Prionosuchus
Encyclopedia
Prionosuchus is a genus of extremely large temnospondyl
amphibian
s from the Late Permian
(270 million years ago) which was found in an area of what is now Brazil
.
Basin of Northeastern Brazil, and it was described by L.I. Price in 1948. Reaching an estimated length of 9 m (30 ft), Prionosuchus is the largest amphibian ever found.
With an elongated and tapered snout, numerous sharp teeth, long body, short legs, and a tail adapted for swimming, its general appearance was very similar to a modern crocodile, particularly to the gharial
, and it probably had a similar lifestyle as an ambush aquatic predator feeding on fish and other aquatic animals.
with P. plummeri being the only species described. The archegosaurs were a group of temnospondyli
that occupied the ecological niche of crocodiles and alligator
s during the Permian, and of which the European genus Archegosaurus
is typical. The group went extinct at the end of the Permian and the niche was subsequently filled by reptiles such as the phytosaur
s in the Triassic
period.
Cox and Hutchinson re-evaluated Prionosuchus in 1991 and synonymized it with the genus Platyoposaurus
from Russia. On the basis of this study, the Pedra do Fogo Formation was reevaluated to be of Middle to Late Permian age. However, Platyoposaurus was comparatively smaller, reaching a total length of only 2.5 meters (8.2 ft), indicating that the two animals are distinct at least at the species level. Alternative studies based on plants and pollens indicate that this formation is rather of Early Permian age, making Prionosuchus not contemporary with Platyoposaurus. Most paleontologists consider Prionosuchus as a valid genus.
Prionosuchus lived in a humid and tropical environment as indicated by the petrified forest of the Pedra do Fogo formation in which the fossil has been found. The strata composed of siltstone
s, shale
s and limestone
s were deposited in lagoon
al and fluvial environments. Other animals discovered in the same rocks include fish (primitive shark
s, palaeoniscids, and lungfish
es) and amphibians.
Temnospondyli
Temnospondyli is a diverse order of small to giant tetrapods—often considered primitive amphibians—that flourished worldwide during the Carboniferous, Permian, and Triassic periods. A few species continued into the Cretaceous. Fossils have been found on every continent...
amphibian
Amphibian
Amphibians , are a class of vertebrate animals including animals such as toads, frogs, caecilians, and salamanders. They are characterized as non-amniote ectothermic tetrapods...
s from the Late Permian
Permian
The PermianThe term "Permian" was introduced into geology in 1841 by Sir Sir R. I. Murchison, president of the Geological Society of London, who identified typical strata in extensive Russian explorations undertaken with Edouard de Verneuil; Murchison asserted in 1841 that he named his "Permian...
(270 million years ago) which was found in an area of what is now Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
.
Description
The fragmentary remains of this animal have been found in the Pedra do Fogo Formation in the ParnaibaParnaíba
Parnaíba is a port city in Piauí, Brazil, on the right bank of the Parnaíba River, 360 km north of the capital, Teresina. It is one of the only four coastal cities of the state....
Basin of Northeastern Brazil, and it was described by L.I. Price in 1948. Reaching an estimated length of 9 m (30 ft), Prionosuchus is the largest amphibian ever found.
Gharial
The gharial , , also called Indian gavial or gavial, is the only surviving member of the once well-represented family Gavialidae, a long-established group of crocodilians with long, slender snouts...
, and it probably had a similar lifestyle as an ambush aquatic predator feeding on fish and other aquatic animals.
Classification
It has been classified as an archegosaurian by Carroll. The genus is monotypicMonotypic
In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...
with P. plummeri being the only species described. The archegosaurs were a group of temnospondyli
Temnospondyli
Temnospondyli is a diverse order of small to giant tetrapods—often considered primitive amphibians—that flourished worldwide during the Carboniferous, Permian, and Triassic periods. A few species continued into the Cretaceous. Fossils have been found on every continent...
that occupied the ecological niche of crocodiles and 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 ....
s during the Permian, and of which the European genus Archegosaurus
Archegosaurus
Archegosaurus is a genus of temnospondyl amphibian which lived during the Asselian to Wuchiapingian stages of the Permian, around 299-253 million years ago. The remains of this animal, consisting of at least 90 partial skeletons , have been found in Germany. The name Archegosaurus was coined by...
is typical. The group went extinct at the end of the Permian and the niche was subsequently filled by reptiles such as the 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...
s in the 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.
Cox and Hutchinson re-evaluated Prionosuchus in 1991 and synonymized it with the genus Platyoposaurus
Platyoposaurus
Platyposaurus was a Temnospondyli amphibian from the late Permain period about 255-250 Mya .One of the discoveries includes a skull 28 cm long with a purported body length of 250 cm representing a carnivorous adult specimen....
from Russia. On the basis of this study, the Pedra do Fogo Formation was reevaluated to be of Middle to Late Permian age. However, Platyoposaurus was comparatively smaller, reaching a total length of only 2.5 meters (8.2 ft), indicating that the two animals are distinct at least at the species level. Alternative studies based on plants and pollens indicate that this formation is rather of Early Permian age, making Prionosuchus not contemporary with Platyoposaurus. Most paleontologists consider Prionosuchus as a valid genus.
Paleoecology
Siltstone
Siltstone is a sedimentary rock which has a grain size in the silt range, finer than sandstone and coarser than claystones.- Description :As its name implies, it is primarily composed of silt sized particles, defined as grains 1/16 - 1/256 mm or 4 to 8 on the Krumbein phi scale...
s, shale
Shale
Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments of other minerals, especially quartz and calcite. The ratio of clay to other minerals is variable. Shale is characterized by breaks along thin laminae or parallel layering...
s and limestone
Limestone
Limestone is a sedimentary rock composed largely of the minerals calcite and aragonite, which are different crystal forms of calcium carbonate . Many limestones are composed from skeletal fragments of marine organisms such as coral or foraminifera....
s were deposited in lagoon
Lagoon
A lagoon is a body of shallow sea water or brackish water separated from the sea by some form of barrier. The EU's habitat directive defines lagoons as "expanses of shallow coastal salt water, of varying salinity or water volume, wholly or partially separated from the sea by sand banks or shingle,...
al and fluvial environments. Other animals discovered in the same rocks include fish (primitive shark
Shark
Sharks are a type of fish with a full cartilaginous skeleton and a highly streamlined body. The earliest known sharks date from more than 420 million years ago....
s, palaeoniscids, and lungfish
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...
es) and amphibians.