(shaped like ancient bird).
Named By: Andrzej Elżanowski & Peter Wellnhofer - 1992.
Classification: Chordata, Reptilia, Dinosauria, Saurischia, Theropoda, Coelurosauria, Troodontidae?
Species: A. deinosauriscus (type).
Size: Total size unknown due to lack of remains. Skull roughly estimated to be about 5 centimetres long.
Known locations: Mongolia - Djadokhta Formation.
Time period: Campanian of the Cretaceous.
Fossil representation: Skull and lower jaw fragments of a possibly juvenile individual.
has proven to be a problematic genus since it has been very difficult
to ascertain exactly what it was. Only known from partial paired
maxilla and dentaries, Archaeornithoides was
first considered to be a
primitive bird because of what were considered distinct bird-like
features. Later discoveries however proved that these distinct bird
features were also seen in many dromaeosaurid
dinosaurs. It seems plausible now that Archaeornithoides
be a maniraptoran dinosaur and possibly a troodontid. There has been
further speculation however that Archaeornithoides
may be a juvenile
form of an already established genus, but it has been noted that in
other troodontids, juveniles are usually distinct enough to identify
a genus, and at the time of writing Archaeornithoides
unlike anything else.
The rear portion of the preserved skull and jaws shows damage that may have been caused by teeth. This has further led to speculation that the teeth may have been those like you would see on a deltatheridiid mammal, and that the bones of the Archaeornithoides holotype may have passed through the digestive system of a mammal before being fossilised. If this theory is correct then this would actually be the earliest known evidence of a mammal eating a dinosaur, though if by active predation or scavenging is uncertain. This would also comfortably beat the commonly established first example of a mammal eating a dinosaur, the genus Repenomamus. In Repenomamus however, we have more direction proof of mammal on dinosaur predation because the dinosaur’s remains have actually been preserved as stomach contents within the Repenomamus remains. For this reason Repenomamus will always be the first conclusive proof of mammals eating dinosaurs, while Archaeornithoides is still only theory.
- Birds in Cretaceous Ecosystems. - Acta Palaeontologia Polonica, 28(1-2): 75-92 - Andrzej Elżanowski - 1983.
- A new link between theropods and birds from the Cretaceous of Mongolia. - Nature 359 (6398): 821–823. - Andrzej Elżanowski & Peter Wellnhofer - 1992.
- Skull of Archaeornithoides from the Upper Cretaceous of Mongolia. - American Journal of Science 293: 235–252. - Andrzej Elżanowski & Peter Wellnhofer - 1993.
- The perinate skull of Byronosaurus (Troodontidae) with observations on the cranial ontogeny of paravian theropods". American Museum Novitates 3657: 1–52. - G. S. Bever, M. A. Norell - 2009.