Two more museums
Over the last two weeks, in addition to preparations for the upcoming Valley of the Mastodons exhibit and workshop, I also found the time to visit two more museum collections. First was the Santa Barbara Museum of Natural History. The most famous fossils at this museum are their beautiful dwarf mammoths, but they also have a small collection of mastodons.
The proportions of the Santa Barbara teeth were pretty much typical for California, although they tended to be on the large side. It's interesting (but not necessarily significant?) that almost all of the longest m3s from California (close to or greater than 200 mm long) come from Ventura and Santa Barbara counties, which border each other (another is from San Benito County, which is just one county over). Several of the Santa Barbara m3s are also unusual in that they have 5 clear lophids plus a talonid, which seems to be a rare condition in mastodons (probably less than 5% of specimens).
Next I headed south to the San Diego Natural History Museum, for another small but significant mastodon collection. One San Diego specimen, the Cerutti mastodon", recently made headlines because of the controversial suggestion that the bones were worked by humans 130,000 year age, more than 100,000 years before humans were thought to have arrived in North America. The museum has put up a nice exhibit explaining the case for this hypothesis:
Regardless of possible human activity, the Cerutti mastodon has teeth that are completely typical for a California mastodon.
More relevant to the Mastodons of Unusual Size project was a partial skeleton from Oceanside. This is one of the more complete individual mastodons from California, with large amounts of postcranial material. Unfortunately most of the skull was not preserved, but there was a well-preserved m2:
This tooth is almost exactly the same size as the m2 in Max, within 1 mm in each dimension. What's exciting is that the extensive postcranial remains allow a more direct size comparison to Max. For example, the Oceanside specimen has a nearly complete femur:
The Oceanside mastodon is absolutely tiny! Its femur is actually the smallest I've ever measured from an adult mastodon, only 817 mm long and 203 mm wide at the knee; for comparison Max's femur is 288 mm wide at the knee. The Oceanside animal (which was apparently a female, based on the tiny tusks) was only about 2/3 of the height of Max, yet their teeth are the same size. These two specimens, taken together, show conclusively that tooth size is not a reliable indicator of body size in mastodons, which is one of the things we set out to test.
We're now only about 3 weeks away from the Valley of the Mastodons workshop and exhibit opening. During the workshop I'll be presenting an update on the Mastodons of Unusual Size project, hopefully our last before submitting the manuscript for review later this year. We'll also have a display about our project in the exhibit.
I'd like to thank Jonathan Hoffman and Paul Collins at the Santa Barbara Museum, and Kesler Randall and Tom Deméré at the San Diego Museum, for their help in examining the collections in their care. I also realized that, in my last lab note, I neglected to thank Meredith Riven at the Burke Museum, and Vanessa Rhue and Sam McLeod at the LA County Museum, for access to the collections at their respective museums.
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