To discover interordinal relationships of living and fossil placental mammals and the time of origin of placentals relative to the Cretaceous-Paleogene (K-Pg) boundary, we scored 4541 phenomic characters de novo for 86 fossil and living species. Combining these data with molecular sequences, we obtained a phylogenetic tree that, when calibrated with fossils, shows that crown clade Placentalia and placental orders originated after the K-Pg boundary. Many nodes discovered using molecular data are upheld, but phenomic signals overturn molecular signals to show Sundatheria (Dermoptera + Scandentia) as the sister taxon of Primates, a close link between Proboscidea (elephants) and Sirenia (sea cows), and the monophyly of echolocating Chiroptera (bats). Our tree suggests that Placentalia first split into Xenarthra and Epitheria; extinct New World species are the oldest members of Afrotheria.

Tree-building with diverse data maximizes explanatory power. Application of molecular clock models to ancient speciation events risks a bias against detection of fast radiations subsequent to the Cretaceous-Paleogene (K-Pg) event. Contrary to Springer et al., post–K-Pg placental diversification does not require “virus-like” substitution rates. Even constraining clade ages to their model, the explosive model best explains placental evolution.

Design by Melisa Beveridge.♾ This paper meets the requirements of ansi/niso z39.48-1992 (permanence of paper).The American Museum of Natural History (AMNH) is one of the world's preeminent scientific, educational, and cultural institutions. Since the museum was founded in 1869, its collections have grown to include approximately 34 million specimens and artifacts. With 45 permanent exhibition halls, including the Rose Center for Earth and Space, the Hayden Planetarium, and the Bernard Family Hall of North American Mammals, there is plenty to experience. The AMNH is the only Ph.D.-granting museum in the Western Hemisphere, conferring a doctorate in Comparative Biology. AMNH image no. 100213470-1 (Sagra, 1839-1857. ABOUT THIS BOOKSince the mid-19th century, the American Museum of Natural History (AMNH) has had an integral and historically important connection with Cuba. This relationship is represented by numerous expeditions and research projects by AMNH scientists in collaboration with Cuban scientists from the Museo Nacional de Historia Natural, La Habana, Cuba (MNHNCu), and other Cuban institutions. Specimens received from Cuba starting in 1857 were among the collections that even preceded the formal establishment of the AMNH in 1869. The first AMNH expedition to Cuba was launched in 1892, followed by many decades of expeditions, collaborative research and education projects, and scholarly exchanges. Cuba, an archipelago of more than 4,000 islands that includes the largest island in the Caribbean, still harbors a remarkable range of both terrestrial and marine habitats and is perhaps the region's most important center of biodiversity. Many of its species are endemic to the Cuban islands, and many more await discovery. The long-standing collaboration between the AMNH and science in Cuba is the foundation for the current effort to better understand the biodiversity and natural history of Cuba, as represented by various recent joint expeditions. A historic 2016 agreement between the AMNH and MNHNCu offers the opportunity for many years of further collaboration in the interest of science and education. SOBRE EL LIBRODesde mediados del siglo XIX, el American Museum of Natural History (AMNH) ha tenido una conexión histórica importante e integral con Cuba. Este vínculo se ha expresado en numerosas expediciones y proyectos de investigación con científicos cubanos del Museo Nacional de Historia Natural, La Habana, Cuba, (MNHNCu), y otras instituciones cubanas. Los primeros especímenes procedentes de Cuba datan de 1857 y se encuentran entre los que precedieron el establecimiento formal del AMNH en 1869. La primera expedición a Cuba se realizó en 1892, seguida por varias décadas de expediciones posteriores, investigaciones conjuntas, proyectos educacionales e intercambios académicos. Cuba, un archipiélago de más de 4,000 islas que incluye la isla más grande del Caribe, atesora una gran gama de hábitats marinos y terrestres, y quizás es el más importante centro de biodiversidad de la región. Muchas de las especies en Cuba...

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