bigeye sixgill shark
Hexanchus nakamurai Teng, 1962
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 of Hexanchus nakamurai (blue) and Hexanchus vitulus (red)
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Open encyclopedia reference
The bigeyed sixgill shark (Hexanchus nakamurai) is a cow shark of the family Hexanchidae. Its dorsal surface has a brownish-gray color, and is sharply separated from the light coloring of its ventral surface. The eyes are a fluorescent green while the shark is alive. The body of this shark is small, slim, and fusiform in shape. As the name suggests, this shark has six gill slits, unusual among most shark species. The head is narrow and somewhat flattened, and the mouth contains 5 rows of large, comb-shaped teeth. This shark's single dorsal fin is pushed back towards the caudal fin, and is behind the pelvic fins. The upper caudal fin is much longer than the lower, with a deep notch near the tip. All fins have thin white margins on the edge. In juveniles, the upper caudal fin has a black tip.
Wikipedia contributors, Bigeyed sixgill shark; see linked history · CC BY-SA 4.0 . Plain-text lead excerpt, at most 180 words; no infobox or later sections Retrieved 2026-10-05T09:02:57.413664+00:00. This reference remains separate from the taxonomic record.
Identity & source status
- Scientific name
- Hexanchus nakamurai Teng, 1962
- Name authority
- Teng, 1962
- Common name
- bigeye sixgill shark
- Rank
- species
- Accepted status
- accepted
- Kingdom
- Animalia
- Phylum
- Chordata
- Class
- Elasmobranchii
- Order
- Hexanchiformes
- Family
- Hexanchidae
- Genus
- Hexanchus
- 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
- orderHexanchiformes Compagno, 1973
- familyHexanchidae Gray, 1851
- genusHexanchus Rafinesque, 1810
- speciesHexanchus nakamurai Teng, 1962
Close classified relatives
These entries share the source’s genus, Hexanchus. They are not necessarily the closest relatives established by molecular evidence.
| Species | Classification | Source status |
|---|---|---|
| sixgill sharkHexanchus vitulus Springer & Waller, 1969 | HexanchidaeChordata | Accepted speciesExtinction status not supplied |
| bluntnose sixgill sharkHexanchus griseus (Bonnaterre, 1788) | HexanchidaeChordata | Accepted speciesExtinction status not supplied |
Names & synonyms
Names explicitly linked to this accepted taxon in the source. Synonymy can change with revision.
| Recorded name | Source status |
|---|---|
| Hexanchus griseus nakamurai Teng, 1962 Teng, 1962 | synonym |
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.
- Teng, H.-T. (1962). Classification and distribution of the Chondrichthyes of Taiwan. Ogawa Press, Maizuru, Japan, 1–304. [In Japanese]. 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:3LGK9. Classification follows source parent identifiers. English common names may vary by region.