Deinosuchus (/ˌdaɪnəˈsjuːkəs/) is an extinct genus of alligatoroid crocodilian, related to modern alligators and caimans, that lived 82 to 73 million years ago (Ma), during the late Cretaceous period.

Knowledge of Deinosuchus remains incomplete, but better cranial material found in recent years has expanded scientific understanding of this massive predator.

Although Deinosuchus was far larger than any modern crocodile or alligator, with the largest adults measuring 10.6 meters (35 ft) in total length, its overall appearance was fairly similar to its smaller relatives.

One study indicated Deinosuchus may have lived for up to 50 years, growing at a rate similar to that of modern crocodilians, but maintaining this growth over a much longer time.

In 1858, geologist Ebenezer Emmons described two large fossil teeth found in the Tar Heel Formation of Bladen County, North Carolina.

Another large tooth that likely came from Deinosuchus, discovered in Tar Heel sediments from neighboring Sampson County, was named Polydectes biturgidus by Edward Drinker Cope in 1869.

[4] A 1940 expedition by the American Museum of Natural History yielded more fossils of giant crocodilians, this time from Big Bend National Park in Texas.

[3][5] The genus name Phobosuchus, which was initially created by Baron Franz Nopcsa in 1924, has since been discarded because it contained a variety of different crocodilian species that turned out to not be closely related to each other.

[3] The American Museum of Natural History incorporated the skull and jaw fragments into a plaster restoration, modeled after the present-day Cuban crocodile.

Colbert and Bird stated this was a "conservative" reconstruction, since an even greater length could have been obtained if a long-skulled modern species, such as the saltwater crocodile had been used as the template.

[8][9] Since the discovery of the earliest fragmentary remains that would come to be known as Deinosuchus, it was considered a relative of crocodiles and initially placed in their family (Crocodylidae) in 1954 based on dental features.

[6] However, the finding of new specimens from Texas and Georgia in 1999 led to phylogenetic analysis placing Deinosuchus in a basal position within the clade Alligatoroidea along with Leidyosuchus.

[12] The species pertaining to Deinosuchus since the resurrection of the generic name in 1979 have been traditionally recognized as D. rugosus from Appalachia and the larger D. hatcheri/riograndensis from Laramidia, characterized by differences of the shape of their osteoderms and teeth.

[16] Modern saltwater crocodiles (Crocodylus porosus) have the strongest recorded bite of any living animal, with a maximum force of 16,414 N (1,673.8 kgf; 3,690 lbf) for a 4.59 meters (15.1 ft), 531 kilograms (1,171 lb) specimen.

[20] The vertebrae were articulated in a procoelous manner, meaning they had a concave hollow on the front end and a convex bulge on the rear; these would have fit together to produce a ball and socket joint.

"[30] Deinosuchus is generally thought to have employed hunting tactics similar to those of modern crocodilians, ambushing dinosaurs and other terrestrial animals at the water's edge and then submerging them until they drowned.

[18] The "side-necked" sea turtle Bothremys was especially common in the eastern habitat of Deinosuchus, and several of its shells have been found with bite marks that were most likely inflicted by the giant crocodilian.

[17] Schwimmer noted no theropod dinosaurs in Deinosuchus's eastern range approached its size, indicating the massive crocodilian could have been the region's apex predator.

[18] A 1999 study by Gregory M. Erickson and Christopher A. Brochu suggested the growth rate of Deinosuchus was comparable to that of modern crocodilians, but was maintained over a far longer time.

[34] Schwimmer noted in 2002 that Erickson and Brochu's assumptions about growth rates are only valid if the osteodermal rings reflect annual periods, as they do in modern crocodilians.

According to Schwimmer, the growth ring patterns observed could have been affected by a variety of factors, including "migrations of their prey, wet-dry seasonal climate variations, or oceanic circulation and nutrient cycles".

[41] Although some specimens have also been found in marine deposits, it is not clear whether Deinosuchus ventured out into the ocean (like modern-day saltwater crocodiles); these remains might have been displaced after the animals died.

[9] Deinosuchus has been described as a "conspicuous" component of a purportedly distinct biome occupying the southern half of Late Cretaceous North America.