The tree-climbing crabs of Trinidad

An annotated list of the brachyuran (12) and anomuran (1) tree-climbing crabs of Trinidad (West Indies) is presented (see Table 1 for species names). Some of the species mentioned (e.g. Aratus pisonii, Goniopsis cruentata) are well-known treeclimbers, in others (e.g. Sesarma roberti, S. ricordi) this peculiar behaviour is recorded for the first time. Some data on the diet and the locomotion of climbing Grapsidae are given. Aratus was found to feed mainly on algae and decayed wood, not on mangrove leaves. A synopsis of pertinent data from literature (Table 2) yielded 30 further species names of tree-climbing crabs. Like in Trinidad, most of these belong to systematic groups comprising many or only semiterrestrial species. The trees ascended are mangroves in about half of all cases. Motives, grades, phyletic routes, predispositions and consequences of the habit of tree-climbing are discussed.