The Doridina form approximately half of the large collection of opisthobranchs made by the Rumphius Biohistorical Expedition (RBE) from Ambon, Indonesia, during November and December 1990, details of which are available in Strack (1993, 1998). An introduction to the nudibranch material present in these collections is given in the first paper describing the Chromodorididae and Hexabranchidae (Yonow, 2001), and is not repeated here. The RBE nudibranchs are supplemented by specimens collected by H. Debelius from Bali and Sulawesi in November 1990, by H. Strack from Ceram during November and December 1997, and by J. Hinterkircher from East Borneo in September 2003. A further few specimens from the Philippines (collected by J. Hinterkircher) and Australia (collected by Prof. R. Cattaneo-Vietti, C. Bryce, and H. Debelius) are also included since they have been reliably recorded from Indonesia: Gymnodorids aurita, G. impudica, Analogium spec. nov. 1, and Phyllidia elegans. Thirty-three species are recorded; eight species were not previously recorded from Indonesia and three species appear to be new to science.
The cryptobranch dorids contain a vast number of species worldwide, with numerous old as well as recently described names (Valdés & Gosliner, 1999b; Dorgan et al., 2002). While the species themselves are often recognizable and identifiable, their generic placement is sometimes more difficult (Dayrat, 2010). The species included in the paper all belong to the family Discodorididae and are listed alphabetically by genus, implying no phylogenetic affinities what so ever. Recently, taxonomic work has lead to the synonymy of many genera [e.g. Miamira and Orodoris with Ceratosoma (Valdés & Gosliner, 1999a), Fryeria with Phyllidia (Valdés & Gosliner, 1999b), and Trippa with Atagema (Valdés & Gosliner, 2001)]. In some cases, this has proved a useful exercise, but in others it makes the classification of the species more difficult, ignoring previously widely accepted distinctions between these genera, and necessitating new names for well-known species (e.g. Notodoris with Aegires, but both have a well-known species named citrinus; Fahey & Gosliner, 2004). Higher systematic studies are certainly important for establishing evolutionary relationships, but knowing the identities of the individual species is essential for zoogeographical, phylogenetic, as well as natural products studies.