THE SYSTEMATICS OF SUNDANIAN FRESHWATER CRABS WITH COMPARATIVE STUDIES ON SELECTED CHARACTERS (CRUSTACEA : BRACHYURA)

Abstract

The systematics of the true freshwater crabs attributed to the superfamilies Potamoidea and Gecarcinucoidea of Sundaland (Peninsular Malaysia, Singapore, Borneo, Sumatra, Java, and Lesser sunda Islands) is revised. 25 genera and 109 species and subspecies are dealt with. Five genera, eight species and two subspecies are described here as new. Three genera, 22 species and subspecies from Sundaland have been earlier described and published during the course of the present study. A review of the taxonomic characters used at present, as well as possible new ones, in freshwater crab taxonomy, and comparative studies of these structures with other marine brachyura is also conducted. A revised classification is proposed for the freshwater crabs of the world. The Gecarcinucoidea is synonymised with the Potamoidea. The families Isolapotamidae and sinopotamidae are synonymised with Potamidae, and the existing subfamilial system is dispensed with. The Parathelphusidae and sundathelphusidae are synonymised with the Gecarcinucidae which becomes a family in the Potamoidea. The ecology, evolution and zoogeography of the Sundanian freshwater crabs is briefly discussed. The distribution of the Potamidae supports the demarcation of fauna indicated by Wallace's Line but not that of the Gecarcinucidae.