Orisarma


Orisarma is a genus of crabs in the family Sesarmidae. These crabs are native to the coasts of East Asia, including Japan and China. They inhabit intertidal and semiterrestrial zones such as mangrove swamps and mudflats, where they feed on detritus and smaller organisms.

Taxonomy

The genus Orisarma was established in 2020 by Christoph D. Schubart and Peter K. L. Ng during a revision of intertidal and semiterrestrial crab genera, including Chiromantes and Pseudosesarma. This revision utilized morphological and molecular phylogenetic data, resulting in the creation of several new genera, including Orisarma. The type species is Sesarma intermedium De Haan, 1835.

Species

The genus Orisarma comprises the following five species:
  • Orisarma magnum
  • Orisarma intermedium
  • Orisarma neglectum
  • Orisarma patshuni
  • Orisarma sinense
  • ''Orisarma dehaani''

    Distribution

Orisarma species are found across East Asia, with documented occurrences in Japan and China, and possibly extending to other parts of the Indo-West Pacific region.

Ecology

Crabs of the genus Orisarma thrive in intertidal and semiterrestrial habitats such as mangrove forests and mudflats. These environments support their semiterrestrial lifestyle, enabling them to transition between water and land. Notably, Orisarma dehaani has been observed damaging rice fields in Japan, highlighting their adaptability to freshwater settings and occasional interactions with agriculture.