The gang discusses two papers that look at the evolutionary history of unique teeth. The first paper looks at the history of tusks and tusk-like structures in synapsids, and the second paper looks at the shape of ancient bird teeth. Meanwhile, James gets to the point, Curt is inspired, and Amanda has a drink.

Up-Goer Five (James Edition):

The group looks at two papers that talk about teeth in different groups of animals. The first paper is interested in big teeth that keep growing and don't have a hard cover around them. While these teeth without a hard cover that don't stop growing are usually only found in animals with hair, one group that is part of the same family but much older also has teeth that seem to get big and never stop growing. However it turns out that many of them still have the hard covering, and only some of them lose it to be like the animals with hair today that have long teeth without a cover that doesn't stop growing. The other paper is looking at animals that fly and usually don't have teeth, but that are very old and so do have teeth. They look at the types of these old teeth to see whether they can tell us what these animals ate. It turns out that it is very hard to tell what these animals ate from their teeth, and it seems that other things like the type of face they have may be more important.

References:

Zhou, Ya-Chun, et al. "Evolution of tooth crown shape in Mesozoic birds, and its adaptive significance with respect to diet." Palaeoworld (2021).

Whitney, M. R., et al. "The evolution of the synapsid tusk: insights from dicynodont therapsid tusk histology." Proceedings of the Royal Society B 288.1961 (2021): 20211670.