Dakotaraptor

On October 31 2015, I remember doing my usual checking on the progress of the ever-developing dinosaur survival video game Saurian when I found concept art of this specific dinosaur:

Dakotaraptor steini, artwork by RJ Palmer aka Arvalis.

I learned it was called Dakotaraptor steini and was just named that year after being known from fossils being found all the way back in 2005. 

Looking into it more, I saw Dakotaraptor was a genus of dromaeosaurid dinosaur that was quite large with an estimated height of nearly six feet which would have allowed it to look a grown man directly in the eyes, an estimated length of 5.5 meters (19.6 feet) and a weight of 453 kg (1,000 lbs). Also interesting was that the lower arm bones showed quill knobs for the attachment of wing feathers supporting that even the largest dromaeosaurids possessed feathers. 

Most exciting however was how Dakotaraptor was found to be from the Late Cretaceous period 66 million years ago in the Hell Creek formation making it sympatric with many important and classical dinosaur genera such as the three-horned Triceratops, the hard-headed Pachycephalosaurus, the armored club-tailed Ankylosaurus, the duck-faced Edmontosaurus, the fleet-footed Ornithomimus and of course good ole’ Tyrannosaurus rex. 

Dakotaraptor’s recognition year of 2015 was also the third year in a row that science officially recognized an exciting new creature from this area as in 2013 we described the other (much smaller) dromaeosaurid Acheroraptor and in 2014 the caengathid oviraptorosaur Anzu wyliei (after being labeled as possible larger, late-surviving individuals of the Campanian Chirostenotes) making the ecosystem even more interesting and diverse. 

Unlike other large dromaeosaurids such as Utahraptor, whose new material showed it to be stocky in body-build similar to a carnosaur or tyrannosaurid that would’ve made it ill-suited for pursuit, Dakotaraptor maintained the slimmer body-build of its smaller cousins making it a pursuit predator of other dinosaurs around its size such as Ornithomimus, Pachycephalosaurus and Thescelosaurus as well as younger individuals of large dinosaurs such as Triceratops Ankylosaurus and Edmontosaurus. 

But of course the main reason Dakotaraptor got lots of excitement from paleontology fans (myself included) was because it lived alongside Tyrannosaurus rex, the most famous non-avian dinosaur of all time. This inspired all sorts of artwork and speculation of this giant dromaeosaurid antagonizing T. rex (a la the climax of Jurassic Park, but this likely would have happened when the rex was a juvenile) and the other way around. Plus this dinosaur also helped fill in the formation’s long-missing role of a medium-sized predator (ignoring the controversial Nanotyrannus, which are certainly young T. rex specimens) and in terms of physical appearance, the closest we got to a Jurassic Park Velociraptor (though certainly with feathers). 

With all of this, Dakotaraptor certainly made an excellent addition to Hell Creek’s charismatic menagerie and to the dromaeosaurid family.

But apparently, this may not have been the case and was only too good to be true. 

Ever since the beginning, Dakotaraptor has always been suspected to be a chimera (in this case a fossil specimen with assigned parts from several different creatures mistakenly described as one) due to being found in a bonebed housing various species with the assigned wishbones being from that of a fossil soft-shelled turtle Axestemys infernalis. While a concerning detail, I thought it was no big deal since it was just one part and no one saying anything else about the either material assigned to it such as teeth, arms, leg bones, tail vertebrate and the giant toe claw that dromaeosaurids are most famous for.

Then in 2023, Italian paleontologist Andrea Cau suggested that the chimera situation might be even worse as he went on to propose that the teeth and claws might actually be from a T. rex, the legs from a caenagnathid and the tail vertebrate from that of an ornithomimid. 

It also should be mentioned that Cau has apparently never actually studied the assigned Dakotaraptor material in person and also been reported to over-exaggerate situational parts of his studies. He also strangely doesn’t mention the arm bones though. What certainly doesn’t help is the specimen described by its discoverer and namer Robert DePalma (whom I’ve heard has been involved in some controversies in the past) has been housed within a private collection, which has prompted some to speculate there’s something to the situation that he doesn’t want anyone to know about.  

Right now Dakotaraptor is currently safely classified as nothing else other than a maniraptoriform. However there is still one bone described as an actual dromaeosaurid that is a vertebra piece of a creature believed to have been around the size of the Early Cretaceous Deinonychus which could belong to Dakotaraptor (potentially proving its validity, albeit smaller than depicted) but it’s also possible that this could instead present a larger specimen of Acheroraptor. This would make Dakotaraptor a junior synonym of Acheroraptor with the latter name having been described first. 

Plus since no one (so far) has made any strong counter arguments against the chimera hypothesis, it may appear that this dinosaur has no hope of being truly valid and thus never existed.

Bottom line, this whole situation truly does suck. Dakotaraptor was indeed such as a fascinating animal that as stated before was described as a real enemy to Tyrannosaurus rex. I myself particularly had story ideas of this speculator dromaeosaurid terrorizing smaller dinosaurs and baby individuals of large dinosaurs when T. rex wasn’t doing so. But with this whole thing going on, I’ve made the hard decision to keep my distance from Dakotaraptor for my more recent story ideas. 

Such an incredible shame for this awesome dinosaur that was once taken seriously but possibly never was a real creature to begin with.

My personal artwork of Dakotaraptor steini.