family
Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
Alligatoridae of
crocodylia
Crocodilia (or Crocodylia, both ) is an order of mostly large, predatory, semiaquatic reptiles, known as crocodilians. They first appeared 95 million years ago in the Late Cretaceous period (Cenomanian stage) and are the closest living ...
ns includes
alligator
An alligator is a large reptile in the Crocodilia order in the genus ''Alligator'' of the family Alligatoridae. The two extant species are the American alligator (''A. mississippiensis'') and the Chinese alligator (''A. sinensis''). Additiona ...
s,
caiman
A caiman (also cayman as a variant spelling) is an alligatorid belonging to the subfamily Caimaninae, one of two primary lineages within the Alligatoridae family, the other being alligators. Caimans inhabit Mexico, Central and South America fro ...
s and their extinct relatives.
Phylogeny
The superfamily
Alligatoroidea
Alligatoroidea is one of three superfamilies of crocodylians, the other two being Crocodyloidea and Gavialoidea. Alligatoroidea evolved in the Late Cretaceous period, and consists of the alligators and caimans, as well as extinct members more c ...
includes all crocodilians (fossil and extant) that are more closely related to the American alligator than to either the
Nile crocodile
The Nile crocodile (''Crocodylus niloticus'') is a large crocodilian native to freshwater habitats in Africa, where it is present in 26 countries. It is widely distributed throughout sub-Saharan Africa, occurring mostly in the central, eastern ...
or the
gharial
The gharial (''Gavialis gangeticus''), also known as gavial or fish-eating crocodile, is a crocodilian in the family Gavialidae and among the longest of all living crocodilians. Mature females are long, and males . Adult males have a distinct b ...
alligators
An alligator is a large reptile in the Crocodilia order in the genus ''Alligator'' of the family Alligatoridae. The two extant species are the American alligator (''A. mississippiensis'') and the Chinese alligator (''A. sinensis''). Additiona ...
, and is more inclusive than the
crown group
In phylogenetics, the crown group or crown assemblage is a collection of species composed of the living representatives of the collection, the most recent common ancestor of the collection, and all descendants of the most recent common ancestor. ...
Alligatoridae. As a crown group, Alligatoridae only includes the
last common ancestor
In biology and genetic genealogy, the most recent common ancestor (MRCA), also known as the last common ancestor (LCA) or concestor, of a set of organisms is the most recent individual from which all the organisms of the set are descended. The ...
of all
extant
Extant is the opposite of the word extinct. It may refer to:
* Extant hereditary titles
* Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English
* Extant taxon, a taxon which is not extinct, ...
(living) alligators, caimans, and their descendants (living or
extinct
Extinction is the termination of a kind of organism or of a group of kinds (taxon), usually a species. The moment of extinction is generally considered to be the death of the last individual of the species, although the capacity to breed and ...
), whereas Alligatoroidea, as a stem-based group, also includes more basal extinct alligator ancestors that are more closely related to living alligators than to
crocodiles
Crocodiles (family Crocodylidae) or true crocodiles are large semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. The term crocodile is sometimes used even more loosely to include all extant memb ...
or
gavialids
Gavialidae is a family of large semiaquatic crocodilians with elongated, narrow snouts. Gavialidae consists of two living species, the gharial (''Gavialis gangeticus'') and the false gharial (''Tomistoma schlegelii''), both occurring in Asia. Man ...
. When considering only living taxa (
neontology
Neontology is a part of biology that, in contrast to paleontology, deals with living (or, more generally, '' recent'') organisms. It is the study of extant taxa (singular: extant taxon): taxa (such as species, genera and families) with members st ...
), this makes Alligatoroidea and Alligatoridae redundant.
The simplified
cladogram
A cladogram (from Greek ''clados'' "branch" and ''gramma'' "character") is a diagram used in cladistics to show relations among organisms. A cladogram is not, however, an evolutionary tree because it does not show how ancestors are related to d ...
below shows Alligatoridae's relationships to other
extant
Extant is the opposite of the word extinct. It may refer to:
* Extant hereditary titles
* Extant literature, surviving literature, such as ''Beowulf'', the oldest extant manuscript written in English
* Extant taxon, a taxon which is not extinct, ...
(living) crocodilians.
The below detailed cladogram shows one proposal for the internal relationships within Alligatoridae (although the exact alligatoroid phylogeny is still disputed).
Evolution
The superfamily
Alligatoroidea
Alligatoroidea is one of three superfamilies of crocodylians, the other two being Crocodyloidea and Gavialoidea. Alligatoroidea evolved in the Late Cretaceous period, and consists of the alligators and caimans, as well as extinct members more c ...
is thought to have split from the crocodile-gharial lineage in the
late Cretaceous
The Late Cretaceous (100.5–66 Ma) is the younger of two epochs into which the Cretaceous Period is divided in the geologic time scale. Rock strata from this epoch form the Upper Cretaceous Series. The Cretaceous is named after ''creta'', the ...
, about 87 million years ago. ''
Leidyosuchus
''Leidyosuchus'' (meaning " Leidy's crocodile") is an extinct genus of alligatoroid from the Late Cretaceous of Alberta. It was named in 1907 by Lawrence Lambe, and the type species is ''L. canadensis''. It is known from a number of specimens fro ...
'' of
Alberta
Alberta ( ) is one of the thirteen provinces and territories of Canada. It is part of Western Canada and is one of the three prairie provinces. Alberta is bordered by British Columbia to the west, Saskatchewan to the east, the Northwest Ter ...
is the earliest known genus. Fossil alligatoroids have been found throughout Eurasia as land bridges across both the North Atlantic and the Bering Strait have connected North America to Eurasia during the Cretaceous,
Paleogene
The Paleogene ( ; British English, also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period, geologic period and system that spans 43 million years from the end of the Cretaceous Period million yea ...
, and
Neogene
The Neogene ( ), informally Upper Tertiary or Late Tertiary, is a geologic period and system that spans 20.45 million years from the end of the Paleogene Period million years ago ( Mya) to the beginning of the present Quaternary Period Mya. ...
periods. Alligators and caimans split in North America during the early Tertiary or late Cretaceous (about 53 million to about 65 million years ago) and the latter reached South America by the Paleogene, before the closure of the
Isthmus of Panama
The Isthmus of Panama ( es, Istmo de Panamá), also historically known as the Isthmus of Darien (), is the narrow strip of land that lies between the Caribbean Sea and the Pacific Ocean, linking North and South America. It contains the country ...
during the Neogene period. The Chinese alligator split from the American alligator about 33 million years ago and likely descended from a lineage that crossed the Bering land bridge during the Neogene. The modern American alligator is well represented in the fossil record of the
Pleistocene
The Pleistocene ( , often referred to as the ''Ice age'') is the geological Epoch (geology), epoch that lasted from about 2,580,000 to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fina ...
. The alligator's full
mitochondrial genome
Mitochondrial DNA (mtDNA or mDNA) is the DNA located in mitochondria, cellular organelles within eukaryotic cells that convert chemical energy from food into a form that cells can use, such as adenosine triphosphate (ATP). Mitochondrial D ...
was sequenced in the 1990s. The full
genome
In the fields of molecular biology and genetics, a genome is all the genetic information of an organism. It consists of nucleotide sequences of DNA (or RNA in RNA viruses). The nuclear genome includes protein-coding genes and non-coding ge ...
, published in 2014, suggests that the alligator evolved much more slowly than mammals and birds.
True alligators
The lineage including alligators proper (
Alligatorinae
Alligatorinae is a subfamily within the family Alligatoridae that contains the alligators and their closest extinct relatives, and is the sister taxon to Caimaninae (the caimans). Many genera in Alligatorinae are described, but only the genus ' ...
) occurs in the fluvial deposits of the age of the
Upper Chalk
The Chalk Group (often just called the Chalk) is the lithostratigraphic unit (a certain number of rock strata) which contains the Upper Cretaceous limestone succession in southern and eastern England. The same or similar rock sequences occur acr ...
in Europe, where they did not die out until the
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58A. mississippiensis'' in the
southeastern United States
The Southeastern United States, also referred to as the American Southeast or simply the Southeast, is a geographical region of the United States. It is located broadly on the eastern portion of the southern United States and the southern por ...
, which can grow to 15.6 ft (4.6 m) and weigh 1000 lbs(453 kg), with unverified sizes of up to 19.2 ft(5.9 m). And the small '' A. sinensis'' in the
Yangtze River
The Yangtze or Yangzi ( or ; ) is the longest list of rivers of Asia, river in Asia, the list of rivers by length, third-longest in the world, and the longest in the world to flow entirely within one country. It rises at Jari Hill in th ...
, China, which grows to an average of 5 ft (1.5 m). Their name derives from the
Spanish
Spanish might refer to:
* Items from or related to Spain:
**Spaniards are a nation and ethnic group indigenous to Spain
**Spanish language, spoken in Spain and many Latin American countries
**Spanish cuisine
Other places
* Spanish, Ontario, Cana ...
''el lagarto'', which means "the lizard".
Caimans
In
Central
Central is an adjective usually referring to being in the center of some place or (mathematical) object.
Central may also refer to:
Directions and generalised locations
* Central Africa, a region in the centre of Africa continent, also known as ...
and
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...
, the alligator family is represented by six species of the subfamily
Caimaninae
A caiman (also cayman as a variant spelling) is an alligatorid belonging to the subfamily Caimaninae, one of two primary lineages within the Alligatoridae family, the other being alligators. Caimans inhabit Mexico, Central and South America fro ...
, which differ from the alligator by the absence of a bony septum between the nostrils, and having ventral armour composed of overlapping bony
scute
A scute or scutum (Latin: ''scutum''; plural: ''scuta'' "shield") is a bony external plate or scale overlaid with horn, as on the shell of a turtle, the skin of crocodilians, and the feet of birds. The term is also used to describe the anterior po ...
s, each of which is formed of two parts united by a suture. Besides the three species in ''
Caiman
A caiman (also cayman as a variant spelling) is an alligatorid belonging to the subfamily Caimaninae, one of two primary lineages within the Alligatoridae family, the other being alligators. Caimans inhabit Mexico, Central and South America fro ...
'', the smooth-fronted caimans in genus ''
Paleosuchus
''Paleosuchus'' is a South American genus of reptiles in the subfamily Caimaninae of the family (biology), family Alligatoridae. They are the smallest members of the order Crocodilia in the Americas.
The genus contains two extant species and a ye ...
'' and the black caiman in '' Melanosuchus'' are described. Caimans tend to be more agile and crocodile-like in their movements, and have longer, sharper teeth than alligators.
''C. crocodilus'', the spectacled caiman, has the widest distribution, from southern Mexico to the northern half of Argentina, and grows to a modest size of about . The largest is the
near-threatened
A near-threatened species is a species which has been categorized as "Near Threatened" (NT) by the International Union for Conservation of Nature as that may be vulnerable to endangerment in the near future, but it does not currently qualify fo ...
''Melanosuchus niger'', the ''jacaré-açu'' or large or
black caiman
The black caiman (''Melanosuchus niger'') is a species of large crocodilian and is the largest species of the family Alligatoridae. It is a carnivorous reptile that lives along slow-moving rivers, lakes, seasonally flooded savannas of the Amazon ...
of the
Amazon River
The Amazon River (, ; es, Río Amazonas, pt, Rio Amazonas) in South America is the largest river by discharge volume of water in the world, and the disputed longest river system in the world in comparison to the Nile.
The headwaters of t ...
basin. Black caimans grow to , with the unverified size of up to . The black caiman and
American alligator
The American alligator (''Alligator mississippiensis''), sometimes referred to colloquially as a gator or common alligator, is a large crocodilian reptile native to the Southeastern United States. It is one of the two extant species in the g ...
are the only members of the alligator family that pose the same danger to humans as the larger species of the
crocodile
Crocodiles (family (biology), family Crocodylidae) or true crocodiles are large semiaquatic reptiles that live throughout the tropics in Africa, Asia, the Americas and Australia. The term crocodile is sometimes used even more loosely to inclu ...
family.
Although caimans have not been studied in depth, scientists have learned their mating cycles (previously thought to be spontaneous or year-round) are linked to the rainfall cycles and the river levels, which increases chances of survival for their offspring.
Taxonomy
† = extinct
* Family Alligatoridae
** Subfamily
Alligatorinae
Alligatorinae is a subfamily within the family Alligatoridae that contains the alligators and their closest extinct relatives, and is the sister taxon to Caimaninae (the caimans). Many genera in Alligatorinae are described, but only the genus ' ...
*** Genus ''
Alligator
An alligator is a large reptile in the Crocodilia order in the genus ''Alligator'' of the family Alligatoridae. The two extant species are the American alligator (''A. mississippiensis'') and the Chinese alligator (''A. sinensis''). Additiona ...
''
**** † ''
Alligator hailensis
''Alligator hailensis'', or Haile alligator, is a large, extinct species of ''Alligator'' known from the early Pleistocene of Florida. It is named after the town of Haile, Florida, where it was found. Its age and skeletal morphology is intermedi ...
''
**** † ''
Alligator mcgrewi
''Alligator mcgrewi'' is an extinct species of alligator described by K.P. Schmidt. They lived in the Early Miocene period,Alligator mcgrewi Schmidt, 1941 in Paleobiology Database (2018). The Paleobiology Database. Checklist dataset https://doi ...
''
**** † ''
Alligator mefferdi
''Alligator mefferdi'' is an extinct species of alligator described by Charles Craig Mook. They lived in the Miocene period, and their range was principally in what is now Nebraska, United States.American alligator
The American alligator (''Alligator mississippiensis''), sometimes referred to colloquially as a gator or common alligator, is a large crocodilian reptile native to the Southeastern United States. It is one of the two extant species in the g ...
**** † ''
Alligator olseni
''Alligator olseni'' (common name Olsen's Alligator, named after Russel Olsen) is an extinct species of alligator. They lived in the Early Miocene period, around 20.4–15.97 million years ago and possibly earlier. Their range was principally in ...
''
**** † ''
Alligator prenasalis
''Alligator prenasalis'' is an extinct species of alligator from the Late Eocene period. It is well known, with many fossils having been collected from the Chadron and Brule Formations in South Dakota. The species was first named in 1904, but wa ...
''
**** ''Alligator sinensis'',
Chinese alligator
The Chinese alligator (; ), also known as the Yangtze alligator (), China alligator, or historically the muddy dragon, is a crocodilian endemic to China. It and the American alligator (''A. mississippiensis'') are the only living species in the ...
**** † ''
Alligator thomsoni
''Alligator thomsoni'' is an extinct species of alligator that existed during the Early Miocene period. Their range was principally in what is now known as Nebraska, United States.“Alligator Thomsoni Mook 1923 (Alligator).” FossilworksFossilw ...
''
*** Genus † ''
Allognathosuchus
''Allognathosuchus'' (meaning "other jaw crocodile") is an extinct genus of alligatorine crocodylian with a complicated taxonomic history. It was named in 1921.
Description
''Allognathosuchus'' was a medium-sized predator up to 1.5 m in leng ...
''
*** Genus † ''
Arambourgia
''Arambourgia'' is an extinct monotypic genus of alligatorine crocodylian from Europe. It was named in 1905 as ''Allognathosuchus gaudryi''. It was made a separate genus ''Arambourgia'' in 1940. This was synonymized with '' Allognathosuchus hau ...
''
*** Genus † ''
Ceratosuchus
''Ceratosuchus'' is an extinct genus of alligatorine crocodylian from latest Paleocene rocks of Colorado's Piceance Basin and earliest Eocene rocks of Wyoming's Bighorn Basin in North America, a slice of time known as the Clarkforkian North Am ...
''
*** Genus † ''
Chrysochampsa
''Chrysochampsa'' is an extinct monospecific genus of alligatorine. Fossils have been found from the Golden Valley Formation of North Dakota and date back to the Wasatchian regional North American faunal stage of the early Eocene. The genus has ...
''
*** Genus † ''
Eoalligator
''Eoalligator'' is an extinct genus of alligatoroid crocodilian from Paleocene deposits in China.
Systematics
''Eoalligator'' was originally classified as an extinct relative of alligators. The holotype of ''E. chunyii'', IVPP V2716, is a partia ...
''
*** Genus † ''
Hassiacosuchus
''Hassiacosuchus'' is an extinct genus of small alligatorid from the early Eocene of Germany, found at the Messel pit. It was named in 1935 by K. Weitzel, and the type species is ''H. haupti''. A second species, ''H. kayi'', was named in 1941 by ...
''
*** Genus † ''
Krabisuchus
''Krabisuchus'' is an extinct genus of alligatoroid crocodylian that existed in what is now Thailand during the Eocene. It was first named by paleontologists Jeremy A. Martin and Komsorn Lauprasert in 2010, and the type species is ''K. siamogall ...
''
*** Genus † ''
Navajosuchus
''Navajosuchus'' is an extinct genus of alligatorine crocodylian. Its fossils have been found in the Paleocene-age Nacimiento Formation of the San Juan Basin, New Mexico (United States). It was named in 1942 by Charles C. Mook, and the original ...
''?
*** Genus † ''
Procaimanoidea
''Procaimanoidea'' ("Before Caiman-forms") is an extinct genus of alligatorid from the Eocene of North America. It was named posthumously in 1946 by Charles W. Gilmore; the type species is ''P. utahensis'', from the Uintan (middle Eocene) of Uta ...
''
*** Genus † ''
Wannaganosuchus
''Wannaganosuchus'' (meaning "Wannagan crocodile", in reference to the Wannagan Creek site where it was discovered) is an extinct genus of small alligatorid crocodylian. It was found in Late Paleocene-age rocks of Billings County, North Dakota, ...
''
** Subfamily
Caimaninae
A caiman (also cayman as a variant spelling) is an alligatorid belonging to the subfamily Caimaninae, one of two primary lineages within the Alligatoridae family, the other being alligators. Caimans inhabit Mexico, Central and South America fro ...
*** Genus † ''
Acresuchus
''Acresuchus'' ("Acre crocodile") is an extinct monospecific genus of medium-sized caiman from the Late Miocene of western Brazil andVenezuela. The genus contains a single species, ''Acresuchus pachytemporalis''. ''Acresuchus'' is a close relativ ...
''
*** Genus † ''
Bottosaurus
''Bottosaurus'' is an extinct genus of alligatorid from the Late Cretaceous-Early Paleocene of New Jersey, Texas, and possibly North Carolina and South Carolina. Two species are currently accepted, with a third requiring re-evaluation.
Taxonomy ...
''
*** Genus ''
Caiman
A caiman (also cayman as a variant spelling) is an alligatorid belonging to the subfamily Caimaninae, one of two primary lineages within the Alligatoridae family, the other being alligators. Caimans inhabit Mexico, Central and South America fro ...
''
**** † ''
Caiman brevirostris
''Caiman brevirostris'' is an extinct species of caiman that lived during the Late Miocene, around 11.6 million years ago, to the end of the Miocene 5.3 million years ago in Acre and Amazonas, Brazil as well as Urumaco, Venezuela. Several specim ...
Broad-snouted caiman
The broad-snouted caiman (''Caiman latirostris'') is a crocodilian in the family Alligatoridae found in eastern and central South America, including southeastern Brazil, northern Argentina, Uruguay, Paraguay, and Bolivia. It is found mostly in fr ...
**** † ''
Caiman lutescans
A caiman (also cayman as a variant spelling) is an alligatorid belonging to the subfamily Caimaninae, one of two primary lineages within the Alligatoridae family (biology), family, the other being alligators. Caimans inhabit Mexico, Central Ame ...
Caiman wannlangstoni
''Caiman wannlangstoni'' is an extinct species of caiman that lived in what is now the Amazon Basin and surrounding areas during the Middle and Late Miocene. Fossils of ''C. wannlangstoni'' have been found in the Pebas Formation near Iquitos ...
''
**** ''Caiman yacare'',
Yacare caiman
The yacare caiman (''Caiman yacare''), also known commonly as the jacare caiman, Spanish yacaré, Paraguayan caiman, piranha caiman, red caiman, southern spectacled caiman, ''jacaré'' in Portuguese, and îakaré in Old Tupi, is a species of cai ...
*** Genus † ''
Centenariosuchus
''Centenariosuchus'' is an extinct genus of caimanine crocodylian known from the Miocene of the Panama Canal Zone of Panama.Chinatichampsus''
*** Genus † ''
Culebrasuchus
''Culebrasuchus'' is an extinct, monotypic genus of caiman alligatorid known from the Early to Middle Miocene (Hemingfordian) of the Panama Canal Zone of Panama. It contains a single species, ''Culebrasuchus mesoamericanus''.
Discovery
''Cule ...
''
*** Genus † ''
Eocaiman
''Eocaiman'' is an extinct genus of caiman containing species living from the Early Paleocene to Miocene in what is now Argentina (Salamanca and Sarmiento Formations), Itaboraí Formation of Brazil and Colombia ( Honda Group).
''
*** Genus † ''
Globidentosuchus
''Globidentosuchus'' is an extinct genus of basal caimanine crocodylian known from the late Middle to Late Miocene of the Middle and the Upper Members of the Urumaco Formation at Urumaco, Venezuela. Its skull was very short and robust, with lar ...
''
*** Genus † ''
Gnatusuchus
''Gnatusuchus'' is an extinct genus of caiman represented by the type species ''Gnatusuchus pebasensis'' from the Middle Miocene Pebas Formation of Peru. ''Gnatusuchus'' lived about 13 million years ago (Ma) in a large wetland system called the P ...
''
*** Genus † ''
Kuttanacaiman
''Kuttanacaiman'' is a monotypic genus of extinct caiman represented by the type species ''Kuttanacaiman iquitosensis''. ''Kuttanacaiman'' lived in what is now the Amazon basin during the Middle Miocene, approximately 13 million years ago (Ma). ...
Black caiman
The black caiman (''Melanosuchus niger'') is a species of large crocodilian and is the largest species of the family Alligatoridae. It is a carnivorous reptile that lives along slow-moving rivers, lakes, seasonally flooded savannas of the Amazon ...
*** Genus † ''
Mourasuchus
''Mourasuchus'' is an extinct genus of giant, aberrant caiman from the Miocene of South America. Its skull has been described as duck-like, being broad, flat, and very elongate, superficially resembling ''Stomatosuchus'' from the Late Cretaceou ...
''
*** Genus † ''
Necrosuchus
''Necrosuchus'' is an extinct genus of caiman from modern day Argentina that lived during the Paleocene epoch (Selandian age, about 60 million years ago). It inhabited the fluvio-lacustrine environment of the Patagonian Salamanca Formation.
Hist ...
''
*** Genus † ''
Orthogenysuchus
''Orthogenysuchus'' is an extinct genus of caimanine alligatorids. Fossils have been found from the Wasatch Beds of the Willwood Formation of Wyoming, deposited during the early Eocene. The type species is ''O. olseni''. The holotype, known as ...
''
*** Genus ''
Paleosuchus
''Paleosuchus'' is a South American genus of reptiles in the subfamily Caimaninae of the family (biology), family Alligatoridae. They are the smallest members of the order Crocodilia in the Americas.
The genus contains two extant species and a ye ...
''
**** ''Paleosuchus palpebrosus'',
Cuvier's dwarf caiman
Cuvier's dwarf caiman (''Paleosuchus palpebrosus'') is a small crocodilian in the alligator family from northern and central South America. It is found in Brazil, Bolivia, Colombia, Ecuador, French Guiana, Guyana, Paraguay, Peru, Suriname, Trinid ...
**** ''Paleosuchus trigonatus'',
Smooth-fronted caiman
The smooth-fronted caiman (''Paleosuchus trigonatus''), also known as Schneider's dwarf caiman or Schneider's smooth-fronted caiman,Protocaiman
''Protocaiman'' is a caimanine genus of crocodylian first described in 2018. The type species ''Protocaiman peligrensis'' was discovered in Argentina's Salamanca Formation, and lived in Patagonia during the Paleocene
The Paleocene, ( ) or Pa ...
''
*** Genus † ''
Purussaurus
''Purussaurus'' is an extinct genus of giant caiman that lived in South America during the Miocene epoch, from the Friasian to the Huayquerian in the SALMA classification. It is known from skull material found in the Brazilian and Peruvian Amazon ...
''
*** Genus † ''
Tsoabichi
''Tsoabichi'' is an extinct genus of caimanine crocodylian. Fossils are known from the Green River Formation in Wyoming, and date back to the Ypresian stage of the Eocene (Wasatchian stage of North American age). The genus was named and describ ...