Belbolla zhangi, Tchesunov & Mokievsky, 2005

Tchesunov, Alexei V. & Mokievsky, Vadim O., 2005, Three new species of free-living nematodes from the Bohai Sea, China, Journal of Natural History 35 (11), pp. 1575-1586 : 1581-1585

Belbolla zhangi sp. nov.

(fi gure 4)

Type material

Holotype: one male ( Station G3 ); paratypes: three males (Station G 3, E4, E5) and two females (Station G 3) .

Type locality

Sublittoral in the Bohai sea. G 3 39 ° 00.08 ' N, 120 ° 00.26 ' E, wa ter depth 21.6 m, silt with M D 0.0241 mm; E4 38 ° 30.15 ' N, 120 ° 00.40 ' E, wa ter depth 27 m, silt with M D 0.0197 mm; E5 38 ° 30.08 ' N, 120 ° 30.10 ' E, water depth 30.7 m, silt with M D 0.0387 mm.

Etymology This species is named in honour of Professor Z. N. Zhang.

Measurements ( table 4 )

- 560 M 2408 Holotype male: 2600 µ m; a =34.7, b =4.6, c =13.5, Sc =56 11 61 75 192

- 590 V 2620 Paratype female 1: 2780 µ m; a =33.1, b =4.7, c=16.3, V =44.6% 11 78 84 160

Description

The anterior end tapers to a very small diameter. Large right ventro-lateral tooth, 7 µ m long, and two less prominent teeth (dorsal and left ventro-lateral in position). Mouth surrounded by six small papillae and 10 cephalic setae, 8–10 µ m, arranged in one circle. Cuticular ring separating the two buccal chambers smooth (no denticles). Oesophagus expands gradually and evenly, posteriorly modi fi ed into eight or nine bulbs (fi rst bulb may not be clear in males). Nerve ring 40–50% oesoph agus length. Tail 2.9–4.0 a.b.d., conico-cylindrical.

Males. Tail relatively stout over most of length narrowing sharply in posterior quarter. Spicules equal, with rounded, blunt proximal ends. G ubernaculum has pair of 40–45 µ m apophyses. Two well-developed pre-cloacal supplements lie close together, distant from the cloacal opening. Anterior supplement 0.6–0.9 a.b.d., posterior 0.5–0.8 a.b.d.

Females. Ovaries paired, equal, opposed, re fl exed. Vulva at 44.6–44.1% of body length.

Differential diagnosis

Belbolla zhangi sp. nov is characterized by the number of oesophageal bulbs, the shape of the spicules and gubernacular apophysis, and the size of the two winged precloacal supplements. It is closest to B. tenuidens Cobb, 1920 which also has a long gubernacular apophysis. There are some minor differences in the shape of spicules and tail, but the principal difference between the two species is in the size of the two winged pre-cloacal supplements which are much longer in B. tenuidens (1.4–1.5 a.b.d.) than in B. zhangi (0.5–0.9 a.b.d.). Whilst it is possible that intermediate forms might be found, we are not inclined to ascribe the present specimens to B. tenuidens , particularly in view of the very different habitats and geographical areas that the two species inhabit ( B. tenuidens is from an intertidal sandy beach at Woods Hole, USA). The number of bulbs is an important feature in keys to the genus presented by Belogurov and Belogurova (1980). In four out of six adult specimens we examined there are nine bulbs.