Neobythitoides serratus, Jørgen G. Nielsen & Yoshihiko Machida, 2006

Jørgen G. Nielsen & Yoshihiko Machida, 2006, Neobythitoides serratus, a new bathyal genus and species from the East China Sea (Teleostei, Ophidiidae)., Zootaxa 1227, pp. 63-68 : 66-68

Neobythitoides serratus n. sp.

Holotype. Department of Biology, Kochi University, BSKU 19514 (female, SL 120 mm), East China Sea, 28°52.6’N, 128°8.5’E, 950 m, bottom trawl, 5 Feb. 1964. Paratype. BSKU 19513 (female, SL 119 mm - same data as holotype)

Diagnosis

See generic diagnosis.

Description of holotype (paratype shown in brackets)

Meristic characters: Dorsal-fin rays 99(97), caudal-fin rays 8(8), anal-fin rays 83(81), ventral-fin rays 2(2), pectoral-fin rays 27/28(27), branchiostegal rays 8(8), vertebrae 12+47(12+45), pseudobranchial filaments 2(2), anterior left gill arch with 10/11(10/11) developed rakers, 4(4) short rakers above and 4-5(5) below the developed ones, anterior dorsal-fin ray above vertebra number 6(6), anterior anal-fin ray below dorsal-fin ray number 20(19) and below vertebra number 16(15), ca. 160 lateral scale rows.

Morphometric characters in % of standard length: Head length 20.5(21.0), depth at origin of anal-fin 15.0(15.0), snout 5.1(5.3), upper jaw 10.5(10.5), horizontal diameter of eye window 2.5(2.7), fleshy interorbital 5.2(5.5), postorbital 13.0(13.0), preanal 37.5(41.0), predorsal 22.0(23.0), bases of ventral-fins to anal-fin 23.5(22.0), pectoral-fin 12.5(12.5), longest ventral-fin ray 11.0(12.0) and shortest 9.6(9.6). Longest gill filament on anterior arch in % of head 5.7(7.2).

General description: Body compressed and slender with tapering caudal part, body and head covered with small, imbricated, cycloid scales, proximal part of dorsal, anal and pectoral-fins also with scales, lateral line indistinct, dorsal-fin origin above base of pectoral-fin, pectoral-fin almost reaching anal origin, ventral-fin rays reaching about halfway to anal-fin, length of head twice in preanal length, diameter of eye about twice in length of snout, anterior nostril with low rim and placed midway between posterior nostril and upper lip, posterior nostril a simple pore-like opening, upper jaw ending well behind eye, maxillaries sheathed postero-dorsally, lower part of hind margin of preopercle with 10-15 soft serrations (Fig. 2), opercular spine strong and straight (slightly curved) not reaching edge of opercle. Four distinct mandibular pores, and suborbital canal with four pores. Anterior gill arch with four short rakers on upper branch, one long raker in the angle and lower branch with 10-11 long and 4-5(5) short rakers. Two very short pseudobranchial filaments.

Dentition (Fig. 3). Small granular teeth in several rows. Those on the flat, v-shaped vomer and palatines somewhat larger than those on dentaries and premaxillaries. A small pair and two median, well separated basibranchial tooth patches (no paired patches).

Axial skeleton (based on radiographs). Tips of all neural and haemal spines pointed; vertebrae 3 to 9(10) with depressed neural spines slightly shorter than spine on second vertebra which is twice the length of the anterior neural spine; base of neural spines 5(4) to 11 enlarged; parapophyses on vertebrae 8(7) to 12; pleural ribs on vertebrae 3-12; epipleural ribs indistinct.

Sagittal otolith (Fig. 4). The otolith is rather compressed with an undivided, centrally placed sulcus, the length of which is 50-55% the length of the otolith, an indistinct ostial channel and elipsoid outer form; it is 1.7 times as long as high and about 4 times as long as thick.

Coloration. Both specimens are brownish to bluish with no indication of any colour pattern. However, the specimens have been preserved since 1964 so patterns could have faded.

Biology

Caught in a bottom trawl at 950 metres. Both specimens are unripe females with diameter of eggs 0.2-0.3 mm. No identifiable contents from stomach and intestine were observed.

Distribution

Both specimens were caught at the same locality in the East China Sea off the Ryu Kyu Islands.

Etymology

The specific name, serratus, refers to the serrated hind margin of the preopercle.