New insights into tateid gastropods and their radiation on Fiji based on anatomical and molecular methods (Caenogastropoda: Truncatelloidea)

Abstract

The South Pacific archipelago of Fiji is characterized by a predominantly Indo-Malesian flora and fauna. We provide a first systematic study on Fiji's tateid gastropods -previously classified as Hydrobiidae -describing 18 new species, combining morphological, anatomical, and molecular data. The molecular phylogeny of tateid gastropods based on 16S rRNA and cytochrome c oxidase subunit I (COI) showed that the species from Fiji were closer related to New Zealand than to Australian or New Caledonian taxa, which is rather exceptional. Performing an ancestral range reconstruction we inferred the colonization history across the two main islands. The radiation had its origin in southern Viti Levu, with a subsequent dispersal over the western and central parts of the island. The chronology of the radiation over eastern Viti Levu and Vanua Levu remained unresolved because of incomplete lineage sorting, a phenomenon typical for young radiations.

The enigmatic pattern of long‐distance dispersal of minute freshwater gastropods (Caenogastropoda, Truncatelloidea, Tateidae) across the South Pacific

“…The radiation on Fiji was divided into three clades but its monophyly was not supported (contra Zielske & Haase, ) suggesting that Fiji was colonized possibly more than once from Vanuatu. However, according to the likelihood approach, this latter route may have been taken also in the opposite direction (see also below).…”

“…Here, we focus on small (few mm in length) freshwater gastropods of the family Tateidae, which probably originated in Australia (Wilke et al ., ) and have a peculiar SP distribution, being known from five islands/archipelagos: (1) Lord Howe Island (LHI) harbours 15 species‐group taxa in three genera (Ponder, ), its volcanic rocks are maximally 6.9 Myr old (McDougall et al ., ); (2) NC harbours seven genera with more than 50 species (Haase & Bouchet, ; Zielske & Haase, ) and was presumably colonized after a phase of submergence 37 Ma (e.g. Swenson et al ., ); (3) Vanuatu with 20 species all attributed to Fluviopupa (Haase et al ., ; Zielske & Haase, ) and continuously emergent probably only since the latest Pliocene (Robin et al ., ; Greene et al ., ); (4) Fiji with 28 known Fluviopupa species (Haase et al ., ; Zielske & Haase, ) and a complex geological history (Rodda, ); and (5) the Austral Islands (AI) in French Polynesia harbouring six Fluviopupa species (Haase et al ., ) extend over 1200 km from the McDonald Seamount volcano in the east to the island of Rimatara in the west and are formed by three volcanic hotspot chains with the oldest island emergent since maximally 12.1 Myr (Bonneville, ; Maury et al ., ). Apart from the Australian mainland and Tasmania, where the estuarine genus Tatea T. Woods, 1879 (Ponder et al ., ) occurs, tateids are known from brackish water habitats only in NZ, where they invaded freshwater three times independently (Haase, ).…”

Revision and Microtomography of the Pheidole knowlesi Group, an Endemic Ant Radiation in Fiji (Hymenoptera, Formicidae, Myrmicinae)

“…However, much work remains to fully document these island faunas–particularly invertebrate taxa–and reconstruct their evolutionary histories. Toward that end, major efforts have been recently mounted to inventory Fiji’s arthropods [ 7 ], and the phylogenetic histories of several groups have been reconstructed [ 8 – 12 ].…”

Five new cryptic freshwater gastropod species from New Caledonia (Caenogastropoda, Truncatelloidea, Tateidae)

“…Our phylogenetic analyses based on DNA sequence data confirmed the suspicion of Haase and Bouchet (1998) that additional cryptic species in this snail fauna will be identified once molecular methods are applied emphasizing the huge morphological variability of certain nominal species. Recent accounts on tateid gastropods from Vanuatu and Fiji ( Zielske and Haase 2014a , b ) have revealed extensive radiations of morphologically very similar species. However, in contrast to the New Caledonian taxa, the radiations on those archipelagos are comparatively young ( Zielske and Haase 2015 ).…”

“…Giusti and Pezzoli 1980 , Radoman 1983 , Haase 1996 , 2008 , Ponder and Colgan 2002 , Liu and Hershler 2005 , Hershler et al 2011 , Delicado and Ramos 2012 ). In the frame of a project aiming at the reconstruction of the colonization of the South Pacific islands by tateids based on molecular data ( Zielske and Haase 2014a , b , 2015 , Zielske, Ponder and Haase in preparation) we visited New Caledonia in May 2012 in order to collect suitable material for sequencing. During this expedition we found five new species of the genera Hemistomia Crosse, 1872 and Leiorhagium Haase & Bouchet, 1998, respectively (Figs 1 , 2 ), which we describe herein based on morphological, anatomical and genetic data.…”