Abstract
The Cenozoic diversification of placental mammals is the archetypal adaptive radiation. Yet, discrepancies between molecular divergence estimates and the fossil record fuel ongoing debate around the timing, tempo, and drivers of this radiation. Analysis of a three-dimensional skull dataset for living and extinct placental mammals demonstrates that evolutionary rates peak early and attenuate quickly. This long-term decline in tempo is punctuated by bursts of innovation that decreased in amplitude over the past 66 million years. Social, precocial, aquatic, and herbivorous species evolve fastest, especially whales, elephants, sirenians, and extinct ungulates. Slow rates in rodents and bats indicate dissociation of taxonomic and morphological diversification. Frustratingly, highly similar ancestral shape estimates for placental mammal superorders suggest that their earliest representatives may continue to elude unequivocal identification.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 377-383 |
| Number of pages | 7 |
| Journal | Science |
| Volume | 378 |
| Issue number | 6618 |
| DOIs | |
| State | Published - Oct 28 2022 |
Bibliographical note
Funding Information:We are indebted to the numerous colleagues, curators, and collections staff at international museums that provided access to specimens for this project, in particular R. Portela Miguez, R. Pappa, P. Brewer, R. Sabin, and L. Tomsett (NHM); P.-H. Fabre (Université de Montpellier); J. Galkin, R. O’Leary, and A. Gishlick (AMNH); G. Rößner (BSP); S. and R. Boessenecker (CCNHM); B. Simpson (FMNH); D. Miao (KU); J. Chupasko (MCZ); S. McLeod, X. Wang, and J. Velez-Juarbe (LACM); J. Ashby and P. Viscardi (LDUCZ); M. Reguero (MLP); G. Billet, J. Cuisin, and G. Veron (MNHN); P. Holroyd, M. Goodwin, and J. Tseng (UCMP); B. Sanders (UMMP); A. Millhouse and S. Peurach (USNM); C. Norris and D. Brinkman (YPM); R. Secord and G. Carter (UNSM); and L. Costeur (NMB). We are grateful to V. Fernandez and B. Clark (NHM) and J. Keller (UMN) for support in microCT scanning and to the “plate-forme de morphometrie” of the UMS 2700 (CNRS, MNHN) for access to the surface scanner. We thank E. Watt (NHM/UCL) for uploading scans to online repositories. We are grateful to the two anonymous reviewers and the editor for their thoughtful comments. We thank V. Herridge for putting a name to this phenomenon. European Research Council grant STG-2014-637171 (to A.G.), National Science Foundation SF-EAR 1349607 (to J.H.G., B.L.B., A.G., and M.C.), Gerstner Scholar Postdoctoral Research Fellowship (to A.C. and N.B.S.), Natural Environment Research Council Doctoral Training Partnership training grant NE/L002485/ 1 (to E.J.C.), Horizon 2020 MCSA Fellowship IF 797373-EVOTOOLS (to J.C.), National Science Foundation EAR 1338262 (to D.L.F.), and Labex BCDiv 10-LABX-0003 (to A.C.F.).
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