10.5061/DRYAD.DT682
Bright, Jen A.
University of California, Santa Barbara
Tiffney, Bruce H.
University of California, Santa Barbara
Wyss, André R.
University of California, Santa Barbara
Data from: A mid-Oligocene (Whitneyan) rhinocerotid from northeastern
California
Dryad
dataset
2015
Oligocene
2015-02-16T15:23:45Z
2015-02-16T15:23:45Z
en
https://doi.org/10.1017/jpa.2014.11
23115753 bytes
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CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Rhinoceroses were important in North American mammal faunas from the late
middle Eocene to the Miocene, but the group’s poor sampling outside the
High Plains and eastern Rocky Mountain regions during their early
evolution significantly hinders understanding of their biogeography. This
limited geographic sampling is particularly true of early–middle Oligocene
time, with the vast majority of Whitneyan localities occurring in the
White River Badlands of South Dakota. Thus, any rhinocerotid from outside
the High Plains during this period is significant. We describe two new
rhinocerotid specimens from the middle Oligocene Steamboat Formation of
the northeastern Warner Mountains of California. Although the Steamboat
Formation is well known for fossil plants, this is the first report of
mammalian fossils from the area: an isolated lower molar recovered in 1974
but not previously described or illustrated, and a mandibular fragment
recovered approximately 20 years later and bearing two molar teeth, most
likely pertaining to the same taxon and horizon. The lack of distinctive
morphological characters suggests both fossils be conservatively referred
to Rhinocerotidae incertae sedis. Based on published tooth measurement
data, Trigonias osborni represents the closest size match, but that
species is currently only known from the Chadronian. Similarly, the
Whitneyan taxon Diceratherium tridactylum is approximately the right size,
but is currently only known from the High Plains and its presence in
California would expand its geographic range substantially. Of greatest
importance here is that sediments of the eastern Warner Mountains may
represent a largely unexplored locale for early–middle Oligocene fossil
vertebrates, and may yield important future finds.
SuppInfo Bright et al., 2015 - Mid-Oligocene rhinocerotidPhotogrammetric
3D reconstructions of tooth fossils UCMP226229 and UCMP121793, created
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California