Euparkeria
Name:
Euparkeria
(Parker’s good animal).
Phonetic: You-par-kare-ree-ah.
Named By: Robert Broom - 1913.
Classification: Chordata, Reptilia,
Archosauromorpha, Archosauriformes, Euparkeriidae.
Species: E. capensis (type).
Diet: Carnivore.
Size: Up to 60 centimetres long.
Known locations: South Africa.
Time period: Olenekian of the Triassic.
Fossil representation: Many specimens known.
Often
misidentified as an early dinosaur, Euparkeria is
still sometimes
hailed as the ancestor to dinosaurs. However this is a slight
misnomer because while Euparkeria represents the
form that the
dinosaurs probably evolved from, there is no evidence to suggest that
Euparkeria itself was ‘the’ ancestor.
Euparkeria
itself is placed within the Archosauromorpha, the group of reptiles
that would lead to dinosaurs as well as todays crocodiles (and birds
when you consider that they are descended from dinosaurs).
Euparkeria is also classed as a thecodont since its
teeth are set into
sockets and also get replaced over the course of its lifetime.
One
of the key features of Euparkeria are the hind legs
which are
considerably longer than the front legs, which has led to most
artistic reconstructions showing Euparkeria to be a
bipedal hunter.
However the ankle joints of the rear legs are quite weak and not
adapted to work in constant bipedal movement. It is more likely that
Euparkeria spent most of its time walking in a
quadrupedal posture,
supporting the upper body to reduce the strain on the rear ankles.
Conversely however, short burst of bipedal running were potentially
possible for the purpose of chasing prey or predator evasion. The
longer rear legs may have also helped Euparkeria to
scramble over
objects and briefly reach up for prey items that would have been out of
the reach of shorter legged hunters.
Euparkeria
seems to have had an appearance similar to crocodiles, although its
armoured scales seem to have been much lighter. This is probably
because not only was Euparkeria likely faster than
other larger
predators, it’s small size meant that it could operate in undergrowth
that was too dense for more dangerous hunters. As such only similarly
sized hunters, or perhaps even members of the same genus would have
been potential threats to Euparkeria, so the
armour only had to
develop strong enough to cope with these threats.
The
scleral rings of Euparkeria are of particular
interest because they
show nocturnal adaptation. While the potential for Euparkeria
being a
specialist night hunter is interesting in itself this may not be the
actual or at least only reason for a nocturnal adaptation. Back in
the Triassic South Africa (where Euparkeria is
known from) was
much further south than it is today, which means that the overall
light level would have been reduced with extended periods of darkness.
This is why a nocturnal adaptation may have been necessary just for
everyday life.
Further reading
- The Anatomy of the Thecodont Reptile Euparkeria capensis
Broom. -
Philosophical Transactions of the Royal Society of London, Series B
248:379-435 - R. F. Ewer - 1965.
- Nocturnality in Dinosaurs Inferred from Scleral Ring and Orbit
Morphology - Science 332. - L. Schmitz & R. Motani - 2011.
- Euparkeriidae. - Geological Society, London, Special Publications.
379: 35–48. - R. B. Sookias & R. J. Butler - 2013.
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