DISSERTATION RESEARCH: Lizards of the Family Teiidae: phylogeny, historical biogeography, and continental-scale species delimitation

Brigham Young University, Provo UT

Investigators

Abstract

The Amazon racerunner (Ameiva ameiva) is distributed across four very different South American biomes that cover an area larger than the continental US. This project will perform the first distribution-wide, phylogeographic study of this lizard species, providing opportunities to find cryptic diversity in the group (i.e., new species) as well as a unique opportunity to evaluate competing hypotheses of diversification in both rainforests and dry habitats. Data collected for the Amazon racerunner will also be used to address future risk to species due to climate change. The work is a collaboration with South American colleagues to study key physiological traits (e.g., temperature preference and performance) to reconstruct species distribution models and assess extinction risk. Because modeling historical distributions is based on paleoclimate data, these same models can be used to predict the effect that increasing temperatures will have on future distributions of organisms. Results from this research will be developed into a teaching module and used to show non-Biology major students real-world observations used in hypothesis testing, here focused on speciation and biogeography. Real examples from the researchers' extensive field and lab work will personalize the data for students and enhance their appreciation of the multi-faceted nature of science, and the nature of its conclusions. Preliminary results suggests that Ameiva ameiva represents a complex of species, which will be tested by sampling as much of the distribution as possible, and generating a combination of Sanger, NextGen, and several classes of morphological data to define species boundaries. Researchers will visit three herpetological collections in Brazil to measure morphological data from museum specimens. In addition to morphological data collection, 100s-1000s of SNPs (ddRADseq) for 200 individuals of A. ameiva will be incorporated into newly developed species delimitation (SDL) methods. A recently developed SDL Bayesian approach that integrates morphological with molecular data (iBPP) was shown to perform well under a variety of scenarios, and this will be the preferred (but not exclusive) method used in this study. Diversification hypotheses for the Amazon and Dry Diagonal of South America will be compared using SNP data with programs that allow the analysis of historical scenarios and a summary approach to estimate the strength of each hypothesis.