First record of three species of soil nematodes of the suborder Cephalobina from Ladakh region , Jammu & Kashmir , India

The present paper reports three species of soil nematodes of the suborder Cephalobina collected from Ladakh region of the Jammu & Kashmir State, India. Two species, Cervidellus vexilliger (de Man, 1880) Thorne, 1937 and Chiloplacus demani (Thorne, 1925) Thorne, 1937 are reported for the first time from India, while, Acrobeloides nanus (de Man, 1880) Anderson 1968 is a first record from Ladakh. The species dealt with here have been adequately described and photomicrographed, with additional notes provided on variations encountered in measurements. The occurrence of these species from trans-Himalayan zone conforms with the zoogeographical pattern of distribution of the invertebrate fauna of the zone which harbours both Palaearctic and Oriental elements.

Ladakh is home to some very beautiful lakes, which play significant hydrological roles.Three of these lakes surveyed were Pangong Tso, Tsomoriri and Tsokar.These lakes have conservation values, particularly as breeding ground for Bar-headed Goose Anser indicus (Latham, 1790) and globally threatened Black-necked Crane Grus nigricollis Przhevalsky, 1876.Ladakh region of the state of Jammu & Kashmir, regarded as the cold desert of India, is least explored in terms of plant and soil nematodes and there are only three species hitherto known from Leh namely, Anguina tritici (Steinbuch, Filipjev) by Zaki & Mir (1994), Laimydorus vulvapapillatus and Mesodorylaimus ladakhiensis by Mushtaq & Ahmad (2006).
The studies on soil nematodes collected from the recent survey of Ladakh (July 2008)  Male: Body usually ventrally curved upon fixation.Reproductive system monorchic.Testis reflexed ventrally.Spicules arcuate with rounded manubrium, calamus as wide as manubrium, lamina ventrally curved and terminus acute.Gubernaculum anteriorly ventrally curved.Five pairs of postanal genital papillae: one pair lateral, one pair subdorsal, one pair subventral and two pairs near tail tip.Tail conical, bearing an acute terminus.
Habitat & Locality: Soil around the root rhizophere of Myricaria around Pangong Tso and around Caragana bushes around Tsomoriri Lake, Ladakh.
Remarks: All the body measurements and description are in conformity with the revised description of the species given by Abolafia et al. (2003) However, slight variation in measurements were observed in body length of males and females (male body length 0.42-0.52mm against 0.24-0.4mm; female body length 0.41-0.45mm against 0.22-0.41mm), pharynx length (101-120 μm against 80-107 μm in males; 109-116 against 72-110 μm in females) and values of c is also greater (c = 16.2-17.5against 10-14.5 in males; 13.7-16.1 against 8.8-15.7 in females).This species is being found for the first time from Cold Desert, Ladakh and it is a new record from India.
Discussion: From the foregoing observations and records of the known occurrence of all the three species reported here, in Europe and other Palaearctic countries, their occurrence in the Cold Desert region of J & K India is not surprising but conforms with the zoogeographical pattern of distribution of the Invertebrate fauna.The Ladakh region in the trans-Himalayan zone is considered to harbour both Palaearctic and Oriental elements.
, revealed two new records for India, Cervidellus vexilliger (de Man, 1880) Thorne, 1937 and Chiloplacus demani (Thorne, 1925) Thorne, 1937, while, Acrobeloides nanus (de Man, 1880) Anderson, 1968 is being recorded for the first time from Ladakh.Material & Methods: The Cold Deserts in the Ladakh (J & K) was surveyed by the Zoological Survey of India Expedition teams under the programme "Rapid Survey for Assessment of Faunal Resources in Cold Desert of Ladakh" from 01 July 2008 to 30 September 2008.Three lakes surveyed were Pangong Tso, Tsomoriri and Tsokar.Pangong Tso is a long brackish lake spanning Indo Chinese border (only one-third is in India and two-third lies in China).It is situated at 33 0 50'N & 78 0 35'E, 4218m and 65000ha area.The water freezes to a depth of several meters in winters.There are some brackish to saline marshes near the western end, whereas surrounding hillside supports low thorn scrub and perennial herbs.Tsomoriri is the largest of the high altitude Trans-Himalayan brackish water lake to lie entirely within Indian Territory.The lake was declared as a Wetland of International Importance under the Ramsar Convention in 2003.The lake now has the distinction of being the highest Ramsar site in the world surpassing Salar de Tara in Chile.The lake is approximately 19km long and 7km wide and is located at an altitude of 4595m and 32 0 59'N & 78 0 20'E.It is fed by a number of small glacial streams.Vegetation does not appear in the deeper part, but occurs in the shallower part.Various species of sedges and reeds grow in the marshes like Carex, Caragana, typical of the surrounding arid steppe vegetation.The third lake surveyed was the Tsokar.Tsokar is a hyper saline lake of 22000ha.It is situated at an altitude of 4539m and at 33 0 50'N & 78 0 35'E.The arid steppe vegetation of surrounding areas is dominated by species of Astragalus and Caragana.The soil samples, for the extraction of nematodes were collected from the root zone (rhizosphere) of the Myricaria, a medicinal shrub and Caragana bushes, which occur very widely around Ladakh wetlands like Pangong Tso, Tsokar and Tsomoriri.The nematodes were isolated from soil by Cobb's sieving and decantation technique, fixed in hot 4% formalin and dehydrated by slow method.Permanent wax slides were prepared for the study of nematodes.Measurements were made with an ocular micrometer on BX51 DIC Olympus microscope and photomicrographs taken with DP20 digital camera.Results: The three species extracted have been studied, photomicrographed and described here as under.1. Cervidellus vexilliger (de Man, 1880) Thorne, 1937 (Fig. 1) 1880.Cephalobus vexilliger de Man, Tijds.Nederland.Dierk.Vereen, 5: 1-104.1937.Cervidellus vexilliger, Thorne, Proc.Helminth.Soc.Wash., 4:1-16 Material Examined: 24.vii.2008,8 females, 4 males, Pangong Tso, Ladakh, J & K, India, coll.A.N. Rizvi, NRS/ ZSI/IV/N/401; 26.vii.2008,7 females, Tsomoriri lake, Ladakh, J & K, India, coll.A.N. Rizvi, NRS/ZSI/IV/N/402.Measurements: Refer Table1.Description: Female: Body generally slightly arcuate ventrally or almost straight upon fixation.Cuticle distinctly annulated.Lateral field with three incisures, of which the middle one diminishes at the anterior end of the phasmid and two outer ones extend beyond phasmid.Lip region with six labial and four cephalic papillae.Primary and secondary axils similar in shape, each with two guarding processes.Lips symmetrical, with three tines each.Labial probolae 3-5 μm long, Y shaped.Stoma cephaloboid.Pharyngeal corpus cylindrical, isthmus short and basal bulb pyriform to ovoid with valves.Cardia conoid.Rectum