PORT PHILLIP BAY


Bear Seaweed Crab 

Notomithrax ursus (Herbst, 1788)

View scientific description and taxonomy

Scientific Details

Carapace pear-shaped, strongly narrowing anteriorly, with hooked setae, with tubercles only in dorsal midline; marginal hepatic spines and 3 marginal branchial spines. Rostral spines diverging. Supraorbital margin comprising eave without (rarely with small) preorbital, with prominent antorbital and intercalated spines, and with a postorbital spine remote from the eye and offering no protection. Basal antennal article broad, with 2 distal spines. Cheliped with carpus having serrate crests. Walking legs with propodi cylindrical.

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:
Notomithrax
Species:
ursus

General Description

Carapace rounded at rear with a pair of spikes in front. Covered with gold-brown hairs. Claws red-orange with white tips. Ridge along claws. Up to 4 cm long (carapace).

Biology

Bear Seaweed Crabs camouflage their body on the reef by attaching pieces of seaweed to the curved hairs that cover their body. Their hairy body may have inspired Dr. Herbst to name them ursus, the bear, in 1788.

Habitat

Rocky shores and reefs.

Reefs

Coastal shores

Distribution guide

New Zealand and south-eastern 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

4 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 3584

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, Bear Seaweed Crab, Notomithrax ursus, in Taxonomic Toolkit for marine life of Port Phillip Bay, Museum Victoria, accessed 13 Jan 2025, http://136.154.202.208:8098/species/4003

Text: creative commons cc by licence