Sixth stop - Denver Museum of Nature and Science
Today was our sixth stop on the Mastodons of Unusual Size tour, the Denver Museum of Nature and Science. Prior to a few years ago, Colorado was not considered a hotbed of mastodon research. There were only a couple of bones known from the state, plus this tooth (discovered a few years ago):
That all changed in 2010 with the discovery of vast numbers of Pleistocene bones at Snowmass Village at an altitude of over 8,800 feet. During a rapid recovery operation nearly 5,000 bones were recovered, and the majority came from over 30 individual mastodons. The only place with a comparable number of mastodons in the west is Diamond Valley Lake, which produced fewer mastodon bones but a comparable number of individuals.
With such a huge number of specimens, Brett and I spent 7 straight hours with no breaks measuring and photographing teeth - 85 of them! They ranged across all ages, from one that was younger than 2 months (maybe even fetal), to another that was so old its last tooth was worn to the roots (there wasn't enough of that one left to measure). For example, here's a partial maxilla with the first, second, and third molars in place:
We also measured an absolutely enormous femur, with a distal width 11% greater than Max's (below is a cast of that specimen):
There is cranial material to go with this skull, but it's being molded for casting and was unavailable for measuring.
There was also a single partial skeleton in the collection from Indiana. This one also had femora a bit larger than Max (but not as large as the Snowmass monster), but its lower teeth were not particularly large (remember that Max also has small teeth). But it also turned out that this specimen had 5 lophids on the lower teeth:
I looked at so many specimens today that it's going to take a bit to get all the data sorted and think about what we have. But at first glance, the Snowmass mastodons don't seem to look much like the California ones. Almost none of the lower m3s are long and narrow, the teeth generally seem bigger, and every mandible we looked at that has the anterior end preserved had lower tusks (or at least sockets for them), something that's never been seen in a Californian mastodon as far as I know.
Today's visit marks the end of the Mastodons of Unusual Size road trip, that was mad possible by the support of all of our donors. We looked at over 150 mastodon teeth from five states, which is going to be crucial in our project. But the end of this trip does not mark the end of the Mastodons of Unusual Size Project. In the coming months we'll be collecting additional data from California specimens we haven't yet examined, presenting preliminary results at the Society of Vertebrate Paleontology meeting this fall, and hopefully publishing the final results early next year. We'll continue to post updates here, as well as on Twitter and at Valley of the Mastodons.
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