Carnivorous dinosaurs other than the famous t-rex and spinosaurus..

[DinoFan83]

For those who don't know about this species, here's a post on Concavenator, one of the best preserved and most unusual of the carcharodontosaurids known thus far.
There are a number of noteworthy and interesting things about this species:

-Its small size. Greg Paul (2016) estimates it at 320 kg, easily surpassed 30 to 33-fold or more by some of its larger relatives like Carcharodontosaurus, Giganotosaurus, and Mapusaurus.

-Its neural spines. As can be seen further down the post, the neural spines close to the hips suddenly experience a significant rise in height, a dip, and then another small rise, creating a concave hump of neural spines on the animal's back that are its namesake. These are not pathological nor an artifact of taphonomy to my knowledge, and some things they could have been used for are display, species recognition, or thermoregulation.

-Its completeness and excellent preservation. The Concavenator holotype (MCCM-LH 6666) is at a similar level of completeness to the infamously complete Tyrannosaurus specimen Sue, as Greg Paul's skeletal shows.

*This image is copyright of its original author

What's more, it's so well preserved it even has some skin impressions, such as crocodilian-like scales on the underbelly and large scutes on the lower legs.

-Its ulnar bumps. A series of bumps along the holotype's ulna have been interpreted by the original authors as evidence for a line of quill knobs, and they theorized that Concavenator could have been proof that feathers and quills evolved earlier in theropods than previously thought. However, there have been some counter-proposals to this.
(Although his blogpost about this doesn't appear to exist anymore), Darren Naish has argued that there are numerous factors that support the ulnar bumps as part of an intermuscular line instead of evidence for quill knobs, and Mickey Mortimer has independently come to that conclusion as well using modern alligators as a guide. Furthermore, Andrea Cau also raises a number of points why Concavenator most likely didn't have quills/feathers, and I think I agree with all of them given that (as was stated in the links) not only are the ulnar bumps wrongly positioned on the ulna to be quill knobs, they are very differently spaced from the quill knobs of species that we know had feathers, myological comparison with modern relatives easily show how the bumps coincide to an intermuscular line, and phylogenetics make it very unlikely that a carcharodontosaurid would have had quills/feathers in the first place.

-Its unexpected morphology given its phylogeny relative to other carcharodontosaurids. Concavenator is often recovered as a basal carcharodontosaurid closely related to animals like Neovenator and Acrocanthosaurus, who are often noted not to be as big headed relative to their size as giganotosaurines like Giganotosaurus or Mapusaurus. However, despite its close relation to these animals, the proportional size of Concavenator's skull seems to blow not only its relatives but every giganotosaurine ever discovered so far completely out of the water. 
Going off of Ville Sinkkonen's skeletal, the skull is 71 cm long, which would equate to a 320 kg animal possessing, in absolute terms, a skull 11 cm larger than that of a 2 tonne hippo. Relative to its size, Concavenator is among the most big headed theropods of all that have been found so far.
Now, I know what you may be thinking: that neither of the skeletals I have shown so far seen to suggest the animal's skull being that big relative to its body size. It should be noted, however, that given measurements for other bones found in the literature, Paul's and Sinkkonen's skeletals of this animal either have the skull too small despite the postcrania being appropriately sized, or have the postcrania too large despite the skull being appropriately sized. Case in point, according to Benson et al. 2014, the Concavenator holotype's femur is 55 cm long, therefore one could then expect a skull length to femur length ratio of slightly above 1.29. However, the scalebar in Ville Sinkkonen's skeletal yields 71.5 cm for femur length, equating to a skull length to femur length ratio of 0.979 and a possibility of the postcrania being oversized 30 percent relative to the skull. Greg Paul's skeletal shows something very similar; given the reported 55 cm femur length, the skull length of his skeletal ends up at about 50.3 cm as opposed to 71 cm, therefore it seems to be undersized by about 39.3 percent. Why both Paul and Sinkkonen have the skulls so undersized I am not sure, but at least the mounted skeletons (photo by Kumiko) do a very good job of showing how large the head is relative to body size.

*This image is copyright of its original author

And here is a life restoration by Durbed on Deviantart: https://www.deviantart.com/durbed/art/Co...-262819757

*This image is copyright of its original author

I hope we end up finding more fossils of this amazing theropod! Reply