Meeting Abstract
Cave-obligate organisms long have captured the imagination and interest of scientists and the general public, yet their evolutionary histories and modes of subterranean adaptation remain poorly understood. The endemic North American fishes in the family Amblyopsidae are one of very few families across the ray-finned fish Tree of Life to contain both surface- and obligate cave-dwelling members; thus, this group is ideal for comparative studies of cave adaptation. Morphological and molecular datasets have presented conflicting evolutionary relationships within the Amblyopsidae, particularly with respect to the placement of eyed species in relation to the blind, cave-obligate taxa. To further elucidate phylogenetic relationships within the Amblyopsidae, we collected genomic data from over 800 ultraconserved element (UCE) loci from 119 samples representing all described taxa as well as additional undescribed lineages. All three states of cave adaptation (surface, facultative-cave, and obligate-cave forms) were sampled. In addition to phylogenomic analysis, we performed an ancestral state reconstruction. Lastly, we assessed how shape variation fit into the larger picture of cave adaptation using geometric morphometrics to quantify body shape differences among amblyopsid species. We recovered each of the eyed fishes as sister to an eyeless cavefish and our ancestral state reconstruction supported an eyeless, cave ancestor at the base of the family, indicating possible independent eye redevelopment in both of the eyed fishes. It also appears that cave adaptation or eye redevelopment leads to changes in body shape. However, we remain healthily skeptical of these results and will perform further analyses. This work will provide insight into the patterns and modes of cave adaptation.
