So perhaps inevitably the fossil beds of Liaoning in China have coughed up yet another fascinating feathered dinosaur. Yutyrannus huali (which translates as the ‘beautiful feathered tyrant’) is big – as big as some of the Late Cretaceous tyrannosaurines with the largest specimen being around 9 m long and estimated to have weighted close to 1.5 tons. In short, this was big. And feathered. While they are not brilliantly preserved, they are clearly present in places and directly associated with the skeleton as should be expected.
There are a few interesting things about this and I’ll go over them in turn, though as ever the first port of call should really be the paper for the real nitty gritty. First off, the specimens themselves – there are three of them, so this is already a well known animal, and two are basically complete. There’s a lot of anatomy right there and yes, I have to confess, rather more than some other tyrannosaurs I could mention. Indeed two of them are preserved together, as a pair, which nicely hints at least (well, I’m going to say so) at the possibility of sociality (theropods being more social than previously suggested, how interesting?). Multiple specimens are always great and animals this size being preserved at all are quite rare in the Jehol, so it’s pretty impressive we have three of them. They are also preserved in that psuedo-3D manner I mentioned the other day so there’s really quite a bit of detail there and they are not badly crushed or mashed (as you can see in the pictures below).
Now it is of course already known that tyrannosaurs were feathered, with the basal Dilong being preserved with feathers. The question is of course, did the bigger ones like T. rex have them? There’s been suggestions that they didn’t as they could overheat and there are hints of scaly, feather-less skin from impressions refereed to Tyrannosaurus. So while at least some tyrannosaurs certainly had feathers, and large ones certainly could have done, this is definitive evidence that they genuinely did. The size issue is of course interesting since indeed, very large animals tend to reduce insulation to avoid overheating (elephants, rhinos, hippos etc. are not that hairy and indeed elephants can struggle to keep cool). The obvious exception being animals that live(d) in cold climates like mammoths, and the researchers note that actually the environment Yutyrannus lived in was likely rather cooler on average than that occupied by a number of later tyrannosaurs, so this may indeed have helped them stay warm.
Below are some pictures of the various fossils. While you’ve probably seen a number of these before on all the other sides my insider contacts means I’ve been sent a few to use which were neither in the paper nor press release. So there’s something novel here for everyone, even if it’s not in the text.
Top image by Brian Choo (used with permission) and the rest courtesy of Xu Xing and colleagues.
Xu, X. et al. 2012. A gigantic feathered dinosaur from the Lower Cretaceous of China. Nature. doi:10.1038/nature10906