Singapore Wild Animals: Crabs

Singapore Crabs

True Crabs (Brachyurans)

Small crabs at Sungei Buloh ©Tan KH

Superfamily Dromioidea

Family Dromiidae (Burrowing Crabs)

Superfamily Calappoidea

Family Calappidae (Box Crabs)
Family Matutidae (Moon Crabs)

Superfamily Carpilioidea

Family Carpiliidae

Superfamily Corystoidea

Family Corystidae (Masked Burrowing Crabs)

Superfamily Dorippoidea

Family Dorippidae (Sponge Crabs)

Superfamily Eriphioidea

Family Menippidae (Stone Crab)
Family Oziidae (Forceps Crab)
Family Eriphiidae

Spotted-belly Forceps Crab (Ozius guttatus) at Chek Jawa ©Tan KH

Superfamily Leucosioidea

Family Leucosiidae (Pebble Crabs)

Superfamily Majoidea (Spider Crabs)

Family Majidae
Family Epialtidae
Family Inachidae (Velcro Crab, etc)

Superfamily Parthenopoidea

Family Parthenopidae (Elbow Crabs)

Superfamily Pilumnoidea

Family Pilumnidae (Hairy Crabs)

Superfamily Portunoidea

Family Portunidae (Swimming Crabs, Flower Crabs, Mud Crabs)

Flower Crabs (Portunus pelagicus) are one of the crabs commonly sold in marketplaces. They have a distinctive "flowery" pattern on their shell. They are a type of Swimming Crab (Family Portunidae), which also includes the Mud Crabs used for chilli and pepper crab.

Moulted shell at Chek Jawa ©Tan KH

Mud Crabs (genus Scylla) are the type of crabs found on our dining table. Fortunately, the local mud crabs are not as large as the Giant mud crab (S. serrata), which is the one commonly used for chilli and pepper crabs. They belong to the family Portunidae (the swimming crabs). Singapore has three species: Orange (S. olivacea), Green (S. paramamosain) and Purple Mud Crab (S. traquebarica). The Orange Mud Crab has orange claws, the Green Mud Crab has green and orange claws, and the Purple Mud Crab has purple claws.

Green Mud Crab ©Tan GC. Purple Mud Crab at Chek Jawa ©Tan KH

Orange Mud Crab at Sungei Buloh ©Tan KH

Superfamily Xanthoidea

Family Xanthidae

Superfamily Grapsoidea

Family Grapsidae

Metopograpsus sp. on Coney Island ©Tan KH

Family Plagusiidae
Family Sesarmidae (Sesarmine Crabs, Vinegar Crabs, etc)

Family Sesarmidae includes the tree-climbing crabs, which are commonly seen at Sungei Buloh.

Chek Jawa ©Sylvia Chua. Lorong Halus ©Lau SY

The most easily recognised are the large Vinegar Crabs (Episesarma sp.). The Violet Vinegar Crab (E. versicolor) has pale or violet claws. The Singapore Vinegar Crab (E. singaporense) and Pink-fingered Vinegar Crab (E. chentongense) both have red claws, but the granules on the claws are white in the former and red in the latter. The Pink-and-white-fingered Vinegar Crab (E. palawanense) has a pale dactyl (movable claw) and a red propus (unmovable claw). The Thai Vinegar Crab (E. mederi) has a violet dactyl and a red propus.

Singapore Vinegar Crab (E. singaporense) or Pink-fingered Vinegar Crab (E. chentongense)

On mud lobster mound. On tree. Both at Sungei Buloh ©Lau SY

On mud lobster mound, Chek Jawa. Eating brown leaf, Sungei Buloh ©Tan KH

Pasir Ris ©Sylvia Chua

Pink-and-white-fingered Vinegar Crab (E. palawanense)

Sungei Buloh ©Tan KH

Violet Vinegar Crab (E. versicolor)

Kranji Nature Trail. Sungei Buloh ©Lau SY

On ground. Cannibalising. Sungei Buloh ©Tan KH

Family Varunidae (Paddler Crabs, etc)

Superfamily Ocypodoidea (Stalk-eyed Crabs)

Family Camptandriidae
Family Dotillidae (Soldier Crabs, Sand Bubbler Crabs, etc)

Family Macrophthalmidae (Sentinel Crabs, etc)
Family Ocypodidae (Ghost Crabs and Fiddler Crabs)

Ghost Crabs (Genus Ocypode) belong to the same family (Family Ocypodidae) as the Fiddler Crabs (Genus Uca). They are so called because they are able to disappear quickly into their burrow when threatened. They are found on sandy coasts. Sometimes, they have one claw larger than the other, but the size difference is not as distinct as the fiddler crabs'. There are two species in Singapore - Horn-eyed Ghost Crabs (O. ceratophthalma) and Common Ghost Crab (O. cordimana).

Fiddler Crabs (Genus Uca) belong to the same family (Family Ocypodidae) as the Ghost Crabs (Genus Ocypode). The male is easily recognised by having a claw disproportionately larger than the other. The female has claws of the same size.

Porcelain Fiddler (U. annulipes)
U. dussumieri (probable)
U. forcipata
U. hesperiae (probable)
Rosy Fiddler (U. rosea)
Purple Fiddler (U. paradussumieri)
U. perplexa (probable)
U. rhizophorae
U. tetragonon (probable)
U. triangularis (probable)
Orange Fiddler (U. vocans)