PORT PHILLIP BAY


Triangle Crab 

Trigonoplax longirostris McCulloch, 1908

View scientific description and taxonomy

Scientific Details

Carapace triangular, as long as wide, walls strongly converging ventrally, anterolateral angles almost absent, surface without defined grooves; rostrum triangular, not separated from dorsal carapace surface by a groove, concealing antennae and most of eyes, with shallow keel; epistome long and bulging. Maxillipeds 3 meeting medially. Chelipeds similar to walking legs in both sexes.

Source: Poore, G.C.B. (2004) Marine decapod Crustacea of southern Australia. A guide to identification (with chapter on Stomatopoda by Shane Ahyong). CSIRO Publishing, Melbourne, 574 pp.

Taxonomy

Phylum:
Arthropoda
Subphylum:
Crustacea
Class:
Malacostraca
Subclass:
Eumalacostraca
Superorder:
Eucarida
Order:
Decapoda
Suborder:
Pleocyemata
Infraorder:
Brachyura
Family:
Hymenosomatidae
Genus:
Trigonoplax
Species:
longirostris

General Description

Carapace as long as wide, walls strongly converging ventrally; rostrum deflexed, with shallow rostral keel. Claws (chelipeds) with weakly spatulate fingers. Walking legs with 7th article (dactyli) widest at midpoint. Up to 1.5 cm wide.

Biology

Nothing is known of the biology of the Triangle Crab but it probably uses its fine claws to pick up tiny fragments of food among the algae where it hides. As with any small benthic invertebrate of soft sediments, hymenosomatids feature in the diet of demersal fishes. This western Pacific genus is represented in Australia by two species, one tropical and one temperate.

Habitat

Estuarine and low intertidal, to depths of 13 m.

Reefs

Coastal shores

Distribution guide

Southern temperate oceans, including southern Australia.

Species Group

Crabs and allies Crabs

Depth

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

Water Column

On or near sea floor

Max Size

15 mm

Diet

Organic matter

Harmful

Not harmful but a nip from large claws could be painful.

Commercial Species

No

Global Dispersal

Native to Australia

Species Code

MoV 1678

Conservation Status

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

Author

article author Taylor, J.

Dr. Jo Taylor is the Sciences Collections Online Coordinator at Museum Victoria.

Author

article author Poore, G.C.B.

Dr. Gary Poore is Principal Curator Emeritus at Museum Victoria.

citation

Cite this page as:
Taylor, J. & Poore, G.C.B., 2011, Triangle Crab, Trigonoplax longirostris, in Taxonomic Toolkit for marine life of Port Phillip Bay, Museum Victoria, accessed 25 Nov 2017, http://portphillipmarinelife.net.au:8098/species/5478

Text: creative commons cc by licence