Phylogenomic Species Delimitation

Species Delimitation research by graduate student Scott Travers and other KU researchers and their collaborators uses cutting edge phylogenomic data and associated analyses to identify species boundaries in several groups of Philippine lizards.

Species delimitation is a central theme of study for many researchers here at the KU Biodiversity Institute. Accurately estimating levels of species diversity is critical for prioritizing conservation efforts and for studying the process of biological diversification at both micro- and macroevolutionary scales. This presents an ongoing challenge for us, as new species discoveries and revisionary studies are continually changing our understanding of species limits in many of the regions where we are currently working. Furthermore, species delimitation studies based on DNA barcoding or few genetic loci can be inaccurate and misleading, potentially obstructing our interpretation of species limits.

Expanding upon several studies from former KU students, we are reanalyzing species limits in two widespread Philippine lizard groups — geckos (Gekko mindorensis) and water monitors (Varanus sp.). Results from our previous studies revealed a rich lineage diversity within the Philippines for each species complex, and surprisingly, that these Philippine lineages were not monophyletic with respect to taxa from other nearby countries (Gekko kikuchii and Varanus salvator ssp.). However, these results were based on relatively few genetic loci, leading to issues of poor topological support, potentially misleading phylogenetic relationships, and questionable species delimitation inferences. Therefore, we are revisiting these studies through the target capture of thousands of ultraconserved genomic elements (UCEs). Using this next-generation sequencing approach, we will evaluate the methodological and computational aspects of species delimitation with a UCE dataset, and how current and historical levels of gene flow may be impacting our inferences in species delimitation studies.