A New Platanistoid (Cetacea, Odontoceti) from the Nye Formation of Oregon



Nelson, Margot D

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This thesis describes an early odontocete, here named Perditicetus yaconensis, gen. et. sp. nov., from the latest Oligocene-earliest Miocene Nye Formation in Oregon. I assign it to the Platanistoidea, a large superfamily of odontocetes whose sole surviving member is Platanista gangetica, the Ganges river dolphin. Despite the diversity of the Platanistoidea, it remains poorly understood and in need of revision. As one of the earliest-diverging clade of crown odontocetes, understanding their distribution, morphology, and phylogeny is crucial to understanding the radiation of basal crown odontocetes in the late Oligocene to the middle Miocene. P. yaconensis, represented by the holotype USNM 335224, possesses several synapomorphies of the Platanistoidea; however, similarity between P. yaconensis and other basal crown odontocetes suggests that these early odontocetes may be closer to the Platanistoidea than initially thought, especially those in the “Chilcacetus clade”. The specimen’s probable location in the lower Nye Formation suggests that P. yaconensis is one of the older platanistoids known in the fossil record.


This thesis has been embargoed for 2 years and will not be available until May 2021 at the earliest.


Platanistoidea, Odontoceti, Nye Formation, Paleontology