PORT PHILLIP BAY


Little Seaweed Crab 

Naxia tumida (Dana, 1852)

View scientific description and taxonomy

Scientific Details

Carapace pear-shaped, strongly narrowing anteriorly, with mesogastric tubercle; surface smooth between groups of strong curled setae. Rostral spines stout, straight, divergent; hepatic spine short, blunt. Anterolateral angle of basal antennal article a spine with an accessory spinule. Preorbital and antorbital angles not produced; intercalated spine separated from supraorbital eave by notch or fused to it; postorbital and hepatic spines well separated at base. Walking legs with propodi strongly expanded.

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:
Naxia
Species:
tumida

General Description

Rostral spines stout, straight, divergent; hepatic spine short, blunt. Intercalated spine separated from supraorbital eave by notch or fused to it; hepatic spine short, blunt; anterolateral spine of basal antennal article with an accessory spinule. Walking legs with propodi strongly expanded. Up to 2.5 cm long.

Biology

Seaweed crabs are so well covered with vegetation that it is usually necessary to remove it in order to determine the species. The legs and carapace are well provided with hooked hairs to which the weed is fastened making the adornment appear natural. The extent of seaweed each crab has varies thus making each one quite unique.

Habitat

Low intertidal, to 25 m depth.

Soft substrates

Reefs

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)

Water Column

On or near sea floor

Max Size

25 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 3583

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, Little Seaweed Crab, Naxia tumida, in Taxonomic Toolkit for marine life of Port Phillip Bay, Museum Victoria, accessed 25 Nov 2017, http://portphillipmarinelife.net.au:8098/species/5487

Text: creative commons cc by licence