Pacific sleeper shark
Somniosus pacificus Bigelow & Schroeder, 1944
Accepted species in Catalogue of Life’s 11 September 2026 base release. This preserves the source classification and available supporting data; it is not a completed species monograph.
Distribution map for Somniosus pacificus
Chris_huh · CC BY-SA 3.0 · Image sourceProvider-generated thumbnail requested at 800 pixels; no local editing Local WebP display rendition; resized without cropping.
Open encyclopedia reference
The Pacific sleeper shark (Somniosus pacificus) is a shark of the family Somniosidae, the sleeper sharks. While primarily associated with temperate and subarctic waters of the Northern Pacific Ocean, it has been documented in the tropical Pacific and Antarctic Ocean as well. Reaching lengths of 4.65 m (15.3 ft), it is one of the world's largest predatory sharks. It is highly adapted to the extreme temperature and pressures of the deep-sea, including specialized liver oils and high concentrations of urea and trimethylamine oxide for survival. The sleeper shark has a sluggish reputation, but is also a versatile hunter and scavenger that migrates vertically. Due to its slow growth and vulnerability to fishing bycatch, it is currently classified as Near Threatened by the International Union for Conservation of Nature (IUCN).
Wikipedia contributors, Pacific sleeper shark; see linked history · CC BY-SA 4.0 . Plain-text lead excerpt, at most 180 words; no infobox or later sections Retrieved 2026-10-05T09:38:12.704502+00:00. This reference remains separate from the taxonomic record.
Identity & source status
- Scientific name
- Somniosus pacificus Bigelow & Schroeder, 1944
- Name authority
- Bigelow & Schroeder, 1944
- Common name
- Pacific sleeper shark
- Rank
- species
- Accepted status
- accepted
- Kingdom
- Animalia
- Phylum
- Chordata
- Class
- Elasmobranchii
- Order
- Squaliformes
- Family
- Somniosidae
- Genus
- Somniosus
- Extinction status
- Not supplied by this source
Source habitat flags: Marine: yes · Freshwater: no · Terrestrial: no. These do not form a complete habitat description.
Classification family tree
Nested taxonomic groups from the source. This is not a direct-ancestor chain, a dated evolutionary tree or a phylogenetic reconstruction.
- domainEukaryota (Chatton, 1925) Whittaker & Margulis, 1978
- kingdomAnimalia
- phylumChordata
- subphylumVertebrata
- infraphylumGnathostomata
- parvphylumChondrichthyes
- classElasmobranchii
- subclassNeoselachii
- infraclassSelachii
- superorderSqualomorphi
- orderSqualiformes Compagno, 1973
- familySomniosidae Jordan, 1888
- genusSomniosus Lesueur, 1818
- speciesSomniosus pacificus Bigelow & Schroeder, 1944
Close classified relatives
These entries share the source’s genus, Somniosus. They are not necessarily the closest relatives established by molecular evidence.
| Species | Classification | Source status |
|---|---|---|
| little sleeper sharkSomniosus rostratus (Risso, 1827) | SomniosidaeChordata | Accepted speciesExtinction status not supplied |
| Somniosus antarcticus Whitley, 1939 | SomniosidaeChordata | Accepted speciesExtinction status not supplied |
| Somniosus longus (Tanaka, 1912) | SomniosidaeChordata | Accepted speciesExtinction status not supplied |
| Greenland sharkSomniosus microcephalus (Bloch & Schneider, 1801) | SomniosidaeChordata | Accepted speciesExtinction status not supplied |
Source literature & publication evidence
References attached to this source record, including nomenclatural citations where supplied. This is a selected bibliography; abbreviated citations remain in the source’s form.
- Bigelow, H. B., & Schroeder, W. C. (1944). New sharks from the western North Atlantic. Proceedings of the New England Zoölogical Club, v. 23: 21–36, Pls. 7–10. Source fields: Taxon.tsv dwc:namePublishedIn, Taxon.tsv dcterms:references
Origins, evidence & remaining research
Name authority and publication references document nomenclature where the source supplies it. They do not establish evolutionary origins or the earliest fossil occurrence.
Specimen-level evidence, morphology, ecological research, phylogenetic studies, a comprehensive bibliography and a located literary passage have not yet been compiled for this record.
Dataset citation & attribution
This exact taxon in ChecklistBank · Catalogue of Life 2026-09-11
Catalogue of Life 2026-09-11; dataset 316321; doi:10.48580/dgz5n. https://creativecommons.org/licenses/by/4.0/ . Retrieved 5 October 2026.
Stable key: col:4Y8YL. Classification follows source parent identifiers. English common names may vary by region.