The family Teiidae is a New World clade of small to large-sized lizards that tend to be active foragers, diurnal, and omnivorous. Whiptails (genus Aspidocelis)in the USA, Racerunners (genus Cnemidophorus) in the Neotropics, the giant Tegus (Tupinmabis and Salvator) in the Neotropics are a few of the major clades. The Ameiva's are primarily Neotropical but also are well represented in the West Indies. In a new paper Tucker et al. (2017) examine the phylogenetic relationships and biogeographic history of Caribbean island ameivas and place them in the genus Pholidoscelis. The authors use phylogenomic and mitochondrial DNA datasets to reconstruct a well-supported phylogeny and assess historical colonization patterns in the group. They obtained sequence data from 316 nuclear loci and one mitochondrial marker for 16 of the 19 extant species of the Caribbean endemic genus Pholidoscelis. To estimate divergence times, they used fossil teiids to calibrate a timetree which was used to elucidate the historical biogeography of these lizards. All phylogenetic analyses recovered four well-supported species groups (clades) recognized previously and supported novel relationships of those groups, including a (P. auberi + P. lineolatus) clade (western + central Caribbean), and a (P. exsul + P. plei) clade (eastern Caribbean). Divergence between Pholidoscelis and its sister clade was estimated to have occurred ~25 Ma, with subsequent diversification on Caribbean islands occurring over the last 11 Myr. Of the six models compared in the biogeographic analyses, the scenario which considered the distance among islands and allowed dispersal in all directions best fit the data. These reconstructions suggest that the ancestor of this group colonized either Hispaniola or Puerto Rico from Middle America. The authors provide a well-supported phylogeny of Pholidoscelis with novel relationships not reported in previous studies that were based on significantly smaller datasets. They propose that Pholidoscelis colonized the eastern Greater Antilles from Middle America based on our biogeographic analysis, phylogeny, and divergence time estimates. The closing of the Central American Seaway and subsequent formation of the modern Atlantic meridional overturning circulation may have promoted dispersal in this group.
Citation
Tucker DB, Hedges SB, Colli GR, Pyron RA, Sites JW. Genomic timetree and historical biogeography of Caribbean island ameiva lizards (Pholidoscelis: Teiidae). Ecology and Evolution. 2017 Aug.