Atergatis integerrimus Red Egg Crab Crustacea Decapoda Brachyura Xanthidae

Red Egg Crab Atergatis integerrimus Crustacea Decapoda Brachyura Xanthidae carapace cm 4.5-6 x 3.5-4.5 (legs not included).
Family: Xanthidae.
Common name: Red Egg Crab.
Syn. Atergatis subdivisus, Cancer integerrimus, Cancer laevis latipes.

Atergatis integerrimus is a red marine crab of the Xanthidae family typical of the coral reefs of South-East Asia.
The carapace is large, egg-shaped with a smooth (not "toothed") edge. The color is variable, from reddish brown, from orange to bright red, usually with scattered white spots. The claws have large pincers with black spoon-shaped tips, both of the same size, while the legs are slightly pierced by fine hairs. Males may have larger claws. Juveniles are light brown with a white band around the edge of the body. It is sometimes mistaken for "stone crabs" (Myomenippe hardwicki), similar but with green shells ringed with red. Stone crabs are also spotless and tend to be gray or beige, although they can sometimes be reddish.
It is usually found in rocky and sandy bottoms and in coral reefs.
This colorful round crab is slow moving, usually hiding under large fragments of coral, but can be quite active at night.
Like most other xanthid crabs, marginal levels of toxicity have been detected in this species that could contribute to human poisoning. Preys on tridacnids.
Precopulatory courtship ritual is common, through olfactory and tactile cues, with sperm transfer usually indirect.