Cervonema pseudodeltensis, 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 : 280-283

Cervonema pseudodeltensis sp. nov.

( Figs. 5 & 6 )

Type locality. Subtidally off the Korean west-south coast (34.410º N 127.577º E), south-east of Oeraro Island , from clayey silt and 19 m water depth .

Additional localities. Paratype males specimens from Korean west-south coast (34.436º N 126.955º E), east of Joyag Island , in a region of intense aquaculture activity, at a depth of 22 m in clayey silt. Juvenile collected subtidally, near the islands of the southern extent of the Tongyeong sea, South Korea (34.5738º N 128.4169º E) at a depth of 42 m in muddy sediment .

Type material. Four males, two females and 1 juvenile. Holotype male NIBRIV000024586. Paratype male NIBRIV000024586 and 2 paratype females NIBRIV000024586-4 on one slide. Two paratype males NIBRIV0000245865and one paratype juvenile NIBRIV000024586, on separate slides as listed. Holotype and all paratype adults collected by Jong-ho Hong from Research Vessel Tam-Gu 17. Juvenile collected by Dong-Ju Lee from Research Vessel Tam-Gu 7 in the Tongyeong sea in June 2010.

Measurements. See Tables 7 and 8 for detailed measurements and calculations.

4 224 - 960 1421 803 1638

male 1 11 51 53 34

3 265 340 943 289 1567 1755

female 1

10 52 56 37

Description. Male holotype ( Fig. 5 ). Habitus tubular, tapering from cloaca to conico-cylindrical tail posteriorly, anterior narrowing more gently from cardia to lips. Cuticle with faint, relatively fine striation throughout body, cylindrical section of tail appears smooth. In the lateral field of the cervical region striations appear as punctations so closely spaces as to appear fused: In the sublateral field of the post-cloacal region, the irregular punctations are clear.

Six small lips indistinct, labial papillae minute. Six anterior cephalic setae (0.6 hd long) located about 0.4 hd from anterior extremity, 4 jointed posterior cephalic setae (0.4 hd long) in distinctly separate crown. Amphid multispiralled with 5.5 turns (diameter 0.6 cbd). Cervical setae scarce, 2 µm long. Somatic setae not observed. Row of 6 subventral post-cloacal setae, 9–3 µm long in conical region of tail, 2 subventral setae pre-cloacally. Row of 3 dorso-sublateral setae in also in conical tail region. Lateroventral setae scattered. Last somatic setae observed 3.1 abd from the cloaca in the cylindrical region of the tail.

Diorchic, outstretched testes, anterior testis 960 µm long, posterior testis 803 µm long. Spicules approximately straight (1 abd long), gubernaculum with indication of posteriorly directed paired apophyses (0.2 abd long), seen only owing to rotation of specimen. Eight ejaculatory glands anterior to cloacal, 3 left lateral, 5 right lateral. One short mid-ventral papilla (3 µm long) located 0.3 abd anterior to cloaca. Five minute precloacal supplements observed, posterior supplement 0.6 abd from cloaca, anterior supplement 2.4 abd [However, 6, 6, & 7 supplements were recorded in other specimens, anterior supplement up to 5.2 abd from cloaca]. Cloaca as lateral slit. Caudal glands start level with cloaca. Tail conico-cylindrical 6.4 abd long, with cylindrical portion 56 % of total, 3 terminal setae, 3 µm long.

Female paratype ( Fig. 6 ). Similar to male, longer (2104 µm), anterior cephalic setae equal to or shorter than posterior cephalic. Vulva at 47 % of body length, as lateral slit. Vagina short and straight without sclerotizations or epiptygmata. Didelphic, outstretched ovaries, anterior 323 µm, posterior 307 µm long. Supplements absent. Cylindrical tail section slightly longer than in males (66 % of total tail length).

Affinities. Cervonema pseudodeltensis sp. nov. is unique within the genus, being the only species so far described which appears to have anterior cephalic setae marginally longer than the posterior cephalic setae. It is superficially similar to C. deltensis Hope and Zhang 1995 , described from the Bohai Sea, and they share similar spicules lengths (as abd), amphid size, oesophageal bulb size and a similar proportional relationship between the conical and cylindrical sections of the tail. However, they differ with regard to body length of adults (male1559 – 1755 µm vs 1201 – 1237 µm; female 1828 – 2104 µm vs 1250 µm), the proportional lengths of the cephalic setae, the relative length of the oesophagus (b = 7.0 – 7.9 vs 6.3 – 6.7) and the number of ejaculatory glands (3 + 5 vs 6 + 6).

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Figures

FIGURE 5. Cervonema pseudodeltensis sp. nov., holotype male: A, oesophagus; B, head; C, pre-cloacal region; D, tail; E, gonads; F, habitus. Scale bars: 10 µm (A–D), 20 µm (E), and 100 µm (F).

FIGURE 6. Cervonema pseudodeltensis sp. nov., paratype female: A, head; B, oesophagus; C, tail; D, gonads; E, habitus. Scale bars: 10 µm (A, B), 20 µm (C), 40 µm (D), and 200 µm (E).