Pebble crab
Coleusia magna
Coleusia magna has the typical pebble-crab shape, with a round and smooth carapace and distinct projecting front, bearing very small eyes. It is clearly separated from the other species by its characteristic colouration. The body is grey with a pair of dark patches anteriorly and thin orange lines running paralel to margins and on posterior mid-line. The legs are banded orange and light-grey. The rest of the body follows similar pattern of grey background with orange lines around margins.
Morphology
Coleusia magna shares with the other species the overall shape of cheliped, with robust segments, rouded granules on merus and thin dactylus. The genus is differentiated from others by the number of coils in the male sexual structures (gonopods). Coleusia magna can be differentiated from the other species in the genus by the presence of 8-9 granules above the cheliped basis (the others have 5 or less).
Evolution
This species was transferred from the genus Leucosia in 2006 when Galil described the new genus Coleusia. Members of the family have a series of morphological adaptations (such as a modified inhalant channel) related to their burrying habit.
Behaviour
Predominantly nocturnal. Leucosiids can bury themselves in the soft sediment by digging backwards (and leaving the front, where the eyes are situates, uncovered).
Method of reproduction
Sexual
Habitat
Marine
Typically associated with sandy bottoms, but can also be found on mud or gravel substrates and near reefs or sponges.
Distribution
Endemic from tropical waters of Australia (Western Australia and Queensland).
Life Cycle
Several planktonic larval stages
| Kingdom: | Animalia |
|---|---|
| Phylum: | Arthropoda |
| Subphylum: | Crustacea |
| Class: | Malacostraca |
| Subclass: | Eumalacostraca |
| Superorder: | Eucarida |
| Order: | Decapoda |
| Suborder: | Pleocyemata |
| Infraorder: | Brachyura |
| Superfamily: | Leucosioidea |
| Family: | Leucosiidae |
| Genus: | Coleusia |
| Species: | magna |
| Name Published Year: | 1962 |
|---|---|
| Scientific Name Authorship: | Tyndale-Biscoe & George |
| Commercial Impact: | None |
| Conservation Assessment: | Least Concern |
Cite this page
Western Australian Museum Collections https://museum.wa.gov.au/online-collections/names/coleusia-magna
Accessed 30 Aug 2023
Rights
We support the open release of data and information about our collections.
Text content on this page is licensed under a Creative Commons Attribution 4.0 International License.
Image content on this page is copyright WA Museum.