Deinosuchus

***Deinosuchus*** (meaning "terrible crocodile") is an extinct genus of alligatoroid crocodilian related to the modern alligator that lived 82 to 73 million years ago (Ma), during the late Cretaceous period. 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 10.6 meters (35 ft) 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.

## Description

### Morphology

Despite its large size, the overall appearance of *Deinosuchus* was not considerably different from that of modern crocodilians. *Deinosuchus* had an alligator-like, broad snout, with a slightly bulbous tip. 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. All the teeth were very thick and robust; those close to the rear of the jaws were short, rounded, and blunt. They appear to have been adapted for crushing, rather than piercing. When the mouth was closed, only the fourth tooth of the lower jaw would have been visible. The skull of *Deinosuchus* itself was of a unique shape not seen in any other living or extinct crocodilians; the skull was broad, but inflated at the front around the nares. Two holes in the premaxilla in front of the nares are present in this genus and are unique autapomorphies not seen in other crocodilians, but nothing is known at present regarding their function.

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) specimen . The bite force of *Deinosuchus* has been estimated to be 18,000 N (1,835 kgf; 4,047 lbf) to 102,803 N (10,483 kgf; 23,111 lbf). It has been argued that even the largest and strongest theropod dinosaurs, such as *Tyrannosaurus*, probably had bite forces inferior to that of *Deinosuchus*.

*Deinosuchus* had a secondary bony palate, which would have permitted it to breathe through its nostrils while the rest of the head remained submerged underwater. 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. 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. Together, the osteoderms and connective tissue would have served as load-bearing reinforcement to support the massive body of *Deinosuchus* out of water. These deeply pitted osteoderms have been used to suggest that, despite its bulk, *Deinosuchus* could probably have walked on land much like modern-day crocodiles.

### Size

The large size of *Deinosuchus* has generally been recognized despite the fragmentary nature of the fossils assigned to it. However, estimates of how large it really was have varied considerably over the years. The original estimate from 1954 for the type specimen of the then-named *"Phobosuchus riograndensis"* were based on a skull of 1.5 meters (4.9 ft) and a lower jaw of 1.8 meters (5.9 ft) long, reconstructed with similar proportions to the Cuban crocodile giving a total estimated length of 15 meters (49 ft). However, this reconstruction is currently considered to be inaccurate. Using more complete remains, it was estimated in 1999 that the size attained by specimens of *Deinosuchus* varied from 8 to 10 meters (26 to 33 ft) with weights from 2.5 to 5 metric tons (2.8 to 5.5 short tons). This was later corroborated when it was noted that most known specimens of *D. rugosus* usually had skulls of about 1 meter (3.3 ft) with estimated total lengths of 8 meters (26 ft) and weights of 2.3 metric tons (2.5 short tons). A reasonably well-preserved skull specimen discovered in Texas indicated the animal's head measured about 1.31 meters (4.3 ft), and its body length was estimated at 9.8 meters (32 ft). 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 12 meters (39 ft) in length and perhaps weighed as much as 8.5 metric tons (9.4 short tons).

A particularly large mandibular fragment from a *D. riograndensis* specimen was estimated to have come from an individual with a skull length of 147.5 centimeters (4.84 ft). This length was used in conjunction with a regression equation relating skull length to total length in the American alligator to estimate a total length of 10.6 meters (35 ft) for this particular specimen. 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*, *Rhamphosuchus*, and *Sarcosuchus* may have equaled or exceeded it in size.

## *Deinosuchus* in The Amazing Dinosaur Adventure

### Anonymous

*Deinosuchus* from *Journey Through the Mists*. It appeared in a flashback