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); antarcticus: -icus (L.), belonging to: the Antarctic (Whitley presumed this to be the first shark recorded from there). (See ETYFish).
More on author: Whitley.
Environment: milieu / climate zone / depth range / distribution range
Marine; benthopelagic; depth range 485 - 1150 m (Ref. 50224). Deep-water
South Indo-Pacific and South Atlantic.
Size / Weight / Age
Maturity: Lm ?  range ? - ? cm
Max length : 438 cm TL male/unsexed; (Ref. 50224); 430.0 cm TL (female)
Morphology | Morphometrics
Vertebrae: 36 - 38. Somniosus antarcticus differs from S. pacificus by the following characters: interdorsal space about 80% of prebranchial length (vs. 70%); height of first dorsal fin about 3.0% of precaudal length (PCL) (vs. 3.7%); height of second dorsal fin about 2.9% of PCL (vs. 3.4%); number of turns in spiral valve 36-41 (mode 39) (vs. 32-37, mode 33); precaudal vertebrae 30-31 (mode 30) (vs. 28-30, mode 29) (Ref. 50224).
Life cycle and mating behavior
Maturity | Reproduction | Spawning | Eggs | Fecundity | Larvae
Yano, K., J.D. Stevens and L.J.V. Compagno, 2004. A review of the systematics of the sleeper shark genus Somniosus with redescriptions of Somniosus (Somniosus) antarcticus and Somniosus (Rhinoscymnus) longus (Squaliformes: Somniosidae). Ichthyol. Res. 51:360-373. (Ref. 50224)
IUCN Red List Status (Ref. 126983)
Threat to humans
Common namesSynonymsMetabolismPredatorsEcotoxicologyReproductionMaturitySpawningSpawning aggregationFecundityEggsEgg development
ReferencesAquacultureAquaculture profileStrainsGeneticsAllele frequenciesHeritabilityDiseasesProcessingNutrientsMass conversion
Estimates based on models
Preferred temperature (Ref. 123201
): 1.7 - 5.8, mean 4 °C (based on 113 cells).
Phylogenetic diversity index (Ref. 82804
= 0.5313 [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
): 4.5 ±0.58 se; based on food items.
Fishing Vulnerability (Ref. 59153
): Very high vulnerability (90 of 100).