Japanese Gissu

This species is distinguished by the following set of characters (holotype measurements in parentheses): supraneural bones 6-7; dorsal-fin rays 54-65 (mode 58); total vertebrae 105-107 (107); pored lateral-line scales 99-109 (105); pre-dorsal scale rows 13-20 (16); head length 23-31 % (mean 27 %) of SL; pectoral-fin length 10-18 % (15 %) of SL; pre-dorsal-fin length 31-39 % (35 %) of SL; dorsal-fin base length 47-56 % (52 %) of SL; postorbital length 9-12 % (10 %) of SL; upper caudal-fin length 16-32 % (21 %) of SL (Ref. 109573).

Spawning occurs in open waters. Eggs are pelagic (Ref. 205).

Dorsal spines (total): 0; Dorsal soft rays (total): 54 - 65; Analspines: 0; Analsoft rays: 10 - 13; Vertebrae: 105 - 107

Found in deep waters.

Found in deep waters.

分布於西北太平洋區，包括日本、東海及臺灣。臺灣分布於東北部及東部海域等。

罕見魚種。

體頗延長而稍側扁，腹部圓。頭中等大，無鬚，黏液管發達。吻尖，可伸出。眼大，無眼瞼。口小，下位。齒細小而呈絨毛狀，上下頜各有1列齒，鋤骨及腭骨則不具細齒。體側被中等圓鱗，頭部則裸露，胸及腹部被鱗；腹鰭基部具1個長方形大腋鱗；側線發達，鱗數為107-113。單一背鰭，基底頗長，起始於胸鰭末端，止於臀鰭中部，鰭條數達58-65；無脂鰭；腹鰭起點稍前於背鰭中部基部的下方：臀鰭短小，接近尾鰭基部。體色銀白，背部略灰暗；各鰭灰色，背鰭具黑緣。

成魚發現於較深之沙泥底海域，棲息深度一般在300-500公尺間，最深可達1000公尺；幼魚期則發現於較淺水域。目前對於本魚種之生態習性不甚瞭解。

Pterothrissus gissu, also known as the Japanese gissu, is a species of ray-finned fish in the family Albulidae. The Japanese gissu is a rare fish that is distributed in deep water off northwest Pacific Ocean. This fish is known to pass through a leptocephalus larval stage, but only metamorphosed (after reaching the fully grown stage) specimens have been available. This species is the only member of its genus.