Dorylaimopsis boucheri, Fu & Leduc & Rao & Cai, 2019

Fu, Sujing, Leduc, Daniel, Rao, Yiyong & Cai, Lizhe, 2019, Three new free-living marine nematode species of Dorylaimopsis (Nematoda Araeolaimida: Comesomatidae) from the South China Sea and the Chukchi Sea, Zootaxa 4608 (3), pp. 433-450 : 439-443

Dorylaimopsis boucheri sp. n.

( Figures 4–6 , Table 2)

Material examined. Type specimens. Holotype male, inventory slide no. Beibuwan 201181 .

The habitat and locality. Beibu Gulf of the South China Sea. Collected on August 2011, 20 °39′N, 108°02′E, water depth 20 m, salinity 33.48‰; 20°38′N, 108°37′E, water depth 32 m, salinity 33.85‰; 20°39′N, 109°32′E, water depth 23 m, salinity 33.48‰; surface sediment layer (0–10 cm), muddy sediment. Male inventory slide no. Beibuwan 201137, 201133, 201171, 2011115. Female inventory slide no. Beibuwan 201112, 201166, 201171 and 201183.

Etymology. This species is named after the French meiofauna scientist Guy Boucher.

Description. Male. Body slender, cylindrical, tapering slightly towards extremities. The cuticle is marked by transverse rows of fine punctuations. Lateral differentiation consisting of 3–4 longitudinal rows of larger dots, beginning about 34 μm posterior to amphids, terminating at the conical part of tail. Lateral differentiation 9 μm wide at mid-body, about 26% of corresponding body diameter. Two circles of six inner labial and six outer labial papillae. Four cephalic setae, equal to 0.3–0.6 corresponding body diameters in length. Amphideal fovea spiral, 2.5 turns, located immediately posterior to cephalic setae. Buccal cavity opens into a cup-shaped anterior portion, followed by a cuticularized tubular portion, with three strong triangular teeth located at the anterior end. Pharynx widened posteriorly, without a distinct bulb. Nerve ring at pre-median of pharyngeal length. Renette located at the level of anterior end of intestine.

Two testes, opposed and outstretched. Anterior testis to the left and posterior testis to the right of the intestine. Spicules paired, equal and arcuate, 1.2–1.6 cloacal body diameter long. Proximal ends of spicules cephalated, with long median cuticularized strip, about one third of spicule length, and with a ventral velum. Gubernaculum with two straight dorsocaudal apophyses. Thirteen to sixteen tubular precloacal supplements present. Tail conico-cylindrical, anterior one fourth of the tail conical, posterior three fourths cylindrical; tip not swollen, and without terminal setae.

Females. Similar to males, but lateral differentiation consisting of 4–6 longitudinal rows of larger dots along entire body. Amphideal fovea spiral, with 2.75 turns. Reproductive system didelphic, with opposed and outstretched ovaries; anterior ovary to the left side of intestine and posterior ovary to the right of intestine. Vulva at pre-median of body length. Vaginal glands present. Spermatheca present, often with numerous spermatozoa.

Diagnosis and relationships. Dorylaimopsis boucheri sp. n. is characterized by amphideal foveal with 2.5 turns in males, 2.75 turns in females. Lateral differentiation consisting of 3–4 longitudinal rows of larger dots in males, 4–6 rows in females; buccal cavity composed of a cup-shaped anterior portion and a cuticularized tubular portion with three strong teeth present at the anterior end; spicules arcuate, 44–48 μm long, thirteen to sixteen tubu- lar precloacal supplements present; tail conico-cylindrical, tip not swollen, and without terminal setae.

Dorylaimopsis boucheri sp. n. is morphologically close to D. halongensis Nguyen et al., 2008 in the pattern of lateral differentiation in males, tail tip not swollen and absence of terminal setae. Dorylaimopsis boucheri sp. n. can be distinguished from D. halongensis Nguyen et al., 2008 by its much shorter tail (158–228 μm vs 369–380 μm), lower value of a (34–43 vs 43–58), lower c′ (5–7 vs 11–14) and larger maximum body diameter (50–60 μm vs 36–48 μm) in the new species.

Figures

FIGURE 4. Dorylaimopsis boucheri sp. n. A: Entire male. B: Reproductive system of female. Scale bars. A = 50 µm; B = 10 µm.

FIGURE 5. Dorylaimopsis boucheri sp. n. A: Male head. B: Anterior body region of male. C: Lateral surface view of male head. D: Cloacal region with spicule, gubernaculum, and precloacal supplements. E: Female tail. Scale bars. A, C, E = 10 µm; B = 50 µm; D = 25 µm.

FIGURE 6. Dorylaimopsis boucheri sp. n. Light micrographs.A: Male head. B: Lateral surface view of female head. C: Anterior body region of male. D: Female reproductive system. E: Cloacal region with spicule, gubernaculum, and precloacal supplements. F: Male tail. Scale bars. A, B, D, E = 10 µm; C, F = 50 µm.