Name:
Protoceratops
(First horned face).
Phonetic: Pro-toe-seh-rah-tops.
Named By: Walter W. Granger & William
King Gregory - 1923.
Classification: Chordata, Reptilia, Dinosauria,
Ornithischia, Cerapoda, Ceratopsia, Protoceratopsidae.
Species: P. andrewsi
(type),
P.
hellenikorhinus.
Type: Herbivore.
Size: Average about 1.8 meters long up to 2
meters long for largest individuals.
Known locations: China. Mongolia.
Time period: Campanian of the Cretaceous.
Fossil representation: Multiple individuals are
known, allowing for accurate reconstruction.
When
first discovered, Protoceratops was heralded as
the ancestor to the
massive North American ceratopsian
dinosaurs such as Triceratops.
However with the advent of new and continuing studies of the group,
Protoceratops is now considered to be more
representative of the
type of dinosaur that led to the larger North American species as
opposed to being 'the' ancestor of them.
Protoceratops
is nevertheless significant in its discovery as it has revealed many
fascinating insights into dinosaur life. The large numbers of remains
found relatively close to one another is taken as evidence of herding
behaviour. Preservation of the scleral rings indicates a cathermal
lifestyle meaning that Protoceratops was active for
short periods
throughout the day, perhaps as a reaction to the arid conditions of
the time. It would make sense to spend shorter amounts of time
foraging before retreating to more sheltered areas when conditions were
too intense such as the heat associated with midday.
The
head of Protoceratops appears to be oversized when
seen in relation to
its body, and this housed a large cropping beak at the front, the
extra size maybe to make use of more powerful jaw muscles allowing the
beak to slice through tough vegetation. Inside its mouth, several
dozen teeth worked to grind the plant material, allowing for more
effective digestion.
Although
Protoceratops did not have the elaborate horns that
were typical of
some ceratopsian dinosaurs, it still possessed a frill that covered
its neck. It also had two greatly enlarged jugal bones, but there
is a great amount of variation in size and shape of both these and the
frill between individuals. Explanations for these variations include
possible indications of age, with older animals having larger
projections, to maybe even signs of sexual dimorphism, with males
having larger frill and jugals for display purposes.
However,
Protoceratops remains have also proved to be a bit
of a 'Red
Herring' on occasion. When the first dinosaur eggs were discovered
in the Gobi Desert, the large number of Protoceratops
remains in the
area was taken as indicative that these eggs belonged to them.
However a specimen of Oviraptor
was also discovered with them, and
since its skull was crushed, it was presumed that the Oviraptor
had
been killed by a Protoceratops that had been
defending the nest.
In
1992 the truth of the matter was revealed when a new study by Mark
Norrel et al on a presumed Protoceratops
egg
revealed the presence of
an Oviraptor embryo. This immediately flipped the
scenario upside
down as the eggs were now confirmed to belong to an Oviraptor,
not a
Protoceratops as had been thought for roughly
seventy years.
If
the Oviraptor had indeed been killed by a Protoceratops,
then the
scenario may be along the lines of a Protoceratops
stumbling upon an
Oviraptor nest and startling the brooding parent.
The Oviraptor,
only thinking of defending its nest immediately begins a threat
display, maybe even an attack on the Protoceratops,
which in turn
perceiving the Oviraptor as a threat to itself,
manages to crush its
skull in its beak.
The
most famous fossil of a Protoceratops is the
'Fighting Dinosaurs'
specimen which features an individual Protoceratops
locked in combat
with a Velociraptor.
Here the Protoceratops can be seen to have the
right forearm of the Velociraptor trapped in its
powerful beak, while
the Velociraptor seems to have one of its killing
claws lunged into
where the Protoceratops would have had its throat
exposed. Both
animals are believed to have been killed by a sudden event such as a
landslide which entombed them both during combat.
Further reading
- Protoceratops andrewsi, a pre-ceratopsian
dinosaur from Mongolia,
with an appendix on the structural relationships of the Protoceratops
beds - American Museum Novitates 72:1-9 - W. Granger & W. K.
Gregory - 1923.
- On Protoceratops, a primitive ceratopsian
dinosaur from the Lower
Cretaceous of Mongolia - American Museum Novitates 156:1-9 - W. K.
Gregory & C. C. Mook - 1925.
- Protoceratopsidae (Dinosauria) of Asia - Palaeontologica Polonica
33:133-181 - T. Maryanska & H. Osmolska - 1975.
- Quantitative aspects of relative growth and sexual dimorphism in
Protoceratops - Journal of Paleontology 50: 929–940
- P. Dodson - 1976.
- A new species of Protoceratops (Dinosauria,
Neoceratopsia) from the
Late Cretaceous of Inner Mongolia (P. R. China) - Bulletin de
l'Institut Royal des Sciences Naturelles de Belgique, Science de la
Terre: 5–28. - O. Lambert, P. Godfroit, H. Li, C. -Y. Shang &
Z. -M. Dong - 2001.
- The Function of Large Eyes in Protoceratops: A
Nocturnal Ceratopsian?
- N. Longrich - 2010. In: Michael J. Ryan, Brenda J. Chinnery-Allgeier,
and David A. Eberth (eds), New Perspectives on Horned Dinosaurs: The
Royal Tyrrell Museum Ceratopsian Symposium, Indiana University Press,
656 pp
- Nocturnality in Dinosaurs Inferred from Scleral Ring and Orbit
Morphology - Science 332 - L. Schmitz & R. Motani.