Champsosaurus
Name:
Champsosaurus
(crocodile lizard.).
Phonetic: Champ-so-sore-us.
Named By: Edward Drinker Cope - 1877.
Synonyms: Champsosaurus annectens, C.
australis, C. brevicollis, C. inelegans, C. inflatus,
C. profundus, C. puercensis.
Classification: Chordata, Reptilia,
Choristodera, Champsosauridae.
Species: C. ambulator, C. albertensis,
C.
australis, C. gigas, C. laramiensis, C. lindoei, C.
lindoei, C. norelli, C. natator, C. tenuis.
Diet: Carnivore/piscivore.
Size: Depending upon the species, anywhere
between 1.5 and 3.5 meters long.
Known locations: Canada and the USA. Some fossil
remains also reported from France.
Time period: Turonian of the Cretaceous through to
the Thanetian of the Paleocene.
Fossil representation: Many individuals, some
almost complete.
Although
Champsosaurus looked like a crocodile and almost
certainly lived like a
crocodile,
the genus was actually a member of the Choristodera.
This is a separate group of diapsid reptiles which means that despite
the physical similarity, Champsosaurus was not
related to the modern
crocodiles that we know today.
Out
of all the modern types of crocodile, Champsosaurus
is most similar
to the gharial. The snout is long and thin which may indicate a
specialisation for hunting smaller organisms such as fish. The rear
proportion of the skull however is greatly expanded allowing the
placement of very large jaw closing muscles. This may indicate that
Champsosaurus had a surprisingly powerful bite given
their narrow
snouts. However an alternative explanation might be that the muscles
were fast acting as opposed to powerful so that the jaws could close
quickly around fast moving prey.
Champsosaurus
has a long taxonomic history that dates back all the way to the ‘bone
wars’, a rivalry between Othniel Charles Marsh and Edward Drinker
Cope in North America during the late nineteenth century. At the time
of writing there are currently seven recognised species of
Champsosaurus, though in the past a great many
more were once named.
Almost one hundred and fifty years of study have seen some of these be
identified as synonyms.
Many
species of Champsosaurus were quite modest in
size, though some,
such as C. gigas could approach up three and a
half meters in length.
Further reading
- On some extinct reptiles and Batrachia from the Judith River and
Fox Hills Beds of Montana - Proceedings of the Academy of Natural
Sciences of Philadelphia 28:340-359 - Edward Drinker Cope -
1876.
- The osteology of Champsosaurus Cope. -
American Museum of
Natural History, Memoirs 9:1-264 - B. Brown - 1905.
- Champsosaurus albertensis, a new species of
rhynchocephalian from
the Edmonton Formation of Alberta. - University of Toronto Studies
of Geological Survey 25:1-48 - W. A. Parks - 1927.
- New species of Champsosaurus from the Belly
River Formation of
Alberta, Canada - Transactions of Royal Society of Canada
27:121-137 - W. A. Parks - 1933.
- The lepidosaurian reptile Champsosaurus in
North America. - The
Science Museum of Minnesota, Monograph (Paleontology) 1:1-91 -
B. R. Erickson - 1972.
- Champsosaurus tenuis (Reptilia:
Eosuchia). A new species
from the Late Paleocene of North America. - Scientific Publications
of the Science Museum of Minnesota New Series 5(1):1-14 - B.
R. Erickson - 1981.
- New choristoderes (Reptilia: Diapsida) from the Upper
Cretaceous and Palaeocene, Alberta and Saskatchewan, Canada, a
phylogenetic relationships of Choristodera - Zoological Journal of
the Linnean Society 124:303-353 - K. -Q. Gao & R.
C. Fox - 1998.
- Champsosaurus (Diapsida: Choristodera)
from the Paleocene of
West Texas: paleoclimatic implications - Journal of
Paleontology, v. 84, p. 341-345 - T. M. Lehman
& K. Barnes - 2010.
- Computed tomography analysis of the cranium of Champsosaurus
lindoei
and implications for the choristoderan neomorphic ossification. -
Journal of Anatomy. 236 (4): 630–659. - Thomas W. Dudgeon, Hillary C.
Maddin, David C. Evans & Jordan C. Mallon - 2020.
- The internal cranial anatomy of Champsosaurus
(Choristodera:
Champsosauridae): Implications for neurosensory function. - Scientific
Reports. 10 (1): 7122 - Thomas W. Dudgeon, Hillary C. Maddin, David C.
Evans & Jordan C. Mallon - 2020.
- Feeding behaviour and functional morphology of the neck in the
long-snouted aquatic fossil reptile Champsosaurus
(Reptilia: Diapsida)
in comparison with the modern crocodilian Gavialis gangeticus. -
Journal of Anatomy. 240 (5): 893–913. - Ryoko Matsumoto, Shin-ichi
Fujiwara & Susan E. Evans - 2021.
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