Especially since the publication of Darwin’s seminal “On the Origin of Species,” animal speciation enjoys a great deal of scientific attention and clever inquiry. Despite this, our understanding of fringe cases can still feel lacking, and is commonly said: ‘in biology, exceptions define the rules.’ In this way, I am quite interested in the process of speciation in the whiptail lizard Aspidoscelis septemvittata. This lizard, along with A. marmorata, are hypothesized to have hybridized to form A. tesselata, a hybrid all-female (parthenogenetic) lineage. In order to accurately understand the parthenogenetic A. tesselata, it is therefore crucial to understand how species resolve in the two ancestral lineages.
Though the phylogenetics of the A. marmorata parent species group (A. tigris) have largely been settled, much work remains for accurate phylogenetic placement of the A. septemvittata group. In all, seven named subspecies (including A. septemvittata) have been attributed to A. gularis, a wide ranging spotted whiptail: A. g. colossus, A. g. gularis, A. g. pallida, A. g. semiannulata, A. g. semifasciata, A. g. septemvittata, and A. g. scalaris. Using animals captured by myself and Jessica, two collaborating labs in Mexico, and several natural history collections, I plan to use nuclear genomic subsampling and species tree inference to delimit species clades in this complicated system.
This work was recently funded by a National Science Foundation Doctoral Dissertation Improvement Grant!
Female and male Aspidoscelis g. gularis. This species complex requires a cohesive phylogenetic description of species. Lake Georgetown, TX – Summer 2012