PORT PHILLIP BAY


Thetis Fish 

Neosebastes thetidis (Waite, 1899)

View scientific description and taxonomy

Scientific Details

Meristics.
Dorsal fin spines/rays: XIII, 7-9
Anal fin spines/rays: III, 5
Caudal fin rays: 15
Pectoral fin rays: 18-21
Ventral fin spines/rays: I, 5-6
Lateral line: 31-38
Gill rakers: 11-20

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 diverse group of bottom-dwelling fishes with a bony ridge, or stay across the cheek connecting the bones under the eye with the gill cover. Most species have spines projecting from bony ridges on the head and some have spines projecting from the gill cover. Many species are well-camouflaged ambush predators, often with elaborate cirri, filaments, leaf-like appendages and spiny ridges enhancing their camouflage. Scales are present or absent. Gurnards (also called searobins) have a pair of rostral spines projecting from the snout, large colourful wing-like pectoral fins and crawl over the bottom on their finger-like pelvic-fin rays. Many species have venomous spines.

Family level detail.
Scorpionfish relatives with a compressed body, a large prominent head, large eyes, a large mouth, with rough scales over most of body, strong ridges and spines on the head, strong venomous fin spines, 13 long robust dorsal-fin spines that are much longer that the fin rays, 6-8 soft dorsal-fin rays and large pectoral fins. Bottom-dwelling fishes, living on the bottom in tropical and temperate environments of the Indo-Pacific; ambush predators, feeding on fishes and crustaceans.

Taxonomy

Phylum:
Chordata
Subphylum:
Craniata
Superclass:
Gnathostomata
Class:
Actinopterygii
Order:
Scorpaeniformes
Family:
Neosebastidae
Genus:
Neosebastes
Species:
thetidis

General Description

Robust head and body, tapering toward tail base, head armed with low spines, region between eyes flat and scaled; anterior dorsal-fin spines very long, only connected at base, 4th spine longest; pectoral fins large, hind margin rounded; underside of lower jaw with 3 large distinct pores on either side. Yellowish, usually with 5 large poorly-defined dark blotches on side, especially below spinous and soft parts of dorsal fin body. To 32 cm.

Biology

Although common, especially in moderately deep waters, this species is rarely seen by anglers. It is taken as bycatch in commercial trawls. The venomous fin spines can inflict a very painful wound. The species is no longer found in Port Phillip (Victoria), although there are confirmed records from the late nineteenth and early twentieth centuries.

Habitat

On and near rocky reefs at depths of 43-288 m, but usually 50-200 m.

Reefs

Distribution guide

Southern Australia.

Species Group

Fishes › Gurnard perches

Depth

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

Water Column

On or near sea floor

Max Size

32 cm

Diet

Carnivore

Harmful

Venomous spines can inflict mild to severe pain.

Commercial Species

Yes

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, Thetis Fish, Neosebastes thetidis, in Taxonomic Toolkit for marine life of Port Phillip Bay, Museum Victoria, accessed 27 Jul 2024, http://136.154.202.208:8098/species/6503

Text: creative commons cc by licence