Discoplax magna
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| Scientific name | ||||||||||||
| Discoplax magna | ||||||||||||
| Ng & Shih , 2014 |
Discoplax magna is a species of land crab that is found on the coasts of the eastern Indian Ocean . Until the taxonomic revision in 2014, the animals were assigned to the species Discoplax hirtipes ( syn. Cardiosoma hirtipes ), which isspread further east.
Description and characteristics
Discoplax magna reaches a carapace length and width of the males up to a maximum of 104 × 81 mm (an animal from Thailand), whereby most of the animals remain noticeably smaller. The females are generally slightly smaller than the males. In living animals, the carapace is brown to gray-brown on the upper side and whitish-orange to yellow on the underside. The third maxillipedas are purple in the middle. The pairs of scissors- carrying legs or chelipeds are colored orange to red, with the tips of the scissor fingers being white. Animals from Western Thailand and the Nicobar Islands are, in contrast, predominantly dark purple with clearly red claws. The (white) -blue coloration characteristic of Discoplax celeste is never pronounced. The transversely egg-shaped (subovate) carapace is convex both transversely and longitudinally, the individual regions are hardly set apart from one another. The epigastric region is noticeably somewhat swollen. In large males, the scissors, which are the same size as one another, are not noticeably elongated, the scissor fingers are long and narrow and laterally flattened.
distribution
The distribution area extends from Christmas Island over the west coast of Java and Sumatra as well as small islets off the coast of Thailand to the Nicobar Islands . On Christmas Island, the species lives together (sympathetically) with the much more common Discoplax celeste , which is endemic to this island . Both species are rarer than the famous red land crab ( Gecarcoidea natalis ) on this island.
The distribution area of Discoplax hirtipes (in the narrower sense) connects to the east without overlapping (parapatric distribution). In some places, such as the northern tip of Java, both species occur relatively close together.
Way of life
The adult animals of the species live exclusively on land (terrestrial); they only go to the sea to reproduce. The habitat is forests on karstified limestone. They occur up to about one kilometer inland from the coast. The species prefers moist soils with a thick litter of rotting vegetation, but is not bound to swamps or wetlands. The crabs dig out hiding places as resting places, mostly in places protected by trees or rocks.
Reproduction
Like most land crabs (Gecarcinidae), they are tied to the sea for reproduction. However, mating takes place on land.
Taxonomy
The species belongs to the genus Discoplax Milne-Edwards, 1867. This was mostly included in the genus Cardiosoma until 1987 , but differs from this in the shape of the thoracic sternum of the males. Six species are known in the genus. According to the genetic data, the sister species of Discoplax magna is the species Discoplax celeste , the sister group of the common clade is a clade from the species Discoplax rotunda and Discoplax hirtipes .
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- Peter KL Ng & Hsi-Te Shih (2014): The systematics of the land crabs of the Discoplax hirtipes (Dana, 1851) species-group (Crustacea: Decapoda: Brachyura: Gecarcinidae), with description of a new species from the eastern Indian Ocean. Raffles Bulletin of Zoology Supplement No. 30: 109-135. PDF