2001/12/14 by William J. Murphy, Eduardo Eizirik, Stephen J. O’Brien +8 · 21 citations
Earth and Planetary Sciences · Environmental Science · Biochemistry, Genetics and Molecular Biology · #Evolution and Paleontology Studies #Wildlife Ecology and Conservation #Genetic diversity and population structure
paper · doi:10.1126/science.1067179
openalex publication_date 2001/12/14 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/01
Molecular phylogenetic studies have resolved placental mammals into four major groups, but have not established the full hierarchy of interordinal relationships, including the position of the root. The latter is critical for understanding the early biogeographic history of placentals. We investigated placental phylogeny using Bayesian and maximum-likelihood methods and a 16.4-kilobase molecular data set. Interordinal relationships are almost entirely resolved. The basal split is between Afrotheria and other placentals, at about 103 million years, and may be accounted for by the separation of South America and Africa in the Cretaceous. Crown-group Eutheria may have their most recent common ancestry in the Southern Hemisphere (Gondwana).