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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).

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 Maturities | Reproduction | Spawnings | Egg(s) | Fecundities | Larvae

Main reference Upload your references | References | Coordinator | Collaborators

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)

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

CITES

Not Evaluated

CMS (Ref. 116361)

Not Evaluated

Threat to humans

Harmless

Human uses

FAO - Publication: search | FishSource |

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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=0.00389 (0.00168 - 0.00901), b=3.13 (2.94 - 3.32), 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).

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Somniosus cheni Hsu, Lin & Joung, 2020