Dorylaimopsis jinyuei, 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 : 443-446

Dorylaimopsis jinyuei sp. n.

( Figures 7–9 , Table 3 )

Material examined. Type specimens. Holotype male, inventory slide no. ChukchiC0431 .

The habitat and locality. Sublittoral zone in the Chukchi Sea (Arctic Ocean). Collected in July 2014, 169°01′ W, 67°40′ N, water depth 50 m, salinity 32.77‰; 168°09′ W, 69°13′ N, water depth 50 m, salinity 32.75‰; 169°00′ W, 69°36′ N, water depth 52 m, salinity 32.63‰; 166°59′ W, 71°00′ N, water depth 45 m, salinity 30.64‰; surface sediment layer (0–10 cm), muddy sediment. Male inventory slide no. ChukchiC0431, ChukchiC01, ChukchiB14 and ChukchiR02. Female inventory slide no. ChukchiR04 and ChukchiC01.

Etymology. This species was named after the second son of the first author Sujing Fu.

Description. Male. Body cylindrical, widest at anterior intestine region, gradually tapering towards both extremities. Cuticle with transverse rows of fine punctuations, with lateral differentiation in the form of 4–7 longitudinal rows of coarse dots extending from posterior edge of amphid to anterior of intestine, and 5–7 longitudinal rows of coarse dots in the conical tail region, not as regular as in pharyngeal region; longitudinal rows of coarse dots absent in middle body. Cephalic region with a distinct constriction. Two circles of six inner labial and six outer labial papillae, four cephalic setae situated at level of constriction. Buccal cavity consists of two portions, a cup-shaped anterior portion and a cuticularized tubular posterior portion. Three triangular teeth present at the anterior end of tubular part of buccal cavity. Amphids spiral, 2.75 turns, anterior border of amphids at level of cephalic setae. Pharynx cylindrical, widening slightly towards posterior end. Nerve ring near middle of pharynx. The ventral gland situated posterior to the cardia level, the excretory pore opens near half of pharyngeal length. Cardia small.

Reproductive system diorchic with two outstretched testes, anterior testis to the right and posterior testis to the left of the intestine. Spicules equal and curved, 1.9–2.5 cloacal body diameters long, with a strong developed capitulum, and proximally with a short central lamina. Gubernaculum with paired dorsocaudal apophyses. Fifteen to twenty fine tubular precloacal supplement present which are often difficult to distinguish. Tail conico-cylindrical, several short caudal setae and three terminal setae. Three caudal glands and distinct spinneret present.

Female. Similar to males. Some female specimens like males in the pattern of lateral differentiation. But the other females with longitudinal rows of coarse dots beginning from posterior edge of amphid with 4–7 rows extending to anterior border of pharyngeal bulb, the longitudinal rows disappear in the middle body, then reappear with 5–7 rows in the tail region, longitudinal rows in the tail region are not as regular as in pharyngeal region. Reproductive system didelphic, opposed, outstretched, with anterior ovary situated on the left of intestine, posterior ovary on the right side of intestine. Vulva at pre-median of body length. Granular vaginal glands present. Spermatheca present, often with numerous spermatozoa. Three caudal glands and distinct spinneret present.

Diagnosis and relationships. Dorylaimopsis jinyuei sp. n. is characterized by cuticle with lateral differentiation in the form of longitudinal rows of larger dots in two separate regions, not along entire body. One region is from posterior edge of amphid with 4–7 rows extending to anterior of intestine, the other is tail region with 5–7 rows. But in some females longitudinal rows of larger dots are distributed from posterior edge of amphid to anterior border of pharyngeal bulb (4–7 longitudinal rows), then reappear in the tail region with 5–7 rows. Amphideal fovea with 2.75 turns and spicules 127–151 μm long with a strongly developed capitulum, and proximally with a short central lamina. Fifteen to twenty fine tubular precloacal supplements present.

Dorylaimopsis jinyuei sp. n. resembles D. coomansi Muthumbi et al., 1997 and D. turneri Zhang, 1992 in the cuticle with lateral longitudinal rows of coarse dots not along entire body, and in the spicules with cephalated proximal end. Dorylaimopsis jinyuei sp. n. differs from the latter species by the different distribution of longtitudinal rows of coarse dots; D. jinyuei sp. n. has lateral longitudinal rows of coarse dots in two regions, one is from posterior edge of amphid to anterior of intestine region or to the anterior border of pharyngeal bulb in some females, the other is the tail region, but in D. coomansi and D. turneri the lateral longitudinal rows of coarse dots begin posteriorly to the pharyngeal region and end at the cloaca/anus. Dorylaimopsis jinyuei sp. n. also differs from D. coomansi by the shape of the gubernacular apophyses, which are distinctly swollen distally in D. coomansi , and not swollen in D. jinyuei sp. n. Dorylaimopsis jinyuei sp. n. differs from D. turneri by its much longer spicules (127–151 μm vs 57–67 μm in D. turneri ) and spicules with small central lamina in the new species.

Dorylaimopsis jinyuei sp. n. resembles D. papilla Guo et al., 2018 in the spicules with cephalated proximal end and with small central lamina. However, D. jinyuei sp. n. differs from the latter in the ratio of the conical portion of the tail to total tail length (2/ 3 in D. jinyuei sp. n. vs 1/ 2 in D. papilla ), and D. papilla has lateral differentiation of two longitudinal rows in the middle region of body which is different from D. jinyuei sp. n.

Figures

FIGURE 7. Dorylaimopsis jinyuei sp. n. A: Male head. B: Lateral surface view of male head. C: Anterior body region of female. D: Male tail. Arrow points to the spicule proximal tip with a short central lamina. E: Female tail. Scale bars. A, B, E = 10 µm; C, D = 50 µm.

FIGURE 8. Dorylaimopsis jinyuei sp. n. A: Entire male. B: Lateral surface view of anterior body region of female. C: Reproductive system of female. D: Male tail. Scale bars. A = 50 µm; B = 45 µm; C = 125 µm; D = 10 µm.

FIGURE 9. Dorylaimopsis jinyuei sp. n. Light micrographs. A: Male head. B: Lateral surface view of male head. C: Lateral surface view of anterior intestine. D: Vulva region. E: Cloacal region with spicule, gubernaculum, and precloacal supplements. F. Spinneret. Scale bar: A, B, C, F = 10 μm; D, E = 20 μm.