Bendiella vivipara, Cai, 2017

Cai, Lizhe, 2017, Two new ovoviviparous species of the family Selachinematidae and Sphaerolaimidae (Nematoda, Chromadorida & Monhysterida) from the northern South China Sea, Zootaxa 4317 (1), pp. 95-110 : 96-100

Bendiella vivipara n. sp.

( Figs. 1 –3, Table 1)

Type material. Male holotype, slide 20140901. Specimen collected from Beibu Gulf, South China Sea in August 2011, coordinates: 21.191° N, 109.562° E, water depth 9.5 m, surface sediment layer (0–10 cm), muddy sediment.

Paratypes, three males, slide 20140702–slide 20140704, specimens collected from Beibu Gulf , South China Sea in August 2011, coordinates: 20.788° N, 109.535° E, water depth 10.2 m, surface sediment layer (0–10 cm), muddy sediment; three females (slide 20140305–slide 20140307, coordinates: 21.226° N, 108.751° E, water depth 16 m, surface sediment layer (0–10 cm), muddy sediment.

Etymology. The species name is related to viviparity of the female.

Description. Males. Body cylindrical, anterior end blunt, not set off. Cuticle transversely striated with transverse rows of punctations, lateral differentiation of cuticle beginning at a short distance posterior to the amphids down to the tail, consisting of 2–4 longitudinal rows of larger dots (two rows anteriorly, four rows from posterior end of pharynx to anterior intestine and three rows posteriorly to anterior intestine to the level of cloacal). Somatic setae short and sparse, irregularly spaced. Amphid spiral with five turns, inner labial papillae short, six outer labial papillae smaller than inner labial papillae situated on the same level with the four cephalic setae. Buccal cavity large, consisting of two parts including a wide anterior and a narrower posterior portion. Anterior portion of buccal cavity cylindrical with twelve cuticularised rhabdions, posterior buccal cavity surrounded by three “V” shaped pairs of rhabdions. About twelve denticles which are extensions of the anterior rhabdions present at the border of anterior and posterior portions of the buccal cavity. Pharynx larger around the stoma, and slightly wider towards its base but without a posterior bulb. Nerve ring not distinct, cardia short and triangular. Secretoryexcretory system with renette cell present, ampulla and pore at about 58% of the pharynx from the anterior end. Intestinal cells contain masses of granules.

Male with paired outstretched testes, anterior testis on right of intestine, posterior testis on left of intestine. Three conoid precloacal papillae, the anterior one situated about 38 µm from cloacal opening. Arcuate paired spicules of similar length, tapering distally. Gubernaculum comprising a pair of lateral pieces without apophyses, about 24 µm long. Tail with an anterior conoid and posterior cylindrical part. Sparse setae irregularly distributed on the tail. Spinneret 10 µm long.

Adult females similar to males. Reproductive system didelphic with two reflexed ovaries. The anterior ovary contains three to four embryos indicative of an ovoviviparous mode of reproduction. Vulva with thick walls situated slightly anterior of median body. Intestine blind. Anus not observed.

Diagnosis. Bendiella vivipara n. sp. is characterized by having an amphideal fovea with five turns, the anterior portion of buccal cavity surrounded by 12 cuticularised rhabdions, each with one pair of pointed projections at the posterior extremity, forming 12 denticles between the two chambers. The posterior chamber is an inverted pyramid surrounded by three V-shaped pairs of cuticularised rhabdions. The new species lacks a posterior pharyngeal bulb, and has a conico-cylindroid tail. Males have plain arcuate spicules, the gubernaculum is arcuate, without apophyses, in addition, they have three papillose precloacal supplements and female is ovoviviparous.

Differential diagnosis. Bendiella vivipara n. sp. is morphologically close to Bendiella thalassa Leduc, 2013 in the structure of the buccal cavity, the head sensillae pattern and the shape of the long tail. Both species have a lateral differentiation of the cuticle, i.e. longitudinal rows of larger dots. The new species differs from Bendiella thalassa in a smaller number of amphidial fovea turns (five turns vs 5.25 turns), the presence of three precloacal supplements and an ovoviviparous mode of reproduction.

Figures

FIGURE 1. Bendiella vivipara n. sp. A: Viviparous female. Total body. B: Anterior body region of male. C: Anterior body region of female. D: Posterior body region of female. E: Posterior body region of male. F: CloaCal region with spiCule, gubernaCulum, and three papillose preCloaCal supplements.