Gryposuchus
Encyclopedia
Gryposuchus is an extinct genus
of gavialoid
crocodilia
n. It is the type genus
of the subfamily
Gryposuchinae
. Fossil
s have been found from Argentina
, Colombia
, Venezuela
, Brazil
and the Peruvian Amazon
. The genus existed during the early and middle Miocene
epoch. One recently described species
, G. croizati, grew to an estimated length of 10 metres (32.8 ft).
of Gryposuchus is G. neogaeus. Specimens from this species were first described from Argentina in 1885, although it was referred to Ramphostoma at the time. It was assigned to the current genus in 1912 along with a newly described species, G. jessei.
Another species, G. colombianus, has been recovered from deposits in Colombia that date back to the Miocene and Pliocene epochs. This species, named in 1965, was originally referred to Gavialis. Fragmentary material of Gryposuchus from the Fitzcarrald Arch in the Peruvian Amazon dating back to the late middle Miocene bear a close resemblance to G. colombianus, but differ in rostrum proportions.
A new species, G. croizati, found from the upper Miocene Urumaco Formation in northwestern Venezuela, can be distinguished from other species of Gryposuchus on the basis of a reduced number of maxilla
ry teeth, a slender parietal
interfenestral bar, and widely separated and reduced palatine
fenestrae, among other things. Based on measurements of the orbital cranial skeleton, the length of the animal has been estimated at around 10.15m in length, with a total mass of around 1745 kg. Measuring the entire length of the skull from the end of the rostrum to the supraoccipital would result in a much larger size estimate, up to three times as great. However, because there is considerable variation seen in rostral proportions among crocodilians, the latter measurements are probably not an accurate way of estimating body mass and length. Despite this, the species is still one of the largest crocodilians known to have existed, and it may indeed have been the largest gavialoid to have ever existed if a recent revision in the estimated size of the large tomistomine Rhamphosuchus
is correct (the genus was once considered to be 15m in length; the new estimate puts it at approximately 10m).
and Piscogavialis
have been found from localities thought to have been deposited in coastal environments. The presence of Gryposuchus in the Urumaco Formation of Venezuela, which does include marine strata, lends credence to the idea that gryposuchines may have been living in coastal environments. However, certain localities where material from the species G. colombianus has been recovered, such as La Venta
, Colombia
, were clearly deposited in non-marine environments, speaking against the proposed coastal lifestyle hypothesis for all gryposuchines.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of gavialoid
Gavialoidea
Gavialoidea is one of three superfamilies of crocodylians, the other two being Alligatoroidea and Crocodyloidea. Although many extinct species are known, only the gharial Gavialis gangeticus and possibly the False gharial Tomistoma schlegelii are alive today.-Classification:Gavialoidea contains the...
crocodilia
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...
n. It is the type genus
Type genus
In biological classification, a type genus is a representative genus, as with regard to a biological family. The term and concept is used much more often and much more formally in zoology than it is in botany, and the definition is dependent on the nomenclatural Code that applies:* In zoological...
of the subfamily
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Gryposuchinae
Gryposuchinae
Gryposuchinae is an extinct subfamily of gavialid crocodylians. Gryposuchines lived mainly in South America during the Oligocene and Miocene epochs. Most were long-snouted coastal forms. The group was named in 2007 and includes genera such as Gryposuchus and Aktiogavialis.-Description:Gryposuchines...
. Fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
s have been found from Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
, Colombia
Colombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
, Venezuela
Venezuela
Venezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...
, 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...
and the Peruvian Amazon
Peruvian Amazon
The Peruvian Amazon is the area of the Amazon jungle included in the territory of Peru, from the east of the Andes to borders with Ecuador, Colombia, Brazil and Bolivia. This region comprises 60% of the country and is marked by a large degree of biodiversity...
. The genus existed during the early and middle Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
epoch. One recently described species
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
, G. croizati, grew to an estimated length of 10 metres (32.8 ft).
Species
The type speciesType species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
of Gryposuchus is G. neogaeus. Specimens from this species were first described from Argentina in 1885, although it was referred to Ramphostoma at the time. It was assigned to the current genus in 1912 along with a newly described species, G. jessei.
Another species, G. colombianus, has been recovered from deposits in Colombia that date back to the Miocene and Pliocene epochs. This species, named in 1965, was originally referred to Gavialis. Fragmentary material of Gryposuchus from the Fitzcarrald Arch in the Peruvian Amazon dating back to the late middle Miocene bear a close resemblance to G. colombianus, but differ in rostrum proportions.
A new species, G. croizati, found from the upper Miocene Urumaco Formation in northwestern Venezuela, can be distinguished from other species of Gryposuchus on the basis of a reduced number of 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...
ry teeth, a slender parietal
Parietal bone
The parietal bones are bones in the human skull which, when joined together, form the sides and roof of the cranium. Each bone is roughly quadrilateral in form, and has two surfaces, four borders, and four angles. It is named from the Latin pariet-, wall....
interfenestral bar, and widely separated and reduced palatine
Palatine bone
The palatine bone is a bone in many species of the animal kingdom, commonly termed the palatum .-Human anatomy:...
fenestrae, among other things. Based on measurements of the orbital cranial skeleton, the length of the animal has been estimated at around 10.15m in length, with a total mass of around 1745 kg. Measuring the entire length of the skull from the end of the rostrum to the supraoccipital would result in a much larger size estimate, up to three times as great. However, because there is considerable variation seen in rostral proportions among crocodilians, the latter measurements are probably not an accurate way of estimating body mass and length. Despite this, the species is still one of the largest crocodilians known to have existed, and it may indeed have been the largest gavialoid to have ever existed if a recent revision in the estimated size of the large tomistomine Rhamphosuchus
Rhamphosuchus
Rhamphosuchus is an extinct relative of the modern false gharial. It inhabited what is now the Indian sub-continent in the Miocene...
is correct (the genus was once considered to be 15m in length; the new estimate puts it at approximately 10m).
Paleobiology
Some gryposuchines such as SiquisiquesuchusSiquisiquesuchus
Siquisiquesuchus is an extinct genus of gavialoid crocodilian...
and Piscogavialis
Piscogavialis
Piscogavialis is an extinct genus of gryposuchine gavialid crocodylian. The only species yet known is P. jugaliperforatus. Fossils of Piscogavialis have been found from the Mio-Pliocene Pisco Formation of the Sacaco Basin in southern Peru...
have been found from localities thought to have been deposited in coastal environments. The presence of Gryposuchus in the Urumaco Formation of Venezuela, which does include marine strata, lends credence to the idea that gryposuchines may have been living in coastal environments. However, certain localities where material from the species G. colombianus has been recovered, such as La Venta
La Venta (Colombia)
La Venta is a settlement between the modern Tolima Department and Huila Department, Colombia. Nearby, one of the richest Neogene fossil assemblages in the whole of South America is known...
, Colombia
Colombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
, were clearly deposited in non-marine environments, speaking against the proposed coastal lifestyle hypothesis for all gryposuchines.
External links
- Gryposuchus in the Paleobiology DatabasePaleobiology Database' is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms.-History:The Paleobiology Database was founded in 2000. It has been funded by the National Science Foundation and the Australian Research Council...
- http://scienceblogs.com/tetrapodzoology/2008/10/worlds_largest_croc_skull.php