Deinosuchus
Encyclopedia


Deinosuchus is an extinct genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 related to the alligator
Alligator
An alligator is a crocodilian in the genus Alligator of the family Alligatoridae. There are two extant alligator species: the American alligator and the Chinese alligator ....

 that lived 73 to 80 Ma (million years ago), during the late Cretaceous
Cretaceous
The Cretaceous , derived from the Latin "creta" , usually abbreviated K for its German translation Kreide , is a geologic period and system from circa to million years ago. In the geologic timescale, the Cretaceous follows the Jurassic period and is followed by the Paleogene period of the...

 period. The name translates as "terrible crocodile" and is derived from the Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...

 deinos (δεινός), "terrible", and soukhos (σοῦχος), "crocodile". The first remains were discovered in North Carolina
North Carolina
North Carolina is a state located in the southeastern United States. The state borders South Carolina and Georgia to the south, Tennessee to the west and Virginia to the north. North Carolina contains 100 counties. Its capital is Raleigh, and its largest city is Charlotte...

 (United States) in the 1850s; the genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 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
American Museum of Natural History
The American Museum of Natural History , located on the Upper West Side of Manhattan in New York City, United States, is one of the largest and most celebrated museums in the world...

. Knowledge of Deinosuchus remains incomplete, but better cranial
Skull
The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates...

 material found in recent years has expanded scientific understanding of this massive predator.

Although Deinosuchus was far larger than any modern crocodile or alligator—measuring up to 12 m (39.4 ft) and weighing up to 8.5 metric tons (9.4 ST)—in overall appearance it was fairly similar to its smaller relatives. It had large, robust teeth that were built for crushing, and its back was covered with thick hemispherical osteoderm
Osteoderm
Osteoderms are bony deposits forming scales, plates or other structures in the dermal layers of the skin. Osteoderms are found in many groups of extant and extinct reptiles, including lizards, various groups of dinosaurs , crocodilians, phytosaurs, aetosaurs, placodonts, and hupehsuchians...

s. One study indicates that 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 period of time.

Deinosuchus fossils have been found in ten U.S. states, including Texas, Montana, and many along the East Coast
East Coast of the United States
The East Coast of the United States, also known as the Eastern Seaboard, refers to the easternmost coastal states in the United States, which touch the Atlantic Ocean and stretch up to Canada. The term includes the U.S...

. Fossils have also been found in northern Mexico. It lived on both sides of the Western Interior Seaway
Western Interior Seaway
The Western Interior Seaway, also called the Cretaceous Seaway, the Niobraran Sea, and the North American Inland Sea, was a huge inland sea that split the continent of North America into two halves, Laramidia and Appalachia, during most of the mid- and late-Cretaceous Period...

, and was an opportunistic apex predator
Apex predator
Apex predators are predators that have no predators of their own, residing at the top of their food chain. Zoologists define predation as the killing and consumption of another organism...

 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
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

. Deinosuchus was probably capable of killing and eating large dinosaur
Dinosaur
Dinosaurs are a diverse group of animals of the clade and superorder Dinosauria. They were the dominant terrestrial vertebrates for over 160 million years, from the late Triassic period until the end of the Cretaceous , when the Cretaceous–Paleogene extinction event led to the extinction of...

s. It may have also fed upon sea turtle
Sea turtle
Sea turtles are marine reptiles that inhabit all of the world's oceans except the Arctic.-Distribution:...

s, fish, and other aquatic and terrestrial prey.

Morphology

Despite its large size, the overall appearance of Deinosuchus was not considerably different from that of modern crocodilians. Deinosuchus had an alligator
Alligator
An alligator is a crocodilian in the genus Alligator of the family Alligatoridae. There are two extant alligator species: the American alligator and the Chinese alligator ....

-like broad snout, with a slightly bulbous tip. Each premaxilla
Premaxilla
The incisive bone is the portion of the maxilla adjacent to the incisors. It is a pair of small cranial bones at the very tip of the jaws of many animals, usually bearing teeth, but not always. They are connected to the maxilla and the nasals....

 contained four teeth, with the pair nearest to the tip of the snout being significantly smaller than the other two. Each maxilla
Maxilla
The maxilla is a fusion of two bones along the palatal fissure that form the upper jaw. This is similar to the mandible , which is also a fusion of two halves at the mental symphysis. Sometimes The maxilla (plural: maxillae) is a fusion of two bones along the palatal fissure that form the upper...

 (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 jaw
Jaw
The jaw is any opposable articulated structure at the entrance of the mouth, typically used for grasping and manipulating food. The term jaws is also broadly applied to the whole of the structures constituting the vault of the mouth and serving to open and close it and is part of the body plan of...

s 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.
Modern American alligators
American Alligator
The American alligator , sometimes referred to colloquially as a gator, is a reptile endemic only to the Southeastern United States. It is one of the two living species of alligator, in the genus Alligator, within the family Alligatoridae...

, with the strongest bite of any living animal, have a maximum force of 9452 newtons (2,124.9 lbf). The bite force of Deinosuchus has been estimated to exceed 18000 newtons (4,046.6 lbf). Even the largest and strongest theropod
Theropoda
Theropoda is both a suborder of bipedal saurischian dinosaurs, and a clade consisting of that suborder and its descendants . Dinosaurs belonging to the suborder theropoda were primarily carnivorous, although a number of theropod groups evolved herbivory, omnivory, and insectivory...

 dinosaurs, such as Tyrannosaurus
Tyrannosaurus
Tyrannosaurus meaning "tyrant," and sauros meaning "lizard") is a genus of coelurosaurian theropod dinosaur. The species Tyrannosaurus rex , commonly abbreviated to T. rex, is a fixture in popular culture. It lived throughout what is now western North America, with a much wider range than other...

, probably had a bite force 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 that 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
Ball and socket joint
A ball and socket joint is a joint in which the distal bone is capable of motion around an indefinite number of axes, which have one common center...

. The secondary palate and procoelous vertebrae are advanced features also found in modern eusuchia
Eusuchia
Eusuchia is a clade of crocodylomorphs that first appears in the Early Cretaceous with Hylaeochampsa. All living crocodilian species are eusuchians, as are many extinct forms.-Description:...

n crocodilians.

The osteoderm
Osteoderm
Osteoderms are bony deposits forming scales, plates or other structures in the dermal layers of the skin. Osteoderms are found in many groups of extant and extinct reptiles, including lizards, various groups of dinosaurs , crocodilians, phytosaurs, aetosaurs, placodonts, and hupehsuchians...

s (scutes) covering the back of Deinosuchus were unusually large, heavy, and deeply pitted; some were of a roughly semispherical shape. Deep pits and grooves on these osteoderms served as attachment points for connective tissues. Together, the osteoderms and connective tissues would have served as load-bearing reinforcement to support the massive body of Deinosuchus out of water. Consequently, despite its bulk, Deinosuchus was probably almost as agile on land as its modern relatives.

Size

Because the known remains of Deinosuchus are so fragmentary, estimates of its size have varied significantly. In 1954, Edwin H. Colbert
Edwin Harris Colbert
Edwin Harris Colbert was a distinguished American vertebrate paleontologist and prolific researcher and author. He received his A.B. from the University of Nebraska, then his Masters and Ph.D. from Columbia University, finishing in 1935.Born in Clarinda, Iowa, he grew up in Maryville, Missouri...

 and Roland T. Bird reconstructed the lower jaw of Deinosuchus with a length of 2 m (6.6 ft), and calculated "on the basis of comparative measurements" that the giant crocodilian's total body length could have been up to 15 m (49.2 ft). A much lower estimate—8 to 10 m (26.2 to 32.8 ft)—was given by Gregory M. Erickson and Christopher A. Brochu in 1999. David R. Schwimmer noted in 2002 that the smaller and more common form of Deinosuchus found in eastern North America usually had skulls about 1 m (3.3 ft) long. Using an equation based on skull size, Schwimmer estimated that they probably had a total body length of about 8 m (26.2 ft), and weighed about 2.3 metric tons (2.5 ST). According to Schwimmer's research, Deinosuchus reached larger sizes in the western portion of the continent. A reasonably well-preserved skull specimen discovered in Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

 indicated that the animal's head measured about 1.31 m (4.3 ft), and from this Schwimmer calculated a body length of 9.8 m (32.2 ft). Although the largest remains of Deinosuchus had skulls too poorly preserved to use this method of estimation, scaling from vertebrae indicates that some of them grew to even larger sizes. Schwimmer estimates that the biggest specimens had a total body length of up to 12 m (39.4 ft), and perhaps weighed 8.5 metric tons (9.4 ST) or more.

Although there is some disagreement as to its exact size, the fossil remains are nonetheless sufficient to indicate that Deinosuchus was substantially larger than any modern crocodilian. Even the relatively low estimate provided by Erickson and Brochu suggests that the maximum weight reached by Deinosuchus exceeded that of currently living species by a factor of three to five. Deinosuchus has often been described as the largest crocodilian of all time, but some other crocodyliforms—including Purussaurus
Purussaurus
Purussaurus is an extinct genus of giant caiman that lived in South America during the Miocene epoch, 8 million years ago. It is known from skull material found in the Brazilian, Colombian and Peruvian Amazonia, and northern Venezuela. The estimated skull length for one large individual of the type...

, Rhamphosuchus
Rhamphosuchus
Rhamphosuchus is an extinct relative of the modern false gharial. It inhabited what is now the Indian sub-continent in the Miocene...

, and Sarcosuchus
Sarcosuchus
Sarcosuchus is an extinct genus of crocodyliform and distant relative of the crocodile that lived 112 million years ago. It dates from the early Cretaceous Period of what is now Africa and is one of the largest giant crocodile-like reptiles that ever lived...

—may have equaled or exceeded it in size.

Habitat

Deinosuchus was present on both sides of the Western Interior Seaway
Western Interior Seaway
The Western Interior Seaway, also called the Cretaceous Seaway, the Niobraran Sea, and the North American Inland Sea, was a huge inland sea that split the continent of North America into two halves, Laramidia and Appalachia, during most of the mid- and late-Cretaceous Period...

. Specimens have been found in ten of the modern-day United States. A Deinosuchus osteoderm from the San Carlos Formation
San Carlos Formation
The San Carlos Formation is a geological formation in west Texas whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.-References:...

 was also reported in 2006, so the giant crocodilian's range may have included parts of northern Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...

. Deinosuchus fossils are most abundant in the Gulf Coastal Plain
Gulf Coastal Plain
The Gulf Coastal Plain extends around the Gulf of Mexico in the Southern United States and eastern Mexico.The plain reaches from the western Florida Panhandle, the southwestern two thirds of Alabama, over most of Mississippi, some of western Tennessee and Kentucky, southwest Arkansas, the Florida...

 region of Georgia, near the Alabama border. All known specimens of Deinosuchus were found in rocks that date to the Campanian
Campanian
The Campanian is, in the ICS' geologic timescale, the fifth of six ages of the Late Cretaceous epoch . The Campanian spans the time from 83.5 ± 0.7 Ma to 70.6 ± 0.6 Ma ...

 stage of the Late Cretaceous
Late Cretaceous
The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...

 period. The oldest examples of this genus lived approximately 80 Ma, and the youngest lived around 73 Ma.

The distribution of Deinosuchus specimens indicates that these giant crocodilians may have preferred estuarine
Estuary
An estuary is a partly enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea....

 environments. In the Aguja Formation
Aguja Formation
The Aguja Formation is a geological formation in North America, exposed in Texas, whose strata date back to the Late Cretaceous. Dinosaur remains are among the fossils that have been recovered from the formation.-Ammonites:-Crurotarsans:...

 of Texas, where some of the largest specimens of Deinosuchus have been found, these massive predators probably inhabited brackish-water
Brackish water
Brackish water is water that has more salinity than fresh water, but not as much as seawater. It may result from mixing of seawater with fresh water, as in estuaries, or it may occur in brackish fossil aquifers. The word comes from the Middle Dutch root "brak," meaning "salty"...

 bay
Bay
A bay is an area of water mostly surrounded by land. Bays generally have calmer waters than the surrounding sea, due to the surrounding land blocking some waves and often reducing winds. Bays also exist as an inlet in a lake or pond. A large bay may be called a gulf, a sea, a sound, or a bight...

s. Although some specimens have also been found in marine
Ocean
An ocean is a major body of saline water, and a principal component of the hydrosphere. Approximately 71% of the Earth's surface is covered by ocean, a continuous body of water that is customarily divided into several principal oceans and smaller seas.More than half of this area is over 3,000...

 deposits, it is not clear whether Deinosuchus ventured out into the ocean (like modern-day saltwater crocodiles
Saltwater Crocodile
The saltwater crocodile, also known as estuarine or Indo-Pacific crocodile, is the largest of all living reptiles...

); these remains might have been displaced after the animals died. Deinosuchus has been described as a "conspicuous" component of a purportedly distinct biome occupying the southern half of Late Cretaceous North America.

Diet

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". Colbert restated this hypothesis more confidently in 1961: "Certainly this crocodile must have been a predator of dinosaurs; otherwise why would it have been so overwhelmingly gigantic? It hunted in the water where the giant theropods could not go." David R. Schwimmer proposed in 2002 that several hadrosaurid
Hadrosaurid
Hadrosaurids or duck-billed dinosaurs are members of the family Hadrosauridae, and include ornithopods such as Edmontosaurus and Parasaurolophus. They were common herbivores in the Upper Cretaceous Period of what are now Asia, Europe and North America. They are descendants of the Upper...

 tail vertebrae found near Big Bend National Park
Big Bend National Park
Big Bend National Park is a national park located in the U.S. state of Texas. Big Bend has national significance as the largest protected area of Chihuahuan Desert topography and ecology in the United States, which includes more than 1,200 species of plants, more than 450 species of birds, 56...

 show evidence of Deinosuchus tooth marks, strengthening the hypothesis that Deinosuchus fed on dinosaurs in at least some instances. In 2003, Christopher A. Brochu did not find the tooth mark evidence to be compelling, but nonetheless agreed that Deinosuchus "probably dined on ornithopod
Ornithopod
Ornithopods or members of the clade Ornithopoda are a group of ornithischian dinosaurs that started out as small, bipedal running grazers, and grew in size and numbers until they became one of the most successful groups of herbivores in the Cretaceous world, and dominated the North American...

s from time to time." 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.

Schwimmer and G. Dent Williams proposed in 1996 that Deinosuchus may have preyed on marine turtles
Sea turtle
Sea turtles are marine reptiles that inhabit all of the world's oceans except the Arctic.-Distribution:...

. Deinosuchus would probably have used the robust, flat teeth near the back of its jaws to crush the turtle shells. The "side-necked
Pleurodira
The Pleurodira are one of the two living suborders of turtles, the other being the Cryptodira. In many cases in the nomenclature of animals, ranks such as suborder are considered of little importance apart from nomenclatural or taxonomic reasons. However, this is not the case with the suborders of...

" sea turtle Bothremys
Bothremydidae
Bothremydidae is an extinct family of side-necked turtle. They belong to sub-order Pleurodira and order Testudines. Bothremydidae lived in fresh water and were amphibious. They were actively mobile omnivores.-Taxonomy:...

 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.

Schwimmer concluded in 2002 that the feeding patterns of Deinosuchus most likely varied by geographic location; the smaller Deinosuchus of eastern North America would have been opportunistic feeders in an ecological niche similar to that of the modern American alligator
American Alligator
The American alligator , sometimes referred to colloquially as a gator, is a reptile endemic only to the Southeastern United States. It is one of the two living species of alligator, in the genus Alligator, within the family Alligatoridae...

. They would have consumed marine turtles, large fish, and smaller dinosaurs. The bigger, but less common, Deinosuchus that lived in Texas and Montana might have been more specialized hunters, capturing and eating large dinosaurs. Schwimmer noted that no theropod dinosaurs in Deinosuchuss eastern range approached its size, indicating that the massive crocodilian could have been the region's apex predator
Apex predator
Apex predators are predators that have no predators of their own, residing at the top of their food chain. Zoologists define predation as the killing and consumption of another organism...

.

Growth rates

A 1999 study by Gregory M. Erickson and Christopher A. Brochu suggested that the growth rate of Deinosuchus was comparable to that of modern crocodilians, but was maintained over a far longer period of time. Their estimates, based on growth rings in the dorsal
Dorsum (biology)
In anatomy, the dorsum is the upper side of animals that typically run, fly, or swim in a horizontal position, and the back side of animals that walk upright. In vertebrates the dorsum contains the backbone. The term dorsal refers to anatomical structures that are either situated toward or grow...

 osteoderms of various specimens, indicate that each Deinosuchus might have taken over 35 years to reach full adult size, and that the oldest individuals may have lived for more than 50 years. This was a completely different growth strategy than that of large dinosaurs, which reached adult size much more quickly and had shorter lifespans. According to Erickson, a full-grown Deinosuchus "must have seen several generations of dinosaurs come and go".

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 in Deinosuchus 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 was biannual rather than annual, this might indicate that Deinosuchus grew faster than modern crocodilians, and had a similar maximum lifespan.

Discovery and naming

In 1858, geologist
Geologist
A geologist is a scientist who studies the solid and liquid matter that constitutes the Earth as well as the processes and history that has shaped it. Geologists usually engage in studying geology. Geologists, studying more of an applied science than a theoretical one, must approach Geology using...

 Ebenezer Emmons
Ebenezer Emmons
Ebenezer Emmons , was a pioneering American geologist.Emmons was born at Middlefield, Massachusetts, on May 16, 1799, son of Ebenezer and Mary Emmons....

 described two large fossil teeth found in Bladen County, North Carolina
Bladen County, North Carolina
-Demographics:As of the census of 2000, there were 32,278 people, 12,897 households, and 8,937 families residing in the county. The population density was 37 people per square mile . There were 15,316 housing units at an average density of 18 per square mile...

. Emmons assigned these teeth to Polyptychodon
Polyptychodon
Polyptychodon is an extinct genus of sauropterygian reptile belonging to the family Pliosauridae that lived during the Cretaceous. Its fossils have been found in Europe and North America....

, which he then believed to be "a genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 of crocodilian reptiles". Later discoveries showed that Polyptychodon was actually a pliosaur
Pliosaur
Pliosauroidea is an extinct clade of marine reptiles. Pliosauroids, also commonly known as pliosaurs, are known from the Jurassic and Cretaceous Periods. The pliosauroids were short-necked plesiosaurs with large heads and massive toothed jaws. These swimming reptiles were not dinosaurs but distant...

, a type of marine reptile. The teeth described by Emmons were thick, slightly curved, and covered with vertically grooved enamel; he assigned them a new species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 name, P. rugosus. Although not initially recognized as such, these teeth were probably the first Deinosuchus remains to be scientifically described. Another large tooth that likely came from Deinosuchus, discovered in neighboring Sampson County
Sampson County, North Carolina
-Demographics:As of the census of 2010, there were 63,431 people, 22,624 households, and 16,214 families residing in the county. The population density was 67.1 people per square mile . There were 26,476 housing units at an average density of 27 per square mile...

, was named Polydectes biturgidus by Edward Drinker Cope
Edward Drinker Cope
Edward Drinker Cope was an American paleontologist and comparative anatomist, as well as a noted herpetologist and ichthyologist. Born to a wealthy Quaker family, Cope distinguished himself as a child prodigy interested in science; he published his first scientific paper at the age of nineteen...

 in 1869.

In 1903, at Willow Creek, Montana
Willow Creek, Montana
Willow Creek is a census-designated place in Gallatin County, Montana, United States. The population was 209 at the 2000 census. It is part of the 'Bozeman Micropolitan Statistical Area'.-Geography:Willow Creek is located at ....

, several fossil osteoderms were discovered "lying upon the surface of the soil" by John Bell Hatcher
John Bell Hatcher
John Bell Hatcher was an American paleontologist and fossil hunter best known for discovering Torosaurus.-Biography:...

 and T.W. Stanton. These osteoderms were initially attributed to the ankylosaurid
Ankylosauridae
An ankylosaurid is a member of the Ankylosauridae family of armored dinosaurs that evolved 125 million years ago and became extinct 65 million years ago during the Cretaceous-Tertiary extinction event...

 dinosaur Euoplocephalus
Euoplocephalus
Euoplocephalus was one of the largest genera of ankylosaurian dinosaurs, at about the size of a small elephant. It is also the ankylosaurian with the best fossil record, so its extensive spiked armor, low-slung body and great club-like tail are well documented.-Description:Among the...

. Excavation at the site, carried out by W.H. Utterback, yielded further fossils, including additional osteoderms as well as vertebrae, rib
Rib
In vertebrate anatomy, ribs are the long curved bones which form the rib cage. In most vertebrates, ribs surround the chest, enabling the lungs to expand and thus facilitate breathing by expanding the chest cavity. They serve to protect the lungs, heart, and other internal organs of the thorax...

s, and a pubis
Pubis (bone)
In vertebrates, the pubic bone is the ventral and anterior of the three principal bones composing either half of the pelvis.It is covered by a layer of fat, which is covered by the mons pubis....

. When these specimens were examined, it became clear that they belonged to a large crocodilian and not a dinosaur; upon learning this, Hatcher "immediately lost interest" in the material. After Hatcher died in 1904, his colleague W.J. Holland
William Jacob Holland
William Jacob Holland was the eighth Chancellor of the University of Pittsburgh and Director of the Carnegie Museums of Pittsburgh. He was an accomplished zoologist and paleontologist, as well as an ordained Presbyterian minister.-Life:Holland was born August 16, 1848 in Jamaica, West Indies, the...

 studied and described the fossils. Holland assigned these specimens to a new genus and species, Deinosuchus hatcheri, in 1909. Deinosuchus comes from the Greek
Ancient Greek
Ancient Greek is the stage of the Greek language in the periods spanning the times c. 9th–6th centuries BC, , c. 5th–4th centuries BC , and the c. 3rd century BC – 6th century AD of ancient Greece and the ancient world; being predated in the 2nd millennium BC by Mycenaean Greek...

 δεινός/deinos, meaning "terrible", and σουχος/suchos, meaning "crocodile".

A 1940 expedition by the American Museum of Natural History
American Museum of Natural History
The American Museum of Natural History , located on the Upper West Side of Manhattan in New York City, United States, is one of the largest and most celebrated museums in the world...

 yielded more fossils of giant crocodilians, this time from Big Bend National Park
Big Bend National Park
Big Bend National Park is a national park located in the U.S. state of Texas. Big Bend has national significance as the largest protected area of Chihuahuan Desert topography and ecology in the United States, which includes more than 1,200 species of plants, more than 450 species of birds, 56...

 in Texas
Texas
Texas is the second largest U.S. state by both area and population, and the largest state by area in the contiguous United States.The name, based on the Caddo word "Tejas" meaning "friends" or "allies", was applied by the Spanish to the Caddo themselves and to the region of their settlement in...

. These specimens were described by Edwin H. Colbert and Roland T. Bird in 1954, under the name Phobosuchus riograndensis. Donald Baird and Jack Horner
Jack Horner (paleontologist)
John "Jack" R. Horner is an American paleontologist who discovered and named Maiasaura, providing the first clear evidence that some dinosaurs cared for their young. He is one of the best-known paleontologists in the United States...

 later assigned the Big Bend remains to Deinosuchus, which has been accepted by most modern authorities. The genus name Phobosuchus, which was initially created by Baron Franz Nopcsa
Franz Nopcsa von Felso-Szilvás
Baron Franz Nopcsa von Felső-Szilvás was a Hungarian-born aristocrat, adventurer, scholar, and paleontologist...

 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.

The American Museum of Natural History incorporated the skull and jaw fragments into a plaster restoration, modeled after the present-day Cuban crocodile
Cuban crocodile
The Cuban crocodile is a small species of crocodile found only in Cuba's Zapata Swamp and the Isle of Youth, and highly endangered, though it formerly ranged elsewhere in the Caribbean...

. Colbert and Bird stated that 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
Saltwater Crocodile
The saltwater crocodile, also known as estuarine or Indo-Pacific crocodile, is the largest of all living reptiles...

 had been used as the template. Because it was not then known that Deinosuchus had a broad snout, Colbert and Bird miscalculated the proportions of the skull, and the reconstruction greatly exaggerated its overall width and length. Despite its inaccuracies, the reconstructed skull became the best-known specimen of Deinosuchus, and brought public attention to this giant crocodilian for the first time.

Numerous additional specimens of Deinosuchus were discovered over the next several decades. Most were quite fragmentary, but they expanded knowledge of the giant predator's geographic range. As noted by Christopher A. Brochu, the osteoderms are distinctive enough that even "bone granola" can adequately confirm the presence of Deinosuchus. Better cranial material was also found; by 2002, David R. Schwimmer was able to create a composite computer reconstruction of 90% of the skull.

Classification

Deinosuchus was classified in the family Crocodylidae
Crocodile
A crocodile is any species belonging to the family Crocodylidae . The term can also be used more loosely to include all extant members of the order Crocodilia: i.e...

 by Colbert and Bird, primarily on the basis of dental features resembling those of modern crocodiles. However, a phylogenetic
Phylogenetics
In biology, phylogenetics is the study of evolutionary relatedness among groups of organisms , which is discovered through molecular sequencing data and morphological data matrices...

 re-evaluation conducted in 1999 by Brochu determined that Deinosuchus was actually a primitive member of Alligatoroidea
Alligatoroidea
Alligatoroidea is a superfamily of crocodilians that evolved in the Late Cretaceous period. Cladistically, it is defined as Alligator mississippiensis and all crocodylians more closely related to A. mississippiensis than to either Crocodylus niloticus or Gavialis gangeticus ....

. Thus, Deinosuchus "is not the world's largest crocodile—it is one of the largest alligators." This classification was bolstered in 2005 by the discovery of a well-preserved Deinosuchus braincase
Skull
The skull is a bony structure in the head of many animals that supports the structures of the face and forms a cavity for the brain.The skull is composed of two parts: the cranium and the mandible. A skull without a mandible is only a cranium. Animals that have skulls are called craniates...

 from the Blufftown Formation of Alabama, which shows some features reminiscent of those in the modern American alligator. Although it was a prehistoric member of the same clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...

, Deinosuchus was not a direct ancestor of modern alligators. Its closest relatives may have been Leidyosuchus
Leidyosuchus
Leidyosuchus is an extinct genus of alligatoroid from the Late Cretaceous of Alberta. It was named in 1907 by Lawrence Lambe, and the type species is L. canadensis. It is known from a number of specimens from the middle Campanian age Dinosaur Park Formation...

 and Diplocynodon
Diplocynodon
Diplocynodon is an extinct genus of alligatoroid that lived during the Paleocene to middle Miocene 49 million years ago in Europe. It looked very similar to the modern caiman in that it was small and had bony armour scutes covering its neck, back, belly, and tail...

.

Schwimmer (2002) considered all Deinosuchus specimens to belong to one species. He noted that there were more similarities than differences between the eastern and western populations, and that most of these differences related only to the larger size of the western specimens. Under the International Code of Zoological Nomenclature
International Code of Zoological Nomenclature
The International Code of Zoological Nomenclature is a widely accepted convention in zoology that rules the formal scientific naming of organisms treated as animals...

's rules of priority, this species would be named D. rugosus. Lucas et al. (2006) also considered Deinosuchus a monospecific
Monospecificity
In zoology, "monospecific" is an adjective describing a genus which contains only one known species. The term comes from the Greek prefix "μονο-" meaning "single" and Latin "species" meaning "kind" or "type". It is thus of hybrid origin....

 genus. However, Brochu (2003) questioned Schwimmer's analysis, suggesting that size might be a significant diagnostic feature and that several of the features used by Schwimmer to establish synonymy
Synonym (taxonomy)
In scientific nomenclature, a synonym is a scientific name that is or was used for a taxon of organisms that also goes by a different scientific name. For example, Linnaeus was the first to give a scientific name to the Norway spruce, which he called Pinus abies...

 between the two populations are actually primitive traits shared by other genera as well. Schwimmer (2002) informally referred to the western populations as D. riograndensis, and several other researchers, including Anglen and Lehman (2000) and Westgate et al. (2006) have also recently assigned western Deinosuchus remains to this species.
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