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Australovenator (megaraptorid theropod) dentary

Ben Creisler

Matt A. White, Phil R. Bell, Alex G. Cook, Stephen F. Poropat & David
A. Elliott (2015)
The dentary of Australovenator wintonensis (Theropoda,
Megaraptoridae); implications for megaraptorid dentition.
PeerJ 3:e1512
doi: https://doi.org/10.7717/peerj.1512

Megaraptorid theropods were an enigmatic group of medium-sized
predatory dinosaurs, infamous for the hypertrophied claw on the first
manual digit. Megaraptorid dentition is largely restricted to isolated
teeth found in association with skeletal parts; however, the in situ
maxillary dentition of Megaraptor was recently described. A newly
discovered right dentary pertaining to the Australovenator holotype
preserves in situ dentition, permitting unambiguous characterisation
of the dentary tooth morphology. The new jaw is virtually complete,
with an overall elongate, shallow profile, and fifteen visible in situ
teeth at varying stages of eruption. In situ teeth confirm
Australovenator exhibited modest pseudoheterodonty, recurved lateral
teeth with a serrate distal carina and reduced mesial carina, similar
to other megaraptorids. Australovenator also combines of
figure-of-eight basal cross-section with a lanceolate shape due to the
presence of labial and lingual depressions and the lingual twist of
the distal carina. Computed tomography and three-dimensional imagery
provided superior characterisation of the dentary morphology and
enabled an accurate reconstruction to a pre-fossilised state. The
newly established dental morphology also afforded re-evaluation of
isolated theropod teeth discovered at the Australovenator holotype
locality and from several additional Winton Formation localities. The
isolated Winton teeth are qualitatively and quantitatively similar to
the in situ dentary teeth of Australovenator, but are also
morphometrically similar to Abelisauridae, Allosauridae,
Coelophysoidea, Megalosauridae and basal Tyrannosauroidea. Qualitative
characters, however, clearly distinguish the teeth of Australovenator
and the isolated Winton teeth from all other theropods. Evidence from
teeth suggests megaraptorids were the dominant predators in the Winton
Formation, which contrasts with other penecontemporaneous Gondwanan