Somniosus (Rhinoscymnus) cheni

Hsu, Lin & Joung, 2020

Classification: Elasmobranchii Squaliformes Somniosidae

Reference of the original description
Hsu, H.-H. & Lin, C.-Y. & Joung, S.-J. (2020)
Somniosus (Rhinoscymnus) cheni sp. nov., A New Species of Sleeper Shark (Squaliformes: Somniosidae) from Eastern Taiwan, with Aspects of Embryo Biology. Zoological Studies, 59, Article 48

Somniosus (Rhinoscymnus) cheni
Holotype: EBFS: FSX0001; Paratype: NMMB: P33387;

Images of types

Description :

Citation: Somniosus (Rhinoscymnus) cheni Hsu, Lin & Joung, 2020: In: Database of modern sharks, rays and chimaeras,, World Wide Web electronic publication, Version 07/2024

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Somniosus (Rhinoscymnus) cheni sp. nov., holotype, (EBFSFSX001), pregnant female, 1340 mm total length. © Photo by C. Y. Lin.
Common names
eng Taiwan Sleeper Shark

Short Description
Diagnosis after HSU, LIN & JOUNG, 2020 [28756]: A species of Somniosus (Rhinoscymnus) can be distinguished from its congeners by a combination of the following characters: no anal fin; two spineless dorsal fins, first dorsal fin higher and larger than second dorsal fin; a short lateral keels on the caudal peduncle, no precaudal pits; caudal fin asymmetrical and paddle-shaped, with a relatively short upper lobe and long lower lobe; rhomboid-shaped dermal denticles; teeth dissimilar in upper and lower jaws, upper-jaw teeth small with lanceolate, in 72 rows, lower-jaw teeth semioblique with low roots, in 28 rows; precaudal vertebrae 60–61, caudal vertebrae 15–18, and 75–78 in total; number of turns in spiral valve 25–26. In mid-term embryo stage (12.8–15.0 cm TL), body color light brown to yellow-grayish; teeth and dermal denticles absent; sexes identifiable; caudal keel present.

eastern Taiwan [28756]

Size / Weight / Age
TL (max, type): 1340 mm, TL (embryo, type): 134.9 mm - 147.0 mm [28756]

marine, depth range: >500 m [28756]

Teeth dissimilar in upper and lower jaws, upper small, with lanceolate, arranged in 72 rows; lower with semioblique with low roots, arrange in 28 rows. [28756]

shark-references Species-ID=16010;