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Dr. Stevens explores interactions between organisms and their environments through time, in particular the relationships between form and function in primates and other animals. She has conducted paleontological field research in over a dozen countries in Africa and the Arabian Peninsula. Her finds document several discoveries new to science, including the first dinosaur trackways from the Arabian Peninsula, and the oldest fossil evidence of the split between Old World monkeys and apes.

Stevens investigates impacts of environmental change through deep time by exploring patterns of biogeography and extinction in the early Cenozoic fossil record. This work draws on comparative vertebrate anatomy and the application of functional morphological approaches to evolutionary questions. Stevens’ vertebrate paleontological field research in critically under-sampled intervals throughout Africa and the Arabian Peninsula aims to provide a comparative dataset to examine geographic and temporal patterns in faunal evolution after the close of the Mesozoic, and prior to large scale faunal exchange with Eurasia in the early Neogene. New fossils help to unravel the roles of phylogeny and environment for shaping the development of morphological differences associated with specific locomotor and dietary patterns. She has focused on expanding vertebrate faunas from subequatorial Africa, particularly from the late Oligocene Nsungwe Formation in the Rukwa Rift Basin of Tanzania. The uniting theme of her work is to explore relationships between environment and morphology through time.

In order to explore the links between form and function in modern animals, Stevens has conducted laboratory and field kinematic studies, with a specific focus on issues relating to arboreal substrate use. In the laboratory setting, she has examined limb postures and interlimb coordination across a broad range of primate morphotypes, incorporating the role of information from the visual and vestibular systems to explore how the sequence and timing of limb movements may be related to specific anatomical features. This work is extended to include non-primate models in the lab, and by testing locomotor hypotheses with data collected in well-calibrated naturalistic settings. She is particularly interested in documenting how critically endangered animals utilize structural habitats that are rapidly changing due to anthropogenic and natural environmental change. Her recent locomotor projects have focused on these questions in several of the world’s 25 most endangered primates, particularly in Madagascar and Vietnam.

Stevens presently leads paleontological exploration in the Cenozoic deposits of the Rukwa Rift Basin of Tanzania, and her international team has discovered several new species of fossil mammals, crocodylians, snakes, frogs, fishes, and invertebrates. Her collaborative projects in this field area have provided new age estimations for the initiation of the Western Branch of the East African Rift System. She engages in collaborations on several other Cenozoic sites throughout Africa and the Arabian Peninsula. Her work also explores modern day extinction dynamics through research on some of the most critically endangered primates on the planet, with projects in Madagascar, Vietnam and Uganda.