Laimella socotris, Barnes & Kim & Lee, 2012

Barnes, Natalie, Kim, Hyeong Geun & Lee, Wonchoel, 2012, New species of free-living marine Sabatieriinae (Nematoda: Monhysterida: Comesomatidae) from around South Korea *, Zootaxa 3368 (1), pp. 263-290 : 270-272

Laimella socotris sp. nov.

( Fig. 2 )

Type locality. Sub-tidally north-west of Socotra Rock (32.1523º N 125.1519º E), at a depth of 51 m, in muddy sediment .

Type material. Single specimen, holotype male NIBRIV0000245035. Collected by Kwang-Soo Kim, in June 2011 from Research Vessel Tam-Gu 8.

Measurements. See Tables 3 and 4 for detailed measurements and calculations.

3 158 - 708 1224 647 1486

male 1

13 26 41 32

Description. Male holotype ( Fig. 2 ). Habitus tubular, tapering to elongate tail posteriorly, slightly narrowed anteriorly. Cuticle with faint punctation mainly seen as sub-cuticular character, striation not observed. Body diameter increases gradually from cephalic setae to mid-oesophageal region, reduces slightly behind cardia, then approximately stable to cloaca. Tail conico-cylindrical.

Labia as 6 small lips, labial papillae minute. Six anterior cephalic setae (0.2 hd long) located about 0.2 hd from anterior extremity, 4 posterior cephalic setae (0.4hd long) directly behind. Amphid multi-spiralled with 3.25 turns

(diameter 0.7 cbd), 0.4 hd from anterior. Cervical setae about 3 µm long, in 4 uneven longitudinal rows, possibly some breakage. Rows of latero-ventral somatic setae continue down body. Post-cloacal setae as latero-dorsal rows.

Last setae observed as a pair at 56 % of the tail length from the cloaca on cylindrical portion of the tail.

Anterior section of buccal cavity shallow cup-shape (4 µm deep) and posterior portion as undifferentiated collapsed tube, with three teeth at anterior margin, 3 µm long. Oesophageal musculature surrounds buccal cavity,

sclerotization not observed, cylindrical to nerve ring, then narrows until rounded oesophageal bulb (23 % of oesophagus length) with thickened lining of lumen. Cardia short (8 µm long). Nerve-ring at 50 % of oesophagus length from anterior, ventral pore posterior to nerve ring (61 % of oesophagus length). Ventral gland small,

elongate, distance from pore to base of gland 90 µm (57 % of oesophagus length).

Diorchic, outstretched testes, anterior testis 708 µm long, posterior testis 647 µm long. Spicules arcuate (1.7

abd long, measured as curve), gubernaculum with posteriorly directed paired apophyses (0.7 abd long). Five ejaculatory glands anterior to cloacal, 3 left lateral, 2 right lateral. One short mid-ventral papilla (4 µm long) located 0.3 abd anterior to cloaca. Eight minute precloacal supplements observed, posteriormost 1.0 abd from cloaca, anteriormost 6.2 abd from cloaca. Cloaca as lateral slit. Caudal glands not observed. Tail 8.1 abd long, with cylindrical portion 68 % of total tail length, terminal setae not observed.

Female. Unknown.

Etymology. The species name refers to the sampling location, about 4.5 km north-west from Socotra Rock, discovered by the British merchant vessel Socotra in 1900.

Affinities. Laimella socotrensis sp. nov. is most similar to L. longicauda and L. filicaudata in having a distinct rounded posterior oesophageal bulb. It differs from L. longicauda however, with regard to the tail length (c' = 8.1 vs 17.7; Cobb 1920) and the relative length of the anterior and cephalic setae (0.2 + 0.4 hd vs 0.4 + 1.5 hd, respectively). It differs from L. filicaudata also with regard to the relative lengths of the anterior and posterior cephalic setae (vs 0.4 + 1.2 hd, respectively).

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Figures

FIGURE 2. Laimella socotris sp. nov., holotype male:, oesophagus; B, head; C, pre-cloacal region; D, tail; E, habitus; F, gonads. Scale bars: 10 µm (A–D), 100 µm (E), and 20 µm (F).