New insights on the phylogeny and genetic status of a highly vagile seabird from East Antarctica

Wilson's storm-petrel (Oceanites oceanicus, family Oceanitidae, order Procellariiformes) breeds in rock cavities along the ice-free coastline of Antarctica, a habitat susceptible to environmental change and human disturbance. Despite extensive presence, high numbers and wide-ranging movement, there are taxonomic ambiguities surrounding species' phylogenetic positioning and data gaps for most parts of its range. In this study, we provide support to the phylogenetic status of family Oceanitidae through new genetic datasets and modern analytical approaches. We generated mitochondrial cytochrome b gene sequences from samples collected from east Antarctica's ice-free regions. Reconstructed trees obtained using Bayesian and maximum likelihood models show Oceanitidae as a monophyletic group where Hydrobatidae (northern storm-petrels) appeared as a basal group to the order Procellariiformes. Phylogeographic network analysis resulted in seven distinct haplotypes with strong genetic differentiation (F_ST > 0.99) between east Antarctic and sub-Antarctic populations. Our study provides one of the first genetic datasets on Wilson's storm-petrel populations in east Antarctica. It serves as a baseline to undertake rigorous investigations into species' population structure, genetic connectivity and demographic responses to human-mediated changes in the austral environment.