Search the Community

Hi, there. I had a question for how to identify a Tyrannosaurid's tooth which is a T.rex, Aspletosaurus, Gorgosaurus or Albertosaurus. Can we only distinguish the types of tooth fossils by the Formation where the tooth found, such as Hell Creek Formation or Lance (Creek) Formation ? Are there other possible criteria for distinguishing ? For example, the shape of the tooth or the measurement data. I was very confused because when I looked at the maxilla teeth of Tyrannosaurid' they all looked the same(Except for Nanotyrannus). Thanks for your guys answers and help.

Hello, I’m thinking about buying this for my first dinosaur tooth. And I was just wondering if you guys think it’s a tyrannosaur rex or nanotyrannus tooth. It’s from hell creek formation.

This topic is more up-to-date on North American Tyrannosaurids I find it interesting when I see Tyrannosaurid material for sale, from the Judith River of Montana, that so little is understood of what actually is being offered. Most sellers call their specimen either Daspletosaurus or Albertosaurus and a few, when it comes to teeth, properly identify them as Tyrannosaurid indet. Very few will label anything Gorgosaurus unless it's really small. Yet none of these Tyrannosaurids have been described from this fauna and Albertosaurus may not even be represented. So what is currently known with the major Tyrannosaurids that are sold. I've tried to look around and gather what information is available and put it together in its simplest form so it's understood, if there are missteps let me know. Sorry, it's from my narrow collector perspective Let me prefix this by saying this is an area that is constantly evolving based with new discoveries and research. Papers just a few years old can already be obsolete and views are changing. The other issue is that since so little material has been discovered in some strata that there may not be consensus among paleontologist but thats not new and we also know that their ego's run high. Not here to debate anything. Tyrannosaurids Described by age/strata: (Those you see sold) Late Maastrichtian deposits 69 - 66 mya (Lance/HellCreek/Scollard Formations et al. ) Tyrannosaurus rex Nanotyrannus lancensis Very Late Campanian / Mid Maastrichtian deposits 73 -67 mya (Horseshoe Canyon Formation) Albertosaurus sarcophagus Late Campanian deposits 75.1 - 74.4 mya (Two Medicine Formation) Daspletosaurus horneri (just described) (this is described just at the very end of the TM FM not all, age of deposit where collected is very important) Mid Campanian deposits 76.6 - 75.1mya (Two Medicine Formation) Gorgosaurus sp. does exist not nammed Mid Campanian deposits 76.7 - 75.2 mya (Belly River Group) Daspletosaurus torosus Mid Campanian deposits 76.7 - 75.1 mya (Dinosaur Park Formation) Gorgosaurus libratus What is important to note is that no Tyrannosaurid's have been described from the Judith River Formation (80-75 mya) of Montana. Since the stratigraphy is similiar to that of eastern Alberta it's fair to assume the Tyrannosaurids like Daspletosaurus and Gorgosaurus would be present but not Albertosaurus which is younger in age. A note from an article I read stated that Albertosaurus and Daspletosaurus are stratigraphically separate, with the former from the late Campanian to Maastrichtian Horseshoe Canyon Formation, and the latter coming from the middle Campanian Belly River Group. Additional discoveries and research will determine if this holds up. So as a collector you need to take a look at what you have labeled and some may need to be updated and keep this in mind with your next acquisition. Remember when trying to acquire tyrannosaurid material don't get hung up on the name, focus on the bone or tooth since it will be with you forever while names can change. Chart clearly showing the distribution by age (the Two Medicine Taxon is now D. horneri) Tyrant Dinosaur Evolution Tracks the Rise and Fall of Late Cretaceous Oceans Mark A. Loewen1*, Randall B. Irmis1, Joseph J. W. Sertich2, Philip J. Currie3, Scott D. Sampson1 PDF: journal.pone.0079420.PDF Carr's Blog (Chart) http://tyrannosauroideacentral.blogspot.com/2017/04/introducing-daspletosaurus-horneri-two.html?m=0 This is an FYI: Appalachiosaurus montgomeriensis no longer considered a Tyrannosaurid but a basal Tyrannosauroid if that's really important or relevant to collectors. (PDF from above)