Postosuchus
Encyclopedia
Postosuchus, meaning "crocodile from Post (Garza, Texas)", was a basal archosaur
that lived in what is now North America
during the middle through to the late Triassic
period (228-202 million years ago). It was a rauisuchia
n, a close relative of crocodiles
, as a member of the clade Pseudosuchia
(or Crurotarsi
) which, along with the lineage that led to dinosaur
s and Birds, forms Archosauria. Its name refers to Post Quarry, a place in Texas
where many fossils of this genus were found. It was one of the apex predator
s of its area during the Triassic, larger than the small dinosaur predators of its time (such as Coelophysis
). It was a hunter which probably preyed on dicynodont
s and many other creatures smaller than itself.
Postosuchus was a quadruped
al reptile
with a wide skull and a long tail. This carnivore
attacked with its large curved claws. It was about 4–5 meters long (12–15 feet), and was held up by columnar legs (a quite uncommon feature in reptiles). A crocodile-like snout, filled with many large-sized dagger-like teeth, was used to kill its prey. Rows of protective plates covering its back formed a defensive shield.
). Postosuchus had very good long distant sight, due to large orbits
, supporting large and sharp eyes, and strong olfaction provided by elongated nostrils. Inside the skull, under the nostrils, there was a hollowing that probably was for the Jacobson's organ, an olfactory sensory organ sometimes referred as the "sixth sense". The jaws held large and sharp serrated teeth and in some points were developed even larger to operate as hooked sabers. A complete tooth found among Postosuchus remains in North Carolina
measured about 7.2 cm in height. Postosuchus possessed heterodonty dentition, which means each tooth was different in size and shape from the others. The upper jaw composed of seventeen teeth, with each premaxilla
bore only four teeth and each maxilla
thirteen teeth. In the lower jaw were counted over thirty teeth. Replacement activity in Postosuchus was different from that of crocodiles, since the replacement tooth didn't fit directly in the pulp cavity of the old tooth, but grew until resorption of the old tooth was complete.
followed by sixteen dorsals, while four co-ossified sacral vertebrae supported the hips. It is thought to be over thirty vertebrae in the tail decreasing in size to the end. The pelvis
with the hooked pubis
and the rod-like ischium looked like those of carnosaur dinosaurs. Along with remains of the skeleton, paleontologists also identify osteoderms, which were thick plates forming scales. These were on its back, neck, and possibly above or under the tail. The ribcage of Postosuchus had typical archosaur structure, composed of large and slender, curved ribs. In some discoveries ribs were found associated with gastralia, dermal bones which located in the ventral region of the body. The limbs were located underneath the body giving Postosuchus an upright stance. With the forelimbs being approximately 64% of the hindlimbs, Postosuchus had small hands bearing five toes. Only the first toe bore a large claw, which used as an offensive weapon, and the forelimbs were robust probably to hold the prey. Peyer et al. 2008, argued that the thick pectoral girdle served for locomotion of the forelimbs. However, this doesn't retract the theory that Postosuchus could walk bipedaly. The feet were much larger than the hands, with the fifth metatarsal forming a hook shape. The hallux
es were more slender than the other toes and the marginal ones couldn't touch the ground. As crurotarsan, the heel and ankle of Postosuchus resemble those of modern crocodiles.
in 1922
. The fossils were composed only of an isolated braincase (UM
7473) and fragments of pelvic bones (UM 7244). Case then mistakenly assigned these specimens to the dinosaur genus Coelophysis
. In the case of the braincase later assigned to Postosuchus, in 2002
paleontologist David J. Gower
argued that the specimen is not complete and may belong to an ornithodire. Between 1932
and 1934
, Case discovered other fossils of caudal vertebrae (UMMP 13670) in Rotten Hill, Texas, and a complete pelvis (UCMP
V72183/113314) near Kalgary, Texas
. Within the same period, paleontologist Charles Lewis Camp
collected over a hundred 'rauisuchian' bones, from what is now the Petrified Forest National Park
of Arizona, which belong to at least seven individuals (UCMP A296, MNA
207C). Later, more remains came to light. In 1943
, Case again described a pelvis along with a pubis (UM 23127) from the Dockum Group
of Texas, which dates from the Carnian
through the early Norian
stages of Late Triassic period. These early findings, from 1932 to 1943, were initially referred to as a new phytosaur
reptile, but assigned forty years later to Postosuchus.
During an expedition in 1980
, paleontologists of the Texas Tech University
discovered a new geological site rich in fossils near Post Town
, Garza County, Texas
, where a dozen of well preserved specimens belonging to a new rauisuchian were found. In the following years further excavation in the Post Quarry, in Cooper Canyon Formation
(Dockum Group), unearthed many remains of late Triassic terrestrial fauna. The holotype of P. kirkpatricki (TTU
P 9000), representing a well-preserved skull and a partial postcranial skeleton, was described along with other findings of this new genus by paleontologist Sankar Chatterjee
in 1985. Chatterjee named the species after Mr. and Mrs. Jack Kirkpatrick who helped during his fieldwork. The first articulated skeleton referred to P. kirkpatricki (CM
73372) was recovered by David S. Berman of the Carnegie Museum of Natural History
, in Coelophysis Quarry at Ghost Ranch
, New Mexico
, between 1988
and 1989
. This specimen was composed of a well preserved skeleton without skull and was described by Long and Murry in 1995
, Weinbaum in 2002 and Novak in 2004
. During more recent research, paleontologists suggested that some bones (such manus
and toe bones) described by Chatterjee back in 1985, are eventually a combination of remains belonging to Chatterjeea, Lythrosuchus, and Postosuchus. Long and Murry also pointed out that many of the juvenile skeletons (TTUP 9003-9011), which Chatterjee assigned to P. kirkpatricki, belong to a distinct genus, named Chatterjeea elegans. Furthermore, in 2006
Nesbitt and Norell argued that Chatterjeea is a junior synonym of Shuvosaurus
.
In 2008, Peyer et al., described a new species of Postosuchus, P. alisonae, which was discovered in 1992
in Triangle Brick Co. Quarry, Durham County
, North Carolina
. The remains were prepared and reconstructed between 1994
and 1998
by the Department of Geological Sciences at the University of North Carolina
. The specific name is in reference to Alison L. Chambers, who worked to popularize paleontology in North Carolina. The skeleton of P. alisonae consists of a few cranial
bones, seven neck, one back, and four tail vertebrae, ribs, gastralia ("belly ribs"), chevrons
, bony scutes, much of the shoulder girdles, most of the forelimbs except the left wrist and hand, most of the hindlimbs except for the thigh bones
, and pieces from the hip. Moreover, the well preserved remains of P. alisonae shed new light on parts of Postosuchus anatomy, which were previously not well known. Specifically, the differences between the manus bones of P. kirkpatricki and P. alisonae confirm the chimera
theory (associated fossils belonging to different animals) suggested by Long and Murry. The holotype specimen of P. alisonae (UNC
15575) is also unusual in its preservation of gut contents: bones from at least four other animals, including a partial skeleton of an aetosaur
, a snout, coracoid, and humerus
of the traversodontid cynodont
Plinthogomphodon
, two phalanges from a dicynodont
, and a possible temnospondyl bone. Furthermore, the Postosuchus was positioned on top of a skeleton of the sphenosuchia
n Dromicosuchus
, which included tooth marks on the skull and neck. P. alisonae represents the largest suchian reptile recovered from the quarry and the first articulated specimen of 'rauisuchian' archosaur found in eastern North America.
, such as Cynepteris, Phelopteris and Clathropteris, gymnosperm
s, represented by Pelourdea, Araucarioxylon, Woodworthia, Otozamites and Dinophyton, and cycads like Sanmiguelia. Plants of the Dockum Group are not well known since the oxidizing of the environment has destroyed most of the plant fossils. However, some of them may provide information about the climate in Dockum Group during the late Triassic period. For example, the discovery of large specimens belonging to Araucarioxylon determine that the region was well watered. The fauna found in Dockum Group confirm that were lakes and/or rivers which contain fish like the cartilaginous
Xenacanthus
, the lobe-finned
Chinlea and the dipnoan
Ceratodus
. On the shores of these rivers lived labyrinthodonts (Latiscopus) and reptiles such as Malerisaurus
and Trilophosaurus
. Also living in the margin of the lakes were the archosaurs Parasuchus, Nicrosaurus
and Rutiodon
. Postosuchus lived in the uplands along with Coelophysis and other archosaurs such as Desmatosuchus
and Typothorax
. Postosuchus was one of the largest animals in that ecosystem and preyed on herbivores such as Trilophosaurus and Typothorax.
's series Walking with Dinosaurs
, where CGI animation
was used to recreate extinct creatures of the Mesozoic
era. In this episode, it appears as the top predator of the Late Triassic Period
, preying on Placerias
, which are large dicynodont
s.
Archosaur
Archosaurs are a group of diapsid amniotes whose living representatives consist of modern birds and crocodilians. This group also includes all extinct non-avian dinosaurs, many extinct crocodilian relatives, and pterosaurs. Archosauria, the archosaur clade, is a crown group that includes the most...
that lived in what is now North America
North America
North America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
during the middle through to the late Triassic
Triassic
The Triassic is a geologic period and system that extends from about 250 to 200 Mya . As the first period of the Mesozoic Era, the Triassic follows the Permian and is followed by the Jurassic. Both the start and end of the Triassic are marked by major extinction events...
period (228-202 million years ago). It was a rauisuchia
Rauisuchia
Rauisuchia is a group of predatory and mostly large Triassic archosaurs. As a clade, Rauisuchia includes these Triassic forms and all crocodylomorphs, which are descendants of Triassic rauisuchians. The group in its traditional sense is paraphyletic, because it does not include crocodylomorph...
n, a close relative of crocodiles
Crocodilia
Crocodilia 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...
, as a member of the clade Pseudosuchia
Pseudosuchia
Pseudosuchia is the name originally given to a group of prehistoric reptiles from the Triassic period. The name has been variously interpreted, and it is still sometimes, if infrequently, used in scientific literature today. A more commonly used name, Crurotarsi, is often substituted for...
(or Crurotarsi
Crurotarsi
The Crurotarsi are a group of archosauriformes, represented today by the crocodiles,...
) which, along with the lineage that led to 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 and Birds, forms Archosauria. Its name refers to Post Quarry, a place 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...
where many fossils of this genus were found. It was one of the 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...
s of its area during the Triassic, larger than the small dinosaur predators of its time (such as Coelophysis
Coelophysis
Coelophysis , meaning "hollow form" in reference to its hollow bones , is one of the earliest known genera of dinosaur...
). It was a hunter which probably preyed on dicynodont
Dicynodont
Dicynodontia is a taxon of anomodont therapsids or mammal-like reptiles. Dicynodonts were small to large herbivorous animals with two tusks, hence their name, which means 'two dog tooth'...
s and many other creatures smaller than itself.
Postosuchus was a quadruped
Quadruped
Quadrupedalism is a form of land animal locomotion using four limbs or legs. An animal or machine that usually moves in a quadrupedal manner is known as a quadruped, meaning "four feet"...
al reptile
Reptile
Reptiles are members of a class of air-breathing, ectothermic vertebrates which are characterized by laying shelled eggs , and having skin covered in scales and/or scutes. They are tetrapods, either having four limbs or being descended from four-limbed ancestors...
with a wide skull and a long tail. This carnivore
Carnivore
A carnivore meaning 'meat eater' is an organism that derives its energy and nutrient requirements from a diet consisting mainly or exclusively of animal tissue, whether through predation or scavenging...
attacked with its large curved claws. It was about 4–5 meters long (12–15 feet), and was held up by columnar legs (a quite uncommon feature in reptiles). A crocodile-like snout, filled with many large-sized dagger-like teeth, was used to kill its prey. Rows of protective plates covering its back formed a defensive shield.
General Description
Postosuchus was one of the largest carnivorous reptiles during the late Triassic, reaching up to 4 meters (13 ft) in length and 2 meters (6.5 ft) in height. In life the animal would weigh about 250 to 300 kilograms (550lb to 660lb). It had a massively built skull bearing dagger-like teeth. The neck was elongated, expanding to a short torso and long tail.Posture
Each one of Postosuchuss two forelimbs was slightly over half the size of the hindlimbs. This characteristic of short forelimbs can usually be seen in bipedal reptiles. Chatterjee suggested that Postosuchus could walk in an erect stance, since the short forelimbs were probably used only during slow locomotion. However, in 1995 Long and Murry stated that Postosuchus was heavily built and quadrupedal. There is debate over whether Postosuchus was bipedal or quadrupedal and scientists aren't certain, yet, about its gait. However, though, it has also been suggested by some palaeontologists that Postosuchus might possibly have been a facultative biped, meaning that it alternated between walking bipedally, occasionally, and quadrupedally.Skull
The skull of Postosuchus was constructed narrow in front and extended wide and deep behind. It was 55 cm in length and 21 cm broad and deep. There are many fenestrae (openings) present in the bones that lighten the skull, providing space for the muscles. Like more derived archosaurs, the lower jaw had mandibular fenestrae (openings at the lower jaw), formed by the junction of the dentary with other jaw bones (surangular and angularAngular
The angular is a large bone in the lower jaw of amphibians and reptiles , which is connected to all other lower jaw bones: the dentary , the splenial, the suprangular, and the articular...
). Postosuchus had very good long distant sight, due to large orbits
Orbit (anatomy)
In anatomy, the orbit is the cavity or socket of the skull in which the eye and its appendages are situated. "Orbit" can refer to the bony socket, or it can also be used to imply the contents...
, supporting large and sharp eyes, and strong olfaction provided by elongated nostrils. Inside the skull, under the nostrils, there was a hollowing that probably was for the Jacobson's organ, an olfactory sensory organ sometimes referred as the "sixth sense". The jaws held large and sharp serrated teeth and in some points were developed even larger to operate as hooked sabers. A complete tooth found among Postosuchus remains 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...
measured about 7.2 cm in height. Postosuchus possessed heterodonty dentition, which means each tooth was different in size and shape from the others. The upper jaw composed of seventeen teeth, with 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....
bore only four teeth and 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...
thirteen teeth. In the lower jaw were counted over thirty teeth. Replacement activity in Postosuchus was different from that of crocodiles, since the replacement tooth didn't fit directly in the pulp cavity of the old tooth, but grew until resorption of the old tooth was complete.
Postcranial Anatomy
The neck of Postosuchus consists of at least eight cervical vertebraeCervical vertebrae
In vertebrates, cervical vertebrae are those vertebrae immediately inferior to the skull.Thoracic vertebrae in all mammalian species are defined as those vertebrae that also carry a pair of ribs, and lie caudal to the cervical vertebrae. Further caudally follow the lumbar vertebrae, which also...
followed by sixteen dorsals, while four co-ossified sacral vertebrae supported the hips. It is thought to be over thirty vertebrae in the tail decreasing in size to the end. The pelvis
Pelvis
In human anatomy, the pelvis is the lower part of the trunk, between the abdomen and the lower limbs .The pelvis includes several structures:...
with the hooked 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....
and the rod-like ischium looked like those of carnosaur dinosaurs. Along with remains of the skeleton, paleontologists also identify osteoderms, which were thick plates forming scales. These were on its back, neck, and possibly above or under the tail. The ribcage of Postosuchus had typical archosaur structure, composed of large and slender, curved ribs. In some discoveries ribs were found associated with gastralia, dermal bones which located in the ventral region of the body. The limbs were located underneath the body giving Postosuchus an upright stance. With the forelimbs being approximately 64% of the hindlimbs, Postosuchus had small hands bearing five toes. Only the first toe bore a large claw, which used as an offensive weapon, and the forelimbs were robust probably to hold the prey. Peyer et al. 2008, argued that the thick pectoral girdle served for locomotion of the forelimbs. However, this doesn't retract the theory that Postosuchus could walk bipedaly. The feet were much larger than the hands, with the fifth metatarsal forming a hook shape. The hallux
Hallux
In tetrapods, the hallux is the innermost toe of the foot. Despite its name it may not be the longest toe on the foot of some individuals...
es were more slender than the other toes and the marginal ones couldn't touch the ground. As crurotarsan, the heel and ankle of Postosuchus resemble those of modern crocodiles.
History
Primarily, it was thought that the fossils of Postosuchus belonged to a dinosaur. Remains of Postosuchus were discovered for the first time in Crosby County, Texas, and described by paleontologist Ermine Cowles CaseErmine Cowles Case
Ermine Cowles Case , invariably known as E.C. Case, was a prominent American paleontologist in the second generation that succeeded Othniel Charles Marsh and Edward Drinker Cope...
in 1922
1922 in paleontology
-Insects:-Newly named dinosaurs:Data courtesy of George Olshevsky's dinosaur genera list and Dr. Jeremy Montague's dinosaur genus database.-New taxa:-Non-mammalian:...
. The fossils were composed only of an isolated braincase (UM
University of Michigan
The University of Michigan is a public research university located in Ann Arbor, Michigan in the United States. It is the state's oldest university and the flagship campus of the University of Michigan...
7473) and fragments of pelvic bones (UM 7244). Case then mistakenly assigned these specimens to the dinosaur genus Coelophysis
Coelophysis
Coelophysis , meaning "hollow form" in reference to its hollow bones , is one of the earliest known genera of dinosaur...
. In the case of the braincase later assigned to Postosuchus, in 2002
2002 in paleontology
-Newly named dinosaurs:Data courtesy of George Olshevsky's dinosaur genera list and Dr. Jeremy Montague's dinosaur genus database.-New taxa:-Pterosaurs:In October, a partial Mesadacylus wing was discovered in the Kingsview Quarry of Colorado...
paleontologist David J. Gower
David J. Gower
David J. Gower is a palaeontologist.Since 2004 he is a herpetology researcher at the Museum of Natural History in London.-External links:* *...
argued that the specimen is not complete and may belong to an ornithodire. Between 1932
1932 in paleontology
-Newly named dinosaurs:Data courtesy of George Olshevsky's dinosaur genera list and Dr. Jeremy Montague's dinosaur genus database.-Non-mammalian:...
and 1934
1934 in paleontology
-Newly named dinosaurs:Data courtesy of George Olshevsky's dinosaur genera list and Dr. Jeremy Montague's dinosaur genus database.-Non-mammalian:...
, Case discovered other fossils of caudal vertebrae (UMMP 13670) in Rotten Hill, Texas, and a complete pelvis (UCMP
University of California Museum of Paleontology
The University of California Museum of Paleontology is a paleontology museum located on the campus of the University of California, Berkeley....
V72183/113314) near Kalgary, Texas
Kalgary, Texas
Kalgary is an unincorporated community in Crosby County, Texas, United States. According to the Handbook of Texas, the community had an estimated population of 70 in 2000.Kalgary is part of the Lubbock Metropolitan Statistical Area.-Geography:...
. Within the same period, paleontologist Charles Lewis Camp
Charles Lewis Camp
Charles Lewis Camp was a notable palaeontologist and zoologist, working from the University of California, Berkeley...
collected over a hundred 'rauisuchian' bones, from what is now the Petrified Forest National Park
Petrified Forest National Park
Petrified Forest National Park is a United States national park in Navajo and Apache counties in northeastern Arizona. The park's headquarters are about east of Holbrook along Interstate 40 , which parallels a railroad line, the Puerco River, and historic U.S. Route 66, all crossing the park...
of Arizona, which belong to at least seven individuals (UCMP A296, MNA
Museum of Northern Arizona
The Museum of Northern Arizona is a museum in Flagstaff, Arizona, USA, that was established as a repository for Native American artifacts and natural history specimens from the Colorado Plateau.The museum was founded in 1928 by zoologist Dr. Harold S...
207C). Later, more remains came to light. In 1943
1943 in paleontology
-Newly named dinosaurs:Data coutersy of George Olshevky's dinosaur genera list.-New taxa:-Non-mammalian:...
, Case again described a pelvis along with a pubis (UM 23127) from the Dockum Group
Dockum Group
The Dockum is a Late Triassic geologic group found primarily on the Llano Estacado of western Texas and eastern New Mexico with minor exposures in southwestern Kansas, eastern Colorado, and Oklahoma panhandle. The Dockum reaches a maximum thickness of slightly over 650 m but is usually much...
of Texas, which dates from the Carnian
Carnian
The Carnian is the lowermost stage of the Upper Triassic series . It lasted from about 228.7 till 216.5 million years ago . The Carnian is preceded by the Ladinian and is followed by the Norian...
through the early Norian
Norian
The Norian is a division of the Triassic geological period. It has the rank of an age or stage . The Norian lasted from 216.5 ± 2.0 to 203.6 ± 1.5 million years ago. It was preceded by the Carnian and succeeded by the Rhaetian.-Stratigraphic definitions:The Norian was named after the Noric Alps in...
stages of Late Triassic period. These early findings, from 1932 to 1943, were initially referred to as a new phytosaur
Phytosaur
Phytosaurs are an extinct group of large semi-aquatic Late Triassic archosaurs. Phytosaurs belong to the family Phytosauridae and the order Phytosauria. They were long-snouted and heavily armoured, bearing a remarkable resemblance to modern crocodiles in size, appearance, and lifestyle, an example...
reptile, but assigned forty years later to Postosuchus.
During an expedition in 1980
1980 in paleontology
-Newly named dinosaurs:Data courtesy of George Olshevsky's dinosaur genera list and Dr. Jeremy Montague's dinosaur genus database.-New taxa:-New taxa:-Non-mammalian:-References:...
, paleontologists of the Texas Tech University
Texas Tech University
Texas Tech University, often referred to as Texas Tech or TTU, is a public research university in Lubbock, Texas, United States. Established on February 10, 1923, and originally known as Texas Technological College, it is the leading institution of the Texas Tech University System and has the...
discovered a new geological site rich in fossils near Post Town
Post, Texas
Post is a city in and the county seat of Garza County, Texas, United States. The population was 3,708 at the 2000 census.There are many ranchers and civic boosters in Garza County, among them Giles McCrary, a former mayor who operates the OS Museum, a hybrid of exhibits from both the American West...
, Garza County, Texas
Garza County, Texas
Garza County is a county located in the U.S. state of Texas southeast of Lubbock. In 2000, its population was 4,872. Its county seat is Post. Garza is named for a pioneer Bexar County family, as it was once a part of that county....
, where a dozen of well preserved specimens belonging to a new rauisuchian were found. In the following years further excavation in the Post Quarry, in Cooper Canyon Formation
Cooper Canyon Formation
-Vertebrate fauna:...
(Dockum Group), unearthed many remains of late Triassic terrestrial fauna. The holotype of P. kirkpatricki (TTU
Texas Tech University
Texas Tech University, often referred to as Texas Tech or TTU, is a public research university in Lubbock, Texas, United States. Established on February 10, 1923, and originally known as Texas Technological College, it is the leading institution of the Texas Tech University System and has the...
P 9000), representing a well-preserved skull and a partial postcranial skeleton, was described along with other findings of this new genus by paleontologist Sankar Chatterjee
Sankar Chatterjee
Sankar Chatterjee is a paleontologist, and is the Paul W. Horn Professor of Geosciences at Texas Tech University and Curator of Paleontology at the Museum of Texas Tech University. He earned his Ph. D. from the University of Calcutta in 1970 and was a Post-doctoral Fellow at the Smithsonian...
in 1985. Chatterjee named the species after Mr. and Mrs. Jack Kirkpatrick who helped during his fieldwork. The first articulated skeleton referred to P. kirkpatricki (CM
Carnegie Museum of Natural History
Carnegie Museum of Natural History, located at 4400 Forbes Avenue in the Oakland neighborhood of Pittsburgh, Pennsylvania, USA, was founded by the Pittsburgh-based industrialist Andrew Carnegie in 1896...
73372) was recovered by David S. Berman of the Carnegie Museum of Natural History
Carnegie Museum of Natural History
Carnegie Museum of Natural History, located at 4400 Forbes Avenue in the Oakland neighborhood of Pittsburgh, Pennsylvania, USA, was founded by the Pittsburgh-based industrialist Andrew Carnegie in 1896...
, in Coelophysis Quarry at Ghost Ranch
Ghost Ranch
Ghost Ranch is a retreat and education center located close to the village of Abiquiu in Rio Arriba County in north central New Mexico. The conference center and lodgings at Ghost Ranch are run by the Presbyterian Church but open to the general public.-History:Ghost Ranch is part of Piedra...
, New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
, between 1988
1988 in paleontology
-Newly named dinosaurs:Data courtesy of George Olshevsky's dinosaur genera list and Dr. Jeremy Montague's dinosaur genus database.* The dubious family, Ornitholestidae is named by Gregory Scott Paul.-New taxa:-Non-mammalian:...
and 1989
1989 in paleontology
-Newly named dinosaurs:Data courtesy of George Olshevsky's dinosaur genera list and Dr. Jeremy Montague's dinosaur genus database.-New taxa:-New taxa:-Non-mammalian:-References:...
. This specimen was composed of a well preserved skeleton without skull and was described by Long and Murry in 1995
1995 in paleontology
-Arachnids:-Insects:-Dinosaurs:* Fossil hunters working on behalf of the Royal Saskatchewan Museum discover a large coprolite from a theropod dinosaur in Maastrichtian strata. In 1997 it is sent to coprolite specialist Karen Chin, who determines that this specimen of fossilized feces was...
, Weinbaum in 2002 and Novak in 2004
2004 in paleontology
-New taxa:-newly named:-newly named:-New taxa:-Newly named dinosaurs:Data courtesy of George Olshevsky's dinosaur genera list and Dr. Jeremy Montague's dinosaur genus database.-New taxa:-New taxa:-Non-mammalian:...
. During more recent research, paleontologists suggested that some bones (such manus
Manus (zoology)
The manus is the zoological term for the distal portion of the fore limb of an animal. In tetrapods, it is the part of the pentadactyl limb that includes the metacarpals and digits . During evolution, it has taken many forms and served a variety of functions...
and toe bones) described by Chatterjee back in 1985, are eventually a combination of remains belonging to Chatterjeea, Lythrosuchus, and Postosuchus. Long and Murry also pointed out that many of the juvenile skeletons (TTUP 9003-9011), which Chatterjee assigned to P. kirkpatricki, belong to a distinct genus, named Chatterjeea elegans. Furthermore, in 2006
2006 in paleontology
-Insects:-Tetrapodomorphs:-Newly named temnospondylians:-Newly named amphibians:-Ichthyosaurs:-Newly named basal lepidosauromorphs:-Newly named plesiosaurs:-Newly named squamates:-Newly named crurotarsans:-Newly named dinosaurs:...
Nesbitt and Norell argued that Chatterjeea is a junior synonym of Shuvosaurus
Shuvosaurus
Shuvosaurus is a genus of beaked reptile from the Late Triassic of Texas. It was described by Sankar Chatterjee in 1993 after it was discovered by his son Shuvo. It was initially interpreted as a Triassic member of the Cretaceous dinosaur family Ornithomimidae...
.
In 2008, Peyer et al., described a new species of Postosuchus, P. alisonae, which was discovered in 1992
1992 in paleontology
- Dinosaurs :* During the 1992 field season a concerted effort was undertaken by the Royal Tyrell Museum to recover the remains of young hadrosaurs. The researchers describe the acquisition that season of 43 specimens as being a success...
in Triangle Brick Co. Quarry, Durham County
Durham County, North Carolina
-Demographics:As of the census of 2000, there were 223,314 people, 89,015 households, and 54,032 families residing in the county. The population density was 769 people per square mile . There were 95,452 housing units at an average density of 329 per square mile...
, 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...
. The remains were prepared and reconstructed between 1994
1994 in paleontology
-Dinosaurs:* Aff. Rebbachisaurus gastroliths documented.* The "Talkeetna Mountains Hadrosaur" specimen was discovered in a quarry being excavated for road material. The quarry is near the Glenn Highway, approximately 150 miles northeast of Anchorage...
and 1998
1998 in paleontology
-Amphibians:A. C. Henrici. 1998. A new pipoid anuran from the Late Jurassic Morrison Formation at Dinosaur National Monument, Utah. Journal of Vertebrate Paleontology 18:321-332-Dinosaurs:...
by the Department of Geological Sciences at the University of North Carolina
University of North Carolina
Chartered in 1789, the University of North Carolina was one of the first public universities in the United States and the only one to graduate students in the eighteenth century...
. The specific name is in reference to Alison L. Chambers, who worked to popularize paleontology in North Carolina. The skeleton of P. alisonae consists of a few 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...
bones, seven neck, one back, and four tail vertebrae, ribs, gastralia ("belly ribs"), chevrons
Chevron (anatomy)
A chevron is one of a series of bones on the ventral side of the tail in many reptiles, dinosaurs , and some mammals such as kangaroos and manatees....
, bony scutes, much of the shoulder girdles, most of the forelimbs except the left wrist and hand, most of the hindlimbs except for the thigh bones
Femur
The femur , or thigh bone, is the most proximal bone of the leg in tetrapod vertebrates capable of walking or jumping, such as most land mammals, birds, many reptiles such as lizards, and amphibians such as frogs. In vertebrates with four legs such as dogs and horses, the femur is found only in...
, and pieces from the hip. Moreover, the well preserved remains of P. alisonae shed new light on parts of Postosuchus anatomy, which were previously not well known. Specifically, the differences between the manus bones of P. kirkpatricki and P. alisonae confirm the chimera
Chimera (paleontology)
In paleontology, a chimera is a fossil which was reconstructed with elements coming from more than a single species of animal. A now classic example of chimera is Protoavis.-List of paleontological chimeras:*Brontosaurus*Lametasaurus...
theory (associated fossils belonging to different animals) suggested by Long and Murry. The holotype specimen of P. alisonae (UNC
University of North Carolina at Chapel Hill
The University of North Carolina at Chapel Hill is a public research university located in Chapel Hill, North Carolina, United States...
15575) is also unusual in its preservation of gut contents: bones from at least four other animals, including a partial skeleton of an aetosaur
Aetosaur
Aetosaurs are an extinct order of heavily armoured, medium- to large-sized Late Triassic herbivorous archosaurs. They have small heads, upturned snouts, erect limbs, and a body covered by plate-like scutes. All aetosaurs belong to the family Stagonolepididae...
, a snout, coracoid, and humerus
Humerus
The humerus is a long bone in the arm or forelimb that runs from the shoulder to the elbow....
of the traversodontid cynodont
Cynodont
Cynodontia or cynodonts are a taxon of therapsids which first appeared in the Late Permian and were eventually distributed throughout all seven continents by the Early Triassic . This clade includes modern mammals and their extinct close relatives. They were one of the most diverse groups of...
Plinthogomphodon
Plinthogomphodon
Plinthogomphodon is a genus of traversodontid cynodont from the Late Triassic of the eastern United States. Fossils have been found from the Deep River basin of North Carolina, part of the larger Newark Supergroup. It is known from a single eroded snout. The type and only species is P....
, two phalanges from a dicynodont
Dicynodont
Dicynodontia is a taxon of anomodont therapsids or mammal-like reptiles. Dicynodonts were small to large herbivorous animals with two tusks, hence their name, which means 'two dog tooth'...
, and a possible temnospondyl bone. Furthermore, the Postosuchus was positioned on top of a skeleton of the sphenosuchia
Sphenosuchia
Sphenosuchia is a suborder of basal crocodylomorphs that first appeared in the Triassic and occurred into the Late Jurassic. Most were small, gracile animals with an erect limb posture. They are now thought to be ancestral to crocodyliforms, which include all living crocodilians.-Stratigraphic...
n Dromicosuchus
Dromicosuchus
Dromicosuchus is an extinct genus of sphenosuchian, a type of basal crocodylomorph, the clade that comprises the crocodilians and their closest kin. It was found in Upper Triassic rocks of North Carolina, United States, and is known from a nearly complete skull and partial skeleton...
, which included tooth marks on the skull and neck. P. alisonae represents the largest suchian reptile recovered from the quarry and the first articulated specimen of 'rauisuchian' archosaur found in eastern North America.
Paleoecology
Postosuchus lived in a tropical environment. The moist and warm region consisted of fernsFern
A fern is any one of a group of about 12,000 species of plants belonging to the botanical group known as Pteridophyta. Unlike mosses, they have xylem and phloem . They have stems, leaves, and roots like other vascular plants...
, such as Cynepteris, Phelopteris and Clathropteris, gymnosperm
Gymnosperm
The gymnosperms are a group of seed-bearing plants that includes conifers, cycads, Ginkgo, and Gnetales. The term "gymnosperm" comes from the Greek word gymnospermos , meaning "naked seeds", after the unenclosed condition of their seeds...
s, represented by Pelourdea, Araucarioxylon, Woodworthia, Otozamites and Dinophyton, and cycads like Sanmiguelia. Plants of the Dockum Group are not well known since the oxidizing of the environment has destroyed most of the plant fossils. However, some of them may provide information about the climate in Dockum Group during the late Triassic period. For example, the discovery of large specimens belonging to Araucarioxylon determine that the region was well watered. The fauna found in Dockum Group confirm that were lakes and/or rivers which contain fish like the cartilaginous
Chondrichthyes
Chondrichthyes or cartilaginous fishes are jawed fish with paired fins, paired nares, scales, two-chambered hearts, and skeletons made of cartilage rather than bone...
Xenacanthus
Xenacanthus
Xenacanthus is a genus of prehistoric sharks. The first species of the genus lived in the later Devonian period, and they survived until the end of the Triassic, 202 million years ago. Fossils of various species have been found worldwide....
, the lobe-finned
Sarcopterygii
The Sarcopterygii or lobe-finned fishes – sometimes considered synonymous with Crossopterygii constitute a clade of the bony fishes, though a strict classification would include the terrestrial vertebrates...
Chinlea and the dipnoan
Lungfish
Lungfish are freshwater fish belonging to the Subclass Dipnoi. Lungfish are best known for retaining characteristics primitive within the Osteichthyes, including the ability to breathe air, and structures primitive within Sarcopterygii, including the presence of lobed fins with a well-developed...
Ceratodus
Ceratodus
Ceratodus was a wide-ranging genus of extinct sarcopterygiian lungfish. Fossil evidence dates back to the Middle Triassic 228 million years ago. A wide range of fossil species from different time periods have been found around the world in places such as the United States, Argentina, England,...
. On the shores of these rivers lived labyrinthodonts (Latiscopus) and reptiles such as Malerisaurus
Malerisaurus
Malerisaurus is an extinct genus of prolacertiform archosauromorph known from Andhra Pradesh of India and Texas of the USA.-Description:...
and Trilophosaurus
Trilophosaurus
Trilophosaurus was a lizard-like Triassic diapsid reptile related to the archosaurs. It was a herbivore up to 2.5 meters long. It had a short, unusually heavily-built skull, equipped with massive, broad flattened cheek teeth with sharp shearing surfaces for cutting up tough plant material...
. Also living in the margin of the lakes were the archosaurs Parasuchus, Nicrosaurus
Nicrosaurus
Nicrosaurus is an extinct genus of phytosaur reptile. Although it looked and probably lived like a crocodile, it was not closely related to these creatures, instead being a good example of parallel evolution...
and Rutiodon
Rutiodon
Rutiodon is an extinct genus of archosaur belonging to the family Phytosauridae. It lived during the Late Triassic period, and was about 10 to 25 feet in length...
. Postosuchus lived in the uplands along with Coelophysis and other archosaurs such as Desmatosuchus
Desmatosuchus
Desmatosuchus is an extinct genus of archosaur belonging to the Order Aetosauria. It was one of the largest aetosaurs, being long and about 1.50 m high. It lived during the Late Triassic in Texas....
and Typothorax
Typothorax
Typothorax is an extinct genus of aetosaur that lived in the Late Triassic. Its remains have been found in North America. Two species are known: T. coccinarum, the type species, and T. antiquum.-Description:...
. Postosuchus was one of the largest animals in that ecosystem and preyed on herbivores such as Trilophosaurus and Typothorax.
In popular culture
Postosuchus appears in the first program of the BBCBBC
The British Broadcasting Corporation is a British public service broadcaster. Its headquarters is at Broadcasting House in the City of Westminster, London. It is the largest broadcaster in the world, with about 23,000 staff...
's series Walking with Dinosaurs
Walking with Dinosaurs
Walking with Dinosaurs is a six-part documentary television miniseries that was produced by BBC, narrated by Kenneth Branagh, and first aired in the United Kingdom, in 1999. The series was subsequently aired in North America on the Discovery Channel in 2000, with Branagh's voice replaced with that...
, where CGI animation
Computer-generated imagery
Computer-generated imagery is the application of the field of computer graphics or, more specifically, 3D computer graphics to special effects in art, video games, films, television programs, commercials, simulators and simulation generally, and printed media...
was used to recreate extinct creatures of the Mesozoic
Mesozoic
The Mesozoic era is an interval of geological time from about 250 million years ago to about 65 million years ago. It is often referred to as the age of reptiles because reptiles, namely dinosaurs, were the dominant terrestrial and marine vertebrates of the time...
era. In this episode, it appears as the top predator of the Late Triassic Period
Late Triassic
The Late Triassic is in the geologic timescale the third and final of three epochs of the Triassic period. The corresponding series is known as the Upper Triassic. In the past it was sometimes called the Keuper, after a German lithostratigraphic group that has a roughly corresponding age...
, preying on Placerias
Placerias
Placerias was a dicynodont that lived during the late Carnian age of the Triassic Period...
, which are large dicynodont
Dicynodont
Dicynodontia is a taxon of anomodont therapsids or mammal-like reptiles. Dicynodonts were small to large herbivorous animals with two tusks, hence their name, which means 'two dog tooth'...
s.