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.‭ ‬albertensis,‭ ‬C.‭ ‬australis,‭ ‬C.‭ ‬gigas,‭ ‬C.‭ ‬laramiensis,‭ ‬C.‭ ‬lindoei,‭ ‬C.‭ ‬lindoei,‭ ‬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.


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