Nanotyrannus STILL Ain't Giving Up!

[suspsy]

Nope. It is hellbent on becoming legitimate. And now it can apparently outrun Velociraptor!

http://www.cbc.ca/news/canada/edmonton/carnivorous-dinosaurs-evolved-for-speed-u-of-a-researcher-finds-1.3422671

[Kovu]

Say what you will about it's legitimacy as an actual genus, but you've got to admit its a tenacious little thing.

[Simon]

The following comment under the article sums up my view concisely (since, well, I'm the one who posted it)  :

"In other news .... the jury is still very much out on whether Nanotyrannus was a separate species or simply a juvenile TRex ... the authors's claim that "it wasn't until leg lengths were compared that it was conclusively determined they were not, in fact, the same species" is 100% erroneous.

It may reflect the view of a few paleontologists, but there are just as many who see evidence that Nanotyrannus was just a juvenile TRex.

We need for a fossil of an adult "Nanotyrannus" to be identified and described before it can conclusively become a different species. RIght now you could flip a coin, and the safer position is that it is a juvenile TRex until proved otherwise."

[CityRaptor]

Looks like Velociraptor wasn't that much faster than Tyrannosaurus. And Allosaurus was slower...probably still frightening fast for something that size.

[Viking Spawn]

Could you imagine watching some herbivores graze in the field when all of a sudden, a large Allosaurus or T-rex comes from out of hiding in the brush and pouncing one of them?!  It would be probably much more impressive than lions stalking their prey!  Yeesh! 

[Dinoguy2]

Looks like Velociraptor wasn't that much faster than Tyrannosaurus. And Allosaurus was slower...probably still frightening fast for something that size.

According to this study, Velociraptor was much, much slower than T. rex. Notice in the chart it's leg to weight ratio is -13 (notice the minus) and T. rex is about +11. The study concludes that dromeosaurids were among the slowest theropods, faster only than very primitive saurischians like Eoraptor and Guaibasaurus.

[CityRaptor]

Oh, you are right. Although one could argue that smaller species would still be faster since they have less mass and can therefore afford to have a lower leg to weight ration.

Also just read the proper article. Here is how they justify Nanotyrannus:

Although in the tyrannosaurs Albertosaurus and Gorgosaurus, small bodied juveniles were found to fall within the same CLP-score range as large-bodied adults, CLP scores calculated for the tyrannosaur Nanotyrannus fell well outside the range of scores calculated for Tyrannosaurus. This result suggests that the proportionately elongate lower legs of Nanotyrannus are not allometrically equivalent to those of Tyrannosaurus and are, therefore, a legitimate character to cite as a morphological discriminator between the two.

[Simon]

What Nanotyrannus specimen did they study? An officially described one?  Or the "Dueling Dinosaurs" specimen that is still privately held?

[Halichoeres]

This study is hilarious and I think the only reason it's in Nature is because Nature thought they could generate press because it pretends to add something to the Nanotyrannus debate. By their measure of cursoriality, a heron is a better runner than a quail.

[Dinoguy2]

Oh, you are right. Although one could argue that smaller species would still be faster since they have less mass and can therefore afford to have a lower leg to weight ration.

Actually that's what this study was looking at, meshing leg ratio with weight to create this new ratio, so it takes total weight into account (unlike earlier studies which found smaller dinosaurs like Compsognathus to be ridiculously fast because they didn't take relative mass into account).

Troodontids, for example, were fond by this study to be among the fastest dinosaurs, since they're small and also have long legs. Dromies are small and have very stubby legs. I'm baffled why anybody ever thought they were particularly fast. They have legs like a weiner dog.