Next in line are small, flying Ambiortus and lchthyornis.za These share similar and distinctive shoulder blades, and are alike in other features such as the retention of big protobird deltoid crests in the forearm. (Walking dinosaur costume)They may, or may not, be close relatives. Their primitive nahre is shown by the rather protobird- like skull with toothed jaws of lchthyornrs, and the suppleclawed fingers of Ambiornrs (the skull is not known in the latter, nor the hand in the first).
Also showing toothy jaws and a protobird-like skull, but very different in body form, are the loonlike diving hesperornithiformes. 2s The retention of primitive characters does not prove that all these toothed, or odontornithians, birds are truly close relatives. On the other hand, odontornithians are so primitive that they are far removed from all other birds.
The peculiar details of the mysterious andbizarre enantiornithian birds of the Cretaceous suggest they were a sister group to the normal and toothless neornithian birds-or perhaps to the odontornithians. (realistic dinosaur costume)Whether enantiornithians had teeth is uncertain.