PORT PHILLIP BAY


Bighead Threefin 

Trianectes bucephalus (McCulloch & Waite, 1918)

View scientific description and taxonomy

Scientific Details

Meristics.
Dorsal fin spines/rays: III; XIV-XVI; 9-11
Anal fin spines/rays: II, 18-22
Caudal fin rays: 13
Pectoral fin rays: 15-16
Ventral fin spines/rays: I, 2
Lateral line: (upper) 25-30 (lower) 6-9

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.
A large and highly diverse group of modern bony fishes many of which have a generalized perch like body form. Most have pelvic fins with one spine and 5 rays and the maxillary bone is excluded from the gape of the mouth. Interrelationships of the group are poorly understood and continue to be studied. They inhabit almost all aquatic habitats from high-altitude strams to the deep sea, although most are marine.

Family level detail.
Small cryptic bottom-dwelling fishes with the dorsal fin in three separate parts; pelvic fins reduced to a single embedded spine and 2-3 segmented rays, positioned on chest in front of the pectoral-fin bases. Triplefins live on tropical and temperate reefs worldwide, with most species found in the Indo-Pacific. Males are often brightly coloured, especially during the breeding season. Temperate species are often well-camouflaged to blend in with their surroundings.

Taxonomy

Phylum:
Chordata
Subphylum:
Craniata
Superclass:
Gnathostomata
Class:
Actinopterygii
Order:
Perciformes
Family:
Tripterygiidae
Genus:
Trianectes
Species:
bucephalus

General Description

Body moderately long and deep, almost cylindrical; head depressed, pointed; eyes large; orbital tentacle small, rounded and fleshy; nasal tentacle a simple lobe. Green, brown or purple above with dark blotches; head similar, or yellow or purple; first dorsal fin usually mottled with black; remaining dorsal and anal fins with diagonal lines; pectoral fin spotted. To 6 cm.

Biology

These little fishes are nocturnally active, and remain hidden during daylight hours.

Habitat

Shallow coastal waters on rocky bottoms, often under small rocks.

Reefs

Distribution guide

Southern Australia, including western and central Victoria.

Species Group

Fishes › Triplefins

Depth

Shore (0-1 m)
Shallow (1-30 m)

Water Column

On or near sea floor

Max Size

6 cm

Commercial Species

No

Global Dispersal

Native to Australia

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, Bighead Threefin, Trianectes bucephalus, in Taxonomic Toolkit for marine life of Port Phillip Bay, Museum Victoria, accessed 13 Jan 2025, http://136.154.202.208:8098/species/6475

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