On Monday Eric Scott and I launched a crowdfunding campaign to support a mastodon research project we've been working on. We believe California (or maybe western) mastodons have different tooth proportions than mastodons from other part of the country, and in order to test that hypothesis we need to travel to other museums to collect measurements on mastodon specimens from as many locations as possible. In recognition of that campaign, for the next month all my Fossil Friday posts will feature mastodons.Above is a left upper 3rd molar from Diamond Valley Lake, shown in occlusal view. This tooth was found shattered and painstakingly reconstructed, so even though it's incomplete it's an impressive specimen. Below is a lingual view of the same tooth:The anterior loph (the large ridge on the crown of the tooth) is mostly missing on this specimen, but the other lophs show little or no wear, so this tooth was either unerupted or had only recently erupted. As an aside, while I haven't checked the numbers to confirm this, a lot of the Diamond Valley Lake mastodons seem to have died when the third molars were partially erupted, maybe in their mid-20s to mid-30s.Since the front of this tooth is missing we can't take a reliable measurement of its length, which means this specimen will probably not end up in our project database; we need to be able to compare the length and width of the tooth crown. But even incomplete, this seems to be a remarkably small tooth even by California standards. Interestingly, our data so far suggests that molar size is not a very good indicator of body size (Max was a big animal with relatively small molars), so even though this tooth is small it doesn't mean it came from a small mastodon.We hope you'll visit experiment.com to help us study these mastodons!