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

Abstract

Aim Tateid freshwater gastropods have an enigmatic distribution in the South Pacific (SP) region. We reconstructed their diversification and dispersal pathways and estimated a timeframe for their radiations. Location New Caledonia, Vanuatu, Fiji, the Austral Islands, further species from Sulawesi, Australia, New Zealand and Lord Howe Island. Methods Bayesian and maximum likelihood methods were used to calculate dated phylogenies based on two mitochondrial and three nuclear gene fragments, test hypotheses and perform ancestral range reconstructions. We compared two calibration strategies based on the COI substitution rate and two sets of island ages selected (1) independent of the ancestral range reconstruction and (2) using information from the latter. Results The common ancestor of the SP Tateidae occurred in Australia. Its descendents colonized Sulawesi and Lord Howe Island and gave rise to the radiations on New Caledonia and New Zealand. The more remote archipelagos harbouring the genus Fluviopupa Pilsbry, 1911 were colonized out of New Zealand. Fluviopupa evolved on the Austral Islands and colonized the archipelago against the progression rule from east to west. Vanuatu was colonized twice independently from the Austral Islands and served as hub for dispersal events to Fiji and Lord Howe Island. The second strategy for calibrating the time trees resulted in considerable younger colonization estimates, was generally well in accordance with the geological record and required fewer ad hoc hypotheses to explain the diversification and dispersal pattern. Main conclusions Our analyses of the evolutionary history of Tateidae across the SP revealed several enigmatic aspects not in accordance with the dominant pattern published for other taxa. In particular, the complex westward dispersal pathways of Fluviopupa, which originated on the Austral Islands but had an ancestor in New Zealand, are unique. Geographical distance was not an appropriate predictor of relationships.

Going under down under? Lineage ages argue for extensive survival of the Oligocene marine transgression on Zealandia

“…We have included the Coprosma–Nertera lineage as having pre‐OMT NZ roots, but as 30 later dispersal events around the Pacific are inferred for Coprosma , we cannot have much confidence that the lineage was specifically located in NZ through the OMT. As with Coprosma , the choice of stem over crown age implies that NZ tateid gastropods survived the OMT in situ (Zielske, Ponder, & Haase, ). Griselinia could well have dispersed to NZ from Australia in the Miocene, but in the absence of more taxa to break the long edge, or more fossil information, it is a moot point (Nicolas & Plunkett, ).…”

Global Diversification Dynamics Since the Jurassic: Low Dispersal and Habitat-Dependent Evolution Explain Hotspots of Diversity and Shell Disparity in River Snails (Viviparidae)

“…Encompassing several global biodiversity hotspots, Southeast Asia is of great interest to biogeographers and evolutionary biologists because it has experienced a dynamic and complex tectonic and climatic history, particularly since the Early Miocene (Woodruff 2010;Lohman et al 2011;Metcalfe 2011;de Bruyn et al 2014;Klaus et al 2016). The interplay of tectonic and climatic processes has triggered extensive in situ diversification in several taxonomic groups, but it has also facilitated widespread biotic exchange via dispersal and vicariance across prominent biogeographical barriers in numerous taxonomic groups (see e.g., Stelbrink et al 2012;de Bruyn et al 2014;Crayn et al 2015 for meta-analyses), including freshwater mollusks (e.g., Köhler and Glaubrecht 2010;von Rintelen et al 2014;Zielske et al 2017).…”

All-inclusive descriptions of new freshwater snail taxa of the hyperdiverse family Tateidae (Gastropoda, Caenogastropoda) from the South Island of New Zealand

“…The phylogenetic analyses (Fig. 2) recovered the major clades from previous analyses (Haase 2005(Haase , 2008Zielske et al 2017). Their relationships were slightly different, however, basally unsupported.…”