Genomic Approaches to Resolving Phylogenies of Antarctic Notothenioid Fishes

This clade offers an unprecedented opportunity to investigate the effects of deep time paleogeographic transformations and periods of global climate change on lineage diversification and facilitation of adaptive radiation. With over 100 species, the Antarctic notothenioid radiation has been the subject of intensive investigation of biochemical, physiological, and morphological adaptations associated with freezing avoidance in the subzero Southern Ocean marine habitats.

However, broadly sampled time-calibrated phylogenetic hypotheses of notothenioids have not been used to examine patterns of adaptive radiation in this clade. The goals of this project are to develop an intensive phylogenomic scale dataset for 90 of the 124 recognized notothenioid species, and use this genomic resource to generate time-calibrated molecular phylogenetic trees. The results of pilot phylogenetic studies indicate a very exciting correlation of the initial diversification of notothenioids with the fragmentation of East Gondwana approximately 80 million years ago, and the origin of the Antarctic Clade adaptive radiation at a time of global cooling and formation of polar conditions in the Southern Ocean, approximately 35 million years ago.