While we know a lot about Sinosauropteryx, to ‘almost’ even the level of colouration, we don’t know enough about Yi qi, the famous bat-like feathered dinosaur… its remains are not well enough preserved to be certain of many details like the extent and size of the wing membrane and its flying abilities… was it like a flying squirrel or a bat? For me it remains the proven, real first flying dinosaur but… Could it flap its wings? Scott Hartman tells me he doesn’t think it could fly battering its wings (the humerus proportions and the short deltopectoral crests wreck the leverage of muscles that would power the up and down stroke)… Scott is not even sure that it had bat wings! If it had them he says it instead used its wings to clamber trees in short jumps propelled by the wings… but he can’t be sure because the specimen is incomplete. Same happens with the shape and length of the legs. But one thing is almost for sure, this was not constructed as a flying squirrel because, dinosaurs are constructed differently: they were NO sprawlers, instead they had a combination of erect legs for running while using its arms for something else… like flapping perhaps?
So what you see here is a compromise…And, while we are still trying to find morphological solutions and more evidence, these two animals are for me yet another excuse to exercise my fascination for feathery colour possibilities. Even if I acknowledge the evidence regarding the “ginger” colouration of Sinosauropteryx (and have changed my previous green versions accordingly), I think there’s much more in dinosaur feathers than reducing them to the current “black, white or ginger” orthodox patterns… nature is never as clear cut, and as this article provided to me by Thom Holtz
https://academy.allaboutbirds.org/how-birds-make-colorful-feathers/
It stresses, that the melanosome evidence is just a little part of what makes a feather of certain colour… and if you add that the fact that fossils never show the complete picture, well, you can imagine. The colouration possibilities continue to endlessly fuel our imagination, even if we now have a few more constrains than before. Proof of that is the new rage about Caihong juji, the ‘rainbow dinosaur’(more on that in a future post). The argument regarding colours of dinosaurs (being feathered or not) continues, but as usual, I find my models in nature together with the possibility that even big dinosaurs had colour vision and cannot be compared to mammals… Time will tell! 
In the meantime, in preparation to the great opening of Dinosaur Families (AKA Hatching The Past) in Copenhagen the first of February and my joint talk with Jakob Vinther (also in Copenhagen) at the end of March… my second “Science And Wine” event with my excellent friends there, here I leave you a couple of Yi pi’s frolicking with a feisty Sinosauropteryx… and a Dinosaur Familier poster…
Dinosaurs were not sprawlers… Totally agree. Why is why I don’t think Yi qi was a glider, or a squirrel-like climber. I like the idea that it used its wings for flapping leaps, to clear obstacles on the ground (like fallen tree trunks).
This fits with an idea that I’ve had for a while, on the broader topic of the origin of bird flight: That flight evolved in terrestrial theropods by flapping leaps. Small theropods used these leaps to travel over uneven terrain, sort of parkour-style. So a ‘flapping-start’ of bird flight. No gliding needed. Nor tree-perching needed (this came much later).
Great restoration of Yi and Sinosauropteryx, BTW.
Just to add… I’m not saying Yi was ancestral to birds. It might have represented an independent ‘experiment’ in leaping/flying, separate from the ancestors of birds. But the same M.O., evolved independently – one with patagial/leathery wings, the other with feathery wings.