Abstract
Three new coastal crabs, Parasesarma aurifrons n. sp., P. sanguimanus n. sp. and P. gemmatum n. sp. (Sesarmidae), are described from Taiwan and the Philippines. Parasesarma aurifrons is morphologically similar to P. ungulatum (H. Milne Edwards, 1853), P. liho Koller, Liu & Schubart, 2010, and P. obliquefrons (Rathbun, 1924); P. sanguimanus most closely resembles P. cricotus (Rahayu & Davie, 2002); and P. gemmatum is related to P. lenzii (De Man, 1895), but they can be distinguished by a suite of characters, including the structures of the chelipeds, gonopods and vulvae. The three new species are also supported by genetic data from the mitochondrial cytochrome oxidase subunit I (COI). Two species, P. lenzii and P. dumacense (Rathbun, 1914), are also recorded from Taiwan for the first time. The poorly known P. obliquefrons (Rathbun, 1924) from Samoa is figured for the first time as part of the comparisons and its taxonomically important gonopod structures are illustrated.