Chatterjee was convinced that some of these crushed bones belonged to two individuals – one old, one young – of the same species. However, only a few parts were found, primarily a skull and some limb bones which moreover do not well agree in their proportions respective to each other, and this has led many to believe that the "Protoavis" fossil is chimaeric, made up of more than one organism: the pieces of skull appear like those of a coelurosaur, while the femur and ankle bone catalogued under TTU P-9200 and TTU P-9201 respectively suggest affinities to non-tetanuran theropods and at least some vertebrae are most similar to those of "Megalancosaurus", a drepanosaurid. However, those supposed similarities between the cervicals of "Protoavis" and drepanosaurids were the same similarities that Feduccia and Wild (1993) used to argue for an affinity between "Archaeopteryx" and drepanosaurids.