A new species of sesarmine crab (Brachyura: Grapsidae) from Japan and Taiwan, previously known as Sesarma erythodactyla Hess, 1865

Abstract

A new species of intertidal sesarmine crab, Parasesarma acts, is described from Japan and Taiwan. This species has been known under the name Sesarma (Parasesarma) erythodactyla Hess, 1865, but it is established here that P. erythodactyla is endemic to the eastern coast of Australia. Parasesarma ads is known to occur from Sagami Bay, Japan, south to Taiwan, but there are no mainland records. The two species can be easily separated on male chela characters, including the shape and number of the dactylar tubercles, and the disposition of the dorsal pectinate crests.