The family Homolidae, known as carrier crabs or porter crabs, contains 14 genera of marine
crab
Crabs are decapod crustaceans of the infraorder Brachyura, which typically have a very short projecting "tail" (abdomen) ( el, βραχύς , translit=brachys = short, / = tail), usually hidden entirely under the thorax. They live in all the ...
s. They mostly live on the
continental slope and
continental shelf
A continental shelf is a portion of a continent that is submerged under an area of relatively shallow water, known as a shelf sea. Much of these shelves were exposed by drops in sea level during glacial periods. The shelf surrounding an island ...
, and are rarely encountered.
Members of the Homolidae have their fifth
pereiopod
The decapod (crustaceans such as a crab, lobster, shrimp or prawn) is made up of 20 body segments grouped into two main body parts: the cephalothorax and the pleon (abdomen). Each segment may possess one pair of appendages, although in various g ...
s (last pair of walking legs) in a sub-dorsal position, which allows them to hold objects in place over the rear half of the
carapace
A carapace is a Dorsum (biology), dorsal (upper) section of the exoskeleton or shell in a number of animal groups, including arthropods, such as crustaceans and arachnids, as well as vertebrates, such as turtles and tortoises. In turtles and tor ...
.
The objects carried include
sponges,
black corals and
gorgonians, and this behaviour may be a defence mechanism against
predators.
Some species have been observed carrying living
sea urchin
Sea urchins () are spiny, globular echinoderms in the class Echinoidea. About 950 species of sea urchin live on the seabed of every ocean and inhabit every depth zone from the intertidal seashore down to . The spherical, hard shells (tests) of ...
s in a
symbiotic
Symbiosis (from Greek , , "living together", from , , "together", and , bíōsis, "living") is any type of a close and long-term biological interaction between two different biological organisms, be it mutualistic, commensalistic, or parasit ...
relationship which allows them to benefit from the protection of the urchin's dangerous spikes.
Genera
A total of 14 genera are currently recognised in the family:
*''
Dagnaudus''
Guinot & Richer de Forges, 1995
*''
Gordonopsis''
Guinot & Richer de Forges, 1995
*''
Homola
Homola (Czech/Slovak feminine: Homolová) is a Czech and Slovak surname. The surname may refer to:
* Bedřich Homola (1887–1943), Czech general
* Bernard Homola (1894–1975), German film score composer
* Craig Homola (born 1958), American ice ...
''
Leach, 1816
*''
Homolax''
Alcock, 1899
*''
Homolochunia''
Doflein, 1904
*''
Homologenus''
A. Milne-Edwards, in Henderson, 1888
*''
Homolomannia''
Ihle, 1912
*''
Ihlopsis''
Guinot & Richer de Forges, 1995
*''
Lamoha''
Ng, 1998
*''
Latreillopsis''
Henderson, 1888
*''
Moloha''
Barnard, 1947
*''
Paromola
''Paromola'' is a genus of crabs within the family Homolidae.
Species
* '' Paromola bathyalis''
* '' Paromola crosnieri''
* ''Paromola cuvieri
''Paromola cuvieri'' is a species of crab in the family Homolidae, the carrier crabs. It occ ...
''
Wood-Mason & Alcock, 1891
*''
Paromolopsis''
Wood-Mason & Alcock, 1891
*''
Yaldwynopsis''
Guinot & Richer de Forges, 1995
See also
* ''
Homola barbata
''Homola barbata'' is a species of crab in the family Homolidae.
Description
They usually have squarish carapaces with forward-pointing spines along the upper front edges. The animal's chelipeds are shorter than their other legs (the back pair ...
'', in the Atlantic Ocean and Mediterranean Sea
* ''
Paromola cuvieri'', in the East Atlantic and Mediterranean Sea
References
Dromiacea
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