Geosesarma De Man, 1892

Ng, Peter K. L., 2017, On the identities of the highland vampire crabs, Geosesarma foxi (Kemp, 1918) and G. serenei Ng, 1986, with description of a new phytotelmic species from Penang, Peninsular Malaysia (Crustacea: Decapoda: Brachyura: Sesarmidae), Raffles Bulletin of Zoology 65, pp. 226-242 : 227

Geosesarma De Man, 1892

Type species. Sesarma (Geosesarma) nodulifera De Man, 1892 , subsequent designation by Serène & Soh (1970).

Remarks. Members of Geosesarma De Man, 1892 , are popularly known as “vampire crabs” because of the bright yellow eyes of a number of species ( Rademacher & Mengedoht, 2011; Ng et al., 2015). The genus currently contains 58 species (cf. Ng et al., 2008; Schubart & Ng, 2014; Ng, 2015; Ng et al., 2015; Manuel-Santos et al., 2016; Ng & Lemaitre, 2017); almost all of which are semiterestrial in habits, living in and around freshwater habitats in Southeast Asia. They are regarded as secondary freshwater crabs by some authors ( Yeo et al., 2008) although most species have large eggs and practice completely abbreviated larval development (cf. Ng, 1988).

Geosesarma foxi ( Kemp, 1918) belongs to a group of Geosesarma species generally characterised by their quadrate carapaces, slender and relatively long ambulatory legs, with the exopod of the third maxilliped not possessing a flagellum, and that usually occur in highlands. Ng (1988) treated the two Malaysian species, Geosesarma foxi ( Kemp, 1918) from Langkawi Island (Kedah), and G. serenei Ng, 1986 , from Bukit Larut in Perak; commenting that the taxonomy of the material referred to “ G. foxi ” from southern Peninsular Thailand needed to be revised in the future. A third species, which may be allied to G. foxi and G. serenei , is G. krathing Ng & Naiyanetr, 1992 , described from Krathing Waterfall in Chantaburi Province in eastern Thailand, near the Cambodian border. While this species shares the quadrate carapace and long slender ambulatory legs of G. foxi and G. serenei (and their male first gonopods are also superficially similar), the exopod of its third maxilliped has a well-developed flagellum ( Ng & Naiyanetr, 1992: fig. 1B).