Hymenocephalus lethonemus Jordan & Gilbert 1904

This species is distinguished by the following characters: pelvic fin rays 11 (rarely 12); pectoral fin rays 13-15; projecting snout, 20-25% HL; no barbel; moderate orbit diameter, 30-33% HL; infraorbital width 13-15% HL; moderately long preopercular supporter, with obtuse angle at rear margin, 3-5% HL; 20-26 gill rakers; ventral striae reaching to ½ distance from pelvic fin bases to periproct; otolith has moderately high predorsal lobe, with colliculi separated, widely placed across collum, terminating at some distance from anterior and posterior rims of otolith; otolith length to height (OL:OH), 1.05-1.1; total colliculum length to pseudocolliculum length (TCL:PCL), 2.4-2.6 (Ref. 98298).

Minimum depth from Ref. 26282.

分布於西太平洋區，由日本南方、中國東海外緣、臺灣東北部及南部至菲律賓等海域。

一般以底拖網捕獲，不具食用價值，通常做為下雜魚用。

體型延長，側扁。頭中大，頭骨薄而易碎。鼻吻部尖，呈一鳥喙狀突起。眼大，眶後長約為眼徑1.4-1.6倍；眼眶上緣從側面觀有兩凹陷。口大，超過眼眶後緣。無頤鬚。腹鰭軟條11-12。體被弱櫛鱗，但胸、腹位被圓鱗。發光器長自臀鰭起點前延伸喉峽部。體呈暗灰色，夾雜少許銀色。

主要棲息於220-485公尺深泥砂底質、水溫5-7℃的水域。深海底棲性魚類，以浮游性甲殼類為主食。是群聚性，快速游動的種類。生殖季為冬末初春。數量不多。

Hymenocephalus lethonemus is a species of rattail. It occurs at depths of up to 485 m (1591 ft) in the waters off southern Japan, the Philippines and northern Taiwan.

This is a small, slender rattail with a total length of up to 14 cm (5.1 in). It has a fairly long, sharp snout, small eyes, a large mouth and no chin barbel. There is a long bioluminescent organ with two external lenses just in front of the anus.