University of Calgary

Jessica Madeleine Theodor

  • Professor
  • Ecology & Evolutionary Biology

Research Interests

My research focuses on understanding the causes of organismal diversity patterns found over geologic time. Extrinsic factors such as climate change play an important role in regulating biodiversity, but the responses of different groups may be mediated by intrinsic factors, such as morphological innovations or constraints, that they inherit through their phylogenetic history. The fossil record provides the only long-term data we have on how organisms have responded to environmental changes, and how those reactions vary from group to group. As such, it is an important tool in understanding and predicting how organisms might respond in similar situations today.
Ungulates (hoofed mammals) are an ideal group to use in studies of diversity patterns for two fundamental reasons: many ungulate groups have living representatives, and ungulates have an exceptionally rich Cenozoic fossil record. We can use information from the living animals, such as molecular, physiological, and developmental data, to interpret extinct relatives. Fossil ungulates are morphologically diverse, occupy a wide variety of niches, and show a wide range of body sizes, all factors which play important roles in diversification.
My research into ungulate diversity patterns has taken two distinct approaches to these factors, one focusing on morphological evolution and patterns of diversification in a single lineage (Cetartiodactyla), and the other on extrinsic causes of changes in diversity in feeding guilds of ungulates during the Miocene.


2021 University of Calgary Teaching Award

Selected Publications

  • Google Scholar Link
  • B Bai, YQ Wang, JM Theodor, J Meng (2023). Small artiodactyls with tapir-like teeth from the middle Eocene of the Erlian Basin, Inner Mongolia, China. Frontiers in Earth Science 11: 1117911, 
  • MC Mihlbachler, CI Barrón-Ortiz, BD Rankin, JM Theodor (2023). Sharpening the mesowear tool: geometric morphometric analysis of cusp shape and diet in ruminants. Frontiers in Ecology and Evolution 11: 950463, 
  • JMG Perry, AR Dutchak, JM Theodor (2023). New primates from the Eocene of Saskatchewan, Canada: Revision of the primates from the Cypress Hills Formation with description of new taxa. Palaeontologia Electronica 26(2): 1-19, 
  • Robson, SV, JA Ludtke, J Theodor (2022). The petrosal and basicranial morphology of Leptoreodon major (Protoceratidae, Artiodactyla). Vertebrate Anatomy Morphology Palaeontology. 9(1): 116-130, 
  • Robson, SV, JM Theodor (2022). A reassessment of protoceratid vertebrarterial canal morphology. Journal of Vertebrate Paleontology, 42:2, 
  • Robson, SV, B Seale, JM Theodor (2021). The petrosal and basicranial morphology of Protoceras celer. PloS One. 16(7): e0251832, 
  • Prothero, DR, D Domning, RE Fordyce, S Foss, C Janis, S Lucas, KL Marriott, G Métais, D Naish, K Padian, G Rössner, N Solounias, M Spaulding, RM Stucky, J Theodor, M Uhen (2021). On the unnecessary and misleading taxon “Cetartiodactyla”. Journal of Mammalian Evolution. 29(1): 93-97, 
  • Maucieri, DG, AJ Ashbaugh, JM Theodor (2021). Sexual dimorphism in bat wing morphology — variation among foraging styles. Canadian Journal of Zoology. 99(11): 953-960, 
  • Malik, Z., D. M. Roth, F. Eaton, J. M. Theodor, D. Graf. (2020). Mesenchymal Bmp7 controls onset of tooth mineralization: a novel way to regulate molar cusp shape. Frontiers in Physiology, 11:698.
  • Cammidge, T. S., B. Kooyman, J. M. Theodor. (2020). Diet reconstructions for end-Pleistocene Mammut americanum and Mammuthus based on comparative analysis of mesowear, microwear, and dental calculus in modern Loxodonta africana. Palaeogeography, Palaeoclimatology, Palaeoecology. 538:109403. https://doi-org/10.1016/j.palaeo.2019.109403
  • Bravo-Cuevas, V. M., E. Ortiz-Caballero, E. Jiménez-Hidalgo, C. I. Barrón-Ortiz, J. M. Theodor. (2020). Taxonomy and dietary behavior of Mammuthus columbi (Proboscidea: Elephantidae) from central and southern Mexico. Boletín de La Sociedad Geológica Mexicana. 72(1): Epub 22-Dic-2020. https://doi. org/10.18268/bsgm2020v72n1a141019 


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