Research

The Messel Pit

The Messel Pit is a UNESCO World Heritage site preserving fossils of breathtaking quality. Its age, about 48 Ma, places it in the Eocene Climatic Optimum, the warmest sustained interval of the last 66 Ma. The Eocene was the last major “greenhouse” phase of Earth’s climate. Messel gives us remarkable insight into a terrestrial ecosystem at this time, and may hold clues to our future. My work at Messel encompasses the taxonomy of the lizards and snakes, taphonomy, and synthetic analyses of community structure, such as species diversity.

Selected publications

Smith, K.T., M. Collinson, A. Folie, J. Habersetzer, F. Hennicke, E. Kothe, T. Lehmann, O. Lenz, G. Mayr, N. Micklich, R. Rabenstein, R. Racicot, S.F.K. Schaal, T. Smith, A. Tosal, D. Uhl, T. Wappler, S. Wedmann & M. Wuttke (2024) The biodiversity of the Eocene Messel Pit. Palaeobiodiversity and Palaeoenvironments 104: 859–940. PDF

Smith, K.T., R. Rabenstein & J. O'Keefe (2024) Was Palaeolake Messel a death-trap? Insight from modern bat drownings and decay experiments. Palaeobiodiversity and Palaeoenvironments 104: 977–997. PDF

Chuliver, M., A. Scanferla & K.T. Smith (2022) Live birth in a 47-million-year-old snake. The Science of Nature 109: 56. PDF

Smith, K.T., S.F.K. Schaal & J. Habersetzer, eds. (2018) Messel: An Ancient Greenhouse Ecosystem. Schweizerbart, Stuttgart. Book

Biogeography, climate, and Paleogene squamates

The Eocene is bounded by dramatic intervals of climate change. It begins with the short-lived Paleocene–Eocene Thermal Maximum, when temperatures rose rapidly, especially at high latitude. At its close, temperature plummeted, inaugurating the “icehouse” climate of today. As poikilotherms, squamate reptiles are particularly sensitive to climate change. I am developing a data-set on squamate assemblages that bracket these episodes of rapid climate change. On the one hand, these data help us understand how species responded to climate change and how it influenced modern patterns of biodiversity. On the other hand, these assemblages allow us to reconstruct ancient climates. This specimen-based work relies on detailed morphological studies and quantitative models.

Selected publications

Smith, K.T. & A.A. Bruch (2025) Persistent greenhouse conditions in Eocene North America point to lower climate sensitivity. Communications Earth and Environment 6: 352. PDF

Pritchard, A.C., J.M. McCartney, G.L. Georgalis & K.T. Smith (2025) A terrestrial snake from the early Eocene of the mid-Atlantic region (Nanjemoy Formation, Virginia) of North America. Acta Palaeontologia Polonica 70(4): 817–826. PDF

Hunt, A.P., S.G. Lucas & K.T. Smith (2026) A new regurgitalite from the early Eocene of Wyoming, USA. Fossil Studies 4: 12. PDF

Smith, K.T. & J.A. Gauthier (2013) Early Eocene lizards of the Wasatch Formation near Bitter Creek, Wyoming: diversity and paleoenvironment during an interval of global warming. Bulletin of the Peabody Museum of Natural History 54: 135–230. PDF

Smith, K.T. (2013) New constraints on the evolution of the snake clades Ungaliophiinae, Loxocemidae and Colubridae (Serpentes). Zoologischer Anzeiger 252: 157–182. PDF

Smith, K.T. (2011) The evolution of mid-latitude faunas during the Eocene: Late Eocene lizards of the Medicine Pole Hills reconsidered. Bulletin of the Peabody Museum of Natural History 52: 3–105. PDF

Smith, K.T. (2009) A new lizard assemblage from the earliest Eocene (zone Wa0) of the Bighorn Basin, Wyoming. Journal of Systematic Palaeontology 7: 299–358. PDF

Neotropical Paleogene vertebrates

Most of what we know about terrestrial life in the Paleogene in the northern hemisphere comes from the middle latitudes. Particularly in North America, these latitudes not only contain huge deposits of fossil-bearing sedimentary rock but they are also arid, affording a lot of exposure. However, the tropical latitudes host the greatest biodiversity today. Therefore, our understanding of Cenozoic ecosystems will remain highly incomplete without tropical assemblages. My colleagues Eduardo Jiménez-Hidalgo and Rosalía Guerrero-Arenas from Universidad del Mar and I have been exploring southern Mexico in search of vertebrate fossils and have discovered the first Paleogene localities in the tropics of North America. Our work was supported, in part, by the National Geographic Society and CONACYT. These fossils from “World’s End” provide the first view of ecosystems contemporaneous with well-known localities in mid-latitude North America.

Selected publications

Jiménez-Hidalgo, E., R. Guerrero-Arenas & K.T. Smith (2018) Gregorymys veloxikua, the oldest pocket gopher (Rodentia: Geomyidae). Journal of Mammalian Evolution 25: 427–439. PDF

Jiménez-Hidalgo, E., K.T. Smith, R. Guerrero-Arenas & J. Alvarado-Ortega (2015) The first late Eocene continental faunal assemblage from tropical North America. Journal of South American Earth Sciences 57: 39–48. PDF

Zooarcheology in the Near East

The human lineage arose in Africa, but hominin species migrated several times out of Africa, ultimately colonizing all major land masses except Antarctica. The Levant forms the nexus between Africa and Eurasia and thus an important bridge in the early expansions of human species. The Levant is also rich in fossil sites containing prehistoric hominins. Such sites, frequently but not exclusively found in caves, often yield concentrations of microvertebrate bone collected by other predators that lived there at about the same time. Mixed in with human artefacts, the microvertebrate species provide important clues to the environment in which ancient hominins lived as well as clues to human behavior and ecology. Together with my colleague Lutz Maul, I work on microvertebrates from sites such as Qesem Cave in Israel (excavation run by Avi Gopher and Ran Barkai from Tel Aviv University), using taxonomic and quantitative ecological methods.

Selected publications

Zanolli, C., D. Alba, T. Caley, M. Cazenave, I. Crevecoeur, I. de la Torre, A. Delagnes, L. Delezene, F. Détroit, R. Joannes-Boyau, A. Le Cabec, T. Lüdecke, A. Margvelashvili, C. Musiba, S. Neubauer, Y. Sahle, F. Schrenk, M. M. Skinner, K.T. Smith, A. Urciuoli, B. Villmoare, B. Wood & O. Kullmer. (2026) The early Homo conundrum: challenges and potential solutions. Evolutionary Anthropology 35(3): e70043. PDF

Smith, K.T., O. Comay, L. Maul, F. Wegmüller, J.M. Le Tensorer & T. Dayan (2021) A model of digestive tooth corrosion in lizards. Scientific Reports 11: 12877. PDF

Smith, K.T., L.C. Maul, F. Flemming, R. Barkai & A. Gopher (2016) The microvertebrates of Qesem Cave: A comparison of the two concentrations. Quaternary International 398: 233–245. PDF

Maul, L.C., A.A. Bruch, K.T. Smith, G. Shenbrot, R. Barkai & A. Gopher (2016) Palaeoecological and biostratigraphical implications of the microvertebrates of Qesem Cave. Quaternary International 398: 219–232. PDF

Maul, L.C., K.T. Smith, G. Shenbrot, A. Bruch, F. Wegmüller & J.-M. le Tensorer (2015) Microvertebrates from unit G/layer 17 of Hummal (El Kowm, Central Syria). L’Anthropologie 119: 676–686. PDF

Smith, K.T., L.C. Maul, R. Barkai & A. Gopher (2013) To catch a chameleon, or actualism vs. natural history in the taphonomy of the microvertebrate fraction at Qesem Cave, Israel. Journal of Archaeological Science 40: 3326–3339. PDF