Champsosauriformes Hay 1930 Neochoristodera is a lineage of specialised crocodile-like fully aquatic choristodere reptiles.

Noted for their long jaws and large size, these animals were predominant across the Northern Hemisphere, occurring in freshwater and coastal environments across the Cretaceous and early Cenozoic.

Neochoristoderes form a monophyletic group, however there is no consensus about the relationships of the genera, which have been recovered as a polytomy in recent studies.

Neochoristodera contains the named genera Champsosaurus, Ikechosaurus, Kosmodraco, Liaoxisaurus, Mengshanosaurus, Simoedosaurus and Tchoiria.

Niche modeling based on the presumed niche of Champsosaurus indicates that neochoristoderes may have had a widespread distribution in Appalachia, but the majority of this habitat was not located in areas conducive for Cretaceous fossilization, leading to only a small margin of optimal habitat in New Jersey that preserved choristodere remains.

[3] Most neochoristoderes have exceptionally large temporal fenestrae, suggesting powerful bite forces; Champsosaurus is estimated to have a bite force around 1194 to 1910 N, as opposed to the modern gharial's 310-497 N.[7] In spite of this, most are thought to have had a diet similar to that of modern gharials due to the long and slender jaws, though Simoedosaurus has a more robust and shorter snout and could have fed on larger prey.