Meeting Abstract
The lungless salamander tribe Spelerpini (Caudata:Plethodontidae) presents an opportunity to study the evolution of aquatic species that arose from terrestrial lineages in a phylogenetic context. Two of five genera (Eurycea and Gyrinophilus) include both aquatic and terrestrial species, the remainder are terrestrial. Additionally, five of the 16 aquatic Eurycea have troglodytic morphology characterized by reduced eyes and elongate skulls relative to surface-dwelling paeodomorphs. Here, we examine if the morphological changes associated with habitat shifts are convergent. We expect species to show convergence due to shared demands, informed by our understanding of hydrodynamics. Relative to terrestrial species, aquatics must deal with different fluid dynamics during locomotion and feeding as well as support gill arches. However, convergence may be in functional ability and not towards a single morphology, as in herbivorous lizards. To explore if salamanders follow the same pattern, we examined species of the tribe Spelerpini, capturing terrestrial and both aquatic morphologies. We gathered 3D microCT scan data from online repositories and by scanning specimens from the Field Museum of Natural History and the Illinois Natural History Survey. A geometric morphometric analysis of the overall head shape of adults from all three habitats captures gross morphological disparity We create a phylomorphospace to show differences between aquatic and terrestrial species and how phylogeny influences the evolution of aquatic groups. These results allow us to test whether aquatic taxa group are closer together in morphospace than their terrestrial sister groups or show parallel trajectories similar to what’s been found in herbivorous lizards.
