Dear Zooarch list,
I am working on identifying the small mammal remains from a late Holocene
paleontological site (wood rate midden) in Yellowstone National Park,
Wyoming. The assemblage is about 13% by NISP (of 3,300 specimens) leporid
remains, which are almost entirely isolated teeth and post-cranial remains;
we have very few mandibular rows and no skulls. We have are having trouble
identifying these to Genus and species.
Based on modern observations, the mostly likely species are L. americanus,
L. californicus, L. townsendii, S. audubonii, and S. nuttallii. Until now, I
have been working primarily with the lower p3s, measuring them and looking
at crenulations (following White 1991). None of our specimens have
crenulations, and their size ranges from 2.24 to 3.39. This size range
overlaps with modern samples of L. americanus, L. californicus, S.
audubonii, and S. nutallii, but not with L. townsendii. According to Orr
(1940), S. nuttallii and S. audubonii teeth are characterized by strong
crenulations. Can anyone confirm this? Can this be used to reliably
distinguish Lepus from Sylvilagus in these species? My measurements on
modern L. americanus p3šs range from 3.56 to 2.81 with a mean of 3.07, so
the smallest fossils are outside of this range. They may be Sylvilagus, but
they lack crenulations. Or L. americanus body size has changed through time.
Are other teeth diagnostic? Upper P2s? No teeth in the sample have
crenulations.
Given the spruce-fir forest surrounding the site, we think L. americanus is
the most likely species. But this species overlaps in body size with
Sylvilagus, creating the problem.
If anyone has any advice or can suggest any references, I would greatly
appreciate it.
Teresa Steele
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Teresa Steele
Dept. of Anthropological Sciences
450 Serra Mall, Bldg. 360
Stanford University
Stanford, CA 94305-3117
Office: Bldg. 80, Rm. 201
650-725-3173
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