On Pontoniinae (Crustacea, Decapoda, Palaemonidae) collected from ascidians

A collection of Pontoniinae associated with ascidians is studied. This collection comprises species belonging to the genera Ascidonia Fransen, 2002; Dactylonia Fransen, 2002; Odontonia Fransen, 2002; Rostronia Fransen, 2002; Pseudopontonia Bruce, 1992; and Periclimenaeus Borradaile, 1915. Two species are described as new to science. Odontonia maldivensis n. sp. can be distinguished from its congeners by the following characters: 1) the absence of a ventral subdistal tooth of the rostrum; 2) the unguis of the ambulatory pereiopods having a distal region with about 25 transverse rows of serrate scales; 3) the absence of a distal accessory tooth on the corpus of the dactylus; and 4) the dactyli of the second chelipeds having a pile of long simple setae on the dorsal surface. Periclimenaeus orbitocarinatus n. sp. is characterized by a pronounced postorbital carina lacking in its congeners. New hosts are recorded for almost all species and their known geographical distribution is extended. A key to species of Periclimenaeus associated with compound ascidians is provided.