Pacific Blackchin, Scopelengys tristis Alcock 1890

Summary:

A uniformly blackish neoscopelid with a darker mouth and belly, and no photophores or luminous tissue. The scales, which are deciduous, are bronze-green with a black margin when fresh.

Cite this page as:

Bray, D.J. 2024, Scopelengys tristis in Fishes of Australia, accessed 25 Jan 2025, https://fishesofaustralia.net.au/Home/species/5739

Pacific Blackchin, Scopelengys tristis Alcock 1890

More Info

Distribution	NW of Exmouth Gulf, Western Australia. Elsewhere the species is circumglobal in tropical and temperate latitudes. Juveniles typically occur at depths of 500 to 800 m, while adults are usually found below 1,000 m.
Features	Dorsal fin.1l-13; Anal fin 12-14; Pectoral fin 14-17; Gill rakers (first arch) 7-11; Branchiostegal rays 8; Vertebrae 29-32. Body moderately slender, maximum body depth at nape, tapering to a narrow caudal peduncle; body depth at dorsal-fin origin 11.7-19.8% SL; least depth at caudal peduncle 5.6-8.3% SL. Dorsal profile of head slightly concave; head length 24.4-33.9% SL; head depth 16.7-25.5% SL; eye small, much shorter than snout length, orbit diameter 3.1-4.2% SL; snout length 7.5-10.1% SL. Upper jaw extending to at least one eye diameter beyond rear margin or eye; width of maxillary as percentage of its length 29.9-36.7 (32.2). Snout dorsal-fin origin 36.1-47.0% SL; Snout anal-fin origin 56.4-72.6%SL; Snout pelvic-fin origin fin origin 34.7-48.0. Photophores and gas bladder absent.
Feeding	Feeds mostly on small crustaceans.
Etymology	The specific name is from the Latin tristis (= sad, mournful, gloomy, dull), presumably in reference to the uniform blackish colour of this species.
Species Citation	Scopelengys tristis Alcock 1890, Annals and Magazine of Natural History (Series 6)6(34): 303. Type locality: Off Elicapeni Bank, Laccadive Sea, 11°12'47"N, 74°25'30"E, Investigator station 104, depth 1000 fathoms.
Author	Bray, D.J. 2024
Resources	Atlas of Living Australia Australian Faunal Directory Catalog of Fishes

Pacific Blackchin, Scopelengys tristis Alcock 1890

References

Alcock, A.W. 1890. Natural history notes from H. M. Indian marine survey steamer `Investigator,' Commander R. F. Hoskyn, R. N., commanding. -- No. 18. On the bathybial fishes of the Arabian Sea, obtained during the season 1889-1890. Annals and Magazine of Natural History (Series 6) v. 6 (no. 34): 295-311. See ref at BHL

Bergman, L.A., Fujiwara, Y., Assad, V.E., et al. 2023. Face-Down, Tail-Up: Unusual In Situ Behavior of the Blackchins Neoscopelus macrolepidotus, Neoscopelus microchir, and Scopelengys tristis (Myctophiformes: Neoscopelidae). Diversity 15(7): 837. https://doi.org/10.3390/d15070837

Butler, J.L. & Ahlstrom, E.H. 1976. Review of the deep-sea fish genus Scopelengys (Neoscopelidae) with a description of a new species, Scopelengys clarkei, from the central Pacific. United States National Marine Fisheries Service Fishery Bulletin 74(1): 142-150. See ref at BHL

Hulley, P.A. 1986. Order Myctophiformes. pp. 282-322 in Smith, M.M. & Heemstra, P.C. (eds). Smith's Sea Fishes. Johannesburg : Macmillan South Africa xx + 1047 pp. 144 pls.

Hulley, P. 2015. Scopelengys tristis. The IUCN Red List of Threatened Species 2015: e.T15601913A15603915. https://dx.doi.org/10.2305/IUCN.UK.2015-4.RLTS.T15601913A15603915.en. Accessed on 14 October 2024.

Moser, H.G. 1996. Neoscopelidae: blackchins, pp. 383-385 in Moser, H.G. (ed.) 1996. The early stages of fishes in the California Current region. Fisheries Investigations Atlas No. 33 Lawrence, Kansas : California Cooperative Oceanic Allen Press, Inc. 1505 pp.