Archaeornithoides
Name:
Archaeornithoides
(shaped like ancient bird).
Phonetic: Ar-kay-or-nif-oy-deez.
Named By: Andrzej Elżanowski & Peter
Wellnhofer - 1992.
Classification: Chordata, Reptilia, Dinosauria,
Saurischia, Theropoda, Coelurosauria, Troodontidae?
Species: A. deinosauriscus
(type).
Diet: Carnivore.
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.
Archaeornithoides
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
and troodontid
dinosaurs. It seems plausible now that Archaeornithoides
may actually
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
is currently
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.
Further reading
- 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.
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