Primate origins, evolution, and supraordinal relationships
We study the oldest known fossil primates and their closest non-primate relatives to understand the initial divergence of primates from other mammals. Plesiadapiforms are a diverse group of mammals from the Paleocene and Eocene of North America, Europe, and Asia, and may represent the first adaptive radiation of primates. We are analyzing some of the oldest and most primitive plesiadapiform fossils in the world to unravel their evolutionary relationships and paleobiology (see Chester et al. 2015 PNAS and Chester et al. 2017 RSOS). We are also preparing fossiliferous limestone nodules in the lab to yield additional skeletons of Paleocene and Eocene plesiadapiforms and euprimates.
Cretaceous-Paleogene Mass Extinction and Recovery
Sixty-six million years ago, the K-Pg mass extinction affected biota all over the globe. Although this event is known mostly for the disappearance of the non-avian dinosaurs, it is also one of the most significant events in mammalian evolutionary history. Following this mass extinction, mammalian faunal composition changed dramatically, and mammals underwent an adaptive radiation in the early Paleocene. We study mammalian recovery following the K-Pg boundary (see Lyson et al. 2019 Science and Bertrand et al. 2022 Science), which includes the oldest dated occurrence of archaic primates in the fossil record (see Wilson Mantilla et al. 2021 RSOS).
“The Tree of Life: An Unprecedented Window into Mammalian Paleoecology after the End-Cretaceous Mass Extinction.”
National Geographic Society Grant NGS-93605R-22 with PI Tyler R. Lyson.
Mammalian Response to Climate Change
The Paleocene-Eocene Thermal Maximum (PETM) is a global warming event that occurred 56 million years ago and marks the appearance of several modern groups of mammals, including lemur-like and tarsier-like euprimates (see Morse et al. 2019 Journal of Human Evolution and video below). The fossil record provides evidence that global warming impacted the evolution of many mammals during the PETM, such as the dramatic decrease in body size documented in the earliest horses (see Secord et al. 2012 Science). We are currently studying whether primates and other mammals responded similarly to climate change during the onset of the Early Eocene Climatic Optimum (EECO) ~53 million years ago, which is the warmest sustained interval of the Cenozoic Era.