Philippine Amphidromus - A Taxonomic and Nomenclatural Puzzle

Several "groups" of Philippine Amphidromus are easily distinguished: the Amphidromus maculiferus complex, the Amphidromus chloris complex, the Amphidromus quadrasi complex, and the Amphidromus enobaptus complex. We here give an overview of the respective groups: we discuss and document them. This is followed by an alphabetical presentation and documentation of the different species. Much attention has been given to a good visual presentation of the Amphidromus and their forms on 39 color plates. A number of taxa is only seen in the figures dispersed in the text, because no recent material was available. Finally, a new species of Amphidromus, Amphidromus escondidus n. sp., is described from Balut Island.