Phylogenetic relationships and historical biogeography of Otus species based on mitochondrial cytochrome b gene sequence
This study analyzed mitochondrial cytochrome b gene sequences to infer Otus species' phylogenetic relationships and historical biogeography. The researchers used Maximum Parsimony and Maximum Likelihood methods to generate the phylogenetic trees. They constructed a Bayesian MCC Chronogram Tree to determine the Otus species' age and speciation events. Paleoclimate and paleogeology maps were also used to correlate the branching out of Otus species with geological time periods and climatic conditions. The results showed five major clusters or clades for the core taxon group (Otus) and one for the sister group (Tyto). The Bayesian tree showed seven major clades for Otus, with the first speciation occurrence dating back to 21.54 mya during the Early Miocene epoch. Most of the core taxon species speciated during the Pliocene Period, with some exceptions. The paleoclimate data indicated that Otus clades branched out during the Icehouse climate state, with the first branching out occurring during the Coolhouse climatic state. The paleogeologic data revealed that the African and American (North and South) continents were already distinct and divided by the Atlantic Ocean during the first branching out of the Otus clade. The distribution areas of Otus species were also mapped using updated Wallace's zoogeographic realms. Overall, this study provides a better understanding of the phylogenetic history of Otus species and their diversification in relation to geological and climatic events. However, the authors caution that all phylogenetic trees, evolutionary studies, and divergence time estimates should be considered hypotheses with significant uncertainty.