The finding of two tiny dinosaurs with bat-like wings was a paleontologist's fantasy a few years ago. They are trying to pin down how flight originated in birds, and looking at this early development of bat-like wings in dinosaurs might give us a hint.
But a team of experts has now found out that it doesn't always imply you're fantastic at flying just because you have wings. They published their findings in iScience.
The two groups of theropod dinosaurs, Yi qi and Ambopteryx longibrachium, existed around 160 million years ago. Each has oddly elongated digits and a skin layer extending across them, close to a bat's wing.
It is a different type of wing than the dinosaurs which later became birds. Unlike them, Yi and Ambopteryx became extinct after just a couple of million years, which is the first indication that these peculiar wings could not match the birds-to-be.
Dinosaurs' Possible Roots
Weird wings on extinct species indicate that several forms of wings (and thus flight) have possibly developed over the years, and therefore the attempts of Yi and Ambopteryx were not the winning technique.
When experts discovered Yi in 2015, the research team proposed that the scale of its wings and other flight features may indicate that it was a gliding bird. Still, unlike every other glider we know about, its mass may have rendered it impossible to glide.
A recent analysis by researchers in the US and China has now looked in even more depth at the flight ability of Yi and Ambopteryx and concluded that they were just not successful at keeping their little feet off the trees in which they resided.
We re-evaluate their anatomy and conduct aerodynamic measurements utilizing laser-stimulated fluorescence imaging covering flight potential, other wing-based activities, and gliding capabilities, "the team writes."
"We find that Yi and Ambopteryx are likely to be arboreal, quite unlikely to have any driven flight, and have severe flapping-based locomotion deficits and restricted gliding skills."
The team's fossil study (Yi seen below) was able to collect tiny soft-tissue information that you can't see with regular light.
And the team designed how dinosaurs might have soared, correcting for factors like weight, wingspan, and positioning of muscles (all factors we can't know from the fossils alone).
Overwhelming Discoveries
They can't do a powered flight," says lead author, Mount Marty University biologist Thomas Dececchi.
So we're looking at flying capabilities considerably worse than a chicken, even worse than the flightless New Zealand parrot, the kakapo, according to Dececchi and his team's model, which is still primarily restricted to gliding from trees but can at least flap to regulate descent.
But while it's a little sad for the Yi and Ambopteryx, it's positive news for us-the results provide even more proof that dinosaurs have produced (or at least attempted to) flight many times.
As the team points out, maybe it shouldn't be a surprise given all the forms of flies, gliders, flying squirrels, and other gliding or flying animals.
We suggest that for non-avialan theropods, this clade was an isolated invasion of the aerial domain. If correct, during the Mesozoic, this will indicate at least two, but more possibly three or more flight attempts (both propelled and gliding) by tiny pennaraptoran theropods, "the team writes in their paper."
"This may perhaps be unsurprising considering the vast number of individual gliding flight occurrences within crown mammals, but it does provide a more complex view of the aerial environment."
