The camaenid species of the Kimberley Islands, Western Australia (Stylommatophora: Helicoidea)
The present paper provides a complete overview of the camaenid land snail fauna of the 22 largest islands along the Kimberley coast, northwesternmost Western Australia, which were surveyed between 2007 and 2010. These islands were found to harbour a total of 104 species (83 new) in 15 genera (5 new), including taxa described recently. Species were essentially delimited by means of comparative analyses of shells (size, shape, sculpture, colouration), genital anatomy (in particular penial anatomy), and genetic differentiation in a mitochondrial marker (partial 16S rRNA sequences). Additionally, the radular and jaw morphology of selected species was studied but found to provide little useful information for taxonomic purposes. Species of the following genera are treated: Amplirhagada Iredale, 1933 (22 species), Carinotrachia Solem, 1985 (2 subspecies), Kimberieymelon Köhler, 2010 (1 species), Kimberleydiscus Köhler, 2010 (1 species), Australocosmica Köhler, 2011 (6 species), Kimboraga Iredale, 1939 (4 species), Xanthomelon Martens, 1860 (1 species), Globorhagada Iredale, 1933 (8 species; the name Globorhagada being removed from synonymy of Xanthomelon), Rhagada Albers, 1860 (8 species), Retroterra Solem, 1985 (3 species), Baudinella Thiele, 1931 (5 species), Setobaudinia Iredale, 1933 (14 species), Torresitrachia Iredale, 1939 (17 species or subspecies). In addition, two new genera, Molema, n. gen. (one species) and Kimberleytrachia, n. gen. (12 species), are described. The taxa Torresitrachia umbonis Solem, 1979, T. deflecta Solem, 1979, and T. crawfordi Solem, 1979, are transferred to the new genus Kimberleytrachia. Species previously assigned to Damochlora are transferred to Setobaudinia; the former genus name likely being a junior synonym of the latter. The following species are delimited differently compared to the latest available revisions: “Xanthomelon” (now: Globorhagada) prudhoensis (E. A. Smith, 1894); “Damochlora” (now: Setobaudinia) rectilabrum (E. A. Smith, 1894); “Torresitrachia” (now: Kimberleytrachia) umbonis (Solem, 1979); Torresitrachia amaxensis Solem, 1979; T. bathurstensis (E. A. Smith, 1894). Most species were found to be island endemics. The work increases the number of known camaenids in northwestern Australia considerably and highlights the region as significant hotspot of land snail diversity.