The freeliving marine nematode genus Sabatieria (Nematoda: Comesomatidae). I. Two new species from Stonington Island, Antarctica H. M. Platt Department of Zoology, British Museum (Natural History), Cromwell Road, London SW7 5BD Introduction As a prelude to an eventual review of the genus Sabatieria, species from various geographical locations and differing habitats are being examined in detail. This first paper describes two new species from the constantly near-freezing Antarctic waters. The specimens were obtained by SCUBA divers on 30 March 1974 from a small inlet, Back Bay, in the vicinity of the former British Antarctic Survey base at Stonington Island; part of a series of collections detailed elsewhere (Platt, 1979). The substrate was fine sand and stones underlayed at about 2 cm with gravel which prevented coring beneath this depth. The methodology employed for studying the organisms and the abbreviations used in their description have been fully described elsewhere (Platt, 1982). Systematic descriptions Sabatieria kelletti sp. nov. (Figs 1-3) MATERIAL STUDIED. Holotype: rfl BM(NH) 1982.5.26. Allotype: 9! BM(NH) 1982.5.32. Paratypes: five males BM(NH) 1982.5.27-31; five juveniles BM(NH) 1982.5.33-37. LOCALITY. 15m depth, Back Bay, Stonington Island, Antarctica. Lat. 68 12-4' S, long. 6659-5' W. MEASUREMENTS (Table 1) Holotype rf: 350 M 2845 p.,. ~, , ,~ A c ,~ 3095 um; a = 36; b = 8-8; c= 12-4; S = 63 urn 19 74 87 61 Allotype 9: -330 1550 3035 I / ^ s 3 _ _ DESCRIPTION. The body narrows suddenly in the region just posterior to the amphid: h.d. 26-33% of the posterior oesophagus c.d. Cuticle punctated: in the lateral field the dots are larger and more irregularly arranged than medially, especially in the oseophagus and tail regions (Fig. 3c, e). The medial dots are more or less arranged in transverse rows (Fig. 3d). In the cylindrical portion of the tail the dots are present but are only very tiny. Somatic setae in four longitudinal files, one on each side of the lateral field: 5-7 um long and spaced 50-130 um apart but closer together at the ends than in the middle of the body. In adults there is a subventral row of three more closely spaced cervical setae (Figs Ic, d & 3a). In stage-4 juveniles (Jl-4) there are ony two setae in this position (Fig. li) and no such setae were observed in what is probably a stage-2 juvenile (J5). There are additional 7-10 um dor-sal and ventral caudal setae in the males (Figs If, j & 2f). The tail tip has three terminal setae, one dorsal and two subventral. Rl sensilla papilliform. R2 sensilla short but clearly setiform. R3 sensilla in adults 42-47% h.d.: the same relative length in juveniles. Amphids Bull. Br. Mus. nat. Hist. (Zool.) 45(5): 239-252 Issued 29 September 1983
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