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Dr. Jessica Theodor

PhD
Pronouns: she/her

Positions

Professor

Faculty of Science, Department of Biological Sciences

Director, Biological Sciences Collections

Faculty of Science, Department of Biological Sciences

Contact information

Email

jtheodor@ucalgary.ca

Web presence

Website

Phone number

Office: +1 (403) 210-9819

Location

Office: BI353

Background

Educational Background

Bachelor of Science Palaeontology, University of Toronto, 1989

Doctor of Philosophy Paleontology, University of California, 1996

Research

Areas of Research

understanding the causes of organismal diversity patterns found over geologic time

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.

Courses

Course number Course title Semester
BIOL 371 Comparative Biology of Plants and Animals Fall 2022
ZOOL 403 An Introduction to Vertebrate Zoology Fall 2022
ZOOL 571 Palaeobiology of Vertebrates Winter 2023

Awards

  • Teaching Award, Full-Time Academic Staff (Professor), University of Calgary . 2021
  • Meierjurgen Fellowship for Visiting Scientists, University of Oregon. 2015
  • University Faculty Award, 2006-2011, Natural Sciences and Engineering Research Council of Canada (NSERC). 2011

Publications

  • The earliest artiodactyls: Diacodexeidae, Dichobunidae, Homacodontidae, Leptochoeridae and Raoellidae. J Erfurt; S Foss; D Prothero; G Métais; Jessica Theodor. Johns Hopkins University Press. 32-58. (2007)
  • Phylogenetic relationship of cetaceans to terrestrial artiodactyls. Jessica Theodor; D Prothero; J Geisler; M Uhen; S Foss; S Foss. Johns Hopkins University Press. 19-31. (2007)
  • Using the extended Price equation to analyze patterns of body size change in mammals across the Paleocene-Eocene Thermal Maximum in North America. Barrón-Ortiz C*; Jessica M Theodor; J* Ludtke; B* Rankin; X* Yang; P Holroyd; A Chew; J Fox. (2013)
  • A preliminary report on paleoecologic change within the mammalian faunas of the Cypress Hills Formation, southwestern Saskatchewan: where we are, and where we're headed. Alex Dutchak; Jessica M Theodor. (2013)
  • Latitudinal effects of climate change on late Miocene ungulate communities.. D* Fraser; Jessica M Theodor. (2010)
  • Assessing patterns of geographic variation in latest Cretaceous mammalian assemblages from North America. B* Rankin; P Holroyd; Jessica M Theodor. 46(6):133. (2014)
  • Using the extended Price equation to analyze patterns of body size change in mammals across the Paleocene-Eocene Thermal Maximum in North America. J* Ludtke; X* Yang; B* Rankin; Barrón-Ortiz C*; J Fox; Jessica M Theodor. (2013)
  • Ungulate diets reveal patterns of North American grassland expansion during the late Miocene. D* Fraser; Jessica M Theodor. (2010)
  • Finite Element Comparison of Cranial Sinus Function in the Dinosaur Majungasaurus and Head-Clubbing Giraffes. Jessica M Theodor. (2011)
  • North American late Pleistocene equids(Mammalia, Perissodactyla): a geometric morphometric study of the upper premolars.. C* Barron-Ortíz; Jessica M Theodor. (2010)
  • Morphology of the auditory region of Hypisodus minimus:implications for the evolution of the mastoid fossa of artiodactyls. Jessica M Theodor. (2010)
  • Diversity of late Paleogene Mammals.. Jessica M Theodor. (2011)
  • Finite element comparison of cranial sinus function in the dinosaur Majungasaurus andhead-clubbing giraffes. Jessica M Theodor; L Witmer; E Snively; R Ridgely; Cotton JR. 1075-1076. (2011)
  • Feeding ecology of the Late Pleistocene equids from El Cedral, San Luis Potosi, Mexico, as evidenced by dental wear.. Jessica M Theodor; C* Barron-Ortíz; J Arroyo-Cabrales. (2011)
  • Petrosal morphology of the protoceratid cetartiodactyl, Protoceras celer. Jessica M Theodor; B* Seale. (2011)
  • Using the extended Price equation to analyze patterns of body size change in mammals across the Paleocene-Eocene Thermal Maximum in North America.. B* Rankin; J* Ludtke; Jessica M Theodor; X* Yang; J Fox; Barrón-Ortiz C*. (2012)
  • Characterization of ungulate buccal cuspshape using outline-based geometric morphometrics and its implication for mesowear analyses.. Barrón-Ortiz C*; Jessica Theodor; B* Rankin. (2012)
  • Ear morphology of Caenomeryx andrelationships of cainotheriids.. S* Dreger; Jessica Theodor; I Ruf; J* Wigg. (2012)
  • Using the extended Price equation to analyze patterns of body size change in mammals across the Paleocene-Eocene Thermal Maximum in North America. Barrón-Ortiz C*; Jessica M Theodor; B* Rankin; X* Yang; J* Ludtke; J Fox. (2013)
  • Herbivory and maximum size evolution in the Cenozoic: the effects of fermentation and feeding style. Dayan, Tamar T.; Harding, L.; A. F.; J. Theodor; Evans, A.; K. S.; H. J.; Saarinen, J.. (2013)
  • Basicranial and ear morphology characters among basal ruminants. Jessica M Theodor. (2013)
  • Using the extended Price equation to analyze species selection in mammalian body size evolution across the Paleocene/Eocene Thermal Maximum. Ludtke*, J.; B.* Rankin; Chew, A.; Fox, J.; M. Theodor., J.. 46(6):74. (2014)
  • The diet and habitat preferences of Capromeryx mexicana (Mammalia: Antilocapridae) from the Late Pleistocene Cedral locality, San Luis Potosí, Mexico. Barrón-Ortiz C*; J Arroyo-Cabrales; Jessica M Theodor; P Morales-Puente; Pérez-Crespo VA; E Cienfuegos-Alvarado. 46(6):332. (2014)
  • Herbivore body size limits and community structure during and after the Middle Miocene Climatic Optimum.. Jessica M Theodor. 46(6):74. (2014)
  • Update on the Cypress Hills Formation faunas of Saskatchewan (Eocene-Oligocene): new localities and new fossils. J. M. Perry; A. Dutchak; J. M. Theodor. (2016)
  • Dietary reconstructions of Mammuthus and Mammut species using dental tartar and mesowear analyses. J. M. Theodor; T. S.* Cammidge; B. Kooyman. (2016)
  • Application of quantitative biostratigraphic methods to the record of terrestrial vertebrates: can we gain new insights?. K. Walters; N. A. Famoso; E. B. Davis; S. S. Hopkins; D. Reuter; E. Biedron; D. Oberg; W. N. Mclaughlin; J. M. Theodor; G. Perdue. (2016)
  • Morphology and function of the toothrow in a rodent knockout model and implications for mammalian tooth evolution. D Graf; C* Zurowski; Heather Jamniczky; Jessica M Theodor. 299:105. (2016)
  • Four toes good, two toes bad: complex patterns of digit reduction in artiodactyls. Jessica M Theodor. (2016)
  • Faunal analysis of the recently discovered Eocene Bactrian Hill, Repo Man and Rose Creek localities of the Cypress Hills Formation, Saskatchewan, with additions to Swift Current Creek locality. A* Friesen; C* Zurowski; T* Cammidge; M* Sveen; K* Anderson; B* Rankin; Jessica M Theodor. (2015)
  • Patterns of diversity among latest Cretaceous mammalian assemblages from North America. Jessica M Theodor; P Holroyd; B* Rankin; M Vavrek. (2015)
  • Functional occlusion in a rodent knockout model and implications for mammalian tooth evolution. C* Zurowski; D Graf; Heather Jamniczky; Jessica M Theodor. (2015)
  • A diminutive new species of Catopsalis (Mammalia, Multituberculata,Taeniolabididae) from the Paleocene of Southern Alberta, Canada. A Weil; Catherine Scott; Jessica M Theodor. (2015)
  • Dietary reconstruction of two populations of Equus conversidens (Mammalia:Equidae) from Mexico: new insights into the dietary plasticity of a widespread Pleistocene equid species. J Arroyo-Cabrales; Jessica M Theodor; C* Barron-Ortiz; E Cienfuegos-Alvarado; P Morales-Puente; Pérez-Crespo V. (2015)
  • Partitioning change in body size among herbivores during the Middle Miocene Climatic Optimum. Jessica M Theodor. (2015)
  • Ear morphology of Hypertragulidae. Jessica M Theodor. (2015)
  • Using the extended Price equation to analyze species selection in latest Paleocene and earliest Eocene mammals. P Holroyd; J Fox; X* Yang; A Chew; J* Ludtke; Jessica M Theodor; Barrón-Ortiz C*; B* Rankin. (2014)
  • The ear region of cainotheres and their relationship to Tylopoda.. Jessica M Theodor. (2007)
  • Assessing the relationship between outline-based mesowear, diet, and habitat in extant ungulates: what influences molar cusp morphology?. Jessica M Theodor; M Mihlbachler; C* Barrón-Ortíz; B* Rankin. (2014)
  • Improving low-magnification microweartechniques using High Dynamic Range Imaging. Robin S Furr; D* Fraser; Jessica M Theodor. (2008)
  • Basicranial morphology and protoceratidrelationships.. Jessica M Theodor; B* Seale. (2008)
  • Size matters: examining patterns of maximum body size of mammals over time and space.. RM, Sibly; SKM, Ernest; DP, Costa; A, Boyer; K, Lintulaakso; Felisa A Smith; Evans A Tamar; M D Uhen; Jessica M Theodor. (2009)
  • High resolution CT studies of ear anatomy in cetartiodactyl phylogeny.. Jessica M Theodor. (2009)
  • Community body size distributions ofmammals differ among trophic groups, but not across time.. M Fortelius; Jessica M Theodor; Tamar; Lyons SKA; J H Brown; Ernest SKM; K Lintulaakso; L Harding; D P Costa; M D Uhen; T Dayan; Amanda Evans; R M Sibly; J Saarinen; Francine Gabriel Smith; S K Lyons; A Boyer. (2009)
  • Size matters: examining patterns of maximum body size of mammals over time and space.. DP, Costa; SKM, Ernest; K, Lintulaakso; Evans A Tamar; Felisa A Smith; M D Uhen; RM, Sibly; A, Boyer; Jessica M Theodor. (2009)
  • Ear morphology of Homacodon vagans: additional data from CT scan analysis. Jessica M Theodor. (2009)
  • The paleoecology of the Coffee Ranch Fauna of Texas and its implications in the interpretation of late Miocene climate change. Jessica M Theodor; D* Fraser. (2009)

In the News

More Information

Publications

Google Scholar Link

  • Bravo-Cuevas, V. M., N. M. Morales-García, C. R. Barrón-Ortiz, J. M. Theodor, M. A. Cabral-Perdomo, 2017. Canid coprolites from the Late Pleistocene of Hidalgo, Central Mexico: Importance for the carnivore record of North America, Ichnos,  http://dx.doi.org/10.1080/10420940.2016.1270209.
  • Bravo-Cuevas, V. M., J. Priego-Vargas, E. Jiménez-Hidalgo, C. R. Barrón-Ortiz, J. M. Theodor, J. M. Castillo-Cerón, 2015. Feeding ecology of Astrohippus stockii form the Late Hemphillian of central Mexico: stable carbon isotopes analysis and dental wear patterns, Ameghiana 52(2):502-516
  • Rankin, B. † , Fox, J., Barrón-Ortiz, C. R. † ,  Chew, A., Holroyd, P., Ludtke, J. † ,  Yang, X. † , Theodor, J. 2015. The extended Price equation quantifies species selection on mammalian body size across the Palaeocene/Eocene Thermal Maximum, Proc. R. Soc. B 282 (1812), 20151097 doi: 10.1098/rspb.2015.1097
  • Janis, C. M., J. M. Theodor, 2014. Cranial and postcranial morphological data in ruminant phylogenetics. Zitteliana, B 32:15-31. http://epub.ub.uni-muenchen.de/22383/
  • Barrón-Ortiz, C. R. † , J. M. Theodor, J. A. Cabrales, 2014. Dietary resource partitioning in the Late Pleistocene horses from Cedral, north-central Mexico: evidence from the study of dental wear. Revista Mexicana de Ciencias Geologícas 31(2), pp.260–269.
  • Snively, E., A. P. Russell, G. L. Powell, J. M. Theodor, M. J. Ryan, 2014. The role of the neck in the feeding behaviour of the Tyrannosauridae: inference based on kinematics and muscle function of extant avians. Journal Of Zoology, 292(4): 290–303. doi:10.1111/jzo.12109
  • Fraser, D.†  , T. Zybutz†  , E. Lightner, J. M. Theodor, 2014. Ruminant mandibular tooth mesowear: a new scheme for increasing paleoecological sample sizes. Journal Of Zoology, 294(1): 41–48. doi:10.1111/jzo.12149
  • Saarinen, J. J., A. G. Boyer, J. H. Brown, D. P. Costa, S. K. M. Ernest, A. R. Evans, M. Fortelius, J. L. Gittleman, M. J. Hamilton, L. E. Harding, K. Lintulaakso, S. K. Lyons, J. G. Okie, R. M. Sibly, P. R. Stephens, J. M. Theodor, M. D. Uhen, F. A. Smith, 2014. Patterns of maximum body size evolution in Cenozoic land mammals: eco-evolutionary processes and abiotic forcing, Proc R Soc B 281(1784): 20132049–20132049. doi: 10.1098/rspb.2013.2049
  • Okie, J. G., A. G. Boyer, J. H. Brown, D. P. Costa, S. K. M. Ernest, A. R. Evans, M. Fortelius, J. L. Gittleman, M. J. Hamilton, L. E. Harding, K. Lintulaakso, S. K. Lyons, J. J. Saarinen, F. A. Smith, P. R. Stephens, J. Theodor, M. D. Uhen, R. M. Sibly, 2013. Effects of allometry, productivity and lifestyle on rates and limits of body size evolution. Proc R Soc B 280(1764): 20131007–20131007. doi:10.1098/rspb.2013.1007
  • Fraser, D.† , J. M. Theodor, 2013. Ungulate diets reveal patterns of grassland evolution in North America. Palaeogeography Palaeoclimatology Palaeoecology, 369(C), pp.409–421.
  • Evans, A. R., D. Jones, A. G. Boyer, J. H. Brown, D. P. Costa, S. K. M. Ernest, E. M. G. Fitzgerald, M. Fortelius, J. L. Gittleman, M. J. Hamilton, L. E. Harding, K. Lintulaakso, S. K. Lyons, J. G. Okie, J. J. Saarinen, R. M. Sibly, F. A. Smith, P. R. Stephens, J. M. Theodor, M. D. Uhen, 2012. The maximum rate of mammal evolution, PNAS doi:10.1073/pnas.1120774109
  • Parham, J., P. Donoghue, C. Bell,T. Calway, J. Head, P.Holroyd, J. Inoue, R. Irmis, W.Joyce, D. Ksepka, J.Patane, N. Smith, J. Tarver, M. van Tuinen, Z. Yang, K. Angielczyk, J. Greenwood, C. Hipsley, L. Jacobs, P. Makovicky, J. Müller, K. Smith, J. Theodor, R. Warnock, M. Benton, 2012. Systematic Biology, 61(2), pp.346–359, doi:10.1093/sysbio/syr107
  • Barrón-Ortiz, C.† , J. M. Theodor, 2011. A Geometric Morphometric Study of North American late Pleistocene equid upper premolars and its potential significance for equid systematics, Current Research in the Pleistocene, 29:147-149.
  • Fraser, D.† ,  J. M. Theodor, 2011. Anterior dentary shape as an indicator of diet in ruminant artiodactyls, Journal of Vertebrate Paleontology, 31:6, 1366-1375, doi:10.1080/02724634.2011.605404
  • Fraser, D.† , J.M. Theodor, 2011. Comparing ungulate dietary proxies using discriminant function analysis. Journal of Morphology, 272:1513–1526, doi:/10.1002/jmor.11001/full
  • Snively, E., J. M. Theodor. 2011. Common functional correlates of head-strike behavior in the pachycephalosaur Stegoceras validum (Ornithischia, Dinosauria) and combative artiodactyls, PLoSOne,  http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0021422,  doi:10.1371/journal.pone.0021422.
  • Smith, F.A., A.G. Boyer, J.H. Brown, D. Costa, T. Dayan, S.K.M. Ernest, A.R. Evans, M. Fortelius, J.L. Gittleman, M. J. Hamilton, L.E. Harding, K. Lintulaakso, S.K. Lyons, C. McCain, J.G. Okie, J.J. Saarinen, R.M. Sibly, P.R. Stephens, J. Theodor, M.D. Uhen, 2010. The Evolution of Maximum Body Size of Terrestrial Mammals. Science, 330:1216-1219, doi:10.1126/science.1194830
  • Fraser, D.† , J. M. Theodor, 2010. The use of gross dental wear in dietary studies of extinct lagomorphs. Journal of Paleontology (4):720-729. doi: 10.1666/09-066.1
  • Theodor, J. M. 2010. Micro-computed tomography scanning of the ear region of Cainotherium: Character analysis and implications. Journal of Vertebrate Paleontology, 29(4):236-243, doi:10.1080/02724630903415979
  • Fraser, D. † , J. Mallon† , R. S. Furr, J. M. Theodor, 2009. Improving the repeatability of low magnification microwear methods using High Dynamic Range Imaging. Palaios, 24:818- 825, doi:10.2110/palo.2009.p09-064r
  • Geisler, J. H., J. M. Theodor. 2009. Hippopotamus and whale phylogeny. Nature, April 19 2009. doi:10.1038/nature07776.