Everyone knows, by now, that birds are descended from dinosaurs. In a very real way, birds are living dinosaurs, just without all the gnashy claws and teeth we’ve come to expect of close relatives of Tyrannosaurus rex.
Which means that dinosaurs have done something that only two other groups of large animals have ever managed – they’ve learned to fly.
Plenty of insects can fly, but for vertebrates – animals with backbones – it’s only been done three times.
The pterosaurs were the first, way back around 220 million years ago or so. Those are the ones you often hear called “flying dinosaurs” but that’s not accurate. Pterosaurs were related to dinos, but they evolved separately.
Then one branch of dinosaurs evolved into birds. It’s the same branch that contains fierce predators such as velociraptor and deinonychus, which also had feathers.
And finally, after the pterosaurs went extinct along with the non-bird dinos 66 million years ago, mammals got their chance, evolving the bats.
But discoveries over the last few years have showed that there was almost/maybe/sort of a fourth branch of flying critters.
They have the unwieldy name of scansoriopterygids. It’s a mouthful, but it means “climbing wings” which is pretty accurate. Some of the first scansoriopterygid fossils were baffling, because of their very long fingers. Their third fingers, in particular, were extraordinarily extended.
A couple of species turned up in China, small, bird-like dinosaurs that were thought to have lived in the trees. But when the blessedly-brief-named Yi qi was discovered, it was realized that they had wings. That long third finger, supported by an odd strut of bone sticking off the wrist, supported a wing membrane.
Could they actually fly?
Maybe not. They may have been more like flying squirrels or sugar gliders, drifting and parachuting about rather than flapping like birds or bats.
Even stranger, Yi qi and its cohorts actually had feathers. The fossilized remains of short, tufted feathers, presumably for warmth, were found on their bodies.
As mysterious to me as their discovery is their disappearance. They were found in late Jurassic deposits, from around 160 million years ago. So what happened to them? Were they outcompeted by their cousins the birds and the pterosaurs? Or was it just bad luck that we don’t still have dino-bats flitting through the skies to this day?
