PORT PHILLIP BAY


Ribbed Spider Crab 

Leptomithrax sternocostulatus (Milne Edwards, 1851)

View scientific description and taxonomy

Scientific Details

Carapace pear-shaped, strongly narrowing anteriorly, with dense tubercles and spines, with 2 branchial spines on margin and third more posterior and dorsal. Rostral spines slender and diverging. Intercalated spine not reaching end of antorbital spine on supraorbital eave, sitting dorsally so that eave and postorbital lobe almost in contact; postorbital lobe truncate apically, with subapical lobe. Walking legs not much longer than carapace length. Sternum of male with deep pits, each with sharp edges lined with beads.

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:
Majidae
Subfamily:
Majinae
Genus:
Leptomithrax
Species:
sternocostulatus

General Description

With 2 branchial spines on margin of carapace and third spine more posterior and dorsal. Intercalated spine not reaching end of antorbital spine on supraorbital eave, sitting dorsally so that eave and postorbital lobe almost in contact; with pits on sternum of male; walking legs not much longer than carapace length. Up to 5 cm long.

Biology

This species of Leptomithrax is much like L. gaimardii but only one-third as big. The carapace, rostral spines and eye orbit are similar but its legs don't extend forward much beyond the rostrum as they do in L. gaimardii. Although it is just as common as the great spider crab over a wide depth range, its denser camouflage ensures it is less commonly seen.

Habitat

Intertidal, to 140 m depth.

Soft substrates

Coastal shores

Distribution guide

Southern temperate oceans, including south-eastern Australia.

Species Group

Crabs and allies Crabs

Depth

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

Water Column

On or near sea floor

Max Size

5 cm

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 703

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, Ribbed Spider Crab, Leptomithrax sternocostulatus, in Taxonomic Toolkit for marine life of Port Phillip Bay, Museum Victoria, accessed 18 Aug 2017, http://portphillipmarinelife.net.au:8098/species/5482

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