Tioman Island Crab

Geosesarma tiomanicum is a semi-terrestrial sesarmid crab endemic to Tioman Island off the east coast of peninsular Malaysia. It was first described from specimens collected in the island's interior forest streams and is characterised by a warm olive-brown to dark chocolate carapace with distinctive pale orange or cream colouration on the leg joints, creating a striking two-tone pattern.

Like other Geosesarma species, G. tiomanicum is primarily terrestrial and requires a humid paludarium environment with both land and water access. It is a nocturnal species that forages actively at night, retreating to sheltered spots among leaf litter or under bark during daylight hours. Its rarity in the hobby makes it a sought-after species for specialist crab keepers.

Captive breeding follows the Geosesarma pattern of direct development, with females brooding large eggs that hatch as fully formed miniature crabs. Groups of mixed sexes can be kept together in suitably large paludariums with adequate food and shelter.

Water: 22–28°C; fresh shallow pool; pH 7.0–8.0; terrarium humidity 75–90%. Tank: minimum 30 L paludarium, humid tropical soil, leaf litter, cork bark hides, shallow pool. Feeding: omnivore — micro crickets, fruit flies, dried fish, blanched greens, leaf litter. Breeding: direct development; female broods 10–30 large eggs; juvenile crabs hatch after 4–6 weeks. Compatibility: sociable with conspecifics in groups; avoid fish or large invertebrate tankmates.