Қасқыр тісті алып крокодил

Genus of a giant crocodylian

Deinosuchus (,/d//aɪ//n//ə/'/sj//uː//k//ə//s/) 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. The name translates as "terrible crocodile" and is derived from the Greek deinos (δεινός), "terrible", and soukhos (σοῦχος), "crocodile". The first remains were discovered in North Carolina (United States) in the 1850s; the genus was named and described in 1909. Additional fragments were discovered in the 1940s and were later incorporated into an influential, though inaccurate, skull reconstruction at the American Museum of Natural History. 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 in total length, its overall appearance was fairly similar to its smaller relatives. It had large, robust teeth built for crushing, and its back was covered with thick hemispherical osteoderms. 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. Deinosuchus fossils have been described from 10 U. S. states, including Texas, Montana, and many along the East Coast. Fossils have also been found in northern Mexico. It lived on both sides of the Western Interior Seaway, and was an opportunistic apex predator in the coastal regions of eastern North America. Deinosuchus reached its largest size in its western habitat, but the eastern populations were far more abundant. Opinion remains divided as to whether these two populations represent separate species. Deinosuchus was probably capable of killing and eating large dinosaurs. It may have also fed upon sea turtles, fish, and other aquatic and terrestrial prey.

In 1858, geologist Ebenezer Emmons described two large fossil teeth found in Bladen County, North Carolina. Emmons assigned these teeth to Polyptychodon, which he then believed to be "a genus of crocodilian reptiles". Later discoveries showed that Polyptychodon was actually a pliosaur, a type of marine reptile. 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. Better cranial material was also found; by 2002, David R. Schwimmer was able to create a composite computer reconstruction of 90% of the skull. although Deinosuchus was not considered a direct ancestor of modern alligators. 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. However, based on the lack of distinctive enough differences beyond size, they have increasingly been considered all the same species. Each premaxilla contained four teeth, with the pair nearest to the tip of the snout being significantly smaller than the other two. Each maxilla (the main tooth bearing bone in the upper jaw) contained 21 or 22 teeth. The tooth count for each dentary (tooth bearing bone in the lower jaw) was at least 22. When the mouth was closed, only the fourth tooth of the lower jaw would have been visible. Modern saltwater crocodiles (Crocodylus porosus) have the strongest recorded bite of any living animal, with a maximum force of for a , specimen. The bite force of Deinosuchus has been estimated to be The secondary palate and procoelous vertebrae are advanced features also found in modern eusuchian crocodilians. The osteoderms (scutes) covering the back of Deinosuchus were unusually large, heavy, and deeply pitted; some were of a roughly hemispherical shape. Deep pits and grooves on these osteoderms served as attachment points for connective tissue. This was later corroborated when it was noted that most known specimens of D. rugosus usually had skulls of about with estimated total lengths of and weights of A reasonably well preserved skull specimen discovered in Texas indicated the animal's head measured about , and its body length was estimated at However, the largest fragmentary remains of D. riograndensis were 1.5 times the size of those of the average D. rugosus and it was determined that the largest individuals of this species may have been up to in length and perhaps weighed as much as This is only slightly lower than previous estimates for the species. Deinosuchus has often been described as the largest crocodyliform of all time. However, other crocodyliforms such as Purussaurus, Gryposuchus, Rhamphosuchus, Euthecodon, and Sarcosuchus may have equaled or exceeded it in size.

In 1954, Edwin H. Colbert and Roland T. Bird speculated that Deinosuchus "may very well have hunted and devoured some of the dinosaurs with which it was contemporaneous". David R. Schwimmer proposed in 2002 that several hadrosaurid tail vertebrae found near Big Bend National Park show evidence of Deinosuchus tooth marks, strengthening the hypothesis that Deinosuchus fed on dinosaurs in at least some instances. 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. A 2014 study suggested that it would have been able to perform a "death roll", like modern crocodiles. Schwimmer and G. Dent Williams proposed in 1996 that Deinosuchus may have preyed on marine turtles. Deinosuchus would probably have used the robust, flat teeth near the back of its jaws to crush the turtle shells. 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". If the ring cycle were biannual rather than annual, this might indicate Deinosuchus grew faster than modern crocodilians, and had a similar maximum lifespan. Specimens have been described from 10 U. S. states: Utah, Montana, Wyoming, New Mexico, New Jersey, Georgia, Alabama, Mississippi, Texas, and North Carolina. David Schwimmer has said Deinosuchus fossils have been found in South Carolina and Delaware as well, but none of them from those two states have been formally described. There is also a report describing a possible Deinosuchus scute from Colorado. Deinosuchus fossils are most abundant in the Gulf Coastal Plain region of Georgia, near the Alabama border. The distribution of Deinosuchus specimens indicates these giant crocodilians may have preferred estuarine environments. 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.