Hypothalassia acerba
| Hypothalassia acerba | |
|---|---|
| Scientific classification | |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Subphylum: | Crustacea |
| Class: | Malacostraca |
| Order: | Decapoda |
| Infraorder: | Brachyura |
| Family: | Hypothalassiidae |
| Genus: | Hypothalassia |
| Species: | H. acerba |
| Binomial name | |
|
Hypothalassia acerba Koh & Ng, 2000 |
|
Hypothalassia acerba is a large crab found in the muddy substrates of the deep seas off the southwestern Australian and New Zealand coasts. Australian distribution, which is correlated to depth and temperature, ranges from a latitude as far north as approximately 27° S on the west coast, southwards, then eastwards on the south coast to a longitude of at least 129° E. The species usually occurs in waters with temperatures of 13–19 °C (55–66 °F) and in depths ranging of 200–255 metres (656–837 ft) on the lower west coast and 90–200 m (300–660 ft) on the south coast. Body size is inversely related to depth of water. There are only two species in the genus Hypothalassia, and H. acerba is not the same champagne crab as the other Hypothalassia species, H. armata, which is found in Japanese waters.
The species has well-defined groves on a hexagonal carapace, with a smooth dorsal surface and a spiny anterior surface. Carapace width is 150 mm. Their branchial openings are partially covered by maxillipeds, and have asymmetrical chelipeds with stiff, brown-black spines of various sizes on their walking legs. The frontal region is beige-cream and covered in many short setae. Walking legs have a dactylus of 3.7–4.3 times as long as wide.
Although life history is not very well known, some data has been collected on reproduction. Hypothalassia acerba reproduction is highly correlated with seasons, due to water temperature fluctuations. Oviposition primarily occurs in the summer between January and March. Females have a tendency to migrate from the south coast eastwards and then northwards to spawn on the lower west coast. The fecundity of this species may be due to its relatively short breeding season, therefore adapting to optimize egg production. Hall et al. (2004) propose that the larvae of this species is planktonic, and is therefore probably carried away from the lower west coast by the Leeuwin Current.
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