New records for Parasesarma leptosoma (Hilgendorf, 1869) (Crustacea: Decapoda: Brachyura: Sesarmidae) from mangroves in Mozambique and South Africa

Abstract

The arboreal sesarmid crab Parasesarma leptosoma is recorded for the first time from Mozambique and South Africa. These herbivorous crabs are found in mangrove forests on Rhizophora mucronata and Bruguiera gymnorrhiza, but not Avicennia marina. The biogeographic distribution of this crab species is discussed in relation to the southerly distribution of its associated mangrove species. Aspects of its ecology, biology and conservation are given. At all the collection sites, both R. mucronata and B. gymnorrhiza have been targeted by the local human communities for building poles. This habitat destruction will have a direct effect on this tree-dependent crab species and may also have an indirect effect via a trophic-cascade through the food web. These mangrove systems thus need to be managed in a sustainable way if their biodiversity is to be maintained.