''Araripesuchus'' is a genus of

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 ...

crocodyliform Crocodyliformes is a clade of crurotarsan archosaurs, the group often traditionally referred to as "crocodilians". They are the first members of Crocodylomorpha to possess many of the features that define later relatives. They are the only pseudo ...

that existed during the

Cretaceous The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of th ...

period of the late

Mesozoic The Mesozoic Era ( ), also called the Age of Reptiles, the Age of Conifers, and colloquially as the Age of the Dinosaurs is the second-to-last era of Earth's geological history, lasting from about , comprising the Triassic, Jurassic and Cretaceo ...

era some 125 to 66 million years ago. Six species of ''Araripesuchus'' are currently known. They are generally considered to be notosuchians (belonging to the

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

Mesoeucrocodylia Mesoeucrocodylia is the clade that includes Eusuchia and crocodyliforms formerly placed in the paraphyletic group Mesosuchia. The group appeared during the Early Jurassic, and continues to the present day. Diagnosis It was long known that M ...

), characterized by their varied teeth types and distinct skull elements. This genus consists of six species: ''A. buitreraensis'', discovered in

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

, ''A. wegeneri'', discovered in

Cameroon Cameroon (; french: Cameroun, ff, Kamerun), officially the Republic of Cameroon (french: République du Cameroun, links=no), is a country in west-central Africa. It is bordered by Nigeria to the west and north; Chad to the northeast; the C ...

and

Niger ) , official_languages = , languages_type = National languagesNiger ) , official_languages = , languages_type = National languagesMadagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...

, ''A. gomesii'' (the

type species In zoological nomenclature, a type species (''species typica'') is the species name with which the name of a genus or subgenus is considered to be permanently taxonomically associated, i.e., the species that contains the biological type specimen ...

), discovered in

Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...

and another species discovered in

, ''A. patagonicus''.

Description

Its length was about with a weight of . ''Araripesuchus'' can be distinguished by their laterally bulged edges of the snout, with the bulge being the most prominent around the area of an enlarged

maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...

ry tooth. The snout and

premaxilla The premaxilla (or praemaxilla) is one of a pair of small cranial bones at the very tip of the upper jaw of many animals, usually, but not always, bearing teeth. In humans, they are fused with the maxilla. The "premaxilla" of therian mammal has b ...

are also smoother than that of most crocodyliforms, without foramina or the typical rugose texture. There are six valid species within this genus, all with slightly differing maxillary or dentary structure. ''A. gomesii, A. wegeneri'' and ''A. tsangatsangana'' all have a mild concavity of the external

alveolar Alveolus (; pl. alveoli, adj. alveolar) is a general anatomical term for a concave cavity or pit. Uses in anatomy and zoology * Pulmonary alveolus, an air sac in the lungs ** Alveolar cell or pneumocyte ** Alveolar duct ** Alveolar macrophage * ...

margin of the premaxilla as viewed from the ventral surface; ''A. rattoides'' may also have this feature, although this part of its skull is not known, as the dentary suggests that this would be the case. ''A. rattoides'' also had the distinctive feature of a highly enlarged and forward-pointing first dentary tooth referred to as an incisiform, resembling the elongated incisors found in

rodent Rodents (from Latin , 'to gnaw') are mammals of the order Rodentia (), which are characterized by a single pair of continuously growing incisors in each of the upper and lower jaws. About 40% of all mammal species are rodents. They are na ...

s (hence the specific epithet). All species of ''Araripesuchus'' had relatively large orbits and hence

eye Eyes are organs of the visual system. They provide living organisms with vision, the ability to receive and process visual detail, as well as enabling several photo response functions that are independent of vision. Eyes detect light and conv ...

s. They also had thin

osteoderm Osteoderms are bony deposits forming scales, plates, or other structures based in the dermis. Osteoderms are found in many groups of extant and extinct reptiles and amphibians, including lizards, crocodilians, frogs, temnospondyls (extinct amp ...

s that covered the entire body, multiple rows of them across the back and paired dorsal ones along the tail. Each side of the tail also had a single row of osteoderms, and there were paired ventral osteoderms across most of the belly and underside as well. The osteoderms were not strongly keeled, which, along with the long limb bones and shoulder, hip and ankle joints that suggest upright posture, indicate that ''Araripesuchus'' was probably more active on land than on water.

Discovery and history

The name of the genus was coined in 1959 with the description of the

''Araripesuchus gomesii'', a notosuchian crocodylian from the famed Santana Group of the Araripe Basin in

. The

holotype A holotype is a single physical example (or illustration) of an organism, known to have been used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of several ...

used to describe the genus, 423-R is currently in the care of the Divisão de Mineralogia e Geologia do Departamento Nacional da Produção Mineral in

Rio de Janeiro Rio de Janeiro ( , , ; literally 'River of January'), or simply Rio, is the capital of the state of the same name, Brazil's third-most populous state, and the second-most populous city in Brazil, after São Paulo. Listed by the GaWC as a b ...

. 423-R consists of a single skull articulating with part of a lower jaw. A more complete specimen, AMNH 24450 is held by the

American Museum of Natural History The American Museum of Natural History (abbreviated as AMNH) is a natural history museum on the Upper West Side of Manhattan in New York City. In Theodore Roosevelt Park, across the street from Central Park, the museum complex comprises 26 inter ...

. A second species, ''A. wegeneri'' was described in 1981. This species was discovered from

Early Cretaceous The Early Cretaceous ( geochronological name) or the Lower Cretaceous (chronostratigraphic name), is the earlier or lower of the two major divisions of the Cretaceous. It is usually considered to stretch from 145 Ma to 100.5 Ma. Geology Pro ...

deposits of

Niger ) , official_languages = , languages_type = National languagesAfrica Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

n continent, as opposed to the

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 ...

n paleodistribution of the other species in the genus. The type specimen for the species, GDF-700 consisting of a few, fragmentary jaw elements, reside at the

Museum National d'Histoire Naturelle The French National Museum of Natural History, known in French as the ' (abbreviation MNHN), is the national natural history museum of France and a ' of higher education part of Sorbonne Universities. The main museum, with four galleries, is loc ...

Paris Paris () is the capital and most populous city of France, with an estimated population of 2,165,423 residents in 2019 in an area of more than 105 km² (41 sq mi), making it the 30th most densely populated city in the world in 2020. S ...

. The holotype's fragmentary nature meant that its placement in the genus was disputed until more remains were found in 2009 by Sereno and Larsson; these, along with the specimens of ''A. tsangatsangana,'' confirmed its place. ''Araripesuchus patagonicus'' was described from a patagonian specimen (MUC-PV 269) in 2000. Another species to be assigned to the genus, was ''

Araripesuchus buitreraensis ''Araripesuchus'' is a genus of extinct crocodyliform that existed during the Cretaceous period of the late Mesozoic era some 125 to 66 million years ago. Six species of ''Araripesuchus'' are currently known. They are generally considered to be n ...

'', described in 2005. This species was described from a single skull (MPCA-PV 235) retrieved from

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 ...

deposits in what is now

. At 130 millimeters, the skull is the largest ''Araripesuchus'' specimen discovered to date. A fifth species, ''Araripesuchus tsangatsangana'' was described in 2006. This species' type specimen was discovered from latest Late Cretaceous deposits from the African island of

Madagascar Madagascar (; mg, Madagasikara, ), officially the Republic of Madagascar ( mg, Repoblikan'i Madagasikara, links=no, ; french: République de Madagascar), is an island country in the Indian Ocean, approximately off the coast of East Africa ...

. Analysis of this specimen solidifies the position of ''A. wegneri'' as a member of the genus. ''A. tsangatsangana'' is the geologically youngest known of this genus. The sixth species, ''A. rattoides'', was found in the

Kem Kem Beds The Kem Kem Group (commonly known as the Kem Kem beds) is a geological group in the Kem Kem region of eastern Morocco, whose strata date back to the Cenomanian stage of the Late Cretaceous. Its strata are subdivided into two geological formations, ...

of the

Sahara , photo = Sahara real color.jpg , photo_caption = The Sahara taken by Apollo 17 astronauts, 1972 , map = , map_image = , location = , country = , country1 = , ...

in a similar location to the specimens of ''A. wegeneri'' found by Sereno and Larsson, and is known only from parts of dentary bones, up to the fourteenth alveolus. It was described in the same paper as ''

Kaprosuchus ''Kaprosuchus'' is an extinct genus of mahajangasuchid crocodyliform. It is known from a single nearly complete skull collected from the Upper Cretaceous Echkar Formation of Niger. The name means "boar crocodile" from the Greek , ''kapros'' ("bo ...

'', ''

Laganosuchus ''Laganosuchus'' is an extinct genus of stomatosuchid crocodyliform. Fossils have been found from Niger and Morocco and date back to the Upper Cretaceous. Discovery The name means "pancake crocodile" from the Greek , ("pancake") and , ("cro ...

'' and '' Anatosuchus''; the four were therefore popularized by the authors as 'RatCroc', 'BoarCroc', 'PancakeCroc' and 'DuckCroc' respectively.

Classification

There are currently six recognized species within the genus ''Araripesuchus'': ''A. patagonicus'', ''A. buitreraensis'', ''A. tsangatsangana'', ''A. wegeneri'', ''A. rattoides'' and the

''A. gomesii''. The placement of the first African species discovered, ''A. wegeneri'' was questioned for a while by various authors. Ortega et al. argued for the assignment of the errant species to another genus based on phylogenetic analysis Further analysis, combined with the discovery of the second African species ''A. tsangatsangana'' has shed more light on the placement of ''A. wegeneri'' within the genus. When analyzed together, the African species support the inclusion of all five first described species into the same genus. The genus was originally assigned by Price to the family

Uruguaysuchidae Uruguaysuchidae is a family of notosuchian crocodyliforms that lived in South America and Africa during the Cretaceous period. It includes the genera ''Araripesuchus ''Araripesuchus'' is a genus of extinct crocodyliform that existed during the ...

in the original 1959 description. This classification was followed by Buffetaut in 1981 with the description of ''A. wegeneri'' also within the same family. However, in their 2000 description of ''A. patagonicus'', Ortega ''et al.'' avoided placing the species within the family. Instead, it was simply noted that ''

Uruguaysuchus ''Uruguaysuchus'' is an extinct genus of crocodylomorphs from the Late Cretaceous Guichón Formation of Uruguay. It was related to ''Simosuchus ''Simosuchus'' (meaning "pug-nosed crocodile" in Greek, referring to the animal's blunt snout) is ...

'' was a possible close relative of the genus. Ortega ''et al.'' and several other studies place ''Araripesuchus'' outside Notosuchia. In some phylogenetic analyses, it is placed closer to the clade Neosuchia, which includes modern crocodilians. In most recent analyses, however, ''Araripesuchus'' is placed as a

basal Basal or basilar is a term meaning ''base'', ''bottom'', or ''minimum''. Science * Basal (anatomy), an anatomical term of location for features associated with the base of an organism or structure * Basal (medicine), a minimal level that is nec ...

notosuchian. The phylogenetic analysis of Soto ''et al.'' (2011) joined ''Araripesuchus'' with ''Uruguaysuchus'', reinstating the family Uruguaysuchidae. This family was found to be the most basal group of Notosuchia. Below is a cladogram from the analysis: Araripesuchus rattoides

Paleoecology

''Araripesuchus'' remains have been recovered from the continents of

and

Africa Africa is the world's second-largest and second-most populous continent, after Asia in both cases. At about 30.3 million km2 (11.7 million square miles) including adjacent islands, it covers 6% of Earth's total surface area ...

suggesting a

Gondwana Gondwana () was a large landmass, often referred to as a supercontinent, that formed during the late Neoproterozoic (about 550 million years ago) and began to break up during the Jurassic period (about 180 million years ago). The final stages ...

n origin for the evolution of the genus. At around the time of ''Araripesuchus' '' existence, South America and Africa were physically adjacent to each other. The various species evolved from the same stock in the general area, radiating outward from a yet-unidentified origin point. The presence of specimens from

further strengthens this evolutionary radiation model.

References

External links

{{Taxonbar, from=Q776081 Uruguaysuchids Terrestrial crocodylomorphs Early Cretaceous crocodylomorphs of South America Late Cretaceous crocodylomorphs of South America Cretaceous Argentina Fossils of Argentina Cretaceous Brazil Fossils of Brazil Early Cretaceous crocodylomorphs of Africa Late Cretaceous crocodylomorphs of Africa Crocodylomorphs of Madagascar Maevarano fauna Cretaceous Cameroon Fossils of Cameroon Cretaceous Malawi Fossils of Malawi Cretaceous Morocco Fossils of Morocco Cretaceous Niger Fossils of Niger Cretaceous Tunisia Fossils of Tunisia Fossil taxa described in 1959 Prehistoric pseudosuchian genera