5) (3.3 – 4.6) (3.6 – 5.8) 52 ± 1 51 ± 1 51 ± 1 50 ± 3 V (%) (50 – 54) (50 – 53) (50 – 53) (45 – 53) 11.5 ± 0.48 10.8 ± 0.8 12.2 ± 0.8 12.2 ± 0.4 Body diameter at lip region (µm) (11 – 12) (10 – 11.5) (11.5– 13) (12 – 13) Lip height (µm) 5 5-6 4-5 3-5 37 ± 2 34 ± 5 35 ± 3 34 ± 4 Body diameter at base of pharynx (µm) (34 – 39) (30 – 39) (31.5 – 39) (29 – 40) 37 ± 2 33 ± 5 33 ± 3 35 ± 5 Body diameter at mid-body (µm) (34 – 39) (30 – 39) (31 – 38) (29 – 42) 21 ± 1 20 ± 1 19 ± 2 19 ± 4 Body diameter at anus (µm) (20 – 21) (19 – 21) (17 – 22) (15 – 24) 186 ± 8 183 ± 6 182 ± 9 194 ± 5 Neck (µm) (176 – 194) (180 – 190) (170 – 195) (188 – 200) 79 ± 6 79 ± 5 78 ± 11 76 ± 3 Corpus ((µm) (71 – 86) (73 – 81) (67 – 89) (73 – 80) 58 ± 8 53 ± 6 64 ± 8 64 ± 2 Istmus (µm) (47 – 65) (49 – 60) (55 – 76) (62 – 67) 28 ± 4 29 ± 2 26 ± 2 29 ± 2 Length of basal pharyngeal bulbus (µm) (23 – 31) (27 – 30) (27 – 23) (26 – 31) 10 ± 2 12 ± 0.8 11 ± 1.7 9 ± 3.8 Length of postbulbal prolongation (µm) (8 – 12) (11 – 13) (8 – 13) (4.5 – 13) 10 ± 2 12 ± 0.0 10 ± 2 11 ± 2 Vagina (µm) (10 – 13) (11 – 12) (7 – 12) (7 – 12) 23 ± 1 23 ± 3 21 ± 1 22 ± 1 Rectum (µm) (22 – 24) (20 – 26) (19 – 23) (21 – 23) 68 ± 6 76 ± 9 73 ± 6 81 ± 10 Tail (µm) (60 – 74) (68 – 85) (65 – 81) (71 – 91) Distance from anterior end to excretory 104 ± 7 99 ± 3 102 ± 10 112 ± 7 pore (µm) (100 – 115) (96 – 105) (93 – 118) (102 – 119) 113 ± 7 107 ± 3 108 ± 5 119 ± 6 Distance from anterior end to deirids (µm) (100 – 115) (105 – 110) (101 – 127) (111 – 125)

82 Table 3. Continued Habitat 7 Habitat 9 Habitat 17 Habitat 26 Character (n=20) (n=20) (n=20) (n=12) 91 ± 5 86 ± 3 91 ± 7 92 ± 7 Distance to beginning of nerve ring (µm) (87 – 98) (82 – 91) (82 – 100) (82 – 100) Annulli at midbody 1.3 – 1.4 1.3 – 1.4 1.2 – 1.4 1.3 – 1.4 21 ± 2 22 ± 3 23 ± 3 24 ± 2 Length of stoma (µm) (19 – 22) (19 – 25) (16 – 25) (22 – 28) Width of gymnostoma apically (µm) 4.5 – 5 4 – 5 4 – 5 4 – 5 Gymnostoma length (µm) 5 5.5 – 6 5 5 – 6 Length of cephalic setae (µm) 2.8 – 3.5 3 – 3.5 3 – 3.5 3 – 3.5 Origin of cephalic setae – annuli after lips 3 3 – 4 3 – 4 3 – 4 Location of amphidial orifice – length from 11 – 14 12 – 16 12 – 17 13 – 16 anterior end to amphids (µm) 2.6 2.5 2.8 3.2 Amphidial orifice diameter (µm) (2.5 – 3) (2.5 – 3) (2.5 – 3.5) Position of amphidial orifice – annuli from lip base 11-12 11 – 12 9 – 11 9 -12 345 ± 16 353 ± 8 347 ± 28 370 ± 14 Distance from anterior end to vulva (µm) (326 – 364) (344 – 359) (298 – 377) (351 – 389) 246 ± 24 259 ± 11 255 ± 18 299 ± 26 Distance from vulva to anus (µm) (224 – 270) (249 – 264) (225 – 279) (265 – 398) Distance from spur to tail tip (without 8 ± 1.3 8 ± 1.2 9 ± 1.2 9 ± 1.3 spinneret) (µm) (7 – 10) (7 – 9) (8 – 11) (8 – 11)

Width of annuli at midbody (µm) 1.3 – 1.4 1.3-1.4 1.3 – 1.4 1.3-1.4

Diameter at lip region /Diameter 5.5 – 6 6 6 5 – 6 of amphidial orifice Diameter at lip region /Diameter 4.4 ± 0.5 4.3 ± 0.5 4.3 ± 0.7 4.2 ± 0.7 of amphidial orifice (3.7 – 4.8) (3.8 – 4.7) (3.8 – 5.2) (3.4 – 5.2) Diameter at base of pharynx / Diameter 3.2 ± 0.3 3.1 ± 0.3 3.4 ± 0.4 4.0 ± 0.5 at lip region (2.8 – 3.4) (2.7 – 3.4) (2.8 – 3.7) (3.2 – 4.4) 3.7 3.4 3.7 4 Diameter at mid body/Vagina (3.2 – 3.7) (3.1 – 3.9) (2.9 – 4.7) (3.2 – 5.4) 3.7 3.4 3.4 3.7 Distance from vulva to anus / Tail (3.2 – 4.5) (3.1 – 3.7) (2.8 – 3.7) (3.1 – 4.4) Rectum / Body diameter at anus 1 – 1.2 1 -1.7 1 – 1.3 1 – 1.4 Cuticle at midbody (µm) 2 – 3 2.5 – 3 2.5 – 3.0 2.5 – 3.5 Cuticle at ventral part of the tail (µm) 2.5 – 3 3.0 – 3.5 2.5 – 3.0 2.5 – 3.5 Width of lateral field (µm) 4 – 5 4-5 4 -5 4 -5

1961), Plovdiv region (Zhivkov, Baicheva, 1974; Katalan-Gateva et al, 1981), Stara Zagora and Haskovo regions (Katalan-Gateva, 1965, Katalan-Gateva et al., 1981), and Blagoevgrad region (Katalan-Gateva, Baicheva, 1976, 1978). Тo our knowledge P. cirratus is the only species of family Plectidae reported from the territory of Turkey. Gadea

83 Fig. 2. Habitus of different species: a – P. assimilis; b – P. armatus, c – Tylocephalus auriculatus; d –Wilsonema otophorum; e – Ereptonema arcticum; f – P. minimus; g, h – P. longicaudatus; i– P. parvus (Scale – 200 µm)

(1978) studied free-living nematodes of mosses in several habitats in continental Turkey. He reported P. cirratus from detritus under moss in Capadokia at 1260 m, Pamukkale at 400 m and the Uludağ mountain in Bursa province at 1850 m. Plectus longicaudatus Bütschli, 1873 Syn. Proteroplectus l. (Bütschli, 1873) Paramonov, 1964 (Table 4; Fig. 2g and h; 8a, b, c, d, n, o, s and t) Our specimens are similar to those described by Andrássy (1985). Cephalic setae 84 Fig. 3. A. granulosus: a. – Neck; b. c – Lip region; c. –Amphid and cephalic papilla; d. – Lateral field with deirid and ventrolateral pores of hypodermal glands; f – Basal bulb; g – Tail tip of male with caudal sensillae, h– Vulva; i. – Spiculae; j – Supplements; k – Tail of female, l, m. – Tail of male; n – Anterior gonad (Scale on a, k, l, m and n – 100 µm; Scale on b, c, d, e, f, g, h, i and j – 20 µm)

85 are fine and orientated forward. Setae are clearly visible on the tail and almost invisible at other body parts. Lateral field is about 4-5 µm with two alae and three incisures. Tail in most of the specimens is strongly ventrally curved. The species was found in zone I: habitats 3 and 20, zone II: 6, 7, 8, 9, 10 and 12, zone III: 13, 15, 27 and 28 and zone IV: 17 with relative density 1-6 individuals per 100 g soil. P. longicaudatus was reported from Bulgaria in natural habitats in the vicinity of Varna, in Vitosha and the Balkan Range (Andrássy, 1958), in Rila (Ilieva, 1998; 2007) and Pirin (Katalan-Gateva, 1968), in Prisad village, Burgas region (Alexiev et al, 1998), and in agricultural areas in Pazardzhik region (Gateva, 1961) and Sofia valley (Stoyanov, 1961). Plectus minimus Cobb, 1893 (Table 4; Fig. 2f; 9a, b, c, d, e, q, r, and s) Our specimens are similar to those described from northern Spain (Hernandes et al., 1998). Cuticle annuli are disctinct and very prominent at tail region. Lateral field is hardly visible with no clear incisures in it. Cephalic setae are very fine and orientated outward. Setae are clearly visible on the tail and almost invisible at other body parts. Deirids are invisible in the most of specimens but in 4 they are seen 5-8 µm after excretory pore. The species was found in zone I: habitats 2 and 3, zone II: 6, 7, 9, 10 and 26, zone III: 15, and zone IV: 16 and 17 with relative density 1-3 individuals per 100 g soil. The only record of P. minimus in Bulgaria is from Tisata reserve (Ilieva et al., 2003). Plectus parietinus Bastian, 1865 (Table 5; Fig. 1a; 6a, f, g and h; 7a, d, g, j, m and n) The species was found in zone I: habitats 2, 18, 19 and 20, zone II: 5, 7, 9, 10, 23 and 26, zone III: 14, 27 and 30, and zone IV: 17 with relative density 1-22 individuals per 100 g soil. P. parietinus has been reported in different natural habitats in Bulgaria: in the coniferous forest belt and the Subalpine belt of Rila (Andrássy, 1958; Ilieva, 2007), in moss and soil in Balkan and the Rhodopes (Andrássy, 1958), in Prisad village, Burgas region (Alexiev et al., 1998) and in a pasture in Novo Panicharevo (Iliev, 1998). The species has also been found in different agricultural fields in Sofia region (Stoyanov, 1961), Pazardzhik, Stara Zagora and Haskovo regions (Katalan-Gateva, 1961, 1965, 1966; Stoyanov, 1979), Karlovo – Plovdiv region (Zhivkov, Baicheva, 1974), and Blagoevgrad region (Katalan- Gateva, Baicheva, 1976, 1978; Katalan-Gateva, Budurova, 1975). Bastian, 1865 Syn. Proteroplectus p. (Bastian, 1865) Paramonov, 1964 (Table 6; Fig. 2i and 8f, g, h, i, j, t and u) The species was found in zone I: habitats 2 and 3, zone II: 6, 7, 9, 10, 23 and 26, zone III: 15, and zone IV: 16 and 17 with relative density 1-3 individuals per 100 g soil. The records of P. parvus in Bulgaria include Rila (Andrássy, 1958; Ilieva, 1998, 2007), Pirin (Katalan-Gateva, 1968), Vitosha (Lazarova et al., 2000), and different

86 Table 4. Morphometric data of Plectus specimens found in the present study. Measurements in the form: mean ± standard deviation (range) Species P. longicaudatus P. minimus Habitat 8 Habitat 27 Habitat 9 Habitat 16 Character (n=12) (n=10) (n=5) (n=7) 598 ± 95 537 ± 39 372 ± 18 387 ± 26 L (µm) (478 – 671) (476 – 579) (339 – 397) (339 – 423) 25 ± 2.5 26 ± 3.7 29 ± 3.6 30 ± 3.5 a (22 – 28) (21 – 30) (24 – 33) (25 – 35) 4.1 ± 0.4 3.8 ± 0.1 3.1 ± 0.2 3.2 ± 0.1 b (3.7 – 4.5) (3.7 – 4.0) (2.7 – 3.5) (3.1 – 3.5) 6.8 ± 0.3 6.9 ± 0.3 12 ± 2.5 12 ± 2.1 c (6.1 – 7.0) (6.5 – 7.2) (7 – 14.5) (7.1 – 15) 7.0 ± 0.9 7.0 ± 0.6 4.0 ± 1.1 3.9 ± 0.9 c’ (5.8 – 8.3) (6.5 – 8.0) (2.9 – 6.0) (3.0 – 6.0) 48± 2 48 ± 1 54 ± 3 55 ± 2 V (%) (45 – 50) (47 – 51) (50 – 58) (52 – 58) 4.8 ± 0.3 5.1 ± 0.4 Body diameter at lip region (µm) 7 – 8 7 – 8 (4.4 – 5) (4.2 – 5) Lip height (µm) 3.0 – 3.5 2.5 – 3.0 2 – 3 2 – 3 23 ± 4.6 19 ± 1.3 12.4 ± 1.3 12.6 ± 1.2 Body diameter at base of pharynx (µm) (18 – 28) (17– 20) (12 – 14) (11– 14) 25 ± 5.9 21 ± 2.7 13 ± 1.8 13 ± 1.1 Body diameter at mid-body (µm) (18 – 30) (17 –24) (11 – 16) (11 –14) 13 ± 2.9 11 ± 0.8 Body diameter at anus (µm) 8 – 9 7 – 9 (10 – 17) (10 –12) 144 ± 12 140 ± 9 119 ± 12 120 ± 9 Neck (µm) (130– 157) (125 – 152) (97 – 137) (97 – 126) 76 ± 9 70 ± 4.8 46 ± 4 49 ± 6 Corpus ((µm) (66 – 89) (61 – 74) (41 – 53) (40 – 59) 40 ± 9 39 ± 8 44 ± 7 40 ± 4 Istmus (µm) (30 – 51) (28 – 50) (38 – 51) (37 – 53) 22 ± 1.3 22 ± 1.4 17 ± 1.4 19 ± 1.8 Length of basal pharyngeal bulbus (µm) (20 – 23) (19 – 23) (16 – 20) (16 – 21) Length of postbulbal prolongation (µm) 8 – 12 5 – 9 5-10 5-12 Vagina (µm) 7 – 12 6 – 7 4.5 – 5 4 – 6 Rectum (µm) 16 – 22 14 – 20 9-11 9-11 88 ± 13 78 ± 6 34 ± 8 32 ± 6 Tail (µm) (68 – 98) (70 – 88) (26 – 48) (26 – 44) Annuli at midbody (µm) 1 1 < 1 < 1 Annuli at tail (µm) 1.2 1.2 1 1 Length of cephalic setae (µm) 3.0 – 3.5 2.5 – 3.0 2 – 3 2 – 3 Origin of cephalic setae 2 2 19 ± 2.5 17 ± 1.3 12.6 ± 0.4 12.5 ± 1.7 Stoma length (µm) (17 – 22) (16 – 19) (12 – 13) (12 – 13)

87 Table 4. Continued Species P. longicaudatus P. minimus Habitat 8 Habitat 27 Habitat 9 Habitat 16 Character (n=12) (n=10) (n=5) (n=7) Width of gymnostoma apically (µm) 2.5 – 3.5 2.5 – 3.5 2.0 – 2.5 2.0 – 2.5 Gymnostoma length (µm) 4.5- 5.0 3.0 – 5.0 Location of amphidial orifice – distance from 8 – 11 7 – 9 7 – 10 7 – 9 anterior end (µm) Amphidial orifice diameter (µm) 2.0 – 3.5 2.0 – 2.5 1.5 – 2 1.5 – 2 Cuticle at midbody (µm) 1.0 – 2.0 1.0 – 1.5 1 1 – 1.2 Cuticle at ventral part of the tail (µm) 1.4 – 2.0 1.2 – 1.5 1 1 85 ± 10 84 ± 1 63 ± 6.5 69 ± 7.7 Distance from anterior end to excretory pore (µm) (74 – 98) (82 –86) (57 – 71) (58 –76) 92 ± 7 91 ± 5 Distance from anterior end to deirids (µm) (84 – 102) (87 – 94) 68 ± 6 64 ± 9 Distance to beginning of nerve ring (µm) (62 – 75) (57 – 74) Distance from spur to tail tip (without 13 – 14 12 – 14 3.5 – 5 4.5 – 5 spinneret) (µm) 290 ± 51 259 ± 18 201 ± 14 214 ± 18 Distance from anterior end to vulva (µm) (228 – 332) (230 – 285) (174 – 214) (174 – 231) 220 ± 34 198 ± 18 136 ± 12 141 ± 13 Distance from vulva to anus (µm) (170 – 248) (176 – 216) (117 – 155) (117 – 163) Diameter at lip region /Diameter of amphids 2.3 – 3.5 3.2 – 4.0 2.2 – 3.3 2.7 – 3.7 Diameter at base of pharynx / diameter at lip region 2.6 – 3.5 3.2 – 4.0 2.4 – 2.6 2.4 – 2.5 Diameter at mid body/Vagina 2.3 – 3.9 2.8 – 3.0 2.2 – 3.7 1.9 – 3.2 Rectum / Body diameter at anus 1.2-1.7 1.1 – 2.0 1.1-1.3 1.1 – 1.3 Distance from vulva to anus / Tail 2.4 – 2.5 2.5 – 2.7 2.4 – 5 2.4 – 5.7 agricultural fields in Sofia valley (Stoyanov, 1961), Pazardzhik region (Katalan-Gateva, 1961), Stara Zagora region (Katalan-Gateva, 1965), Kazanlak and Troyan regions (Katalan-Gateva et al., 1981), Stara Zagora and Haskovo regions (Katalan-Gateva, 1965, Katalan-Gateva et al., 1981), and Blagoevgrad region (Katalan-Gateva et al., 1982). Plectus rhyzophilus de Man, 1880 Syn. Proteroplectus r. (de Man, 1880) Paramonov, 1964 (Table 6; Fig. 1e and 8f, g, h, i, p, q, u and v) The species was found in zone I: habitat 2, zone II: 7 and 9, and zone III: 27 with relative density 1-3 individuals per 100 g soil. The records of P. rhyzophilus in Bulgaria include the city of Varna, Rila, the Rhodopes and the Balkan (Andrássy, 1958) and different agricultural fields Pazardzhik region (Katalan-Gateva, 1961; Stoyanov, 1979) and Haskovo and Plovdiv regions (Katalan-Gateva, 1966).

88 Fig. 4. P. andrassyi: a. – Neck; b. c, d, – Lip region; e. – Amphidial orifice; f., g, h. – Basal bulb; i. – Excretory duct; j., k., l. – Vulva; m. – Tail tip; n., o., p. – Tail (Scale on a, n, o and p – 100 µm; Scale on b, c, d, e, f, g, h, i, j, k, l and m – 20 µm)

Plectus armatus Bütschli, 1873 (Table 7; Fig. 2b and 9(k, l, m, n, o, p, v, w and x) Syn. Ceratoplectus a. (Buetschli, 1873) Andrassy, 1985 ; Proteroplectus a. (Buetschli, 1873) Paramonov, 1964

89 Table 5. Morphometric data of specimens of P. parietinus found in the present study. Measurements in the form: mean ± standard deviation (range)

Habitat 14 Habitat 19 Habitat 30 Character (n=12) (n=9) (n=7) 1285 ± 228 1356 ± 106 1138 ± 279 L (µm) (1026 – 1455) (1246 – 1375) (941 – 1335) 19 ± 4 17 ± 2 19 ± 1 a (17 – 22) (15 – 18.5) (17 – 19) 4.5 – 0.5 4.7 – 0.1 4.2 – 0.5 b (3.9 – 4.9) (4.5 – 4.7) (3.8 – 4.6) 14 ± 3 13 ± 4 12 ± 2 c (12 – 17) (10 – 17) (11 – 14) 2.9 ± 0.5 2.7 ± 0.8 3.3 ± 1 c’ (2.6 – 3.6) (2.0 – 3.6) (2.3 – 4.3) 50 ± 2 49 ± 1 51 ± 1 V (%) (49 – 52) (49 – 53) (51 – 53) 16.3 ± 0.6 16 ± 0.1 14.5 ± 1 Body diameter at lip region (µm) (16 – 17) (16 – 17) (13.5– 15) Lip height (µm) 5 – 6 5 – 6 5 – 6 65 ± 12 72 ± 5 56 ± 3 Body diameter at base of pharynx (µm) (52 – 75) (66 – 75) (50 – 61) 73 ± 17 82 ± 8 58 ± 4 Body diameter at mid-body (µm) (54 – 88) (73 – 89) (56 – 61) 42 ± 7 41 ± 4 30 ± 3 Body diameter at anus (µm) (34 – 46) (38 – 46) (29 – 34) 285 ± 20 289 ± 14 268 ± 23 Neck (µm) (263 – 300) (275 – 292) (245 – 291) 113 ± 16 124 ± 6 114 ± 17 Corpus ((µm) (98 – 131) (119 – 130) (102 – 126) 99 ± 13 94 ± 11 84 ± 14 Istmus (µm) (84 – 110) (81 –102) (74 – 93) 39 ± 4 41 ± 3 39 ± 4 Length of basal pharyngeal bulbus (µm) (36 – 42) (37 – 44) (36 – 42) 16 ± 2 17 ± 2 19 ± 3 Length of postbulbal prolongation (µm) (15 – 18) (15 – 18) (17 – 21) 24 ± 6 22 ± 5 21 ± 2 Vagina (µm) (18 – 28) (18 – 28) (20 – 23) 34 ± 3 32 ± 1 26 ± 6 Rectum (µm) (32 – 37) (32 – 33) (22 – 30) 114 ± 24 112 ± 29 97 ± 40 Tail (µm) (88 – 133) (80 – 135) (68 – 125) Distance from anterior end to excretory 170 ± 22 171 ± 13 172 ± 25 pore (µm) (146 – 190) (161 – 175) (154 – 190) 170 ± 31 173 ± 8 168 ± 31 Distance from anterior end to deirids (µm) (135 – 194) (165 – 180) (146 – 190)

90 Table 5. Continued Habitat 14 Habitat 19 Habitat 30 Character (n=12) (n=9) (n=7) 149 ± 14 149 ± 10 146 ± 25 Distance to beginning of nerve ring (µm) (133 – 161) (146 – 153) (128 – 163) 37 ± 7 31 ± 3 31 ± 3 Length of stoma (µm) (30 – 43) (30 – 35) (29 – 33) Width of gymnostoma apically (µm) 4.5-5 5.5 – 6 4.5 – 6 Gymnostoma length (µm) 5-6 6 6 Length of cephalic setae (µm) 3.5 – 4 4 3.5-4.5 Origin of cephalic setae – annuli after lips 3 3 2 – 3 Location of amphidial orifice – distance 13 – 16 15 – 16 15 – 16 from anterior end (µm) Amphidial orifice diameter (µm) 3 – 4 4 3 – 4 Position of amphidial orifice – annuli 8 – 9 8 – 9 8 – 9 from lip base 641 ± 92 669 ± 18 580 ± 34 Distance from anterior end to vulva (µm) (538 – 715) (631 – 684) (485 – 675) 462 ± 104 575 ± 27 462 ± 87 Distance from vulva to anus (µm) (338 – 535) (545 – 598) (388 – 538) Distance from spur to tail tip (without 7 – 8 7 – 8 7 spinneret) (µm) Diameter at lip region /Diameter of 4.0 – 5.7 4.0 – 4.5 4.5 – 5.2 amphideal orifice Diameter at base of pharynx / diameter at 3.1 – 4.7 4.1 – 4.7 3.6 – 4.1 lip region Diameter at mid body/Vagina 2.5 – 3.1 3.1 – 4.1 3.6 – 4.1 5.7 5.4 5.0 Distance from vulva to anus / Tail (4.5 – 7.5) (4.0 – 7.5) (4.3 – 5.7) Rectum / Body diameter at anus 0.8 – 0.9 0.7 – 0.8 0.7 – 1.0 Cuticle at stoma (µm) 2 – 3 2 – 3 2 – 3 Cuticle at midbody (µm) 3 – 4 2.5 – 4 2.5 – 4.0 Cuticle at ventral part of the tail (µm) 3 – 3.7 3.0 – 4.0 4.0 – 6.0 Width of lateral field (µm) 4 – 6 4.5 – 6 5 – 6 Annulli at stoma (µm) 1.2 – 1.6 1.2 – 1.6 1.1 – 1.5 Annulli at midbody (µm) 1.2 – 1.8 1.2 – 1.8 1.2 – 1.5 Annuli at tail (µm) 1.2 – 1.6 1.3-1.6 1.2 – 2.0

Specimens in the present study are generally similar to those of De Ley, Coomans (1994). In our specimens body was full of fat drops at anterior part and it was almost impossible to find the exact border between corpus and isthmus. Cephalic setae are tick and directed forward almost frontally. The species was found in zone I: habitats 2 and 22, zone II: 9 and 24, zone III: 15 and zone IV: 16 and 17 with relative density 1-3 individuals per 100 g soil.

91 Fig. 5. P. cancellatus: a – Neck; b, c–Stoma; d, e – Lip region; f, g–Amphidial orifice; h – Excretory duct; i, j – Basal bulb; k, l – Vulva; m – Lateral field and cuticle structure at mid body; n Tail; o – Rectum; p – Tail tip; q – Posterior part of tail (Scale on and n – 100 µm; Scale on b, c, d, e, f, g, h, i, j, k, l, m, o, p and q – 20 µm)

92 Table 6. Morphometric data of specimens of Plectus found in the present study. Measurements in the form: mean ± standard deviation (range)

Species P. parvus P. rhyzophilus Habitat 5 Habitat 14 Habitat 23 Habitat 9 Habitat 27 Character (n=7) (n=4) (n=5) (n=5) (n=4) 390 ± 22 478 ± 40 464 ± 7 790 ± 133 776 ± 87 L (µm) (368 – 412) (453 – 525) (457 – 471) (698 – 942) (683 – 855) 24 ± 2 25 ± 1 24 ± 2 21 ± 3 20 ± 2 a (22 – 26) (24 – 27) (22 – 27) (17 – 24) (18 – 22) 3.5 – 0.1 3.8 – 0.2 3.8 – 0.2 4.9 – 0.6 4.8 – 0.4 b (3.4 – 3.5) (3.6 – 4.1) (3.4 – 4.2) (4.4 – 5.6) (4.3 – 5.0) 7.5 ± 0.8 8.4 ± 1.1 8.3 ± 1.2 7.5 ± 0.9 7.0 ± 0.5 c (7.0 – 8.4) (7.1 – 9.1) (7.0 – 9.4) (6.9 – 8.6) (6.4 – 7.3) 5.0 ± 0.2 5.2 ± 1.1 4.9 ± 1.5 5.4 ± 0.7 5.5 ± 0.3 c’ (4.8 – 5.2) (4.3 – 6.4) (3.5 – 6.2) (5.0 – 6.2) (5.2 – 5.9) 53% ± 2% 51% ± 3% 49% ± 3% 48% ± 2% 49% ± 1% V (52% – 56%) (48% – 53%) (47% – 52%) (47% – 49%) (48% – 51%) Body diameter at lip 5.8 ± 1.3 6.0 ± 1.1 6.6 ± 2.1 7.8 ± 0.3 8.3 ± 0.2 region (µm) (4.5 – 7.0) (5.0 – 7.0) (5 – 7.5) (7.5 – 8) (8.0 – 9.0)

Lip height (µm) 3.0 – 3.5 3.0 – 3.5 3.0 – 4 4 3.5 – 4.0

Body diameter at base of 18.3 ± 1 20 ± 2 36 ± 4.4 38 ± 2.0 17 – 18 pharynx (µm) (17 – 19.5) (18 – 22) (31 – 39) (36 – 40) Body diameter at mid- 17 ± 0.1 19 ± 3 19 ± 2 38 ± 4.0 38 ± 2.5 body (µm) (16 – 17.5) (17 – 22) (17 – 21) (33 – 40) (36 – 41) Body diameter at anus 10.3 ± 0.2 11 ± 1 12 ± 2 20 ± 2.5 20 ± 1 (µm) (10 – 11) (10 – 12) (10 – 14) (17 – 22) (19 – 21) 113 ± 5 125 ± 5 121 ± 1 161 ± 7 163 ± 7 Neck (µm) (108 – 117) (120 – 129) (118 – 123) (155 – 196) (159 – 171) 43 ± 5 49 ± 3 47 ± 5 79 ± 5 75 ± 6 Corpus ((µm) (37 – 47) (47 – 53) (42 – 48) (75 – 82) (71 – 82) 37 ± 4 41 ± 1 43 ± 2 53 ± 3 58 ± 1 Istmus (µm) (34 – 41) (39 – 42) (40 – 44) (50 – 55) (57 –59) Length of basal 14 ± 1 16 ± 2 15 ± 0.1 23 ± 1.2 23 ± 1.5 pharyngeal bulbus (µm) (13 – 15) (15 – 18) (15 – 16) (22 – 24) (21 – 24) Length of postbulbal 10 ± 3.5 9 ± 3.2 6 – 8 7 – 9 8 – 9 prolongation (µm) (6 – 13) (5 – 11) 11.3 ± 0.6 12 ± 1.0 Vagina (µm) 5 – 6 6 – 7 6 – 7 (11 – 12) (11 – 13) 22 ± 2 23 ± 2.6 Rectum (µm) 11 – 12 12 – 13 11 -13 (20 – 24) (21 – 26) 52 ± 3 57 ± 7 57 ± 4 103 ± 5 111 ± 6 Tail (µm) (49 – 55) (50 – 64) (51 – 63) (100 – 110) (106 – 117) Distance from anterior 68 ± 11 80 ± 11 63 ± 16 90 ± 3 91 ± 7 end to excretory pore (60 – 80) (67 – 88) (47 – 79) (83 – 92) (84 – 97) (µm)

93 Table 6. Continued Species P. parvus P. rhyzophilus Habitat 5 Habitat 14 Habitat 23 Habitat 9 Habitat 27 Character (n=7) (n=4) (n=5) (n=5) (n=4) Distance from anterior 73 ± 13 85 ± 8 66 ± 10 92 ± 2.5 93 ± 8.5 end to deirids (µm) (63 – 87) (75 – 90) (52 – 81) (90 – 95) (84 – 101) Distance to beginning of 60 ± 2 69 ± 3 69 ± 5 70 ± 3.2 70 ± 1.2 nerve ring (µm) (58 – 62) (65 – 71) (63 – 73) (66 – 72) (69 – 71) 18 ± 2 17 ± 3 17 ± 2 20 ± 0.5 20 ± 0.6 Length of stoma (µm) (15 – 19) (16 – 19) (15 – 19) (19 – 21) (19 – 20) Width of gymnostoma 2.0 2.0 – 2.5 2.0 – 3.0 2.5 – 3.0 2.5 – 3.0 apically (µm) Gymnostoma length (µm) 4 4 – 4.5 4.0 – 4.5 5 4.5 – 5 Length of cephalic setae (µm) 2.5 -3.0 2.0 – 2.5 2.0 – 3.0 2.5 – 3.0 3.0 Origin of cephalic setae – 2 2 2 2 2 annuli after lips Location of amphidial orifice – distance from 10 – 11 11 – 13 10 – 13 12 – 13 11.5 – 13 anterior end (µm) Amphidial orifice 2 – 3 2 – 3 2 – 2.5 2.5 – 3.0 2.5 – 3.0 diameter (µm) Position of amphidial orifice 9 – 10 8 – 9 8 – 9 9 9 – 10 – annuli from lip base Distance from anterior 208 ± 16 244 ± 26 228 ± 15 376 ± 57 384 ± 47 end to vulva (µm) (190 – 219) (220 – 272) (219 – 246) (341 – 441) (339 – 443) Distance from vulva t 144 ± 13 177 ± 16 169 ± 9 309 ± 73 281 ± 38 o anus (µm) (126 – 158) (163 – 195) (158 – 175) (253 – 391) (238 – 305) Distance from spur to tail 9 – 10 8 – 10 8 – 10 18 – 21 18 – 20 tip (without spinneret) (µm) Diameter at lip region / Diameter of amphideal 2.0 – 2.4 2.0 – 2.8 2.2 – 3.0 2.7 – 3.0 2.7 – 3.6 orifice Diameter at base of 4.6 ± 0.7 4.6 ± 0.5 pharynx / diameter at lip 2.4 – 4.0 2.8 – 3.7 3.1 – 3.7 (3.9 – 5.2) (4.0 – 5.0) region Diameter at mid body/ 2.7 – 3.4 2.4 – 3.1 2.8 – 3.7 3.0 – 3.3 3.2 – 3.3 Vagina Distance from vulva to 2.9 ± 0.6 2.5 ± 0.3 2.4 – 3.0 2.7 – 3.4 2.7 – 3.5 anus / Tail (2.5 – 3.6) (2.2 – 2.8) Rectum / Body diameter 1.0 – 1.2 1.0 – 1.2 0.9 – 1.2 1.1 – 1.2 1.1 – 1.3 at anus Cuticle at midbody (µm) <1 <1 <1 1.5 1.5 Cuticle at ventral part of 1 1 1 1.5 – 2.0 1.5 – 2.0 the tail (µm) Width of lateral field (µm) 3 3 3 4.5 – 5 4.5 – 5 Annulli at midbody (µm) <1 <1 <1 1 1

94 Fig. 6. P. parietinus: a – Neck; f – Tail; g – Spur; h – Spinneret; P.cirratus Bastian, 1865: b – Neck; e –Tail; i – Spur; j – Spinneret; P. accuminatus: c – Neck; d – Tail; k – Spinneret and spur. (Scale on a, b, c, d, e and f – 100 µm; Scale on g, h, i, j and k – 20 µm)

P. armatus has been reported from Rila (Ilieva, 1998, 2007), Vitosha (Lazarova et al., 2000), and Prisad village, Burgas region (Alexiev et al., 1998). Andrássy (1984) includes Bulgaria in the area of distribution of the species but in his first study carried out in the country (Andrássy, 1958) he mentions P. communis. According to the presented ratios and body size the species may actually be P. armatus, but in his revision of the genus (Andrássy, 1985) he does not refer specifically to his own material from Bulgaria.

95 Table 7. Morphometric data of specimens of Plectus found in the present study. Measurements in the form: mean ± standard deviation (range)

Species P. armatus P. assimilis Habitat 17 Habitat 22 Habitat 7 Habitat 29 Character (n=6) (n=5) (n=9) (n=7) 359 ± 88 325 ± 13 847 ± 120 691 ± 44 L (µm) (307 – 515) (310 – 337) (701 – 994) (633 – 739) 18 ± 3 16 ± 0.9 15 ± 1.2 16 ± 0.3 a (15 – 22) (15 – 17) (14 – 17) (15 – 16.5) 3.6 – 0.1 3.6 – 0.3 4.7 – 0.2 4.4 – 0.1 b (3.6 – 3.7) (3.4 – 3.7) (4.4 – 4.9) (4.2 – 4.5) 8.3 ± 0.6 8.0 ± 0.6 11.3 ± 0.5 10.9 ± 0.5 c (7.4 – 8.9) (7.4 – 8.6) (9.0 – 12) (10.4 – 11.8) 3.7 ± 0.5 3.9 ± 0.4 4.1 ± 0.4 3.4 ± 0.3 c’ (3.3 – 4.5) (3.5 – 4.6) (3.7 – 4.5) (3.1 – 3.8) 51 ± 1 50 ± 0.4 51 ± 2 51 ± 2 V (%) (50 – 51) (50 – 51) (48 – 53) (49 – 54) 9.2 ± 0.4 9 ± 0.0 15 ± 1.4 15 ± 0.8 Body diameter at lip region (µm) (9 – 10) (14 – 17) (14 – 15.5) Lip height (µm) 3.0 2.5 – 3.0 3.0 – 5.0 3.0 – 4.0 20 ± 3 21 ± 1 48 ± 6 40 ± 3 Body diameter at base of pharynx (µm) (16.5 – 24) (20 – 21) (41 – 55) (38 – 44) 20 ± 3 21 ± 1.0 55 ± 7 43 ± 3 Body diameter at mid-body (µm) (16 – 23) (20 – 22) (48 – 63) (40 – 47) 12 ± 1 11 ± 1 18 ± 1 19 ± 1 Body diameter at anus (µm) (10.5 – 13) (10 – 12) (17 – 19) (17 – 20) 99 ± 24 92 ± 4 181 ± 19 156 ± 6 Neck (µm) (85 – 141) (86 – 94) (160 – 203) (150 – 163) 68 ± 11 62 ± 3 75 ± 8 63 ± 4 Corpus (µm) (55 – 86)* (57 – 65)* (65 – 84) (59 – 69) 71 ± 10 59 ± 2 Istmus (µm) (61 – 84) (56 – 60) 16 ± 1.2 16 ± 0.6 35 ± 1 34 ± 1 Length of basal pharyngeal bulbus (µm) (15 – 18) (15 – 16) (34 – 37) (32 – 35) Length of postbulbal prolongation (µm) 3 – 4 3 8 – 15 6 – 9 5.2 ± 0.4 4.9 ± 0.3 16.0 ± 1.0 15.1 ± 0.6 Vagina (µm) (5.0 – 6.0) (4.5 – 5.0) (15.0 – 17.0) (14.5 – 16.0) 9.6 ± 0.9 9.3 ± 0.5 20 ± 3.7 19 ± 1.8 Rectum (µm) (9.0 – 11.0) (9.0 – 10.0) (16 – 24) (18 – 22) 42 ± 9 41 ± 3 75 ± 9 63 ± 4 Tail (µm) (36 – 58) (38 – 47) (66 – 86) (60 – 68) Distance from anterior end to excretory 60 ± 7 57 ± 5 107 ± 12 96 ± 5 pore (µm) (55 – 71) (51 – 62) (91 – 120) (88 – 101) 48 ± 3.2 49 ± 1.2 100 ± 8 87 ± 3 Distance to beginning of nerve ring (µm) (45 – 62) (47 – 54) (88 – 107) (85 – 91)

96 Table 7. Continued Species P. armatus P. assimilis Habitat 17 Habitat 22 Habitat 7 Habitat 29 Character (n=6) (n=5) (n=9) (n=7) 14.8 ± 1.3 14.5 ± 0.6 26 ± 4.3 24 ± 1.3 Length of stoma (µm) (14 – 17) (14 – 15) (25 – 30) (23 – 26) Width of stoma (µm) 2.5 – 3.0 2.5 – 3.0 4 – 6 4 – 4.5 Length of cephalic setae (µm) 4.0 – 5.5 4.0 3.5 – 5.0 3.5 – 4.0 Location of amphidial orifice – distance 10 ± 1.5 10 ± 1.0 12 – 13 11.5 – 13 from anterior end (µm) (8 – 11) (8 – 10) Amphidial orifice diameter (µm) 2.5 – 3.0 2.5 – 3.0 3 – 3.5 3 – 3.5 Position of amphidial orifice – annuli 8 – 9 8 – 9 3 – 4 3 – 4 from lip base 182 ± 47 163 ± 7 433 ± 70 354 ± 24 Distance from anterior end to vulva (µm) (155 – 265) (153 – 170) (368 – 530) (336 – 388) 133 ± 33 121 ± 5.7 363 ± 10 274 ± 29 Distance from vulva to anus (µm) (113 – 192) (113 – 126) (358 – 378) (232 – 296) Distance from spur to tail tip (without 4 – 5 4.0 – 4.5 6 – 7 5.5 – 8 spinneret) (µm) Diameter at lip region /Diameter of 3.0 – 3.3 3.0 3.5 – 4.2 4.0 – 4.5 amphideal orifice Diameter at base of pharynx / diameter at 2.2 ± 0.2 2.3 ± 0.1 3.2 ± 0.3 2.7 ± 0.1 lip region (1.8 – 2.4) (2.2 – 2.3) (2.9 – 3.6) (2.5 – 2.9) Diameter at mid body/Vagina 3.2 – 4.5 4.0 – 4.9 3.2 – 3.7 2.7 – 3.1 3.1 ± 0.2 3.0 ± 0.2 Distance from vulva to anus / Tail 4.4 – 5.4 3.9 – 4.9 (2.7 – 3.3) (2.7 – 3.2) Rectum / Body diameter at anus 0.8 – 0.9 0.8 – 1.0 0.9 – 1.3 1.0 – 1.1 Cuticle at midbody (µm) <<1 <<1 1.2 – 1.5 1.0 – 1.5 Width of lateral field (µm) 3 3 5.0 4.5 -5.0 Annulli at midbody (µm) <1 <1 1.5 – 1.7 1.5 *Measurment is Corpus + Istmus (µm) because pharyngeal area is full of fat drops and is is impossible to point out the exact border between structures.

Plectus assimilis Bütschli, 1873 Syn. Ceratoplectus a. (Buetschli, 1873) Andrássy, 1985; Proteroplectus a. (Buetschli, 1873) Paramonov, 1964 (Table 7; Fig.2a, 8j, k, l, m. r, w, x and y) The species was found zone II: habitats 7, 8 and 9 and zone III: 29 with relative density 1-5 individuals per 100 g soil. P. assimilis has been reported from the Balkan and Vitosha (Andrássy, 1958), and Rila Mountain (Andrássy, 1958; Ilieva, 1998, 2007). Subfamily Wilsonematinae Chitwood, 1951 Ereptonema arcticum Loof, 1971 Syn. Plectus (Wilsonema) agrarum (Nesterov, 1973) Zell, 1993 apud Ilieva et al. (2003) (Table 8; Fig. 2e, 10c and d, 11d, e and f)

97 Fig. 7. P. parietinus: a – Stoma; d – Amphidial orifice; g – Cephalic setae; j – Basal bulb; m, n – Vulva;P. cirratus Bastian, 1865: b – Stoma; e –Amphidial orifice; h – Cephalic setae; k – Basal bulb; o, p – Vulva; P. accuminatus: c – Stoma; f – Amphidial orifice; i – Cephalic setae; l – Basal bulb; q, r – Vulva. (Scale – 20 µm)

The morphometric data of the studied specimens are similar to those of populations from Roztochya Natural Reserve, Ukraine and Altai Mountains, Russia of Holovachov et al. (2003). The species was found only in zone IV, habitat 16, with relative density 1-3 individuals per 100 g soil. No males were isolated. In a previous research (Ilieva et al., 2003) W. agrarum was reported from Tisata reserve. Even though the slides are not in a very good condition, we now consider those specimens as E. arcticum. The species is relatively rare and the two Bulgarian locations from which it was reported are both characterized with very poor soils and scarce sclerophyllous vegetation. Tylocephalus auriculatus (Bütschli, 1873) Anderson, 1966 Syn. Plectus a. Buetschli, 1873; Plectus (Wilsonema) a. Buetschli, 1873 (Mikoletzki, 1922) (Table 9; Fig. 2c; 10e and f; 11g, h and i)

98 Table 8. Morphometric data of specimens of E. arcticum and W. otophorum found in the present study. Measurements in the form: mean ± standard deviation (range)

Species E. arcticum W. otophorum Habitat 16 Habitat 15 Habitat 25 Character (n=6) (n=5) (n=5) 314 ± 25 272 ± 25 286 ± 27 L (µm) (289 – 341) (256 – 308) (265 – 317) 17 ± 1 17.2 ± 0.9 16.9 ± 1.3 a (16 – 17) (16.0 – 18.1) (15 – 17.7) 3.4 ± 0.1 3.3 ± 0.2 3.8 ± 0.8 b (3.3 – 3.6) (3.1 – 3.6) (2.9 – 4.3) 7.9 ± 0.5 9.0 ± 0.9 8.6 ± 1.6 c (7.4 – 8.5) (8.3 – 10.2) (7.1 – 10.2) 4.0 ± 0.2 3.4 ± 0.5 3.8 ± 0.8 c’ (6.6 – 4.2) (2.9 – 4.1) (2.9 – 4.3) 54 ± 0.5 51 ± 1 50 ± 2 V (%) (53 – 55) (50 – 52) (49 – 52) 8 ± 0.5 8.7 ± 0.6 Body diameter at lip region (µm) 7 (7 – 9) (8 – 9) 18 ± 0.3 15.8 ± 0.5 17.2 ± 1.0 Body diameter at base of pharynx (µm) (17 – 18) (15 – 16) (16– 18) 19 ± 1 16 ± 1 17 ± 2 Body diameter at mid-body (µm) (18 –20) (15 – 17) (15 –18) 10 ± 1 Body diameter at anus (µm) 9 9 (9 – 11) 92 ± 4 83 ± 2.5 80 ± 6 Neck (µm) (88 – 99) (80 – 86) (72 – 88) 32 ± 2 Corpus (µm) (31 – 34) 40 ± 2 Istmus (µm) (38 – 41) 21 ± 2 16.3 ± 0.5 15.7 ± 0.6 Length of basal pharyngeal bulbus (µm) (19 – 23) (16 – 17) (15 – 16) Length of postbulbal prolongation (µm) 4-5 4-5 169 ± 11 138 ± 12 143 ± 13 Distance from anterior end to vulva (µm) (158 – 182) (128 – 155) (134 – 157) 107 ± 12 104 ± 8.5 109 ± 12 Distance from vulva to anus (µm) (93 – 119) (98 – 116) (102 – 123) Rectum (µm) 10-11 10-11 10-12 40 ± 1 31 ± 5 34 ± 7 Tail (µm) (38 – 40) (26 – 37) (26 – 39) Flabellum length (µm) 3.5 – 4 8-9 9 9.5 ± 0.5 Expansion length (µm) 5 5-5.5 (9 – 11) 16.3 ± 0.2 Expansion width (µm) 15-16 5-5.5 (16 – 17)

99 Table 8. Continued Species E. arcticum W. otophorum Habitat 16 Habitat 15 Habitat 25 Character (n=6) (n=5) (n=5) Expansion – number of annuli 7 – 8 no no 10.2 ± 1 12.3 ± 1.5 11± 1.7 Length of stoma (µm) (10 – 13) (10 – 13) (10 – 13) Location of amphidial orifice – distance from 5 ± 0.5 8-9 9 anterior end (µm) (5 – 6) 2.4 ± 0.3 Amphidial orifice diameter (µm) 2-2.5 2 (2.0 – 2.5) 62 ± 3 Position of amphidial orifice – annuli from lip base 45-46 43-45 (58 – 66) 66 ± 3 49 ± 2 Distance from anterior end to deirids 48-50 (62 – 68) (47 – 51) Distance from spur to tail tip (without 7 4-5 4-5 spinneret) (µm) Cuticle at midbody (µm) 1 ≤ 1 ≤ 1 Cuticle at ventral part of the tail (µm) 1 1 1 Width of lateral field (µm) 3 Annuli at midbody (µm) 1 < 1 < 1 1.3 ± 0.1 Annuli at tail (µm) 1 1 (1.2 – 1.5) Diameter at lip region /Diameter of amphideal 3.0 ± 0.4 3.5 ± 0.9 4.3 ± 0.3 orifice (2.8 – 3.5) (2.8 – 4.5) (4.0 – 4.5) Diameter at base of pharynx / diameter at lip region 2.4 – 2.6 1.1 – 1.2 1.1-1.3 Distance from vulva to anus / Tail 2.4 – 3.0 Rectum / Body diameter at anus 0.9 – 1.0 1.1 – 1.2 1.1 – 1.3

Specimens are similar to those described by Holovachov et al. (2003) Somatic setae as hardly visible in smaller specimens. No annulation at stoma region The species was found in the habitats as follows zone I: 19 and 20, zone II: 5, 8, 9, and 12, zone III: 15, 27, 28 and 29, and zone IV: 16 and 17 with relative density 1-10 individuals per 100 g soil. The most abundant population was in Bataka locality (11) with 10 individuals per 100 g soil sampled in November, 2009 and April, 2010. T. auriculatus has been reported from the vicinity of Varna (Andrassy, 1958), Vitosha (Andrassy, 1958; Lazarova et al., 2000), the Rhodopes (Andrassy, 1958), Rila (Andrassy, 1958; Ilieva, 1998, 2007), vicinity of Blagoevgrad (Katalan-Gateva, Budurova, 1975) and Pirin (Katalan-Gateva, 1968). Among subfamily Wilsonematinae T. auriculatus appears to be the most frequent species in mountainous habitats. Wilsonema otophorum (de Man, 1880) Cobb, 1913 Syn. Plectus othophorus de Man, 1880; Plectus (Wilsonema) othophorus de Man, 1880 (Mikoletzki, 1922) (Table 8; Fig. 2d, 10 a and b; 11a, b and c)

100 Fig. 8. P. longicaudatus: a – Neck; b – Lips; c – Stoma; d – Amphidial orifice and setae; n – Basal bulb; o – Vulva; s – Tail; t – Spinneret and spur; P. rhyzophilus: f – Neck; g – Stoma; h – Cephalic setae; i – Amphidial orifice; p – Basal bulb; q – Vulva; u – Tail; v – Spinneret and spur; P. assimilis: j – Neck; k – Stoma; l – Amphidial orifice; m – Vulva – lateral view; r – Basal bulb; w – Tail; x – Spur; y – Spinneret. (Scale on a, f, j, s, u and w – 100 µm; Scale on l, c, d, g, h, i, k, l, m, n, o, p, q, r, t, v, x and y –20 µm)

101 Fig. 9. P. minimus: a – Neck; b – Lips; c – Amphidial orifice; d – Basal bulb; e – Vulva; q – Rectum; r – Spinneret and spur; P. parvus: f – Neck; g – Stoma; h – Amphidial orifice; i – Basal bulb; j – Vulva; t – Tail; u – Spinneret and spur; P. armatus: k – Neck; l – Stoma; m – Amphidial orifice and setae; n – Basal bulb; o, p – Vulva – lateral and ventral view; v – Tail; w – Spinneret; x – Tail – lateral view. (Scale 20 µm)

102 Table 9. Morphometric data of specimens of T. auriculatus from some of the habitats found in the present study. Measurements in the form: mean ± standard deviation (range) Habitat 5 Habitat 17 Habitat 29 Character (n=5) (n=8) (n=4) 383 ± 29 391 ± 44 418 ± 35 L (µm) (355 – 412) (341 – 429) (393 – 466) 12 ± 1 13 ± 2 15 ± 3 a (11 – 14) (11 – 16) (13 – 17) 3.3 ± 0.3 3.7 ± 0.7 4.1 ± 0.2 b (2.8 – 3.6) (3.0 – 4.3) (3.8 – 4.3) 10.8 ± 0.8 11.7 ± 1.5 12 ± 1 c (10 – 11.5) (10 – 13.4) (11 – 12.5) 2.7 ± 0.1 c’ 2.6-2.7 2.8 – 2.9 (2.5 – 2.8) 52 ± 2 50 ± 6 49 ± 1 V(%) (48 – 55) (48 – 56) (48 – 50) Body diameter at lip region (µm) 10 10-11 10 31 ± 1 27 ± 0.5 31 ± 1 Body diameter at base of pharynx (µm) (29 –30) (26– 28) (30 – 32) 31 ± 1 28 ± 1 31 ± 1 Body diameter at mid-body (µm) (29 –30) (27 –30) (30 –33) 11 ± 1 12.2 ± 1.6 13.5 ± 1 Body diameter at anus (µm) (10 – 11.5) (9 – 14) (12 – 14.5) 111 ± 3 107 ± 4 105 ± 4 Neck (µm) (108 – 114) (102 – 115) (100 – 111) 35 ± 2 32 ± 4 30 ± 2 Corpus (µm) (32 – 37) (30 – 37) (29 – 32) 34 ± 3 33 ± 1 30 ± 1 Istmus (µm) (30 – 37) (29 – 34) (29 – 31) 17 ± 2 17 ± 1 17.5 ± 0.4 Length of basal pharyngeal bulbus (µm) (16 – 19) (17 – 19) (17 – 18) Length of postbulbal prolongation (µm) 5 5-6 6 200 ± 6 207 ± 16 210 ± 2 Distance from anterior end to vulva (µm) (190 – 207) (195 – 225) (207 – 215) 93 ± 12 151 ± 28 197 ± 12 Distance from vulva to anus (µm) (86 – 102) (96 – 181) (182 – 225) Rectum (µm) 15 14-15 15 32 ± 1 35 ± 1 40 ± 0.5 Tail (µm) (30 – 33) (30 – 37) (38 – 40) Cornua length (µm) 8 8-10 8-10 16.5 ± 0.5 18 ± 2.5 18 ± 0.5 Expansion length (µm) (16 – 17) (14 – 19) (18 – 19) 19.4 ± 0.4 20 ± 1 Expansion width (µm) 18 (17 – 21) (19 – 21) Expansion – number of annuli 10-12 9-12 10-13 17 ± 1 17.5± 0.5 18.8 ± 1 Length of stoma (µm) (16 – 18) (17 – 18) (18 – 20)

103 Table 9. Continued Habitat 5 Habitat 17 Habitat 29 Character (n=5) (n=8) (n=4) Location of amphidial orifice – distance from anterior 10 8-10 10-11 end (µm) Amphidial orifice diameter (µm) 2.5 2.5 2.5 69 ± 2 68 ± 6 73 ± 3 Distance from anterior end to excretory pore (µm) (65 – 72) (60 – 75) (60 – 79) 73 ± 5 76 ± 1 77 ± 2 Distance from anterior end to deirids (69 – 79) (74 – 77) (72 – 82) Distance from spur to tail tip (without spinneret) (µm) 5 5-6 5 Cuticle at midbody (µm) 1 1-2 1.5-2 Cuticle at ventral part of the tail (µm) 1.2-1.5 1.5-2 1.5-2 Width of lateral field (µm) 5 5 5 Annuli at midbody (µm) About 1 About 1 1.2 Annuli at tail (µm) 1 1-1.2 1.2-1.3 Diameter at lip region /Diameter of amphids 4 4 4 Diameter at base of pharynx / diameter at lip region 3 2-3 2-3 Rectum / Body diameter at anus 1.3 1.2 – 1.3 1.0-1.2

Fig. 10. W. otophorum: a. – Neck; b. – Tail; Ereptonema arcticum Loof, 1971: c. – Neck; d. – Tail; T. auriculatus: e. – Neck; f. – Tail (Scale – 20 µm)

104 Fig. 11. W. otophorum: a. – Lip region; b. – Amphidia; c – Vulva region; E. arcticum: d. – Lip region; e. – Amphidia; f – Vulva region; T. auriculatus: g. – Lip region; h. – Amphidia; i – Vulva region (Scale – 20 µm) *Cornu as described by Holovachov et al. (2003) was visible in studied specimens but it was impossible to take clear photo under light microscope.

In all studied specimens corpus and istmus are indistinguishable. Setae are clearly visible on the tail and almost invisible at other body parts. In two specimens was observed something like longitudinal striation of cuticle in the pharyngeal region. The species was found only in zone II, habitat 25 and zone III, habitat 15 with relative density 1-3 individuals per 100 g soil. W. otophorum has been reported from natural habitats in different parts of the country: the Rhodopes (Andrássy, 1958), Rila (Andrássy, 1958; Ilieva, 1998; 2007) and Pirin (Katalan-Gateva, 1968), Tisata reserve (Ilieva et al., 2003). The species has also been isolated from agricultural land: strawberry fields in the vicinity of Blagoevgrad (Katalan-Gateva, Bududrova, 1975). W. otophorum can be regarded as rare for the region of Strandzha.

105 CONCLUSION

For the period 2009-2011, a total of 15 species of family Plectidae were found in Strandzha region: 15 in the Bulgarian part and 12 in the Turkish part of the mountain. To our knowledge the only representative of the family reported from Turkey is P. cirratus and the following 11 species are new geographical records: Anaplectus granulosus, Plectus acuminatus, P. andrassyi, P. armatus, P. assimilis, P. cancellatus, P. longicaudatus, P. minimus, P. parvus, Tylocephalus auriculatus and Wilsonema otophorum. All 15 species found in the Bulgarian part of the mountain are new for the region. Two new species for Bulgarian fauna, P. cancellatus and E. arcticum, are reported. Thus the list of representatives of family Plectidae in Bulgaria now comprises 24 species; more that 60% of them are found in Strandzha and, in this respect, the region is highly diverse. The most frequent and abundant species in Strandzha areP. acuminatus, P. cirratus, A. granulosus. P. longicaudatus and P. parvus are also very frequent but never in high abundance. All other species appear to have a more limited distribution in the region. The presented information on habitats, the exact geographical records, morphometrics and photographs of the species will facilitate future studies in the region and add more certainty to the distribution data of the group.

Acknowledgments. The study is partly supported by Bulgarian Science Fund, Ministry of Education and Science, project of N: DО 02-159/16.12.08.

REFERENCES

Akyazi, F., S. Yildiz, O. Dede, A. F. Felek. 2012. Biodiversity of Nematodes in Potato Growing Areas of Ordu, Turkey. J. of and Veterinary Advances, 11, 2660-2664. Doi: 10.3923/javaa.2012.2660.2664 Akyazi, F., S. Yildiz, A. F. Felek. 2014. Soil nematode communities associated with hazelnut orchards in Turkey. J. of Entomology and Nematology, 6(8), 112-121. Doi: 10.5897/JEN2014.0104. Alexiev, A., L. Budurova, O. Baicheva. 1998. Biomonitoring investigations of the phytonematode communities in the rhyzosphaere of Quercus frainetto in the region of Debelt (Burgas destrict). Biotechologia and Biotechnology Equipment, 12(1), 109-115. Andrássy I. 1958. Erd-und Suisswasse nematoden aus Bulgarien. Acta Zoologica Academiae Scientiarum Hungaricae, 4(1-2), 1-88. Andrássy, I. 1984. Klasse Nematoda (Ordnungen Monhysterida, Desmoscolecida, Aerolaimida, Chromadorida, Rhabditida). Berlin, Deutschland, Academie-Verlag, 509. Andrássy I. 1985. The genus Plectus Bastian, 1865 and its nearest relatives (Nematoda: Plectidae). Acta Zoologica Academiae Scientiarum Hungaricae, 31(1-3), 1-52. Boström S. 1995. Plectus acuminatus Bastian, 1865 and Panagrolaimus magnivulvatus n.sp. from nunataks in Dronning Maud Land, East Antarctica. Fundamental and Applied Nematology, 18, 25-34 Boström S. 1997. Chiloplectus masleni sp. nov. and variability in populations of Plectus acuminatus Bastian 1865 (Nematoda: Plectidae) from the nunatak Basen, Vestfjella, Dronning Maud Land, East Antarctica. Polar Biology, 17, 74-80. De Ley, P., A. Coomans. 1994. Terrestrial nematodes from the Galápagos Archipelago. IV: The genus Plectus Bastian, 1865, with description of three new species (Leptolaimina: Plectidae). – Bulletin de l’InstitutRoyal des Sciences Naturelles de Belgique, Biologie, 64, 43-70. Gadea, E. 1978. Nematodos muscicolas de Anatolia (Turquia). Miscellania zoológica, 4(2), 17-24.

106 Gussev, Ch., Tzonev R. 2014. Natural habitats of European significance in the protected area ‘Strandzha’. Directorate, Malko Tarnovo, 304, ISBN 978-954-92404-5-0 (In Bulgarian). Hernandes, M.A., A. Imaz, I. Armendaris, 1998. Description of a new species of Plectus Bastian, 1865 (Nematoda: Plectidae) and the males of two other species from northern Spain. Nematologica, 44, 631-642. Holovachov, O. 2006. Morphology and systematics of the order Plectida Malakhov, 1982 (Nematoda). PhD Thesis, Wageningen University and Research Centre, the Netherlands. 244, ISBN 90-8504-334-4. Holovachov, O., S. Bostrцm, T. I. De Ley, P. De Ley, A. Coomans. 2003. Morphology and systematics of the genera Wilsonema Cobb, 1913, Ereptonema Anderson, 1966 and Neotylocephalus Ali, Farooqui et Tejpal, 1969 (Leptolaimina: Wilsonematinae). J of Nematode Morphology and Systematics, 5, 73-106. Holovachov O., Boström S., Tandingan De Ley I., De Ley P., Coomans A. 2003. Morphology and systematics of the genera Wilsonema Cobb, 1913, Ereptonema Anderson, 1966 and Neotylocephalus Ali, Farooqui & Tejpal, 1969 (Leptolaimina: Wilsonematinae). J. of Nematode Morphology and Systematics, 5, 73-106. Holovachov, O., S. Boström, G. Winiszewska, L. Hánĕl. 2004. Description of two known and one new species of the genus Anaplectus De Coninck et Schuurmans Stekhoven, 1933 (Nematoda: Plectida) from Europe, and a revised of the genus. Russian J. of Nematology, 12 (I), 45-58. Holovachov, O., P. de Ley. 2006. Order Plectida. – In: Freshwater Nematodes: Ecology and Taxonomy. Ed. E. Adebe, I. Andrassy, W. Trausburger, CABI publishing, 611-614, ISBN 13: 978-0-85199-009-5. Holovachov, O., A. Susulovsky, S. Boström. 2000. Description of two species of Chiloplectus Andrassy, 1984 (Nematoda: Plectidae) from Ukraine and revised taxonomy of the genus. Nematologyca, 2(4), 381- 394. Doi: 10.1163/156854100509240. Iliev, I. 1992. Contribution to the phytonematode fauna of Bulgaria. I. Annuaire de L’Universite de Sofia ‘K. Ohridski’, Faculte of Biologie, Livre 1 – Zoologie, 83, 13-16 (In Bulgarian, English summary). Iliev I., 1998. Nematode fauna of a pasture nearby the village Novo Panicharevo in the south eastern part of Bulgaria. – In: ‘Nematode communities of the temperate grassland ecosystems’. Eds. R. De Goede, T. Bongers, DEGREE: 17-22, ISBN 9783883494715. Iliev, I. 2014. Soil free-living and plant parasitic nematodes in Natural park ‘Strandzha’. PhD Thesis, Faculty of Biology, University of Sofia ‘St. K. Ohridski’, 173 (In Bulgarian, English summary). Iliev, I., Zh. Ilieva. 2014. Nematode Communities in Beech Forests in ‘Strandzha’ Natural Park, Bulgaria. 1. Species composition. Bulgarian J. of Agricultural Science, 20 (Supplement 1): 143-150. Ilieva, Zh. 1998. Nematodes from grassland in Parangalitsa reserve. – In: ‘Nematode communities of northern temperate grassland ecosystems’ Eds. R.G.M. de Goede, T. Bongers, 1998, Focus, Giessen, 131-138. ISBN 9783883494715. Ilieva, Zh. 2007. Soil nematodes communities from the Biosphere Reserve Parangalitca. PhD Thesis, Plant Protection Institute, Kostinbrod, 288 (In Bulgarian, English summary). Ilieva, Zh., I. Iliev, M. Mitov. 2003. Morphometrics of Nematodes of the Tisata reserve: Rhabdolaimidae Chitwood, 1951 and Plectidae Oerley, 1880. Silva Balkanica 3(1), 25-34. Katalan-Gateva, S. 1961. Contribution to nematode fauna of wild and culture plants of Bulgaria. Helmintologia, Bulgarian Academy of Sciences, 3,127-138 (In Russian, English summary). Katalan-Gateva, S. 1965. Study on soil and plant parasitic nematodes in Pazardzhik region. – Annuaire de L’Universite de Sofia ‘K. Ohridski’, Faculte de Biologie, Livre 1 – Zoologie, Physiologie et Biochimie des Animaux, 58, 151-184 (In Bulgarian, English summary). Katalan-Gateva, S. 1966. Soil and plant parasitic nematodes on the Solanaceae in Thrace valley. – Fauna of Thracia, III, 149-180 (In Bulgarian, English summary). Katalan-Gateva, S. 1968. Die phytonematode Fauna der Hochgebirspflanzen und endemischen Pflanzen in dem Piringebirge. Annuaire de L’Universite de Sofia ‘K. Ohridski’, Faculte de Biologie, Livre 1 – Zoologie, Physiologie et Biochimie des Animaux (1966-67), 61, 171-184 (In Bulgarian, German summary). Katalan-Gateva, S. 1985. List of plant parasitic nematodes in Bulgaria established in 1903-1983. Annuaire de L’Universite de Sofia ‘K. Ohridski’, Faculte de Biologie, Livre 1 – Zoologie, 79, 92-119 (In Bulgarian, English summary).

107 Katalan-Gateva, S., A. Alexiev, I. Iliev, Zh. Ilieva. 1991. On the species composition and distribution of the family Criconematidae (Taylor, 1936) Thorne, 1949 (Nematoda) in Bulgaria. Acta Zoologica Bulgarica, 41, 53-57. Katalan-Gateva, S., O. Baicheva. 1976. Study on nematode fauna of two tobacco varieties – Rila-9 and Kulsko in the region of Blagoevgrad. Helminthology, Bulgarian Academy of Sciences, 1, 43-48 (In Bulgarian, English summary). Katalan-Gateva, S., O. Baicheva, 1978. Nematode fauna of tobacco brand Oriental-261 from Blagoevgrad region. II. Helminthology, Bulgarian Academy of Sciences, 5, 47-59. Katalan-Gateva, S., L. Budurova. 1975. Soil and plant nematodes in strawberries of the ‘Madame Moutot’ variety from district of Blagoevgrad. Annuaire de L’Universite de Sofia ‘K. Ohridski’, Faculte de Biologie, Livre 1 – Zoologie, 67, 131-135 (In Bulgarian, English summary). Katalan-Gateva, S., L. Budurova. 1978. Structural analysis of the phytonematode populations in the biocoenose of apple plantation in the destrict of Blagoevgrad. I. Nematodes found on the root system of theapple (Malus domestica Borkh.). Bulgarian Academy of Sciences, Ecology, 4, 32-44 (In Bulgarian, English summary). Katalan-Gateva, S., L. Budurova, B. Choleva. 1982. Nematode faune of grape (Vitis vinifera L.) of the destrict of Blagoevgrad. Annuaire de L’Universite de Sofia ‘K. Ohridski’, Faculte de Biologie, Livre 1 – Zoologie, 70 (1976-1977), 55-61 (In Bulgarian, English summary). Katalan-Gateva S., Milkova M. 1978. Phytonematode coenoses in two varieties of hop. – Ecology, Bulgarian Academy of Sciences, 5, 11-20 (In Bulgarian, English summary). Katalan-Gateva S., Stefanov D. 1978. Influence of the nematocide Vydate on the nematode coenoses in the soil and the root system of tobacco. I. Ecology, Bulgarian Academy of Sciences, 4, 79-90 (In Bulgarian, English summary). Katalan-Gateva, S., M. Tzenkova, B. Choleva. 1981. The phytonematode Fauna in the Roots and Rhizosphere of the Rose (Rosa damascena Mill.) in Bulgaria. Helmintologia, Bulgarian Academy of Sciences, 12, 12-53. Lazarova, S., V. Peneva, R. Neilson. 1998. Nematodes of the genus Tripyla Bastian, 1865 (Nematoda: Enoplida) from woodlands in Bulgaria. Russian J. of Nematology 6(2), 165-174. Lazarova, S., V. Peneva, L. Penev. 2000. Nematode assemblages from the moss Hypnum cupressiforme Hedw. growing on different substrates in a balkanic durmast oak forest (Quercus dalechampii Ten.) on Mount Vitosha, Bulgaria. Nematology, 2(3), 263-272. Doi: 10.1163/156854100509132. Paramonov, А. А. 1963. Method of thermal dying of nematodes by polychrome blue. – In: Methods of investigations of soil, plant and entomopathogenic nematodes. Edition of Zoological Institute of ASci USSR, Leningrad, 128-129 (In Russian). Seinhorst, J. W. 1959. A rapid method for the transfer of nematodes from fixative to anhydrous glycerin. Nematologica, 4, 67-69, Doi: 10.1163/187529259X00381. Stoyanov, D. 1961. Contribution to nematode fauna of some wild and culture plants. Rastitelna zashtita, 3, 50-64 (In Bulgarian). Stoyanov, D., 1979. The nematode fauna on rice in Bulgaria. – Rastenievadni nauki (Plant Science), 16(1), 115-120 (In Bulgarian, English summary). Van Bezooijen, J. 2006. Methods and Techniques for Nematology. Manual of Wageningen University, 112, Last visited on 4 May 2016 https://www.wageningenur.nl/upload_mm /4/e/3/f9618ac5-ac20-41e6- 9cf1- c556b15b9fa7_MethodsandTechniquesforNematology.pdf. Zhivkov D., O. Baicheva, 1974. On the nematode fauna of Mentha piperita and Lavandula vera in the Karlovo area. Bulletin of the Central Helminthological Laboratory, 16, 73-79 (In Bulgarian, English summary).

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