Somniosus longus

(TANAKA, 1912)

Little sleeper shark
Classification: Elasmobranchii Squaliformes Somniosidae

Reference of the original description
TANAKA, S. (1912)
Figures and descriptions of the fishes of Japan, including the Riukiu Islands, Bonin Islands, Formosa, Kurile Islands, Korea, and southern Sakhalin. Figures and Descriptions of the Fishes of Japan, 6: 87–108

Synonyms / new combinations and misspellings
Heteroscymnus longus, Rhinoscymnus longus, Somniosus (Rhinoscymnus) longus

Somniosus longus

Heteroscymnus longus
Holotype: ZUMT: 3204 (lost)

Description :

Citation: Somniosus longus (TANAKA, 1912): In: Database of modern sharks, rays and chimaeras,, World Wide Web electronic publication, Version 03/2021

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Common names
Frog Shark

Short Description
77 - 79. Somniosus longus is distinguished from S. rostratus in having a relatively longer second dorsal fin where overall length is almost equal to first dorsal fin 91-100% (vs. 76-88%); slightly larger eye with horizontal diameter more than 37% (mean 46%) of length from snout tip to eye (vs. <37, mean 33%); higher number of tooth rows in upper jaw 56-57 (vs.53); and slightly higher spiral valve counts 26-27 (vs. 23 ) [3722]

Known from only the northwest Pacific, southwest Pacific and possibly the southeast Pacific, but probably much more widespread. [18934]

Size / Weight / Age
to at least 143 cm total length, but probably larger [18934]

Marine; bathydemersal; depth range 250 - 1160 m [18934]

56-57/31-32 [3722]

shark-references Species-ID=6496;