Dorylaimopsis nodderi, Leduc, 2012

Leduc, Daniel, 2012, Deep-sea nematodes (Comesomatidae) from the Southwest Pacific Ocean: five new species and three new species records, European Journal of Taxonomy 24, pp. 1-42 : 20-24

Dorylaimopsis nodderi sp. nov.

urn:lsid:zoobank.org:act:A19205F2-A989-49EA-9002-46CA34F64CCA

Figs 9-11 , Table 4

Etymology

This species is named after Dr. Scott D. Nodder.

Material examined

Holotype

Ƌ, collected 5 Oct.2001,Chatham Rise crest (350 m water depth), 43.4333°S, 178.5000°E.Characteristics of surface sediment layer (0-5 mm): mostly fine sand (35.7%), silt/clay (33.0%), and very fine sand (23.5%); calcium carbonate content: 40.5%; total organic matter content: 4.5%; chloroplastic pigment concentration: 3359 ng /gDW sediment (NIC 84446).

Paratypes

4 ƋƋ, 4 ♀♀, same data as holotype (NIC 84447).

Description

Males

Body cylindrical, tapering slightly towards both extremities. Cuticle punctate from level of amphid to near tail tip, with lateral differentiation consisting of three longitudinal rows of larger dots in pharyngeal and caudal regions, two rows of larger dots elsewhere. Cuticle in lateral field consisting of 1 μm thick basal layer, 4 μm thick median layer with forked columns (side view), and 2 μm thick cortical layer ( Fig. 11A ). Cuticle thinner in caudal region. Eight longitudinal rows of short, sparse somatic setae. Head set-off by constriction immediately posterior to cephalic setae. Six inner labial papillae, six outer labial papillae, and four cephalic setae. Anterior portion of buccal cavity cup-shaped. Posterior portion of buccal cavity cylindrical, cuticularised, narrow, 13-16 μm deep, with three cuticularised projections (teeth) at border to anterior portion. Amphideal fovea spiral, 2.5-3.0 turns, located immediately posterior to cephalic setae. Pharynx gradually swelling, not forming true bulb. Marginal tubes beginning from base of stoma. Cardia short. Nerve ring near middle of pharynx, situated anteriorly to secretory-excretory pore. Cellular body of ventral gland at level of cardia. Intestine wall with numerous small granules, interspersed with numerous regularly-spaced clear areas without granules, circular or irregular in shape ( Fig. 9E ).

Reproductive system diorchic, opposed, outstretched. Anterior testis to left of intestine, posterior testis to right of intestine. Spicules paired, equal, 1.8-2.9 abd long, with rounded ventral projection at one third of spicule length from distal end, giving appearance of a joint. Spicules straight proximally, strongly bent at level of joint. Gubernaculum surrounding spicules, with wide triangular base and pair of long, straight caudal apophyses. Rectal gland surrounds gubernaculum. Twelve to sixteen tubular pre-cloacal supplements. Tail conico-cylindrical, with several short caudal setae and three short terminal setae. Three caudal glands.

Females

Similar to males, but with slightly smaller amphideal fovea, 2.5-2.75 turns. Reproductive system didelphic, opposed, outstretched, with anterior branch to left of intestine and posterior branch either to right or left of intestine. Vulva slightly pre median. Granular vaginal glands present, pars proximalis vaginae surrounded by constrictor muscle.

Diagnosis and relationships

Dorylaimopsis nodderi sp. nov. is characterised by cuticle with lateral differentiation consisting of three longitudinal rows of larger dots in pharyngeal and caudal regions, two rows of larger dots in middle region of body, cephalic setae 4-7 μm long, amphideal fovea with 2.5-3.0 turns, and spicules 98-112 μm long with rounded ventral projection at one third of spicule length from distal end, giving appearance of a joint.

Dorylaimopsis nodderi sp. nov. differs from most other species of the genus (except D. punctata Ditlevsen, 1918 and D. magellanense Chen & Vincx, 1998 ) in the presence of spicules with ventral projections. D. nodderi sp. nov. can be distinguished from D. punctata by its smaller body length (1080- 1656 vs.> 1900 μm), presence of three rows of enlarged dots in pharyngeal and caudal regions of both males and females (two rows in D. punctata ), and fewer pre-cloacal supplements (12-16 vs. 18-22). D. nodderi sp. nov. can be distinguished from D. magellanense by its smaller body length (1199-1602 vs. 1708-2261 μm), and the smaller number of rows of enlarged dots in the lateral fields: three rows in pharyngeal and caudal regions (four or five in D. magellanense ) and two rows in middle region of body (three or four in D. magellanense ).

Figures

Fig. 9. Dorylaimopsis nodderi sp. nov. A. Anterior region of Ƌ. B. Lateral surface view of Ƌ head. C. Ventral view of ♀ head (cross-section). D. Entire Ƌ. E. Ƌ gut, mid-body. Scale bar: A = 50 μm; B and C = 25 μm; D = 70 μm; E = 30 μm.

Fig. 10. Dorylaimopsis nodderi sp. nov. A. ♀ reproductive system. B. Ƌ posterior region, showing copulatory apparatus. C. ♀ tail. D. Ƌ posterior body region, showing copulatory apparatus. Scale bar: A = 90 μm; B = 40 μm; C and D = 55 μm.

Fig. 11. Dorylaimopsis nodderi sp. nov. light micrographs. A. ♀ cuticle in pharyngeal region showing the cortical, median, and basal layers. B. Ventral view of ♀ head showing posterior portion of buccal cavity. C. ♀ mid-body region showing vulva and mature eggs. D. Sperm cells with nuclei. Scale bar: A = 8 μm; B = 12 μm; C = 50 μm; D = 30 μm.