Microvenator
Name:
Microvenator
(small hunter).
Phonetic: My-kro-ven-ah-tor.
Named By: John Ostrom - 1970.
Classification: Chordata, Reptilia, Dinosauria,
Saurischia, Theropoda, Oviraptorosauria, Caenagnathidae.
Species: M. celer (type), M.
chagyabi.
Diet: Uncertain.
Size: Holotype is estimated at about 1.2 meters
long, but this is of a juvenile. Adult size roughly estimated at
about 3 meters long.
Known locations: USA, Montana - Cloverly
Formation. Wyoming - Cloverly Formation.
Time period: Albian of the Cretaceous.
Fossil representation: Partial remains.
The
holotype individual of Microvenator was first
discovered by the famed
American palaeontologist Barnum Brown in 1933. Brown noted that the
holotype individual had what he thought was a disproportionately large
head, and so came up with the name Megadontosaurus.
A reference to
the large head, but also the teeth found near it. Two problems
occurred however. The first is that the teeth attributed to this
dinosaur actually came from the dromaeosaurid
Deinonychus,
one of the
more common predatory small theropod dinosaurs living in North America
during the later stages of the Early Cretaceous. Second, the name
Megadontosaurus was never actually published, meaning it was never
recorded as valid.
After
studying the partial remains of this dinosaur, another
palaeontologist named John Ostrom used this to formally describe the
genus Microvenator which means small hunter, a
reference to the small
body size of the holotype individual. Ostrom also added a tooth
(YPM 5366) from a Yale Peabody Museum collection to the genus.
Then in 1998 a study by Mackovicky and Sues finally shed some
clearer light upon this dinosaur.
Microvenator
is now known to have been an oviraptosaurid
dinosaur, and since it
was living in what is now the USA during the Albian of the
Cretaceous, it is at the time of writing the earliest known genus of
oviraptosaur
that lived in North America. This also explains Browns
original interpretation of this dinosaur having an unusually large
head. Brown only ever had partial fragmentary remains of the
skull and lower jaw to study, so he never knew for certain the true
form, but oviraptosaurs generally do have skulls that are larger and
bulkier than those seen in other theropod dinosaurs. Oviraptosaurs
however usually also have toothless jaws, again confirming that the
Deinonychus teeth should not have been included,
but also supporting
the conclusion by Mackovicky and Sues that the tooth YPM 5366
should not be included in with the genus.
Further reading
- Stratigraphy and paleontology of the Cloverly Formation (Lower
Cretaceous) of the Bighorn Basin area, Wyoming and Montana. -
Peabody Museum Bulletin 35:1-234. - J. H. Ostrom - 1970.
- Anatomy and phylogenetic relationships of the Theropod Dinosaur
Microvenator celer from the Lower Cretaceous of Montana. - American
Museum Novitates. Number 3240, 27pp. 27 August 1998. -
Peter J. Mackovicky & Hans-Dieter Sues - 1998.
- Late Cretaceous oviraptorosaur (Theropoda) dinosaurs from
Montana, by D. J. Varricchio. In Mesozoic Vertebrate Life.
Indiana University Press, Indianapolis, Indiana, pp 42-57,
D. H. Tanke & K. Carpenter (eds) - 2001.
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