Champsosaurus is an extinct genus of a crocodile-like reptile of the family Champsosauridae. They lived in the Late Cretaceous and early Paleogene periods of Europe and North America (Campanian-Paleocene). The term Champsosaurus (Diapsida: Choristodera) is believed to have been derived from champsai as in the Ancient Greek source from the Egyptian word for 'crocodiles' with saurus meaning 'lizard.' The elongated, long snouts of these species resembled gharials and crocodilians. Also, Champsosaurus preferred freshwater environments where they were natives and easily catching fish using their strong jaws like gharials and crocodilians. This genus was the first one to be described within the order Choristodera. Edward Drinker Cope gave this name in 1876 from isolated Champsosaurus vertebrae belonging to Late Cretaceous strata, Judith River Formation (80-75 million years ago) on the bank of Judith River, Fergus County in Montana. Cope designated type species as C. annectens. However, the first-named species of this genus was C. profundus. There are 16 species named, but currently, only seven are considered valid. Also, the type species is considered nomen dubium.
The pronunciation of Champsosaurus is 'Champ-so-saw-rus.'
These animals of the suborder Neochoristodaera and class Reptilia are extinct crocodile-like choristoderes. They might have primarily fed on fish like gharial species and might have been ambush predators like crocodile species. These choristoderes were semi-aquatic, sharing their environments with dinosaurs for around 110 million years. There are seven valid species within this group. The literal meaning of Champsosaurus is crocodile-lizard. The Choristoderes group has evolved throughout history.
These choristoderes roamed Earth around 90 million years ago (first appeared) in the Turonian Stage of the Late Cretaceous period. They also lived in the early Paleogene (43 million years ago).
The Champsosaurus dinosaur (Diapsida: Choristodera) of the Late Cretaceous period lived through the mass extinction that took place around 66 million years ago during the Cretaceous-Paleogene extinction event. These choristoderes became extinct around 56 million years ago in the Paleocene Epoch of the Tertiary period.
These extinct choristoderes of the Late Cretaceous were spread across Europe and North America. The Champsosaurus fossil remains were collected in Saskatchewan, Montana, Alberta, New Mexico, Wyoming, Texas, Colorado, France, and Belgium that were from the Upper Cretaceous and Late Paleocene eras.
The range of the Champsosaurus habitat probably extended throughout semi-aquatic regions.
These extinct animals might have lived in a group.
The research on the maximum or average Champsosaurus lifespan is not yet available.
The reproduction of these aquatic choristoderes was viviparous. There is not much information available related to the breeding process and incubation of these species. However, it has been shown that these female reptile species laid their eggs on land for which their limbs were more robust than males.
The Champsosaurus' skull was flattened dorsoventrally and temporal arches expanded in the lateral and posterior directions, which gave the Champsosaurus skull a heart shape when viewed from the top. The snout was long and elongated resembled that of the gharial. The snout was almost four times longer than wide and was half the length of the skull. This allowed them to adapt well to aquatic life. The body of these choristoderes was flat and narrow. Compared to the body the legs were puny. The jaws (muscles) were so strong that these reptiles could shut their mouth within a fraction of a second. They had an elongated mandibular symphysis that was over half the length of the row of teeth. Like Ikeshosaurus and Tchoiria, Champsosaurus teeth had striated enamel on the tooth and there was an enamel infolding at the base. There have been reports of the skin of these animals, which consisted of small rhomboid and pustulate scales. Also, unlike many crocodilians or lizards with overlapping scales, these reptiles had a smooth cover of scales.
There is not much information available related to the number of bones in the body of these crocodiles of the upper Cretaceous period.
There is no clear data on the communication process of these choristoderes of the Upper Cretaceous period. These animals might have communicated through
These reptile species were of the upper cretaceous measure about 5-8 ft (1.5-2.4 m) long. The largest animal of this genus, C. gigas reaches up to 10-12 ft (3-3.5 m) in length. The average length of choristoderes is 10 ft (3 m). These species are almost twice the size of choristodere, Irenosaurus.
There was not much research on the fossils of these aquatic crocodile-lizard animals, so we do not know how fast they would have moved.
These animals resembling crocodiles weighed around 22.6-27.2 kg (50-60 lb).
There is no specific name given to either of these choristoderes female or males.
There is no specific name given to these baby reptiles.
These animals used their strong jaws for catching fish. Along with fish, it is also suggested that these reptiles might have fed on turtles.
It is not known how aggressive these animals were, but they hunted pretty aggressively.
These reptiles belonged to a group called Diapsida meaning there were two holes behind the skull, which is common in crocodilians, and lizards.
During the Early Cretaceous of Asia, choristoderes underwent huge evolutionary radiation.
C. ambulator species had more robust limbs and limb girdles than C. laramiensis. C. laramiensis had long bones. C. albertensis had shorter epipodials than other species, however, this was suggested to be not very significant. C. natator had a more robust skull than C. lindoei. C. tenuis species had an extremely slender and long snout with smaller limbs compared to other species. C. lindoei a smaller compared to others of this genus with a more slender snout of the same size of the skull. These species were found in Hell Creek Formation, Tullock Formation, Frenchman Formation, Dinosaur Park Formation, and Bullion Creek Formation.
Edward Drinker Cope originally erected choristodera as a Rhyncocephalia suborder in 1876. These are associated with fish, frogs, turtles, crocodyliforms, and salamanders, exclusively occupied warm temperate climates. It is presumed that these species were major piscivores. There were 18 fully developed embryos found in the mother Hyphalosaurus' body. Another specimen of this same species, however, showed that there were soft-shelled eggs too.
These species are classified within the clade Sauria. This group consists of the most common and recent ancestors of lepidosaurs (like liards and their kin) and archosaurs (dinosaurs, crocodilians, and more). This clade lies within the greater subgroup called Sauropsidae of which the species are close relatives of reptiles than to mammals. Sauria's name was previously used for a suborder with lizards. Some features or characters might have been modified or lost through multiple lineages, especially among lizards and birds. These features also allow identifying of these species from Sauropsidae or Diapsida,
These animals are larger compared to their Mesozoic relatives. C. gigas is the largest species measuring up to 10-12 ft (3-3.5 m) long.
In the fossil record, these reptiles lived or first came into existence in the Early Cretaceous Period of Asia and are believed to have evolved in absences of crocodyliforms.
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