Our colleague and palaeontologist Thierry Smith has discovered a 70 million year old mammal with red teeth in Transylvania, Romania. Iron strengthened Barbatodon transylvanicus’ incisors and molars and gave them their red colour. Barbatodon is the oldest known fossil mammal with iron in its teeth and its skull is the most complete mammal fossil from the Upper Cretaceous period in Europe.
yo what the FUCK is going on with that lower jaw?! AMAZING
That’ll be the plagiaulacoid! It’s a highly modified premolar tooth that’s grown into a (relatively) massive, serrated blade.
Barbatodon is a multituberculate (”multies”), an extinct lineage of mammals that are characterised by the presence of plagiaulacoids in their lower jaws. These teeth started out smaller and they had more of them, but in derived multies they lost all but the last pair and grew them into the giant saw-looking things you see here.
That said, the pictures there make it look a bit more ridiculous than it was, though only just. The tip of the lower jaw is missing in that specimen, which had a pair of rodent-like incisors, and based on other multies the complete skull would have probably looked something like this:
Plagiaulacoids basically functioned as you’d expect from how they look; they were specialised for slicing and cutting through food, whatever that may have been (grains, nuts, insect exoskeletons, maybe even meat and bones!). The iron tips in the teeth of Barbatodon, including the plagiaulacoid, suggest that it may have been chewing on some very tough stuff indeed for a multie.
