Name: Eocursor
(Dawn runner).
Phonetic: E-oh-cur-sor.
Named By: Richard J. Butler, Roger M. H.
Smith & David B. Norman - 2007.
Classification: Chordata, Reptilia, Dinosauria,
Ornithischia.
Species: E. parvus (type).
Diet: Herbivore?
Size: About 1 meter long.
Known locations: South Africa - Lower Elliot
Formation.
Time period: Norian of the Triassic.
Fossil representation: With the exception of the
tail and ribs, most of the post cranial skeleton is known as well as
skull fragments.
Not
only is Eocursor one of the earliest known
ornithischian dinosaurs,
it is also one of the most completely preserved, and for this reason
the genus has become something of a benchmark when studying early
ornithischian dinosaurs. The holotype specimen of Eocursor
was of an
individual approximately one meter long, though because of the lack
of tail remains, this figure is based upon comparisons to other
ornithischian dinosaurs.
Though
the ornithischian dinosaurs were mostly herbivorous (plant
eaters), there is a little uncertainty about Eocursor.
The teeth
of the lower jaw and the maxilla (posterior tooth bearing bone in the
upper jaw) are arranged in tightly packed rows and would have been
great for processing plants. However, the teeth of the premaxilla
(anterior tooth bearing bone in the upper jaw) are sharp and conical
like in a meat eating dinosaur, and this observation coupled with the
primitive nature of Eocursor have led to
speculation that that it might
have been an omnivore (eating both plants and meat).
If
Eocursor occasionally ate meat, it still was no
apex predator, with
sources of meat including everything from snatching up insects and
small lizards, to scavenging carcasses left over from the work of
true predators. If anything, Eocursor was a
dinosaur that made a
point to stay out of the way of predators, and the rear legs are a
good indication of this. Eocursor would have been
a bipedal
dinosaur, and the lower leg bones are proportionately larger than the
upper leg bones, a clear sign of legs that were suited for fast
running. In fact it is this running adaptation that was part of the
inspiration for the name Eocursor which means
‘Dawn runner’.
Further reading
- A primitive ornithischian dinosaur from the Late Triassic of South
Africa, and the early evolution and diversification of Ornithischia.
- Proceedings of the Royal Society of London B: Biological
Sciences 274:2041-2046. - Richard J. Butler, Roger M. H.
Smith & David B. Norman - 2007.