Chasmagnathus

For the crab species also originally described as Ocypode convexus, see Golden ghost crab.

Chasmagnathus convexus is a common mud-flat crab of the family Varunidae, which is endemic to East Asia.^[2][3] In Japan, this crab is commonly called hamagani. This crab has two forms that differ in color; one is olive green and the other is purple.^[2] Differences in diet are believed to be responsible for the color variation between the two forms. C. convexus is large, relative to related crabs, and can reach 4.5 to 5 centimetres (1.8 to 2.0 in) wide across its carapace.^[4] It is predominantly nocturnal.^[2]

Chasmagnathus
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Arthropoda
Class:	Malacostraca
Order:	Decapoda
Suborder:	Pleocyemata
Infraorder:	Brachyura
Family:	Varunidae
Genus:	Chasmagnathus De Haan, 1833[1]
Species:	C. convexus
Binomial name
Chasmagnathus convexus (De Haan, 1835)[1]
Synonyms[1]
Ocypode (Chasmagnathus) convexus De Haan, 1833 Helice spinicarpa H. Milne-Edwards, 1853