Australian Museum, Sydney NSW, Australia Molecular phylogeny and taxonomic revision of the genera Baudinella Thiele, 1931, Retroterra Solem, 1985 and Molema K€ ohler, 2011 endemic to the coastal Kimberley, Western Australia (Gastropoda, Camaenidae) FRANCESCO CRISCIONE and FRANK K € OHLER Abstract Baudinella Thiele, 1931, Retroterra Solem, 1985 and Molema K€ ohler, 2011 are three genera of camaenid land snail endemic to coastal regions of the Western Australian Kimberley. Each of these genera has fairly distinct shells, but all exhibit a rather similar configuration of the reproductive system, which is characterized by lack of a penial sheath and presence of an elongated and coiled bursa copulatrix. By combining comparative morphology of shell and penial anatomy with analyses of the mitochondrial DNA fragments 16S rRNA (16S) and cytochrome c oxidase subunit 1 (COI), the phyloge- netic relationships amongst representative species of these genera are addressed to test the monophyly of taxa and to identify new species. Our results show that all three genera are members of a single camaenid radiation. Five new species are described: two new species of Baudinella, B. magna n. sp. from the Institute and Montesquieu Archipelagos and B. margaritata n. sp. from Pitta Gorge in the Prince Regent Reserve, one new species of Molema, Molema tenuicostata n. sp., from near Talbot Bay, and two new species of Retroterra, R. dichroma, and R. nana, from the Prince Regent Reserve. Key words: Stylommatophora – Helicoidea – mitochondrial DNA – genetic distances – new species Introduction For its remoteness and inaccessibility, the Western Australian Kimberley has remained the most poorly known region in Aus- tralia in terms of its biodiversity. However, several large surveys conducted in the past four decades have improved the documen- tation of biotic patterns throughout the Kimberley, which has since emerged as one of Australia’s biodiversity hot spots (McKenzie 1991; Gibson and McKenzie 2012). With respect to camaenid land snails, the Kimberley is argu- ably the major hot spot in Australia, for no other Australian region of comparable size harbours more species. The inventory of Kimberley land snails, including camaenids, has made signifi- cant leaps forward during recent years. Collectively, the most significant contributions to the current knowledge of the Kimber- ley Camaenidae are the works of Alan Solem, who systemati- cally surveyed and completely revised the entire fauna. In all, Solem (1981a,b, 1984, 1985, 1988) newly described more than 100 camaenid species. At the time, Solem’s works on the Kim- berley fauna quadrupled the number of known species highlight- ing the Camaenidae as the taxonomically and ecologically most diverse land snail group in the Kimberley. Ongoing revisions have doubled species numbers again. Most significantly, K€ ohler (2011a) newly described 83 species from islands off the Kimber- ley coast. In addition, a series of taxonomic revisions contained descriptions of many new species in several genera (K€ ohler 2010a,b, 2011b,c; Criscione et al. 2012; K€ ohler and Johnson 2012; Criscione and K€ ohler 2013a,b; K€ ohler and Criscione 2013a) raising the number of known species to 250. Systematic studies have demonstrated that land snails are not equally distributed over the land surface but that rainfall patterns, soil type and topography govern the distribution of vegetation types and, hence, patterns of species richness of local land snail communities throughout the Kimberley (Solem and McKenzie 1991; Gibson and K€ ohler 2012; K€ ohler et al. 2012). Accord- ingly, the richest land snail communities are found in vine thicket patches in the high-precipitation zone of the north-wes- tern coastal region between the Admiralty Gulf to the north and the Camden Sound to the south (Solem and McKenzie 1991). Fifteen camaenid genera are represented in this part of the Kimberley, several of which are exclusively found here, such as Youwanjela K€ ohler and Shea, 2012 (K€ ohler and Shea 2012). Amongst these endemic camaenids of the high rainfall zone, the taxonomy of three presumably closely related genera is revised, Baudinella Thiele, 1931, Retroterra Solem, 1985, and Molema K€ ohler, 2011. Their close relationships are underpinned by sev- eral shared features of the shell and genital anatomy (Solem 1985; K€ ohler 2011a). Baudinella comprises seven presently recognized species, most of which are island endemics. Two species are found on the mainland: B. baudinensis (Smith, 1893) occurs on Baudin Island and Cape Voltaire, and B. regia Solem, 1985 in the Prince Regent Nature Reserve (Fig. 1). Solem (1991) also listed two undescribed taxa from coastal localities in the York Sound and Prince Frederick Harbour. Baudinella species have repeatedly been found in sympatry with species of Setobaudinia Iredale, 1933 having very similar, small and flat shells with reflected apertural lips and widely open umbilici (K€ ohler 2011a; Criscione and K€ ohler 2013c). Despite these similarities, the two genera clearly differ in their genital anatomy and are phylogenetically distinct (Solem 1985; Criscione and K€ ohler 2013c). Retroterra is restricted to the wettest part of the Kimberley, the Prince Regent Reserve (Solem 1985, 1991), including two nearby islands, Unwins and Bongaree Islands, and Hanover Bay (K€ ohler 2011a; Fig. 2). Retroterra species differ from other cam- aenids in having a rather large, flat shell with extremely wide umbilicus and regular radial sculpture. Typical features of the genital anatomy include a well-developed penial verge and long, convoluted bursa copulatrix (Solem 1985). The only species of Molema, M. stankowskii K€ ohler, 2011, is only known from north-west of Molema Island, Talbot Bay. The species has a discoidal shell with a relatively large aperture whose lip is expanded and reflected bearing no indentations. A large stimulatory pilaster is a distinctive penial feature (K€ ohler 2011a). Corresponding author: Frank K€ ohler (frank.koehler@austmus.gov.au) Contributing authors: Francesco Criscione (francesco.criscione@austmus. gov.au) J Zoolog Syst Evol Res (2014) 52(4), 273--284 Accepted on 16 February 2014 © 2014 Blackwell Verlag GmbH J Zoolog Syst Evol Res doi: 10.1111/jzs.12065