Neogyptis vostokensis, Pleijel & Rouse & Sundkvist & Nygren, 2012

Pleijel, Fredrik, Rouse, Greg W., Sundkvist, Tobias & Nygren, Arne, 2012, A partial revision of Gyptis (Gyptini, Ophiodrominae, Hesionidae, Aciculata, Annelida), with descriptions of a new tribe, a new genus and five new species, Zoological Journal of the Linnean Society (Zool. J. Linn. Soc.) 165 (3), pp. 471-494 : 491-493

NEOGYPTIS VOSTOKENSIS SP. NOV. ( FIG. 13 )

Type material: Holotype ( SIO-BIC A2498 ), c. 75 paratypes SIO-BIC A2499 – A2504 ).

Type locality: Sea of Japan, Peter the Great Bay , Vostok Bay, Vostok Marine Biological Station, 42°53.7′N, 132°44.0′E, 0.5–1 m, amongst lumps of Modiolus modiolus (Linnaeus, 1758) .

Etymology: Named for Vostok Bay, the type locality.

Material examined: Russia, Sea of Japan, Peter the Great Bay , Vostok Bay , Vostok Marine Biological Station. Holotype ( SIO-BIC A2498 , fixed in formaldehyde), 42°53.7′N, 132°44.0′E, 0.5–1 m, amongst lumps of M. modiolus , colls FP and Radashevsky 11.v.1994; 17 paratypes ( SIO-BIC A2499 , fixed in formaldehyde), same collecting data as holotype; eight spms ( FP collection, fixed in formaldehyde; mounted on SEM stubs for SEM), same collecting data as holotype; c. 25 paratypes ( SIO-BIC A2500 , fixed in formaldehyde), 42°53′N, 132°44′E, 6–8 m, amongst lumps of M. modiolus and mud with H 2 S, SCUBA, coll. Belokonev 13.v.1994; nine paratypes ( SIO-BIC A2501 , fixed in formaldehyde), 42°53′N, 132°44′E, 3–5 m, amongst Crassostrea gigas (Thunberg, 1793) , SCUBA, coll Belokonev 15.v.1994; ten paratypes ( SIO-BIC A2502 , fixed in formaldehyde), 42°53.7′N, 132°44.0′E, 0.5– 1 m, amongst Mytilus sp. growing on buoy, colls FP and Radashevsky 17.v.1994; three paratypes ( SIO- BIC A2503 , fixed in formaldehyde), 42°53.5′N, 132°44.1′E, 3 m, sand, SCUBA, coll. Radashevsky 19.v.1994; c. 25 paratypes ( SIO-BIC A2504 , fixed in formaldehyde), Point Pashennikov, 42°53.0′N, 132°43.9′E, 6–8 m, coarse gravel with some detritus, SCUBA, coll. Radashevsky 20.v.1994.

Description: Length up to 4.5 mm for 27 segments. Live animals transparent yellowish white, eyes black; preserved yellowish white. Body outline in dorsal view of equal width with tapering posterior end ( Fig. 13A ). Prostomium rounded rectangular, slightly wider than long ( Fig. 13B ). Palpophores cylindrical, palpostyles cylindrical to elongated ovoid with rounded tips; palpophores and palpostyles of equal length. Paired antennae about as long as palps but slightly thinner, cylindrical with tapering, rounded tips. Median antenna much shorter than paired antennae, elliptical with rounded tip, inserted anterior to anterior pair of eyes. Eyes medium-sized, anterior pair twice as large and positioned slightly further apart. Nuchal organs ciliated bands along lateral sides of prostomium ( Fig. 13B ). Lip pads absent. Proboscis smooth, with terminal ring of ten small, elongated papillae. Segment 1 dorsally reduced, segment 2 fully developed. Dorsal cirri and cirrophores segment 1–5 much longer and stouter than following ones, with dorsal cirri segment 2 and 4 reaching about segment 10–11. Ventral cirri segment 1–4 with well-delineated cirrophores and longer and stouter cirri than on following segments ( Fig. 13C ). Segment 5 with neuropodial lobes, neurochaetae and ventral cirri similar to following segments, segment 6 with notopodial lobes and notochaetae. Elevated and slightly stouter dorsal cirri on segment 8, 12, 15, 17, 19, 21, and 23. Median segments with dorsal cirri reaching as far as chaetae ( Fig. 13A ). Weakly developed transverse dorsal ridges across median and posterior segments ( Fig. 13A, D ). Notopodial aciculary lobes small, conical. Notochaetae of two kinds, single dorsally bent aciculary chaeta inserted anterior to other chaetae, and c. 25 capillary chaetae, both with two alternating rows of teeth. Neuropodial lobes elongated triangular. Neurochaetae c. 25, all unidentate compounds with shafts with distinct internal chambers and longitudinal canals, dorsal and median blades up to seven times longer than ventral ones. Single or double noto- and neuroaciculae. Ventral cirri inserted distally near tip of neuropodium, with distinct, elongated tips ( Fig. 13E ; usually with more elongated tips than on picture). Pygidium with long pygidial cirri, similar in shape to dorsal cirri; pygidial papilla absent.

Habitat: Sand and mud, amongst mussels and oysters, 0.5–8 m.

Distribution: Only known from Vostok Bay in Peter the Great Bay, Sea of Japan.

Remarks: Morphologically, N. vostokensis sp. nov. belongs to a group of small Neogyptis species that have brown-black eyes, and that also includes N. fauchaldi sp. nov., from Belize, and N. hongkongensis sp. nov. It can be separated from the latter by the absence of lip glands, from the former by the absence of notochaetae with the conical side subdistally serrated, and from both by the shape of the ventral cirri, which are stouter and lack welldemarcated tips. Unfortunately, no specimens were available for molecular study.

Figures

Figure 13. Neogyptis vostokensis sp. nov., specimens from the type locality, scanning electron microscopy photographs. A, entire specimen, dorsal view. B, prostomium, dorsal view. C, anterior end, ventral view. D, median parapodia, right side, anterodorsal view. E, segment 5 and 6, right side, anteroventral view. Scale bars: A = 500 Mm, B = 50 Mm, C = 200 Mm, D, E = 100 Mm.