Hopperia ancora, 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 : 26-31

Hopperia ancora sp. nov.

urn:lsid:zoobank.org:act:42970B24-CF4B-4D54-9CFF-B278BE09C60C Figs 12-14 , Table 5

Etymology

The species name is derived from the Latin ancora (= anchor), in reference to the distal hook on the spicules.

Material examined

Holotype

Ƌ, collected 7Jun. 2007, Challenger Plateau (264 m water depth), 39.6463°S, 172.1530°E. Characteristics of surface sediment layer (0-5 mm): mostly silt/clay (90.1%), with very fine sand (3.0%), and fine sand (3.0%); calcium carbonate content: 27.4%; total organic matter content: 1.94%; chloroplastic pigment concentration: 3039 ng /gDW sediment (NIC 84448).

Paratypes

3 ƋƋ and 3 ♀♀, same data as holotype (NIC 84449).

Description

Males

Body cylindrical, tapering slightly towards anterior extremity. Cuticle punctated from level of amphid to near tail tip, with lateral differentiation consisting of larger, irregularly-spaced dots. Eight longitudinal rows of short, sparse somatic setae. Head set-off by depression at level of cephalic setae. Six inner labial papillae, six outer labial papillae, and four conical cephalic setae in three distinct circles. Amphideal fovea spiral, 2.5-3.0 turns, located immediately posterior to cephalic setae.Anterior portion of buccal cavity cup-shaped. Posterior portion of buccal cavity cylindrical, strongly cuticularised, 4-5 μm wide, 20-27 μm deep, with three strongly cuticularised teeth at border to anterior portion. Teeth everted in some specimens ( Fig. 14A ). Marginal tubes of pharynx beginning from base of stoma. Pharynx gradually swelling, not forming true bulb. Cardia short. Nerve ring near middle of pharynx, situated anteriorly to

excretory pore. Cellular body of ventral gland situated just posteriorly to cardia. Intestine wall with numerous small, clear granules, and oval cells with more closely-packed granules ( Figs 13A , 14B ).

Reproductive system diorchic, opposed, outstretched. Anterior testis to left of intestine and posterior testis to right of intestine in all specimens except one specimen with opposite arrangement. Sperm cells globular with outer radial lines. Spicules paired, equal, arcuate, 1.5-1.7 abd long, with swollen proximal end and central internal cuticularised projection (lamella) extending one fourth of spicule length from proximal end. Spicules with velum and conspicuous hook-like projection at distal end ( Fig. 14C ). Gubernaculum appearing to completely surround spicules, with bent dorso-caudal apophyses. Rectal gland surround distal end of spicules and gubernaculum. Eleven to thirteen tubular pre-cloacal supplements, one pre-cloacal seta. Tail long, conico-cylindrical, gradually tapering, with several short caudal setae and no terminal setae. Three caudal glands.

Females

Similar to males, but with slightly longer tail. Reproductive system didelphic, opposed, outstretched, with anterior and posterior branches either to left or right of intestine, but always on opposite sides. Vulva slightly pre median. Granular vaginal glands present, pars proximalis vaginae surrounded by constrictor muscle ( Fig. 14D ).

Diagnosis and relationships

Hopperia ancora sp. nov. is characterised by body length 1876-2011 μm, short conical cephalic setae, amphideal fovea with 2.5-3.0 turns, buccal cavity with three teeth, spicules 54-68 μm in length with hook-like projection at distal end, gubernaculum with bent apophyses, 11-13 pre-cloacal supplements, and gradually tapering conico-cylindrical tail without swollen tip or terminal setae.

Hopperia ancora sp. nov. most closely resembles H. massiliensis Vitiello, 1969 and H. indiana Muthumbi et al., 1997 in body size, values of a, b, and c, size and shape of the cephalic setae, amphideal fovea, and tail, but can be distinguished from them (and all other species of the genus) by the presence of a conspicuous hook-like projection at distal end of spicules.

Figures

Fig. 12. Hopperia ancora sp. nov. A. Anterior region of Ƌ. B. Lateral surface view of Ƌ head. C. Lateral view of ♀ head. D. Ƌ posterior body region, showing copulatory apparatus. E. ♀ tail. Scale bar: A = 45 μm; B and C = 20 μm; D = 35 μm; E = 50 μm.

Fig. 13. Hopperia ancora sp. nov. A. Entire Ƌ. B. ♀ reproductive system. Scale bar: A = 240 μm; B = 110 μm.

Fig. 14. Hopperia ancora sp. nov. light micrographs. A. Ƌ head, showing everted tooth. B. Intestine wall of Ƌ, with arrows pointing to oval cells with larger, more closely packed granules than surrounding cells. C. Everted spicule. D. Vulva. Scale bar: A, D = 15 μm; B = 22 μm; C = 20 μm.