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Morphobank Project 773: The Placental Mammal Ancestor and the Post K-Pg Radiation of Placentals.

Sponsored by National Science Foundation : Divisions of Environmental Biology and Earth Sciences Assembling the Tree of Life program

Maureen A. O'Leary: Project Administrator

Duration: 2007-02-02 to 2013-02-06


We scored 4,541 phenomic characters (an order of magnitude more than previous studies) to investigate mammal phylogeny. Numerous fossils are included providing critical data on the evolution of anatomy, behavior and biogeography. Analyzed with molecular sequences and calibrated with fossils, the combined data phylogenetic tree shows placental orders originating after the Cretaceous-Paleogene (KPg) boundary. The phenomic signal dominates the molecular signal to determine the sister taxon of Primates (here Sundatheria [Dermoptera + Scandentia]), a close link between Proboscidea (elephants) and Sirenia (sea cows), and the monophyly of echolocating Chiroptera (bats). Placentalia first split into Xenarthra and Epitheria, and extinct New World species are the oldest members of Afrotheria. We provide the first phylogenetic reconstruction of the extinct ancestor of Placentalia from extensive phylophenomic data. Link to Project Overview: