Coming to America: multiple origins of New World geckos

Abstract

Geckos in the Western Hemisphere provide an excellent model to study faunal assembly at a continental scale. We generated a time-calibrated phylogeny, including exemplars of all New World gecko genera, to produce a biogeographic scenario for the New World geckos. Patterns of New World gecko origins are consistent with almost every biogeographic scenario utilized by a terrestrial vertebrate with different New World lineages showing evidence of vicariance, dispersal via temporary land bridge, overseas dispersal, or anthropogenic introductions. We also recovered a strong relationship between clade age and species diversity, with older New World lineages having more species than more recently arrived lineages. Our data provide the first phylogenetic hypothesis for all New World geckos and highlight the intricate origins and ongoing organization of continental faunas. The phylogenetic and biogeographical hypotheses presented here provide an historical framework to further pursue research on the diversification and assembly of the New World herpetofauna.

Evaluating evolutionary history in the face of high gene tree discordance in Australian Gehyra (Reptilia: Gekkonidae)

“…Divergence dates across squamates and geckos were largely concordant with previous studies (Gamble et al, 2008a(Gamble et al, , 2010Sanders et al, 2008). This indicates that date estimates for splits within Gehyra are likely to be reasonable given the available calibrations.…”

“…Divergence times between representatives of major Gehyra lineages were estimated from the RAG1 data due to the availability of data on Genbank and previous studies with which to compare our estimated divergence dates (Gamble et al, 2010;Sanders et al, 2008) (Supplementary Appendix S1) using Bayesian inference implemented in BEAST v1.6.1 (Drummond and Rambaut, 2010). All non-Gehyra sequences were obtained from Genbank.…”

“…Output was evaluated using TRACER v1.4.1 (Drummond and Rambaut, 2010) to confirm acceptable mixing, stationarity of the MCMC parameter sampling and adequate effective sample sizes (4500). Due to the lack of Gekkotan fossils, which can be placed with enough phylogenetic precision to act as molecular clock calibrations (Sanders et al, 2008;Oliver and Sanders, 2009;Gamble et al, 2010), a number of robust external fossil calibrations were used. Our chosen calibrations are similar to those of Sanders et al (2008) and are summarized in Table 2.…”

Out of Asia: Natricine snakes support the Cenozoic Beringian Dispersal Hypothesis

“…Therefore, the natricine dispersal into the NW provides yet another line of evidence of support for the Cenozoic Beringian Dispersal Hypothesis, and rejects the Thulean and de Geer Land Bridges as potential routes of colonization. Although the distances between the Western Palearctic and Nearctic were massive in the Miocene for dispersal across the Atlantic Ocean, such routes have been demonstrated for some lizard groups (Carranza et al, 2000;Carranza and Arnold, 2003;Vidal et al, 2008;Gamble et al, 2011). While we have no evidence for long-distance oceanic dispersal in natricines (or other colubrids), Thamnophis validus has dispersed across the Sea of Cortez and Nerodia clarkii across the Florida Straits from Florida to Cuba (de Queiroz and Lawson, 2008).…”

Jurassic primates, immobile ducks and other oddities: a reply to Heads’ review of The Monkey’s Voyage

“…(6) Plausible explanations for the distributions of widespread groups that show multiple disjunctions often involve a combination of vicariance and LDD (e.g. Gamble et al 2011;Krosch et al 2011;Simonsen et al 2011;Springer et al 2012;Thomas et al 2014;Pyron 2014;Thornhill et al 2015). In fact, such results are so common that the default expectation for disjunctions in such taxa might be that they are not fully explained by either pure vicariance or pure LDD scenarios.…”