Classification / Names
Common names | Synonyms | Catalog of Fishes(genus, species) | ITIS | CoL | WoRMS | Cloffa
Elasmobranchii (sharks and rays) > Squaliformes
(Sleeper and dogfish sharks) > Somniosidae
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
Marine; bathydemersal; depth range 500 - ? m (Ref. 123759). Subtropical
Northwest Pacific: Taiwan.
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 14.7 cm TL male/unsexed; (Ref. 123759); 13.6 cm TL (female)
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
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. 126983)
Threat to humans
Common namesSynonymsMetabolismPredatorsEcotoxicologyReproductionMaturitySpawningSpawning aggregationFecundityEggsEgg development
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingNutrientsMass conversion
Estimates based on models
Phylogenetic diversity index (Ref. 82804
= 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).