Author: Garman, 1884
Chlamydoselachus anguineus Garman, 1884
Status in World Register of Marine Species:
Accepted name: Chlamydoselachus anguineus Garman, 1884 (updated 2009-06-25)
Diagnosis: elongate, almost eel-like body, head with reptilian appearance. Mouth large, sub-terminal; almost all teeth with 3 major cusps and some smaller ones. Gill-slits 6, with frill-like appendages to give 'collared' appearance. Colour: uniform dark brown or grey/brown, lighter ventrally, with a darker streak along flanks. Size: males to about 1.50 m, females to 2m TL.
Habitat: mesopelagic or benthic at considerable depths (120-1,100 m), but once recorded from surface waters (California). Food: only fishes recorded. Reproduction: ovoviviparous, litters of about 4-12; apparently about 60 cm at birth; eggs large, gestation period assumed long (1-2 years).
Distribution: Atlantic coasts from Madeira to the Shetlands and northern Norway. Elsewhere, North and South Atlantic, Japan, Taiwan, California, Chile, New Zealand and probably Australia.
Because of its occurrence in deepwater, the species probably escapes capture, but may be worldwide in temperate seas.
Note: The name H. vitulus Springer and Waller, 1969 was erroneously replaced by H. nakamurai Teng, 1962 during the final preparation of the manuscript.
The situation regarding the correct scientific name of the Bigeyed six-gill shark has been adequately summarized by Compagno (1984: 21): 'Comparison of the original description of H. griseus nakamurai and of H. vitulus strongly suggests that the two are synonyms. I retain H. vitulus because the question exists as to whether Teng's (1962) work was actually published and if his names are available. lt has been cited as a publication by Chen ( 1963) and Springer ( 1979), but may be an unpublished Ph.D thesis (Dr S. C. Shen, pers. comm. to Dr P. C. Heemstra). Chen (1963: 1) stated that "Hexanchus griseus nakamurai n.subsp." was a synonym of H. griseus, and under that species (p. 6) listed nakamurai as a synonym. If Teng's name is not available from his 1962 monograph, it is an open question whether its citation in Chen establishes it beyond the status of nomen nudum.'
In the present circumstances it seems preferable to retain the wellknown name Hexanchus vitulus Springer and Waller, 1969.
Complementary iconography. Gudger and Smith, 1933: fig. 1-31, 5 pl. | Gudger, 1940: pl. 6 (e.g.)
Eggs, larvae and young stages. Gudger and Smith, 1933: 298 | Gudger, 1940: 521, fig. 1-33, 6 pl.