Presenter: Danielle Oberg
Mentors: Samantha Hopkins and Edward Davis, Geology
Poster: 48
Major: Geology
Insectivores (euliptophylans) are not well understood in the Miocene of Oregon. Recent discoveries from a new locality, Cave Basin, in the John Day Formation suggest a greater diversity of insectivores than was previously known. Early Miocene records are extremely poor and lack small mammals entirely. However, the Middle and Late Miocene explode with new families never seen before in southern Oregon. The Middle Miocene has the greatest insectivore diversity with occurrences of ancient shrews (heterosoricidae), red-toothed shrews (soricidae), true moles (talpidae), and hedgehogs (erinaceidae) clustering around the Oregon-California border in southeastern Oregon. Fourteen Middle Miocene localities have red-toothed shrews and true moles, while hedgehogs and ancient shrews are found in two localities. Diversity rapidly decreases for ancient shrews and hedgehogs throughout the Late Miocene and into the Clarendonian, but remains relatively constant for true moles and red-toothed shrews. Red-toothed shrew Late Miocene localities are further south and less clustered than Middle Miocene ones. True mole localities have a greater spread across eastern Oregon, ranging from the Oregon-Washington state line to the southern corner of Oregon. These new discoveries in the Oregon Miocene are a significant addition to the understanding of the Oregon fossil record. Furthermore, these insectivores reveal new insight into the paleoecology of the Miocene, changes in diversity over time, and evolution of insectivores that are still found in Oregon today.