What were early mammaliaforms like and what were their roles in ancient ecosystems? How did they differ from today's mammals? The morphology of fossils and their geological context hold clues to function, ecology, and paleobiology of extinct organisms. 

Ecomorphology

  • ​We use various methods to quantify morphology: 2D and 3D imaging, linear and geometric morphometrics, dental topographic analysis, microwear, and osteohistology.​
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  • We infer functional or ecological traits in extinct mammaliaforms by using correlations of morphology and function or ecology (e.g., body size, diet, locomotion) that we establish in small-bodied extant mammals.
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  • We use these inferred traits to track ecomorphological patterns of diversity in paleocommunities and clades through deep time.​

Functional analysis
  • Biomechanical analyses help constrain functional inferences in extinct mammaliaforms.​

  • We use morphology to quantify biomechanical properties of teeth, bones, and muscles.
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  • For example, we estimate bite force by measuring the length of lever arms and estimating physiological cross-sectional areas of adductor muscles. We also constrain prey type and size by estimating the capacity of the jaw or the teeth to withstand orthal and torsional forces from prey.

Geological context

  • Clues to the paleohabitat, behavior, and ecology of extinct mammaliaforms can be inferred from geological context of fossils. 
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  • Sedimentology and taphonomy, for example, provide clues about how fossils were deposited, the paleohabitat of the extinct animals, and how the animals lived and died.
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  • For example, collaborative research with Dave Varricchio, Luke Weaver, Alexandria Brannick, and Willie Freimuth on exceptionally preserved specimens from the Egg Mountain locality have led to novel insights into the paleobiology of early mammals.
Funding: NSF EAR-SGP 1325674 "Taphonomy, paleoecology, and evolution of mammals and squamates from Egg Mountain: An exceptional view of a Late Cretaceous ecosystem," UW Royalty Research Fund, NSF Postdoctoral Research Fellowship (D. Grossnickle).

Relavant Publications

  • ​​​Evans, A., G.P. Wilson, M. Fortelius, and J. Jernvall. 2007. High-level similarity in dentitions of carnivorans and rodents. Nature 445:78–81.
  • 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.
  • Wilson G.P., A.R. Evans, I. J. Corfe, P. D. Smits, M. Fortelius and J. Jernvall. 2012. Adaptive radiation of multituberculate mammals before the extinction of dinosaurs. Nature 483:457–460.
  • Chen, M. and G.P. Wilson. 2015. A multivariate approach to infer locomotor modes in Mesozoic mammals. Paleobiology 41(2):280–312.
  • Wilson, G.P., E.G. Ekdale, J.W. Hoganson, J.J. Calede, and A. Vander Linden. 2016. A large carnivorous mammal from the Late Cretaceous and the North American origin of marsupials. Nature Communications 7(1):13734. doi:10.1038/ncomms13734.
  • Brannick, A.L. and G.P. Wilson. 2018. New specimens of the Late Cretaceous metatherian Eodelphis and the evolution of hard-object feeding in the Stagodontidae. Journal of Mammalian Evolution 27(1):1–16. doi:10.1007/s10914-018-9451-z.
  • Chen, M., C.A.E. 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 Sciences, U.S.A. 116:9931–9940 ​
  • 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.
  • 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.
  • Freimuth, W.J., D.J. Varricchio, A.L. Brannick, L.N. Weaver, G.P. Wilson Mantilla. 2021. Mammal-bearing gastric pellets potentially attributable to Troodon formosus at the Cretaceous Egg Mountain locality, Two Medicine Formation, Montana, U.S.A. Palaeontology 64(5):699–725. https://doi.org/10.1111/pala.12546.
  • Weaver, L.N., H.Z. Fulghum, D.M. Grossnickle, W.H. Brightly, Z.T. Kulik, G.P. Wilson Mantilla, and M.R. Whitney. Multituberculate mammals show evidence of a life history strategy similar to that of placentals, not marsupials. The American Naturalist 200(3):383–400.
  • Brannick, A.L., H.Z. Fulghum, D.M. Grossnickle, and G.P. Wilson Mantilla. Dental ecomorphology and macroevolutionary patterns of North American Late Cretaceous metatherians. Palaeontologia Electronica 26(3):a48. doi:10.26879/1177​
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