{{Otheruses}}{{pp-semi-protected|small=yes}}{{Otheruses}}{{pp-semi-protected|small=yes}}
{{Taxobox
| image = Deinosuchus hatcheri.JPG
| image_caption = Life restoration of
Deinosuchus rugosus
| fossil_range = {{fossil range|80|73}}Late
CretaceousThe Cretaceous , Latin language for "chalky", 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 on the Jurassic period and is followed by the Paleogene period of the...
| regnum =
AnimalAnimals are a major group of mostly multicellular, eukaryotic organisms of the kingdom Animalia or Metazoa. Their body plan eventually becomes fixed as they develop, although some undergo a process of metamorphosis later on in their life. Most animals are motile, meaning they can move spontaneously...
ia
| phylum =
ChordataChordates are animals which are either vertebrates or one of several closely related invertebrates. They are united by having, for at least some period of their life cycle, a notochord, a hollow dorsal nerve cord, pharyngeal slits, an endostyle, and a post-anal tail...
| classis =
SauropsidaReptiles, or members of the class Reptilia, are air-breathing, generally "cold-blooded" amniotes that generally have skin covered in scales or scutes. They are tetrapods and lay amniote eggs, whose embryos are surrounded by the amnion membrane...
| ordo =
CrocodiliaCrocodilia is an order of large reptiles that appeared about 84 million years ago in the late Cretaceous Period . They are the closest living relatives of birds, as the two groups are the only known survivors of the Archosauria...
| subordo =
EusuchiaEusuchia 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:...
| superfamilia =
AlligatoroideaAlligatoroidea 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 ....
| genus =
Deinosuchus
| genus_authority =
HollandWilliam Jacob Holland was the eighth Chancellor of the University of Pittsburgh and Director of the Carnegie Museums of Pittsburgh...
, 1909
| subdivision_ranks =
SpeciesIn biology, a species is:* a taxonomic rank or* a unit at that rank ....
| subdivision =
- D. rugosus (Emmons
Ebenezer Emmons , American geologist, was born at Middlefield, Massachusetts, on the 16th of May 1799, son of Ebenezer and Mary Emmons.He studied medicine at Albany, and after taking his degree practised for some years in Berkshire county...
, 1858 [originally PolyptychodonPolyptychodon 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....
rugosus])(typeIn taxonomy, a type species is a technical phrase, involved in the application of formal names...
)
- ?D. riograndensis (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 Bird, 1954)
| synonyms =
- Polydectes 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 quickly distinguished himself as a child prodigy interested in science; he published his first scientific paper at the age of...
, 1869
- Phobosuchus Nopsca
Baron Franz Nopcsa von Felső-Szilvás was a Hungarian-born aristocrat, adventurer, scholar, and paleontologist...
, 1924}}
Deinosuchus ({{pron-en|ˌdaɪnəˈsuːkəs}} {{respell|DYE|no|S
OO|kəs}}) is an extinct relative of the
alligatorAn Alligator is a crocodilian in the genus Alligator of the family Alligatoridae. The name alligator is an anglicized form of el lagarto the Spanish term for "lizard", the name by which early Spanish explorers and settlers in Florida called the alligator...
that lived 80 to 73
MaAnnum is a form of the Latin noun annus meaning year, from which are derived words such as annual and annuity. Annum is the accusative singular of the 2nd declension masculine noun annus , anni...
(million years ago), during the
Late CretaceousThe Late Cretaceous is the youngest of two epochs in which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...
period. The name translates as "terrible crocodile" and is derived from the
GreekAncient Greek is the historical stage in the development of the Greek language spanning across the Archaic , Classical , and Hellenistic periods of ancient Greece and the ancient world. It is predated in the 2nd millennium BC by Mycenaean Greek...
δεινός/
deinos ("terrible") and
σουχος/
soukhos ("crocodile"). The first remains were discovered in
North CarolinaNorth Carolina is a state located on the Atlantic Seaboard 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...
in the 1850s, but it was not until 1909 that the
genusIn biology, a genus is a taxonomic unit used in the classification of living and fossil organisms. The term comes from Latin genus "descent, family, type, gender" , cognate with – genos, "race, stock, kin" ..In addition, genus is a taxonomic rank in the hierarchy In biology, a genus (plural:...
was named and described. Additional fragments were discovered in the 1940s and were later incorporated into an influential, though inaccurate, skull reconstruction at the
American Museum of Natural HistoryThe American Museum of Natural History , located on the Upper West Side, Manhattan, New York, USA, is one of the largest and most celebrated museums in the world...
. Knowledge of
Deinosuchus remains incomplete, but better
cranialThe skull is a bony structure found in the head of many animals. The skull supports the structures of the face and protects the head against injury....
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 {{Convert|12|m|ft|sigfig=1|abbr=on|abbr=on}} and weighing up to {{convert|8.5|MT|ST}}—its overall appearance was fairly similar to its smaller relatives. It had large, robust teeth that were built for crushing, and its back was covered with thick semispherical
osteodermOsteoderms 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 Nanchangosaurus...
s. One study indicates that
Deinosuchus may have lived for up to 50 years, growing at a similar rate 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. stateA U.S. state is any one of 50 federated states of the United States of America that share sovereignty with the federal government . Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile...
s, as well as northern Mexico. It lived on both sides of the
Western Interior SeawayThe 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 during most of the mid and late Cretaceous Period.-Origin and geology:The Seaway was created as the...
, and was an opportunistic
apex predatorApex predators is a predator that has virtually no predators of its own, residing at the top of its food chain...
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
speciesIn biology, a species is:* a taxonomic rank or* a unit at that rank ....
.
Deinosuchus was probably capable of killing and eating large
dinosaur{{Otheruses}}{{pp-semi-protected|small=yes}}{{Otheruses}}{{pp-semi-protected|small=yes}}{{Taxobox|name = Dinosaurs|fossil_range = {{Fossil range|230|65|earliest=230|latest=0|PS=
Descendant taxon Aves survives to present.}}|image = field_dinos_2.jpg...
s. It may have also fed upon
sea turtleSea Turtles inhabit all the world's oceans except the Arctic.-Distribution:The superfamily Chelonioidea has a worldwide distribution; sea turtles can be found in all oceans except for the polar regions. Some species travel between oceans...
s, fish, and other aquatic and terrestrial prey.
Morphology
Despite its massive size, the overall appearance of
Deinosuchus was not considerably different from that of modern crocodilians.
Deinosuchus had an
alligatorAn Alligator is a crocodilian in the genus Alligator of the family Alligatoridae. The name alligator is an anglicized form of el lagarto the Spanish term for "lizard", the name by which early Spanish explorers and settlers in Florida called the alligator...
-like broad snout, with a slightly bulbous tip. Each
premaxillaThe 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
maxillaThe 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 is sometimes called "upper maxilla", with the mandible being the "lower 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
jawThe 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.
The bite force of
Deinosuchus has been estimated to exceed {{convert|18000|N|lbf}}. In contrast, modern
American alligatorsThe American Alligator, Alligator mississippiensis, is one of the two living species of Alligator, a genus within the family Alligatoridae. The American Alligator is native only to the Southeastern United States, where it inhabits wetlands that frequently overlap with human-populated areas...
, with the strongest bite of any living animal, have a maximum force of {{convert|9452|N|lbf}}. Even the largest and strongest
theropodTheropods are a group of bipedal saurischian dinosaurs. Although they were primarily carnivorous, a number of theropod families evolved herbivory during the Cretaceous Period...
dinosaurs, such as
TyrannosaurusTyrannosaurus was a genus of 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 tyrannosaurids...
, 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
vertebraA vertebra is an individual bone in the flexible column that defines vertebrate animals, e.g. humans. The vertebral column encases and protects the spinal cord, which runs from the base of the cranium down the dorsal side of the animal until reaching the pelvis. From there, vertebra continue into...
e 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 jointA 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
eusuchiaEusuchia 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
osteodermOsteoderms 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 Nanchangosaurus...
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. ColbertEdwin 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 {{Convert|2|m|ft|sigfig=2|abbr=on|abbr=on}}, and calculated "on the basis of comparative measurements" that the giant crocodilian's total body length could have been up to {{Convert|15|m|ft|sigfig=1|abbr=on|abbr=on}}. A much lower estimate—{{Convert|8|to|10|m|ft|sigfig=2|abbr=on|abbr=on}}—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 {{Convert|1|m|ft|sigfig=2|abbr=on}} long. Using an equation based on skull size, Schwimmer estimated that they probably had a total body length of about {{Convert|8|m|ft|sigfig=2|abbr=on}}, and weighed about {{convert|2.3|MT|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
TexasTexas is the second-largest U.S. state in both area and population, and the largest state in the contiguous United States.The name had wide usage among native Americans, meaning "friends" or "allies"...
indicated that the animal's head measured about {{Convert|1.31|m|ft|sigfig=3|abbr=on}}, and from this Schwimmer calculated a body length of {{Convert|9.8|m|ft|sigfig=3|abbr=on}}. 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 {{Convert|12|m|ft|sigfig=1|abbr=on}}, and perhaps weighed {{convert|8.5|MT|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
PurussaurusPurussaurus was a giant caiman living 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, besides in the north of Venezuela...
,
RhamphosuchusRhamphosuchus is an extinct relative of the modern gharial and false gharial. It inhabited what is now the Indian sub-continent in the Miocene and Pliocene. It is only known from incomplete sets of fossils, mostly teeth and skulls...
, and
SarcosuchusSarcosuchus is an extinct genus of crocodyliform and distant relative of the crocodile. 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 appears to have had a wide distribution throughout the United States, and was present on both sides of the
Western Interior SeawayThe 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 during most of the mid and late Cretaceous Period.-Origin and geology:The Seaway was created as the...
. Specimens have been found in
AlabamaAlabama is a state located in the southeastern region of the United States of America. It is bordered by Tennessee to the north, Georgia to the east, Florida and the Gulf of Mexico to the south, and Mississippi to the west. Alabama ranks 30th in total land area and ranks second in the size of its...
,
GeorgiaGeorgia is a state in the United States. One of the original Thirteen Colonies that revolted against British rule in the American Revolution, it had been the last of the Thirteen Colonies to be established, in 1733. Georgia was the fourth state to ratify the United States Constitution, on January...
,
MississippiMississippi is a state located in the Southern United States. Jackson is the state capital and largest city. The state's name comes from the Mississippi River, which flows along its western boundary, and takes its name from the Ojibwe word misi-ziibi . The state is heavily forested outside of the...
,
MontanaMontana is a state in the Western United States. The western third of the state contains numerous mountain ranges; other 'island' ranges are found in the central third of the state, for a total of 77 named ranges of the Rocky Mountains. This geographical fact is reflected in the state's name,...
,
New JerseyNew Jersey is a state in the Mid-Atlantic region of the United States. It is bordered on the north by New York, and to the east by the Hudson River, Upper New York Bay, the Kill Van Kull, Newark Bay, the Arthur Kill, Raritan Bay, Sandy Hook Bay, Westchester County, New York City, Long Island, and...
,
New MexicoNew Mexico is a state located in the southwestern region of the United States. Inhabited by Native American populations for many centuries, it has also been part of the Imperial Spanish viceroyalty of New Spain, part of Mexico, and a U.S. territory. Among U.S...
,
North CarolinaNorth Carolina is a state located on the Atlantic Seaboard 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...
,
TexasTexas is the second-largest U.S. state in both area and population, and the largest state in the contiguous United States.The name had wide usage among native Americans, meaning "friends" or "allies"...
,
UtahUtah is a western state of the United States. It was the 45th state admitted to the Union, on January 4, 1896. Approximately 80 percent of Utah's 2,736,424 people live along the Wasatch Front, centering around Salt Lake City. In contrast, vast expanses of the state are nearly uninhabited, making...
, and
WyomingWyoming is a state in the Western United States. The majority of the state is dominated by the mountain ranges and rangelands of the Rocky Mountain West, while the easternmost section of the state includes part of a high elevation prairie region known as the High Plains. While the tenth largest...
. A
Deinosuchus osteoderm from the
San Carlos FormationThe 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
MexicoThe 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 PlainThe Gulf Coastal Plain extends from the Florida Parishes of Louisiana over most of Mississippi, some of western Tennessee and Kentucky, the southwestern 2/3 of Alabama, and the western Florida Panhandle and Southern Texas. Its southern boundary is the Gulf of Mexico and its western boundary the...
region of Georgia, near the Alabama border. All known specimens of
Deinosuchus were found in rocks that date to the
CampanianThe 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 CretaceousThe Late Cretaceous is the youngest of two epochs in 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
estuarineAn estuary is a semi-enclosed coastal body of water with one or more rivers or streams flowing into it, and with a free connection to the open sea. Estuaries are thus subject to both marine influences, such as tides, waves, and the influx of saline water; and riverine influences, such as flows of...
environments. In the
Aguja FormationThe 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.-References:...
of Texas, where some of the largest specimens of
Deinosuchus have been found, these massive predators probably inhabited
brackish-waterBrackish 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 "salten" or "salty"...
bayA bay is an area of water mostly surrounded or otherwise demarcated by land. Bays generally have calmer waters than the surrounding sea, due to the surrounding land blocking some waves and often reducing winds....
s. Although some specimens have also been found in
marineAn ocean is a large body of saline water, and a principal component of the hydrosphere. Approximately 75% 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 crocodilesSaltwater or estuarine crocodile is the largest of all living reptiles. It is found in suitable habitats throughout Southeast Asia, Northern Australia, and the surrounding waters...
); these remains might have been displaced after the animals died.
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
hadrosauridHadrosaurids 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 ParkBig Bend National Park is a national park located in the U.S. state of Texas. For more than 1,000 miles , the Rio Grande / Río Bravo forms the international boundary between Mexico and the United States, and Big Bend National Park administers approximately along that boundary.Big Bend National...
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
ornithopodOrnithopods are a group of bird-hipped 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 landscape...
s from time to time."
Deinosuchus is generally thought to have employed similar hunting tactics to 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 turtlesSea Turtles inhabit all the world's oceans except the Arctic.-Distribution:The superfamily Chelonioidea has a worldwide distribution; sea turtles can be found in all oceans except for the polar regions. Some species travel between oceans...
.
Deinosuchus would probably have used the robust, flat teeth near the back of its jaws to crush the turtle shells. The "
side-neckedPleurodira are a group of southern-hemisphere turtles. They are called side-necked turtles, because in order to hide its head in its shell, the turtle must fold its neck to one side, instead of withdrawing it directly under its spine as in Cryptodira. Plus usually their necks are longer. There are...
" sea turtle
BothremysBothremydidae 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.-References:*...
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 alligatorThe American Alligator, Alligator mississippiensis, is one of the two living species of Alligator, a genus within the family Alligatoridae. The American Alligator is native only to the Southeastern United States, where it inhabits wetlands that frequently overlap with human-populated areas...
. 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 predatorApex predators is a predator that has virtually no predators of its own, residing at the top of its food chain...
.
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 dorsalIn 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, geologistFor other uses, see Geologist .A geologist is a scientist who studies the solid and liquid matter that constitutes the Earth and terrestrial planets...
Ebenezer EmmonsEbenezer Emmons , American geologist, was born at Middlefield, Massachusetts, on the 16th of May 1799, son of Ebenezer and Mary Emmons.He studied medicine at Albany, and after taking his degree practised for some years in Berkshire county...
described two large fossil teeth found in Bladen County, North CarolinaBladen County is a county located in the U.S. state of North Carolina. As of 2000, the population was 32,278. Its county seat is Elizabethtown.- History :...
. Emmons assigned these teeth to PolyptychodonPolyptychodon 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 genusIn biology, a genus is a taxonomic unit used in the classification of living and fossil organisms. The term comes from Latin genus "descent, family, type, gender" , cognate with – genos, "race, stock, kin" ..In addition, genus is a taxonomic rank in the hierarchy In biology, a genus (plural:...
of crocodilian reptiles". Later discoveries showed that Polyptychodon
was actually a pliosaurThe Pliosaurs were marine reptiles from the Jurassic and Cretaceous Periods. They originally included members of the family Pliosauridae, of the Order Plesiosauria, but several other genera and families are now also included; the number and details of which vary according to the classification used...
, 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 speciesIn biology, a species is:* a taxonomic rank or* a unit at that rank ....
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 CountySampson County is a county located in the U.S. state of North Carolina. As of 2000, the population was 60,161. Its county seat is Clinton.- History :...
, was named Polydectes biturgidus
by Edward Drinker CopeEdward Drinker Cope was an American paleontologist and comparative anatomist, as well as a noted herpetologist and ichthyologist. Born to a wealthy Quaker family, Cope quickly distinguished himself as a child prodigy interested in science; he published his first scientific paper at the age of...
in 1869.
In 1903, at Willow Creek, MontanaWillow Creek is a census-designated place in Gallatin County, Montana, United States. The population was 209 at the 2000 census.-Geography:Willow Creek is located at ....
, several fossil osteoderms were discovered "lying upon the surface of the soil" by John Bell HatcherJohn Bell Hatcher was an American paleontologist and fossil hunter best known for discovering Torosaurus....
and T.W. Stanton. These osteoderms were initially attributed to the ankylosauridAn 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 EuoplocephalusEuoplocephalus meaning 'well-armored head' was one of the largest genera of ankylosaurian dinosaurs, at about the size of a small elephant...
. Excavation at the site, carried out by W.H. Utterback, yielded further fossils, including additional osteoderms as well as vertebrae,
ribIn vertebrate anatomy, ribs are the long curved bones which form the ribcage. In most vertebrates, ribs surround the chest they enable lungs to expand by expanding the chest, they also protect the lungs, heart, and other internal organs of the thorax...
s, and a
pubisThe android 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.It is divisible into a body, a superior ramus and an inferior ramus....
. 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. HollandWilliam Jacob Holland was the eighth Chancellor of the University of Pittsburgh and Director of the Carnegie Museums of Pittsburgh...
studied and described the fossils. Holland assigned these specimens to a new genus and species, Deinosuchus hatcheri
, in 1909. Deinosuchus
comes from the GreekAncient Greek is the historical stage in the development of the Greek language spanning across the Archaic , Classical , and Hellenistic periods of ancient Greece and the ancient world. It is 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 HistoryThe American Museum of Natural History , located on the Upper West Side, Manhattan, New York, USA, is one of the largest and most celebrated museums in the world...
yielded more fossils of giant crocodilians, this time from Big Bend National ParkBig Bend National Park is a national park located in the U.S. state of Texas. For more than 1,000 miles , the Rio Grande / Río Bravo forms the international boundary between Mexico and the United States, and Big Bend National Park administers approximately along that boundary.Big Bend National...
in TexasTexas is the second-largest U.S. state in both area and population, and the largest state in the contiguous United States.The name had wide usage among native Americans, meaning "friends" or "allies"...
. These specimens were described by Edwin H. Colbert and Roland T. Bird in 1954, under the name Phobosuchus riograndensis
. Donald Baird and Jack HornerJohn "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 NopscaBaron 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 crocodileThe Cuban Crocodile is a small species of crocodile found only in Cuba's Zapata Swamp and the Isla de Juventud, and highly endangered, though it formerly ranged throughout 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 crocodileSaltwater or estuarine crocodile is the largest of all living reptiles. It is found in suitable habitats throughout Southeast Asia, Northern Australia, and the surrounding waters...
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 CrocodylidaeA crocodile is any species belonging to the family Crocodylidae . The term can also be used more loosely to include all 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 phylogeneticIn biology, phylogenetics is the study of evolutionary relatedness among various 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 AlligatoroideaAlligatoroidea 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
braincaseThe skull is a bony structure found in the head of many animals. The skull supports the structures of the face and protects the head against injury....
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 cladeA clade is a term used in modern alpha taxonomy, the scientific classification of living and fossil organisms, to describe a monophyletic group, defined as a group consisting of a single common ancestor and all its descendants.[The term "monophyletic group" is used in this article...]
, Deinosuchus
was not a direct ancestor of modern alligators. Its closest relatives may have been LeidyosuchusLeidyosuchus is an extinct genus of alligatorid 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 DiplocynodonDiplocynodon is an extinct genus of alligatoroid that lived from the Paleocene to the Miocene of Europe. Specimens in excellent preservation have been found at the Messel Pit in Germany.-Sources:...
.
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 NomenclatureThe International Code of Zoological Nomenclature is both a book containing a set of rules and recommendations on the formal naming of animals, and that set itself. Among zoologists it is often referred to simply as "the Code"...
's rules of priority, this species would be named D. rugosus
. Lucas et al.
(2006) also considered Deinosuchus a
monospecificIn 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
synonymyIn scientific nomenclature, synonyms are different scientific names used for a single taxon. Usage and terminology are different for zoology and botany.- Zoology :...
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.