Alternate Evolution of Ornithodira

We all know Dinosaurs and Pterosaurs, those two ruling reptile groups that dominated much of the Mesozoic. They are descended from a common ancestor, and both groups have distinct features. But what if this common ancestor went through an alternate scenario during the Mesozoic?

Maybe the Triassic was completely ruled on land by Therapsids, and the Ornithodirans only ruled the air? We might see a form not quite pterosaur and not quite dinosaur, like this:

Perhaps this form then gave rise to the new ruling group after the large Therapsida died out in the Triassic-Jurassic mass extinction.

We would see dinosaurish, and non-dinosaurish froms dominate for the whole of the Jurassic and Cretaceous, on land and in the air, but none are exactly like Pterosaurs or Dinosaurs. The herbivores, for a start, are all quadrupedal, secondarily flightless, and vary from scaly to feathery, with only 2 functioning front toes.

Skull.

Smaller, agile form.

Iguanodont-like form.

Hadrosaur-like form.

Giant, sauropod-like form.

And the carnivores vary from large heavy quadrupedal hunters, to agile bipeds that somewhat resemble Theropods, were it not that they had cruel hooked beaks, as well as sharp teeth.

Skull

Small agile form.

Another theropod-like form.

Mid-sized theropod-like predator with big claws.

Heavy, robust quadrupedal predator.

Giant quadrupedal predator.

And of course the flying forms are still there, some resemble a hybrid of bird and pterosaur, larger ones resemble hybrids of pterosaur, dinosaur, AND bird.

Small, athletic, starling-shaped form.

Mid-sized, long legged, omnivorous form.

Large, stork-like form.

It is interesting to speculate in a laterally-thinking way about dinosaurs and pterosaurs, as so much as has been done in a direct way already.

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