help: sinosaurus triassicus hand

[brandem]

Hey all have been looking but info is coming up sparce:

Sinosaurus, vestigial fourth finger a la dilophosaurus or developed three finger hand a la crylophosaurus
I'm leaning three but a nice source would be helpful.

[Dinoguy2]

Unknown.

We don't know how many fingers Sinosaurus OR Cryolophosaurus had, since no hand bones are preserved for either. They may have had 3 or 4 depending on how closely related to the orionides they are. All orionides have three fingers, and since Dilophosaurus had four, the loss of the fourth must have happened somewhere in between.

Cryolophosaurus is often depicted with three fingers, but this is speculation based on the idea that it's a basal tetanuran, a position which is still up in the air. Even if it was a basal tetanuran, we don't know if finger 4 was lost before or after tetanurans evolved, so it could be a primitive, 4-fingered tetanuran.