Richardoestesia
Name:
Richardoestesia
(after the palaeontologist Richard Estes).
Phonetic: Rik-ard-o-tee-se-ah.
Named By: Phillip Currie, John Keith Rigby
& Robert Evan Sloan - 1990.
Classification: Chordata, Reptilia, Dinosauria,
Saurischia, Theropoda, Dromaeosauridae?
Species: R. gilmorei (type),
R. isosceles.
Diet: Carnivore.
Size: Unknown due to lack of fossil material.
Known locations: Canada - Alberta - Judith
River Formation, Horseshoe Canyon Formation and Scollard Formation.
USA - Wyoming - Lance Formation, Texas - Aguja
Formation, and possibly Utah - Cedar Mountain Formation.
Time period: Campanian of the Cretaceous (possibly
earlier to the Barremian).
Fossil representation: Pair of mandibles (lower
jaw bones) and large amounts of teeth.
To
start with the discovery, fossil specimens that would be raised as
Richardoestesia where actually described as
belonging to the type
species of another dinosaur named Chirostenotes.
Study in the
1980‘s however yielded the revelation that Chirostenotes
was an
oviraptorid,
which means that the more classic theropod jaws and
teeth could not possibly be placed within this genus. A new genus
honouring palaeontologist Richard Estes was chosen, and in keeping
with standardised Latin they created the genus Ricardoestesia.
However a spelling error resulted in Richardoestesia
(with an
‘h’) being submitted, repeated and accepted as the official
binomial name of this genus. The type species name R.
gilmorei is
in honour of Charles Whitney Gilmore, the palaeontologist who had
first assigned the Richardoestesia fossils to Chirostenotes
in 1924.
A
lot has been suggested about Richardoestesia, but
practically nothing
is known for certain about this dinosaur. The most complete remains,
a set of jaw bones was recovered from the Judith River Formation,
but all subsequent fossils from other fossil formations have only been
of the teeth. Some similar teeth that are longer and less curved than
the rest have been found in the Aguja Formation of Texas and used to
establish a second species, R. isosceles,
based upon the
triangular shape.
What
can be said about Richardoestesia is that the jaws
are slender, long
and housed teeth that were quite small but finely serrated. There are
as many as five to six serrations per millimetre of tooth, and it is
this feature that has allowed further teeth to have been attributed to
the genus. Richardoestesia was likely a small
theropod, possibly
belonging within the Dromaeosauridae,
or perhaps even the
Troodontidae.
The range of teeth from Fossil Formations stretching
across Southern Canada all the way down to the Southern USA suggests
that Richardoestesia was widespread across Western
North America that
back in the Cretaceous was an Island continent called Laramidia.
Further reading
- Theropod teeth from the Judith River Formation of southern Alberta,
Canada - P. J. Currie, J. K. Rigby, Jr., and R. E. Sloan. - In K.
Carpenter & P. J. Currie (eds.), Dinosaur Systematics:
Perspectives and Approaches. Cambridge University Press, Cambridge
107-125. - 1990.
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