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This dinosaur skeleton is incomplete. But, it doesn't look that way to us, because the parts it's missing are parts we don't have.

See how there are ribs on the bottom? Those are called gastralia. That's right, dinosaurs had ribs on their stomachs as well, and modern crocodiles and alligators still have them! (Also, notice that the ribs keep going to the hips instead of stopping above the waist. This is also true of modern birds, and why a bird can't have a concave stomach!)

Next, notice that ring floating in the center of the eye socket? That's called a sclerotic ring! Fish, reptiles, birds--with the exception of mammals (and, oddly enough, crocodilians), pretty much all modern vertebrates still have them! It's literally an eyeball bone. Afaik we haven't found a T-rex specimen with any intact, but since we've found them in other dinosaurs, it's very likely they had them too.