https://www.smithsonianmag.com/science-nature/the-ancestors-of-flying-pterosaurs-were-sleek-reptiles-that-ran-on-the-ground-180980898/
Scleromochlus taylori. The reptile was lightly-built, with longer hind legs than front legs, and over time paleontologists started to suspect that this little runner was an early forerunner of pterosaurs. The long legs and narrow feet of Scleromochlus,
especially, resembled the legs and feet of pterosaurs.
[DD: I think it was terrestrio-arboreal, high-speed bipedal, lightweight & longtailed like gecko, with unusual feeding strategy.]
The emerging picture of the reptile is quite a bit different from its later relatives. In specific terms, Scleromochlus belonged to a group of reptiles called lagerpetids that have recently been associated with the origin of pterosaurs. The bones of
Scleromochlus don’t show any specific adaptations to climbing, hopping [DD: lightweight & small!] or any sort of behavior that might be considered relevant to how pterosaurs evolved flight. Yet the anatomy of the animal still shows a connection to the
fliers, meaning that Scleromochlus represents an animal from what paleontologists often call a stem lineage, or the evolutionary branches that we can see leading up to the emergence of a particular group.
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