PORT PHILLIP BAY


Three-pronged Sea Spider 

Halicarcinus ovatus Stimpson, 1858

View scientific description and taxonomy

Scientific Details

Carapace subcircular; surface usually with distinct H-shaped pattern of grooves; postero- and anterolateral angles obtuse; lateral carapace wall with acute spine; rostrum trilobite, medial lobe slightly longer than lateral lobes, arising level with or below carapace rim; epistome broad. Maxilliped 3 broad. Walking legs with dactyli having 2 rows of teeth.

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:
Halicarcinus
Species:
ovatus

Other Names

  • Oval Spider Crab

General Description

Carapace flat, variably coloured, usually in symmetrical patterns of red-black, red-white or brown-white. Three short spikes (prongs) between the eyes. Legs very thin. Up to 1.5 cm wide (carapace).

Biology

Three-pronged Spider Crabs are cryptic, hiding between fronds of seaweed and seagrass. Despite being difficult to see, they are one of the most common crabs in many sheltered environments in the Melbourne region. They are presumed to be scavengers but might be micropredators. They feature in the diet of several species of bottom feeding fishes.

Habitat

Muddy seagrass or algae areas on shallow reefs, to depth of 85 m.

Soft substrates

Reefs

Seagrass meadows

Coastal shores

Distribution guide

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

1.5 cm

Diet

Carnivore

Harmful

Not harmful but a nip from claws could be painful.

Commercial Species

No

Global Dispersal

Native to Australia

Species Code

MoV 701

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, Three-pronged Sea Spider, Halicarcinus ovatus, in Taxonomic Toolkit for marine life of Port Phillip Bay, Museum Victoria, accessed 19 Aug 2017, http://portphillipmarinelife.net.au:8098/species/3949

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