Geosesarma is genus of small freshwater or terrestrial crabs, typically less than across the carapace. They live and reproduce on land with the larval stages inside the egg. They are found in India, Indonesia, Malaysia, Thailand, the Philippines, the Solomon Islands and Hawaii.
In the pet trade, they are called vampire crabs. This has nothing to do with their feeding habits, but rather with the bright, contrastingly yellow eyes of some Geosesarma species.. However not all vampire crab species have bright yellow eyes; some species have white or black eyes.
Species Geosesarma contains these species:
Geosesarma aedituens Naruse & Jaafar, 2009 Geosesarma albomita Yeo & Ng, 1999 Geosesarma ambawang Ng, 2015 Geosesarma amphinome (De Man, 1899) Geosesarma anambas Ng, Wowor & Yeo, 2023 Geosesarma angustifrons (A. Milne-Edwards, 1869) Geosesarma araneum (Nobili, 1899) Geosesarma aurantium Ng, 1995 Geosesarma batak Manuel-Santos, Ng & Freitag, 2016 Geosesarma bau Ng & Jongkar, 2004 Geosesarma bicolor Ng & Davie, 1995 Geosesarma bintan T. M. Leong, 2014 Geosesarma cataracta Ng, 1986 Geosesarma celebense (Schenkel, 1902) Geosesarma clavicrure (Schenkel, 1902) Geosesarma confertum (Ortmann, 1894) Geosesarma danumense Ng, 2003 Geosesarma dennerle Ng, Schubart & Lukhaup, 2015 Geosesarma foxi (Kemp, 1918) Geosesarma gordonae (Serène, 1968) Geosesarma gracillimum (De Man, 1902) Geosesarma hagen Ng, Schubart & Lukhaup, 2015 Geosesarma hednon Ng, Liu & Schubart, 2003 Geosesarma ianthina Pretzmann, 1985 Geosesarma insulare Ng, 1986 Geosesarma johnsoni (Serène, 1968) Geosesarma katibas Ng, 1995 Geosesarma krathing Ng & Naiyanetr, 1992 Geosesarma larsi Ng & Grinang, 2018 Geosesarma lawrencei Manuel-Santos & Yeo, 2007 Geosesarma leprosum (Schenkel, 1902) Geosesarma maculatum (De Man, 1892) Geosesarma malayanum Ng & Lim, 1986 Geosesarma mirum Shy & Ng, 2019 Geosesarma nannophyes (De Man, 1885) Geosesarma nemesis Ng, 1986 Geosesarma nigripes Ng & Wowor, 2024 Geosesarma noduliferum (De Man, 1892) Geosesarma notophorum Ng & C. G. S. Tan, 1995 Geosesarma ocypodum (Nobili, 1899) Geosesarma penangense (Tweedie, 1940) Geosesarma peraccae (Nobili, 1903) Geosesarma protos Ng & Takeda, 1992 Geosesarma rathbunae (Serène, 1968) Geosesarma riani Ng & Wowor, 2024 Geosesarma rouxi (Serène, 1968) Geosesarma sabanum Ng, 1992 Geosesarma sarawakense (Serène, 1968) Geosesarma scandens Ng, 1986 Geosesarma serenei Ng, 1986 Geosesarma solomonense (Serène, 1968) Geosesarma starmuhlneri Pretzmann, 1984 Geosesarma sumatraense Ng, 1986 Geosesarma sylvicola (De Man, 1892) Geosesarma ternatense (Serène, 1968) Geosesarma teschi Ng, 1986 Geosesarma thelxinoe (De Man, 1908) Geosesarma tiomanicum Ng, 1986 Geosesarma vicentense (Rathbun, 1914)
As of March 2015, professor Peter Ng of National University of Singapore has named 20 Geosesarma species, and he "has another half a dozen or so newly collected Geosesarma species from Southeast Asia in his lab, and these species still need to be named and described."
Threats Geosesarma dennerle and Geosesarma hagen, both originally from Java, are threatened by illegal overcollection for the aquarium trade.
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