PORT PHILLIP BAY


Bluefin Leatherjacket 

Thamnaconus degeni (Regan, 1903)

View scientific description and taxonomy

Scientific Details

Meristics.
Dorsal fin spines/rays: II; 33-38
Anal fin spines/rays: 32-37
Caudal fin rays: 12
Pectoral fin rays: 12-14
Vertebrae: 19

Interpreting fin count meristics.
Spines are in Roman numerals and soft rays are in Arabic numerals. Spines and rays that are continuous in one fin are separated by a comma. Fin sections are separated by semicolons.

Detailed descriptions of fin count and other meristics are in:
Gomon. M.F., Bray, D.J. & Kuiter, R.H. (eds) (2008) Fishes of Australia's Southern Coast. Sydney : Reed New Holland 928 pp.

Order level detail.
The Tetraodontiformes is a very diverse and specialized group of bony fishes that share the loss, reduction or fusion of many bony structures in the head and body. Fins and their supporting elements are reduced or lost, and vertebrae are reduced in number. They have small mouths with modified teeth that may be enlarged or fused into a beak-like structure, or incorporated into the jaw bones. The gill opening is reduced to a small slit near the pectoral-fin base, and most have thick skin, covered in scales that are modified into spines, ossicles or fused bony plates. Some groups are poisonous, and the puffers and porcupinefishes are highly inflatable. Puffers adn their allies are found worldwide in temperate and tropical seas, and a few species enter freshwaters.

Family level detail.
Members of the Family Monacanthidae are small to moderate sized mostly deep-bodied, compressed fishes with oval to circular bodies, tough leathery skin covered in rough spines, a prominent depressible spine over the eye that can locked in an upright position by a tiny second dorsal-fin spine. They also have a small mouth and gill slit, and long-based soft dorsal and anal fins. Pelvic fins are either absent, or reduced to a bony element fused to the rear of the pelvic bone.

Taxonomy

Phylum:
Chordata
Subphylum:
Craniata
Superclass:
Gnathostomata
Class:
Actinopterygii
Order:
Tetraodontiformes
Family:
Monacanthidae
Genus:
Thamnaconus
Species:
degeni

General Description

Body very elongate, oblong in large males, of moderate depth in females and juveniles; ventral flap small; central pair of teeth in jaws pointed; skin velvety to touch; no spines or bristles on tail base; first dorsal spine slender with very small to minute barbs. Males pale brownish-grey to pale greenish-grey, with scattered bright blue spots and a bright blue line along dorsal and anal fin bases; fin rays greenish, tail fin membranes bright blue. Females and juveniles pale brown, often with small brown spots above. To 29 cm.

Biology

A schooling species usually found in deeper offshore waters.

Habitat

Offshore waters, occasionally in coastal bays, in depths of 10-70 m.

Reefs

Distribution guide

Southern Australia, including western and central Victoria.

Species Group

Fishes › Leatherjackets

Depth

Shallow (1-30 m)
Deep ( > 30 m)

Water Column

On or near sea floor

Max Size

29 cm

Diet

Carnivore

Commercial Species

Yes

Global Dispersal

Native to Australia

Identify

Conservation Status

  • DSE Advisory List : Not listed
  • EPBC Act 1999 : Not listed
  • IUCN Red List : Not listed

Author

article author Bray, D.J.

Di Bray is a Senior Collection Manager of ichthyology at Museum Victoria.

Author

article author Gomon, M.F.

Dr. Martin Gomon is a Senior Curator of ichthyology at Museum Victoria.

citation

Cite this page as:
Bray, D.J. & Gomon, M.F., 2011, Bluefin Leatherjacket, Thamnaconus degeni, in Taxonomic Toolkit for marine life of Port Phillip Bay, Museum Victoria, accessed 25 Feb 2025, http://136.154.202.208:8098/species/6525

Text: creative commons cc by licence