Cryptic diversity, molecular phylogeny and biogeography of the rock- and leaf litter-dwelling land snails of Belau (Republic of Palau, Oceania)

Abstract

The endemic diplommatinid land snails (Caenogastropoda: Mollusca) of Belau (Republic of Palau, Micronesia) are an exceptionally diverse group of largely undescribed species distributed among rock and leaf litter habitats on most of Belau's 586 islands. Diplommatinid shell morphology (e.g. shell sculpture) reflects habitat type. In this study, I analysed a subset of the 90 diplommatinid species representing a broad geographical spread of islands in order to reveal the species' phylogenetic relationships and biogeography within the Belau archipelago. Diplommatinid species from the islands of Yap, Pohnpei, Kosrae and Guam are also included in the analysis. One nuclear (28S rRNA) and two mitochondrial (16S rRNA, COI ) gene regions comprising 1906 bp were used for phylogenetic reconstruction. Results show that (i) the Belau Diplommatinidae are not monophyletic, as Guam and Yap species should be included as part of the radiation, (ii) Pohnpei and Kosrae species are highly divergent from Belau diplommatinids, (iii) there is little evidence for in situ radiation within individual Belau islands, (iv) spined and heavily calcified rock-dwelling species form a well-supported clade, and (v) Belau diplommatinid genera are in need of revision.

Opole (Poland) - a key locality for middle Miocene terrestrial mollusc faunas

“…Diplommatinidae are generally widely distributed in eastern and southern Asia, northern Australia, the Pacific islands and South America (Páll-Gergely et al 2017). Similarly, Palaina species have been described from localities throughout the western Pacific, Australasia and Southeast Asia (Rundell 2008). Convergent shell morphologies, however, are frequent within Diplommatinidae, which hampers clear generic identifications (Páll-Gergely et al 2017).…”

“…Convergent shell morphologies, however, are frequent within Diplommatinidae, which hampers clear generic identifications (Páll-Gergely et al 2017). Molecular phylogenies showed that "Palaina" is non-monophyletic (Rundell 2008, Webster et al 2012). Nevertheless, all phylogenetic studies demonstrated that "Palaina", along with other Diplommatinidae genera like Hungerfordia and Opisthostoma, belongs to geologically young (Miocene or younger) Indo-Pacific and Pacific radiations (Rundell 2008, Webster et al 2012.…”

“…Molecular phylogenies showed that "Palaina" is non-monophyletic (Rundell 2008, Webster et al 2012). Nevertheless, all phylogenetic studies demonstrated that "Palaina", along with other Diplommatinidae genera like Hungerfordia and Opisthostoma, belongs to geologically young (Miocene or younger) Indo-Pacific and Pacific radiations (Rundell 2008, Webster et al 2012. Neubert & Bouchet (2015) even discuss a restriction of Palaina s.s. to the Lord Howe and Palau radiations and assume that the species from Fiji that have been attributed to the genus might represent a radiation on its own.…”

Phylogenetic reconstruction and shell evolution of the Diplommatinidae (Gastropoda: Caenogastropoda)

“…The currently recognized subfamilies Diplommatininae and Cochlostomatinae consist of ten Central Indo-Pacific genera with hundreds of species, and a single European genus, respectively (Beesley et al, 1998;Bouchet et al, 2005;Vermeulen, 1993). The subfamilies have been considered separate families on occasion (Fehér, 2004), and the taxonomic structure within the Diplommatininae has been hampered by convergence in shell shape (Rundell, 2008;Solem, 1959;Tillier, 1981;Vermeulen, 1994). Rundell (2008) produced a molecular phylogeny for the three genera found on Belau, viz.…”

Introduction. Evolution on Pacific islands: Darwin's legacy

“…These deal with beetles in Japan (Sota & Nagata 2008), land snails in Belau (Rundell 2008) and the Ogasawara Islands (Davison & Chiba 2008), iguanas in Fiji (Keogh et al 2008), crickets in New Zealand, Australia and New Caledonia (Pratt et al 2008), weevils in the Galápagos (Sequeira et al 2008) and moths in the Galápagos (Schmitz et al 2008) and Hawaii (Rubinoff 2008).…”