Name: Aardonyx
(Earth claw).
Phonetic: Ard-oh-nix.
Named By: Yates et al. - 2010.
Classification: Chordata, Reptilia, Dinosauria,
Saurischia, Sauropodomorpha, Prosauropoda.
Species: A. celestae.
Type: Herbivore.
Size: 6 meters long.
Known locations: South Africa - Elliot Formation.
Time period: Hattangian to Sinemurian of the
Jurassic.
Fossil representation: Partial remains including
vertebra, ribs, parts of shoulder girdle, fore and aft limbs,
ischium, pubis and partial skull. These remains have been
confirmed to come from two juveniles.
Aardonyx
is a
very special sauropodomorph
as it represents the transitional stage
between bipedal ancestors and quadrupedal descendants. This change is
most evident when examining the legs, which show adaptations for a
slower, yet more powerful method of walking. These changes combined
with an increasingly quadrupedal method of weight bearing would allow
the sauropods
to grow to truly gigantic sizes.
When
determining an animal’s
age at the time of death, scientists can count the growth rings
present in cortical bone structures. When this was done for
Aardonyx, both individuals were found to be no
more than ten years of
age. The exact nature of their deaths is undetermined, but both
were found together with a small amount of bone scattering. The fact
that they were largely undisturbed might point to natural causes such
as two Aardonyx being drowned in a flash flood and
then being deposited
together. The fact that two that were of the same age died together
may indicate that they were also wandering around together in life,
and were perhaps part of a larger group.
Further reading
- A new transitional sauropodomorph dinosaur from the Early Jurassic of
South Africa and the evolution of sauropod feeding and quadrupedalism -
Proceedings of the Royal Society B 277 (1682): 787–794 - A. M. Yates,
M. F. Bonnan, J. Neveling, A. Chinsamy & M. G. Blackbeard -
2010.