Hopperia beaglense Chen & Vincx, 1998

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 : 31-34

Hopperia beaglense Chen & Vincx, 1998

Figs 15-17 , Table 5

Material examined

5 ƋƋ and 4 ♀♀, collected 5 May 2010, Kaikoura Canyon axis (1061 m water depth), 42.5081°S, 173.6325°E (NIC 84450).

Description

Males

Body cylindrical, tapering slightly towards anterior extremity. Cuticle punctate from level of amphid to near tail tip, with lateral differentiation consisting of larger, irregularly-spaced dots. Somatic setae short and sparse, in four dorso- and ventro-lateral longitudinal rows. Six inner labial papillae, six outer labial papillae, and four cephalic setae in three distinct circles. Anterior portion of buccal cavity cupshaped. Posterior portion of buccal cavity cylindrical, strongly cuticularised, 24-26 μm deep, extending into three strongly cuticularised teeth at border to anterior portion. Teeth everted in some specimens. Cuticularisation of posterior portion of buccal cavity extends posterior to junction of marginal tubes with pharyngeal lumen ( Fig. 15B ). Amphideal fovea spiral, 3.0-3.5 turns, located immediately posterior to cephalic setae. Pharynx with oval posterior bulb. Cardia short. Nerve ring near middle of pharynx, situated anteriorly to secretory-excretory pore. Cellular body of ventral gland large (up to 37 x 20 μm), situated just posteriorly to cardia. Intestine wall with numerous small, clear granules, and small clusters of round, clear inclusions, sometimes with smaller orange-brown granules ( Fig. 17B ).

Reproductive system diorchic, opposed, outstretched. Anterior testis to left of intestine and posterior testis to right of intestine. Spicules paired, equal, arcuate, strongly cuticularised, 1.3-1.6 abd long, with swollen proximal end and internal cuticularise projection (lamella) extending one fourth of spicule length from proximal end, no velum. Gubernaculum with straight dorso-caudal apophyses, tapering distally. One pre-cloacal seta and 7-8 conspicuous, cup-shaped pre-cloacal supplements. Tail short, cylindrical, with rounded tip, several short caudal setae and no terminal setae. Three large caudal glands and well-developed spinneret ( Fig. 17C ).

Females

Similar to males, but slightly greater maximum body diameter and smaller amphids, 3.0 turns. Reproductive system didelphic, opposed, outstretched, with anterior branch to left of intestine and

posterior branch to right of intestine, except for one individual with opposite arrangement. Vulva slightly post median. Granular vaginal glands present, vagina uterina surrounded by constrictor muscle.

Discussion

My specimens closely resemble the description given by Chen & Vincx (1998) based on specimens from the Beagle Channel, Chile (100-110 m water depth). My specimens, however, have slightly lower a (range: 29-36 vs. 30-41; mean: 34.2 vs. 39.1) and c values (range: 14-19 vs. 19-22; mean: 15.8 vs. 20.6), have 7-8 supplements instead of 6-7, and lack the supplement-like structure situated halfway down the ventral side of the tail ( Fig. 15F ). This is the first record of this species outside the type locality.

Within the Dorylaimopsinae , cuticularisation of the posterior buccal cavity does not usually extend into the pharyngeal lumen (i.e., cuticularisation stops before marginal tubes begin) (fig. 2E in Jensen 1979). My specimens are unusual in that the cuticularisation of the buccal cavity extends into the anteriormost portion of the pharyngeal lumen (see Fig. 15B ). It is unclear whether this is also a feature of the type specimens, however, because Chen & Vincx (1998) did not describe the marginal tubes.

Figures

Fig. 15. Hopperia beaglense Chen and Vincx, 1998. A. Anterior region of Ƌ. B-C. Lateral view of Ƌ head. D. Lateral surface view of ♀ head. E. ♀ tail. F. Ƌ copulatory apparatus and vas deferens. Arrow shows approximate position of supplement-like structure observed in type specimens from Chile. Scale bar: A = 30 μm; B-D = 22 μm; E-F = 32 μm.

Fig. 16. Hopperia beaglense Chen and Vincx, 1998. A. Entire ♀. B. Ƌ posterior region, showing testes and copulatory apparatus. Scale bar = 100 μm.

Fig. 17. Hopperia beaglense Chen and Vincx, 1998 light micrographs. A. Anterior region of Ƌ. B. Ƌ gut, showing clusters of small round inclusions with smaller orange-brown granules. C. Spinneret. Scale bar: A = 30 μm; B = 12 μm; C = 24 μm.