Comparison of predatory dinosaurs' teeth?

[fabricious]

Hey folks! I'm in need of some assistance.

Over the weekend, I was representing our paleobiology-department at a university-anniversary-celebration here in Vienna and we had Struthiosaurus austriacus on display, the only properly described dinosaur from Austria. But, since our preparation department is not the best, they had a tooth from a carnivorous dinosaur pinned onto a plate with the remains of Struthiosaurus.

This tooth is the only fragment of a theropod dinosaur that we have, and now I was wondering if there are any good comparisons to determine what kind of predatory dinosaur (family) this could have belonged to. It is/was said that it belonged to some sort of Megalosauridae, which doesn't really make sense (in my opinion), seeing as Struthiosaurus was found in late cretaceous rock and Megalosauridae are limited to the Jurassic period.

I'd love to dive deeper into this topic, since I'll most likely be the lucky bachelor's student who is able to work on the few remains of austrian mesozoic history.

[DinoLord]

This is the kind of thing specialist paleontologists are great at. Maybe try contacting Thomas Holtz on Facebook? He'll 'friend' just about anyone (and frequently shares interesting paleontology articles and news as well).


In the meanwhile, I'm guessing that if the teeth are from what was Laurasia they're likely from either a dromaeosaurid, troodontid, or tyrannosauroid (unless some abelisaurs that we don't yet know about made it north). Other theropods present in the northern hemisphere (caenagnathids & ornithomimids) generally didn't have teeth.

Troodontid teeth should be fairly distinctive, as the serrations tend to be very course (almost like some herbivorous dinosaurs), though some species are known to have a fair amount of needle-like teeth as well. Tyrannosauroids tend to have a pretty distinctive dentition as well - the premaxillary teeth tend to be D-shaped in cross-section. The more derived tyrannosaurids have maxillary & mandibular teeth that are thick and circular in cross-section, as opposed to the blade-like cross-sections of early tyrannosauroids' (and most other theropods') teeth.

[fabricious]

Thanks for the input, I'll try contacting T. Holtz about it later. My personal guess is dromaeosaurid, since the tooth is rather flat, the tip tilted to one side and the serrations are visible on both sharp edges. It appears to be much too flat for a tyrannosaurid.

[DinoLord]

Based on that description I would make the same guess. Though tyrannosauroids didn't have the circular cross-sectioned teeth, their teeth were still rather robust (like this Dryptosaurus tooth).




If you want to get more specific, Currie (1995) defines the subfamily Velociraptorinae as possessing maxillaries and dentaries with anterior denticles (serrations) significantly smaller than the posterior dentacles.