Vasostoma aurata D, K & D, 2012, n. sp.
Creators: name: D, Leduc
name: K, Probert P.
name: D, Nodder S.
Publisher: name: Zenodo
Year: 2012
Subjects: Biodiversity
Taxonomy
Animalia
Nematoda
Adenophorea
Desmodorida
Comesomatidae
Vasostoma
Vasostoma aurata

description: Vasostoma aurata n. sp. (Fig. 2–4, Table 1)
Material examined. Holotype Male, collected 6 April 2007, Chatham Rise (1240 m water depth), 44º29.1ʹS, 177º8.6ʹE. Characteristics of surface sediment layer (0–5 mm): mostly silt/clay (82.9%), with very fine sand (10.2%), and fine sand (8.4%); calcium carbonate content: 38.4%; total organic matter content: 1.91%; chloroplastic pigment concentration: 3501 ng /gDWsediment (NNCNZ 272).
Paratypes Two males, three females, one J 4 juvenile, same data as holotype (NNCNZ 2653-8); three males, three females, same data as holotype (NIWA 71586-7).
Description. Males Body cylindrical, medium-sized, tapering towards both extremities. Cuticle with transverse rows of dots, no lateral differentiation. No somatic setae except on tail. Lateral, dorsal, and ventral chords conspicuous in most specimens, consisting of two bands of irregular cell bodies, <1−4 Μm in size, with outline often golden-coloured, fusing into single band near anterior and posterior ends of body (Figure 4). Head distinctly set-off by constriction immediately posterior to cephalic setae. Six inner labial papillae, six outer setiform outer labial papillae, and four cephalic setae, the latter two very close to each other. Anteror portion of buccal cavity cupshaped. Posterior portion of buccal cavity cylindrical to conical, cuticularised, 13 Μm deep, with three cuticularised projections (teeth) at border with anterior portion. Amphid spiral, 4.5 turns. Pharynx gradually swelling, not forming true bulb. Cardia short. Nerve ring near one third of pharynx length from anterior. Cellular body of ventral gland at level of cardia, excretory pore near middle of pharynx.
Reproductive system diorchic, opposed, outstretched. Anterior testis to left of intestine, posterior testis to right of intestine. Spicules paired, equal, curved, 1.4–1.5 abd long, proximal end slightly enlarged, central lamella well developed. Gubernaculum with pair of straight caudal apophyses. Cloacal gland cells surround posterior portion of spicules and gubernaculum. Up to seven tubular pre-cloacal supplements, often difficult to distinguish, one pre-cloacal seta. Tail conico-cylindrical, with several short caudal setae and three short terminal setae. Three large caudal glands.
Females Similar to males, but with slightly larger maximum body diameter, amphid smaller, 3.5 turns. Reproductive system didelphic, opposed, outstretched. Anterior ovary to left of intestine, posterior ovary either to right or left of intestine. Vulva slightly post median. Granular vaginal glands present, vagina uterina surrounded by constrictor muscle.
Fourth stage juveniles Similar to adults but smaller body size, smaller amphid with 4.25 turns. Lateral chords conspicuous.
Diagnosis and relationships. V. a u r a t a n. sp. is characterised by a distinctly set-off head, amphid with 4.5 turns, conspicuous chords consisting of two bands of irregular, often golden-coloured cell bodies, short spicules, and faint tubular supplements.
V. aurata n. sp. is similar to the type species V. spiratum Wieser 1954, but can be distinguished from the latter by its greater body length (2017–2432 vs 1370–1850 Μm), higher a values (41–47 vs 26–36), higher c values (14–19 vs 9–13), shorter tail (2.3–3.5 vs 4 abd), presence of conspicuous chords, and the presence of faint tubular supplements (as opposed to 11 well-developed supplements in V. s p ir a t um).
Etymology. The specific name (“gilded with gold”) refers to the intricate golden patterns of the chords.
Discussion. V. a ur a ta n. sp. specimens from the type locality were found exclusively in subsurface (1–5 cm) sediments. A study of the nematode community at the type locality found that V. aurata n. sp. (referred to as Vasostoma sp. A therein) was the fourth most common species at that site, and accounted for 3.6% of total nematode abundance (Leduc et al. 2010a).
description: Published as part of D, Leduc, K, Probert P. & D, Nodder S., 2012, Two new free-living nematode species (Comesomatidae) from the continental slope of New Zealand, with keys and notes on distribution, pp. 40-55 in Zootaxa 3348 on pages 43-48, DOI: 10.5281/zenodo.210400