Common Black Dragonfish, Idiacanthus atlanticus Brauer 1906


Other Names: Atlantic Dragonfish, Black Dragonfish

A female Common Black Dragonfish, Idiacanthus atlanticus, collected during the 2003 NORFANZ Expedition to survey seamounts in the Tasman Sea. Source: Robin McPhee & Mark McGrouther / NORFANZ Founding Parties. License: All rights reserved

Summary:
Males and females are extremely sexually dimorphic. The long slender black females have a long chin barbel with a bioluminescent tip, barbed fang-like teeth, two rows of photophores along each lower side, and the dorsal-fin origin behind the pelvic-fin origin. The dark brownish males are much smaller and have large eyes, a non-functional gut, and lack teeth, pelvic fins and a chin barbel.

Cite this page as:
Dianne J. Bray, Idiacanthus atlanticus in Fishes of Australia, accessed 20 Nov 2018, http://fishesofaustralia.net.au/home/species/1810

Common Black Dragonfish, Idiacanthus atlanticus Brauer 1906

More Info


Distribution

Off southern Queensland southwards to off Tasmania, and west to off central Western Australia. Elsewhere the species is circumglobal in temperate and cold temperate waters of the Southern Hemisphere. 
Females usually inhabit depths below 500 m during the day and undertake vertical migration at night to shallower waters. The much smaller males occur in depths of about 1,000-2,000 m.

Features

Females: Body extremely elongate, body depth approximately 2–6% SL; head small, 5–10% SL; mouth large, about equal to head in length; jaws with barbed, fang-like teeth; eye small, 1–3% SL; A chin barbel about twice head length with a laterally compressed, unpigmented bioluminescent tip; skin is smooth, black, scaleless. 

Head and body covered in numerous small photophores; OA and IC photophores numerous, closely spaced; postorbital photophore much smaller than eye. 
Pectoral fins absent; pelvic fin short, positioned at about midbody; dorsal-fin origin anterior to midpoint of body, well in advance of anal-fin origin.
Males: larval in appearance, much smaller than females, attaining about 50 mm SL; barbel absent, postorbital photophore much larger than eye diameter; pectoral and pelvic fins absent.

Feeding

Feeds mostly on fishes.

Biology

Males and females show marked sexual dimorphism. Males are much smaller than females, only growing to about 15% of the female body size. They have large eyes, a non-functional gut, and lack teeth, pelvic fins and a chin barbel. The larvae are transparent and their eyes are positioned at the ends of long stalks.

Similar Species

Differs from Idiacanthus fasciola in having the dorsal-fin origin in advance of the pelvic-fin origin, and 14-16 photophores from pelvic-fin origin to anal-fin origin, vs. dorsal-fin origin behind the pelvic-fin origin, and 19-23 photophores from pelvic-fin origin to anal-fin origin in I. fasciola.

Species Citation

Idiacanthus atlanticus Brauer 1906, Die Tiefsee-Fische 15: 62, Fig. 21. Type locality: west coast of South Africa, 25°25'03"S, 6°12'04"E, eastern Atlantic Ocean, depth 2000 m.

Author

Dianne J. Bray

Resources

Australian Faunal Directory

Common Black Dragonfish, Idiacanthus atlanticus Brauer 1906

References


Brauer, A. 1906. Die Tiefsee-Fische. 1. Systematischer Teil. Wissenschaftliche Ergebnisse der Deutschen Tiefsee-Expedition auf dem Dampfer "Valdivia" 1898–1899 15(1): 1-432 figs 1-176 pls 1-18

Collins, S.P. & Baron, M.P. 1981. Demersal and pelagic trawling survey of the M.T. Denebola in southern Australian waters, 1979–80 summer. Tasmanian Fisheries Research 24: 2-48.

Gon, A. 1990. Stomiidae. Scaly dragonfishes. In Gon, O. & Heemstra, P.C. (eds) Fishes of the Southern Ocean. Grahamstown : J.L.B. Smith Institute of Ichthyology 462 pp.

Harold, A.S. 1999. Families Gonostomatidae, Sternoptychidae, Phosichthyidae, Astronesthidae, Stomiidae, Chauliodontidae, Melanostomiidae, Idiacanthidae, Malacosteidae. pp. 1896-1917 in Carpenter, K.E. & Niem, V.H. (eds). The Living Marine Resources of the Western Central Pacific. FAO Species Identification Guide for Fisheries Purposes. Rome : FAO Vol. 3 pp. 1397-2068.

Harold, A. 2015. Idiacanthus atlanticus. The IUCN Red List of Threatened Species 2015: e.T21133032A21909414. http://dx.doi.org/10.2305/IUCN.UK.2015-4.RLTS.T21133032A21909414.en. Downloaded on 12 February 2016.

Hulley, P.A., 1986. Idiacanthidae. p. 234-235, in Smith, M.M. & Heemstra, P.C. (eds). Smith's Sea Fishes. Johannesburg : Macmillan South Africa xx + 1047 pp. 144 pls.

Kenaley, C.P., Harold, A.S. & Gomon, M.F. 2008. Family Stomiidae. pp. 240-254 in Gomon, M.F., Bray, D.J. & Kuiter, R.H. (eds). Fishes of Australia's Southern Coast. Sydney : Reed New Holland 928 pp.

Robertson, E.M. & Gomon, M.F. 1994. Families Stomiidae, Chauliodontidae, Astronesthidae, Melanostomiidae, Malacosteidae, Idiacanthidae. pp. 251-263 figs 225-235 in Gomon, M.F., Glover, C.J.M. & Kuiter, R.H. (eds). The Fishes of Australia's South Coast. Adelaide : State Printer 992 pp.


Stewart, A.L. & Kenaley, C.P. 2015. Systematic Accounts. Family Stomiidae, 68 Subfamily Astronesthinae (471-486), Family Stomiidae, 72 Subfamily Idiacanthinae (521-523). In: C.D. Roberts, A.L. Stewart & C.D. Struthers (eds). The Fishes of New Zealand  2: 1-574.

Quick Facts


CAAB Code:37113002

Biology:Bioluminescent

Conservation:IUCN Least Concern

Depth:500-3500 m

Habitat:Mesopelagic, bathypelagic

Max Size:53 cm TL

Species Image Gallery

Species Maps

CAAB distribution map