Mammals today exhibit a striking diversity, from the tiny, flying bumblebee bat to the titanic, fully aquatic blue whale. Some of this diversity and diversity in extinct mammaliaform clades accumulated in geologically short bursts via adaptive radiation. Our research aims to detail the patterns and driving forces behind these critical deep-time evolutionary processes.

Paleocene Rise of Placentals

  • The textbook scenario suggests placental mammals underwent a Paleocene adaptive radiation following the extinction of non-avian dinosaurs, rapidly diversifying into a wide array of ecological niches.
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  • Patterns of increasing diversity have been well-documented but mostly on broad spatiotemporal scales (continental/global & 1- to 2-Ma intervals) and using indirect measures of ecomorphological diversity.
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  • By inferring diet, body size, and locomotion in these taxa, we can correlate ecospace expansion with changes in vegetation and climate to test hypothesized drivers of diversification.
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Upper-molar morphospace occupancy and relative shape changes of latest Cretaceous HCb (bottom panel) and earliest Paleocene TUa (top panel) therians from PCA of geometric morphometric data. See Wilson 2013 for more infromation

Mesozoic Radiations of Mammaliaforms   

  • A flood of discoveries of skulls and skeletons that began in the 1990s has revealed an unexpected ecomorphological diversity of Mesozoic mammaliaforms.

  • We have conducted large-scale ecomorphological analyses that have shown some mammaliaform clades (multituberculates, eutriconodonts) ecologically diversified before non-avian dinosaurs went extinct.
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  • By mapping ecospace occupation of Jurassic, Cretaceous, Eocene, and modern mammaliaform communities, we have shown that assembly of modern mammal community structure arose between the Late Cretaceous and Eocene, likely driven by the rise of angiosperms, tribosphenic molar evolution, and extinction of non-avian dinosaurs.
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  • Detailed study of new and existing collections from the Campanian Judith River Fm of central Montana aims to track ecomorphological diversity of Late Cretaceous mammaliaform communities.
Funding: ​Myhrvold and Havranek Charitable Family Fund, UW Royalty Research Fund, NSF EAR-SGP 2321341 “Assembling the foundation of modern mammal community structure in the first 7 million years after the K/Pg mass extinction" PIs: G.P. Wilson Mantilla, Courtney Sprain, T. Tobin, P. Renne.

Relavant Publications

  • Clemens, W.A. and G.P. Wilson. 2009. Early Torrejonian mammalian local faunas from northeastern Montana, U.S.A. Papers on Geology, Vertebrate Paleontology and Biostratigraphy in Honor of Michael O. Woodburne. Albright, L.B. III (ed). Museum of Northern Arizona Bulletin 65:111–158.
  • Wilson, G.P. 2013. Mammals across the K/Pg boundary in northeastern Montana, U.S.A.: dental morphology and body-size patterns reveal extinction selectivity and immigrant-fueled ecospace filling. Paleobiology 39(3):429–469. ​
  • Williamson, T.E., S.L. Brusatte, and G.P. Wilson. 2014. The origin and early evolution of metatherian mammals: The Cretaceous record. ZooKeys. 465:1–76.​
  • Chen, M. and G.P. Wilson. 2015. A multivariate approach to infer locomotor modes in Mesozoic mammals. Paleobiology 41(2):280–312.
  • ​Chen, M.*, Z.-X. Luo, and G.P. Wilson. 2017. The postcranial skeleton of Yanoconodon allini from the Early Cretaceous of Hebei, China and its implications for locomotor adaptation in eutriconodontan mammals. Journal of Vertebrate Paleontology 37(3):e1315425.
  • ​Grossnickle D.M., S.M. Smith, and G.P. Wilson. 2019. Untangling the multiple ecological radiations of early mammals. Trends in Ecology & Evolution. 34 (10):936–949.
  • ​​Chen, M., CAE Strömberg, and G.P. Wilson. 2019. Assembly of modern mammal community structure driven by Late Cretaceous dental evolution, rise of flowering plants, and dinosaur demise. Proceedings of the National Academy of Science 116(20):9931–9940.
  • Wilson Mantilla, G.P., S.G.B. Chester, W.A. Clemens, J.R. Moore, C.J. Sprain, B.T. Hovatter, W.S. Mitchell, W.W. Mans, R. Mundil, and P.R. Renne. 2021. Earliest Palaeocene purgatoriids and the initial radiation of stem primates. Royal Society Open Science 8:210050. doi:10.1098/rsos.210050 ​
  • Weaver, L.N., D.J. Varricchio, E.J. Sargis, M. Chen, W.J. Freimuth, and G.P. Wilson Mantilla. 2021. Early mammalian social behaviour revealed by Late Cretaceous multituberculates from a dinosaur nesting site. Nature Ecology & Evolution 5(1):32–37. doi:10.1038/s41559-020-01325-8
  • Weaver, L.N. and G.P. Wilson. 2021. Patterns of shape disparity in the blade-like p4s of multituberculate mammals reveal functional constraints that influenced the evolution of herbivory. Journal of Mammalogy 102(4):967–985. doi:10.1093/jmammal/gyaa029
  • Brannick, A.L., H.Z. Fulghum, D.M. Grossnickle, and G.P. Wilson Mantilla. 2023. Dental ecomorphology and macroevolutionary patterns of North American Late Cretaceous metatherians. Palaeontologia Electronica 26(3):a48. doi:10.26879/1177
  • Hovatter, B.T., S.G.B. Chester, and G.P. Wilson Mantilla. 2024. New records of early Paleocene (earliest Torrejonian) plesiadapiforms from northeastern Montana, U.S.A., provide window into the diversification of stem primates. Journal of Human Evolution 192:103500.  
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