Aucasaurus
Name:
Aucasaurus
(Auca lizard).
Phonetic: Aw-cah-sore-us.
Named By: Coria, Chiappe & Dingus -
2002.
Classification: Chordata, Reptilia, Dinosauria,
Saurischia, Theropoda, Abelisauridae, Carnotaurinae,
Brachyrostra, Carnotaurini.
Species: A. garridoi (type).
Diet: Carnivore.
Size: Up to 5 meters long.
Known locations: Argentina - Anacleto Formation.
Time period: Santonian of the Cretaceous.
Fossil representation: Almost complete skeleton,
but skull is damaged.
With
only the end of the tail missing, Aucasaurus has
the most complete
single abelisaurid
skeleton currently known. This has allowed for
more accurate general features which are thought to be common to the
group such as the famously underdeveloped arms that are even more puny
than those that appear upon Tyrannosaurus,
to be accurately
catalogued to allow for easier identification of future dinosaur fossil
discoveries.
The
skull of Aucasaurus is of special interest as the
damage on it appears
to have been caused by another dinosaur. The fact that this damage is
limited to the skull suggests that it was probably not a case of
scavenging but was instead an attack upon this Aucasaurus.
This does
not reveal the motivation of the attack, but possible reasons could
include this Aucasaurus attacking a large
herbivore, conflict over a
carcass, territory defence, to possibly even attempted
cannibalism, behaviour which has been suggests for another
abelisaurid called Majungasaurus.
The conflict with a herbivore
theory was recreated for the 2003 documentary series Dinosaur
Planet when a Saltasaurus
fell on top of an attacking Aucasaurus,
crushing its skull.
Whatever
the cause and reason, this skull injury is probably what led to the
individual’s death. Analysis of the fossil site reveals that it was
formed from lake sediment which indicates that the Aucasaurus
either
received the injury while in a lake or that it survived for a short
period before stumbling into the lake and sinking to the bottom. This
would explain the exceptionally high level of preservation in the
remains which would have been submerged from other terrestrial
predators, preventing them from being damaged and scattered by their
scavenging.
Further reading
- A new close relative of Carnotaurus sastrei
Bonaparte 1985
(Theropoda: Abelisauridae) from the Late Cretaceous of Patagonia - R.
A. Coria, L. M. Chiappe & L. Dingus - 2002.
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