| Allogalathea elegans | |
|---|---|
 | |
| Scientific classification | |
| Kingdom: | |
| Phylum: | |
| Subphylum: | |
| Class: | |
| Order: | |
| Family: | |
| Genus: | |
| Species: | A. elegans |
| Binomial name | |
| Allogalathea elegans (Adams & White, 1848) | |
| Synonyms [1] | |
| |
Allogalathea elegans (known as the feather star squat lobster, crinoid squat lobster or elegant squat lobster) is a species of squat lobster that is sometimes kept in marine aquariums. Despite their common name, they are more closely related to hermit crabs than lobsters. [2]
Allogalathea elegans is bilaterally symmetrical. [3] The cephalothorax of Allogalathea elegans is droplet-shaped. The extremity of the body corresponds to the triangular rostrum of the animal, which are positioned on each side the pedunculated eyes. The rostrum is elongated and dorsally flattened and length varies. [4] They have between five and nine lateral teeth. [4] The chelipeds or the first pair of legs are endowed with pincers and are longer than the animal body. The last pair of legs are wasted. The body and mainly the legs are covered with small hairs. The animal's size depends on the sex. Females are usually bigger than males but never grow over 2 cm. [5] The animal's coloration is variable and is matching the colours of its host but not systematically. [6] It can be uniform and varied from dark red, blackish-purple, orange or brown. But generally, the observed animals have longitudinal stripes which the thickness, the number and the tint varies. [7]
Allogalathea elegans lives in the tropical waters of the Indo-Pacific area, Red Sea included. [8] They can be found from the eastern coast of Africa to the Fiji Islands and from Japan to Southern Australia. [9] They have also recently been found in Korean waters. [10]
Allogalathea elegans is a commensal species living in association with crinoids in which it gets protection and an ideal support for its feeding. They are capable of living outside its host, but its life expectancy will be shorter because it will not be shielded from predators. [11] They are generally found in shallow waters at depths between 0 and 146 m. [4]
Allogalathea elegans are planktotrophic feeders. [3] They take advantage of their crinoid host who has the same diet and who always positions in the best catchment areas for the plankton to feed. [12]
Allogalathea elegans may be found living alone or in large aggregations together. [3] Many A. elegans have a symbiotic relationship with crinoids, [9] most often feather sea stars. [13] These crinoids help protect them from their biggest predator, fish. [14] A. elegans are often found living close to or on top of crinoids. [15] When the need and opportunity to mate comes around, Allogalathea elegans participate in precopulatory rituals involving various sensory cues. [16]
Female Allogalathea elegans are multiple spawners that lay eggs that hatch into larvae. [17] Most females produced three or four broods during the annual reproductive period. [18] Reproductive females exhibit group-synchronous gonadal development as well as breeding synchrony. [17]
Allogalathea elegans goes through four zoeal stages before reaching the megalopal stage and then into the juvenile and adult stages. [9] The duration of the four zoeal stages ranges from 13–16 days altogether. [9] Beginning at the megalopal stage, Allogalathea elegans look like smaller versions of the adult stage until they reach their adult stage. [3]
In an aquarium, A. elegans requires a water temperature of 77–79 °F (25–26 °C), a pH of 8.1–8.3 and a salinity of 1.020–1.024. Small crevices in rocks act as hiding places for this shy crustacean. A. elegans prefers thawed food but will also eat small freeze-dried items. [11]
Squat lobsters are dorsoventrally flattened crustaceans with long tails held curled beneath the cephalothorax. They are found in the two superfamilies Galatheoidea and Chirostyloidea, which form part of the decapod infraorder Anomura, alongside groups including the hermit crabs and mole crabs. They are distributed worldwide in the oceans, and occur from near the surface to deep sea hydrothermal vents, with one species occupying caves above sea level. More than 900 species have been described, in around 60 genera. Some species form dense aggregations, either on the sea floor or in the water column, and a small number are commercially fished.
Nanogalathea raymondi is a species of squat lobster from the Bay of Bengal. It is the only species in the genus Nanogalathea. It can be distinguished from other squat lobsters by the lack of any teeth along the edge of the rostrum. The specific epithet raymondi commemorates the carcinologist Raymond B. Manning.
Alainius crosnieri is a species of squat lobster in a monotypic genus in the family Galatheidae.
Anomoeomunida is a monotypic squat lobster genus in the family Munididae. The sole a species of is Anomoeomunida caribensis. It occurs in the western Atlantic.
Anoplonida is a genus of squat lobsters, which are flattened dorsoventrally, in the family Munididae, containing the following species:
Bathymunida is a genus of squat lobsters in the family Munididae, containing the following species:
Crosnierita is a genus of squat lobsters in the family Munididae, containing the following species:
Enriquea leviantennata is a species of squat lobster in a monotypic genus in the family Munididae.
Galacantha is a genus of squat lobsters in the family Munidopsidae, containing the following species:
Janetogalathea californiensis is a species of squat lobster in a monotypic genus in the family Galatheidae.
Lauriea is a genus of squat lobsters in the family Galatheidae, containing the following species:
Leiogalathea is a genus of squat lobsters in the family Munidopsidae, containing the following species:
Neonida grandis is a species of squat lobster in a monotypic genus in the family Munididae.
Onconida is a genus of squat lobsters in the family Munididae, containing the following species:
Paramunida is a genus of squat lobsters in the family Munididae, containing the following species:
Raymunida is a genus of squat lobsters in the family Munididae, containing the following 11 species:
Setanida cristata is a species of squat lobster in a monotypic genus in the family Munididae.
Shinkaia crosnieri is a species of squat lobster in a monotypic genus in the family Munidopsidae. S. crosnieri lives in deep-sea hydrothermal vent ecosystems, living off of the chemosynthetic activity of certain bacteria living on its setae.
Tasmanida norfolkae is a species of squat lobster in a monotypic genus in the family Munididae.
Garymunida procera is a species of squat lobster in the family Munididae, and was first described by Shane Ahyong and Gary Poore in 2004. The specific name is derived from procerus, a Latin word meaning "slender", which is in reference to its slender cheliped that distinguish it from the similar Agononida soelae. The females measure from 14.3 to 21.4 millimetres. It is found off of Eastern Australia and New Caledonia and near the Lord Howe Rise, where it is found at depths from 450 to 960 metres.
Media related to Allogalathea elegans at Wikimedia Commons