Identity Crisis: the Curious Case of Captorhinus

 

“…we shall have to treat species in the same manner as those naturalists treat genera, who admit that genera are merely artificial combinations made for convenience.” Charles Darwin, The Origin of Species

When I first read Origin of Species, I was struck by Charles Darwin’s prophetic view of what biology would look like in his future. Darwin argued that species are fluid and constantly changing over time, and that the boundaries we assign between them are arbitrary. If you think about it, one of the reasons why we bother to assign species in palaeontology in the first place has to do with the incompleteness of the fossil record. The rarity of “intermediate species” between different kinds of animals actually makes assigning fossils to different species easier, because there are fewer overlaps between different kinds of organisms. But what happens when the lines between species become…blurry? Darwin’s work implied that a palaeontologist’s worst nightmare might actually be a complete fossil record, because we wouldn’t be able to place boundaries between different kinds of “species” as they changed across space and time. This is a story about one such case in palaeontology, where the fossil record is just complete enough to leave us scratching our heads. Continue reading

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Weighing in on the “mosasaur tooth debate”: doing science on ancient teeth

In my previous post, I summed up the decades-long fascination palaeontologists have had with mosasaur teeth. It seems like an odd subject, but this interest in mosasaur teeth and their attachment to the jaws turned centuries of assumptions about tooth evolution on their heads. The debate is about the spongy mass of tissue that forms the bases of mosasaur teeth and whether this tissue has any equivalent in mammals or other reptiles. So this post is dedicated to my approach to the “mosasaur tooth debate” and provides a window into how a palaeontologist uses the scientific method to pursue a question about ancient teeth. Continue reading

Why are palaeontologists so interested in mosasaur teeth?

Mosasaurs have a special place in my heart. I worked on them for my Master’s degree, but I also re-visited them as a PhD student. This post explores how mosasaur teeth became some of the most thoroughly studied among any reptile, and how the findings from the debates surrounding them have inadvertently re-shaped our understanding of dental evolution. This is also a story about the origin of my PhD thesis! Continue reading

Dinosaur Dentistry, Part 3: steak knives and dental batteries

In the third and final entry about the Dinosaur Dentistry event held at the University of Alberta, I wanted to talk about what makes studying dinosaur teeth so interesting. I’ve pointed out previously how at a fundamental level dinosaur teeth and human teeth are built from the same building blocks. That’s because the teeth in dinosaurs and mammals are made of the same dental tissues: enamel, dentine, and the periodontal tissues. Sure, there are differences in the thicknesses and arrangements of these tissues around a given tooth, but the tissues themselves are the same. But what this entry focuses on are some of the creative ways that dinosaurs used these dental tissues to make some very different and complex structures. This is a story about steak knives and dental batteries! Continue reading