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Elasmobranchii (sharks and rays) > Squaliformes (Sleeper and dogfish sharks) > Somniosidae (Sleeper sharks)
Etymology: Somniosus: Latin for sleepy, reflecting Lesueur’s surmise that these sharks are slow or sluggish because of their relatively small fins (hence the name sleeper sharks) (See ETYFish); cheni: In honor of Wen-Jong Chen, Taitung Xin Gang District Fisherman’s Association, for contributions of chondrichthyan fish samples and research assistance with Taiwan and international research for over 30 years (See ETYFish).
Eponymy: Wen-Jong Chen, of the Taitung Xin Gang District Fisherman’s Association, was honoured for his contributions of shark samples and his assistance with Taiwanese and international shark research for over 30 years. (Ref. 128868), visit book page.

Environment: milieu / climate zone / depth range / distribution range Ecology

Marine; bathydemersal; depth range 500 - ? m (Ref. 123759). Subtropical

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Northwest Pacific: Taiwan.

Size / Weight / Age

Maturity: L_m ? range ? - ? cm
Max length : 14.7 cm TL male/unsexed; (Ref. 123759); 13.6 cm TL (female)

Short description Identification keys | Morphology | Morphometrics

Vertebrae: 75 - 79. This species is distinguished from its congeners by the following set of characters: no anal fin; two spineless dorsal fins, first dorsal fin higher and larger than second dorsal fin; short lateral keels on the caudal peduncle, precaudal pits absent; caudal fin is 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, total 75-78; number of turns in spiral valve 25-26 In mid-term embryo stage (12.8-15.0 cm TL); no teeth and dermal denticles; sexes identifiable; caudal keel present. Colouration: body light brown to yellow-grayish (Ref. 123759).

This species was collected in canyons surrounded by deep-sea longliner off eastern Taiwan at a depth greater than 500 m (Ref. 123759).

Life cycle and mating behavior Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae

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Hsu, H.-H., C.-Y. Lin and S.-J. Joung, 2020. Somniosus (Rhinoscymnus) cheni sp. nov. A new species of sleeker shark (Squaliformes: Somniosidae) from Eastern Taiwan, with aspects of embryo biology. Zool. Stud. 59:48. (Ref. 123759)

IUCN Red List Status (Ref. 130435: Version 2024-1)

Data deficient (DD) ; Date assessed: 06 March 2022

CITES

Not Evaluated

CMS (Ref. 116361)

Not Evaluated

Threat to humans

Harmless

Human uses

Fisheries: of no interest

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Estimates based on models

Phylogenetic diversity index (Ref. 82804): PD₅₀ = No PD50 data [Uniqueness, from 0.5 = low to 2.0 = high].

Bayesian length-weight: a=0.00380 (0.00164 - 0.00880), b=3.14 (2.95 - 3.33), in cm total length, based on LWR estimates for this (Sub)family-body shape (Ref. 93245).

Trophic level (Ref. 69278): 3.5 ±0.4 se; based on size and trophs of closest relatives

Resilience (Ref. 120179): Medium, minimum population doubling time 1.4 - 4.4 years (Preliminary K or Fecundity.).

Fishing Vulnerability (Ref. 59153): Low vulnerability (10 of 100).

Somniosus cheni Hsu, Lin & Joung, 2020