Undescribed vampire crab, Geosesarma sp. – of Sarawak & Kalimantan / Borneo around 1000m ASL.

Note: This Geosesarma will be described shortly.

Geosesarma De Man, 1892 (Sesarmidae) is a genus of small, semi-terrestrial freshwater crabs occurring primarily in Southeast Asia, where they inhabit humid leaf-litter and stream bank habitats close to clear, shallow waters. Many species shelter in burrows or under logs and stones and venture to the water mainly for moisture and shelter rather than for prolonged swimming. Reproduction is characteristic: females produce relatively few, large eggs and development is direct, so juveniles hatch as miniature crabs without planktonic larval stages. Species diversity is high on islands and in fragmented drainage systems, yielding numerous localized endemics and ongoing taxonomic revision. Several vividly colored species are popular in the terrarium trade and are colloquially known as “vampire crabs,” a name that refers to eye and body coloration rather than diet. Etymology: the name combines Greek geo- (“earth”) with Sesarma (a related sesarmid genus), alluding to the group’s largely terrestrial habits; the genus was established by J. G. de Man in 1892.