Zupaysaurus
Name:
Zupaysaurus
(Devil lizard - from the Quechua word zupay which means
’devil’).
Phonetic: Zoo-pay-sore-us.
Named By: A. B. Arcucci & A. C
Rodolfo - 2003.
Classification: Chordata, Reptilia,
Dinosauria, Saurischia, Theropoda, Neotheropoda.
Species: Z. rougieri (type).
Diet: Carnivore.
Size: Skull 45 centimetres long, total body
length about 4 meters long.
Known locations: Argentina, La Rioja Province -
Los Colorados Formation.
Time period: Rhaetian of the Triassic to Hettangian
of the Jurassic.
Fossil representation: Almost complete skull,
right lower leg and ankle, right shoulder girdle, twelve assorted
vertebrae.
Zupaysaurus
is often reconstructed with a pair of crests rising from the top of its
skull like the more famous Dilophosaurus.
Indeed, Zupaysaurus
also has a similar upper jaw arrangement to Dilophosaurus
with a
notable gap between the teeth of the maxilla and premaxilla forming a
small notch. However if a 2005 presentation by M. D. Ezcurra
& F. E. Novas is correct, then these ‘crests’ were
actually formed when skull was crushed during fossilisation, the
resulting pressures pushing the lacrimal bones of the skull upwards,
making look like they were crests in life.
Zupaysaurus
was once considered to be one of the first tetaneuran
theropods (stiff tailed theropods that would become the dominant
forms during the Jurassic and Cretaceous periods), though today it
is considered by most to be a basal coelophysoid theropod, something
that again confirms a connection with Dilophosaurus
on the grounds of
family relationship. In addition the 2006 description of
Dracovenator
placed Zupaysaurus in a group with Dracovenator
and
Dilophosaurus as a dilophosaurid, though not all
palaeontologists are
convinced about this assessment, preferring to treat Zupaysaurus
as
related but separate. Zupaysaurus is also
considered to be even more
primitive than other coelophysoids such as Coelophysis,
Liliensternus
and Megapnosaurus.
Zupaysaurus
has been found in the Los Colorados Formation of
Argentina, and other dinosaurs from this formation include
Coloradisaurus,
Lessemsaurus
and Riojasaurus.
Only Coloradisaurus
is confirmed to match Zupaysaurus for a Rhaetian
era deposit,
revealing at possible predator prey interaction for these two genera.
Lessemsaurus and Riojasaurus
were earlier in the Norian period, but
if they managed to overlap into the Rhaetian, or Zupaysaurus
first
appeared earlier in the Norian (neither proven by current fossils)
then Zupaysaurus, or an ancestor of may have
preyed upon juveniles
of these genera.
Further reading
- A new Triassic carnivorous dinosaur from Argentina, A. B.
Arcucci & A. C Rodolfo - 2003.
- Phylogenetic relationships of the Triassic theropod *Zupaysaurus
rougieri* from NW Argentina. Presented in August 2005
during
the II Latin American Congress of Vertebrate Paleontology, M. D.
Ezcurra & F. E. Novas - 2005.
- A new theropod dinosaur from the Early Jurassic of South Africa and
its implications for the early evolution of theropods, A. M.
Yates - 2006.
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