Gryposuchinae Temporal range:Middle Oligocene -Holocene,28–0.117 Ma PreꞒ Ꞓ O S D C P T J K Pg N
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Clade:	Archosauromorpha
Clade:	Archosauriformes
Order:	Crocodilia
Family:	Gavialidae
Subfamily:	†Gryposuchinae Vélez-Juarbeet al., 2007
Genera
†Aktiogavialis †Dadagavialis †Gryposuchus †Hesperogavialis †Ikanogavialis †Piscogavialis †Siquisiquesuchus

Gryposuchinae is an extinctsubfamily ofgavialidcrocodylians. Gryposuchines lived mainly in theMiocene ofSouth America. However,"Ikanogavialis" papuensis may have survived more recently, into the LatePleistocene/Holocene. Most were long-snouted coastal forms. The group was named in 2007 and includes genera such asGryposuchus andAktiogavialis, although a 2018 study indicates that the group might beparaphyletic and rather anevolutionary grade towards thegharial.

Gryposuchines had long, narrow snouts and protruding eye sockets. One distinguishing feature of the group is the lack of a large exposure of theprootic bone around the trigeminal foramen, a hole in the side of thebraincase wall.^[1]

Gryposuchinae was named in 2007 as a subfamily of closely related gavialid crocodilians. It wascladistically defined as astem-based taxon includingGryposuchus jessei and all crocodilians more closely related to it than toGavialis gangeticus (thegharial) orTomistoma schlegelii (theFalse gharial).^[1] Thetomistomines (including the livingfalse gharial) were long thought to be classified ascrocodiles and not closely related togavialoids.^[2] However, recent molecular studies usingDNA sequencing have consistently indicated that thefalse gharial (Tomistoma) (and by inference other related extinct forms inTomistominae) actually belong toGavialoidea (andGavialidae).^{[3][4][5][6][7][8][9]}

Aphylogenetic analysis conducted in the 2007 study found Gryposuchinae to include the generaAktiogavialis,Gryposuchus,Ikanogavialis,Piscogavialis, andSiquisiquesuchus. The belowcladogram is from the 2007 analysis showing the phylogenetic relationships of gryposuchines amonggavialoids.^[1]Hesperogavialis was excluded due to a lack of skull material, andDadagavialis due to its 2018 discovery.^[10]

Alternatively, phylogenetic studies recovering thetomistomines (including the livingfalse gharial) withinGavialidae have indicated that the members of Gryposuchinae and thegenusGryposuchus may in fact beparaphyletic and rather anevolutionary grade towardsGavialis and thegharial,^[11][8] as shown in the cladogram below:^[11]

The subfamily Gryposuchinae are the sole members of the superfamilyGavialoidea to occupy South America, the duration of which is entirely limited to the Miocene. However, although most of their history is recorded on the continent, dispersion was achieved via a prior presence in the Caribbean (Aktiogavialis, the oldest known gryposuchine, from in the Middle Oligocene of Puerto Rico, andDadagavialis in the Early Miocene of Panama, respectively).^[1][12] Furthermore, indeterminate gavialoid remains have recovered from the Oligo-Miocene boundary of coastal Brazil.^[13] The origin of these gryposuchines is unclear, although traditionally, an African origin has been favoured as gavialids would have been more likely to cross theAtlantic Ocean than the longer expanses of thePacific Ocean. Moreover, warm equatorial currents run across the Atlantic from Africa to the Americas, assisting in travel.

Gryposuchus,Ikanogavialis andSiquisiquesuchus represent the first known members of Gryposuchinae in Early Miocene of South America, colonizing around Colombia and Venezuela. Additionally, indeterminate finds of gavialoids (all in either coastal or marine sediments) are present in early MioceneJimol Formation and for the early/middle MioceneCastilletes Formation in Colombia,^[14][15] and from the Oligo-Miocene boundaryPirabas Formation of coastal Brazil,^[13]Gryposuchus andIkanogavialis persist into the Middle Miocene, with the freshwater-adaptingGryposuchus expanding throughout thePebas mega-wetlands into inland Peru and Argentina. In the Late Miocene, Gryposuchinae diversity explodes, withGryposuchus andIkanogavialis being joined byHesperogavialis, of Venezuela and Brazil,Piscogavialis of coastal Peru, andAktiogavialis, re-appearing in the fossil record once more, also in Venezuela. At this point, five of the seven genera are present in the Late Miocene, with four genera overlapping in theUrumaco Formation of Venezuela alone, a particular hotspot for crocodilian diversity in the Miocene. Based on the deposits in which they were found, most genera of gryposuchines were solely estuarine, coastal or marine-dwelling; only the generaGryposuchus andHesperogavialis had some level of freshwater presence. On the flipside, whereas most gryposuchines were restricted to a certain coastal region and time period,Gryposuchus enjoyed a continent wide distribution, spread from Andeo-Venezuelan drainage basin to Argentina from the Middle Miocene onwards. Additionally, whereas the other genera had one or two species each,Gryposuchus had five, one of which (G. croizati) was the largest of the superfamily on record, at an estimated length of 10m.^[16]

At the Miocene/Pliocene boundary, all gryposuchines, and thus the entire superfamily of Gavialoidea, along with the first wave ofcrocodyloids (Brasilosuchus andCharactosuchus, which also colonized during the Miocene) were likely extirpated from South America, withCaimaninae undergoing a severe reduction in size and diversity as well. This was likely due to the continuing elevation of the northern sections of the Andes chain reshaping the future Amazonian drainage system, re-rerouting flow to the Venezuelan Caribbean to the much cooler Atlantic, and transforming the mega-wetlands into a fully developed riverine system. The co-current aridification of the continental interior, and isolation of the peripheral wetland basins, also restricted the space and food resources of these large, food intensive specialist crocodilians, and has thus also been suggested as an essential factor in their extinction.^[15][17][18] Several othergavialid taxa also went extinct globally, suggesting a major global climate change event. However, there may be evidence thatPiscogavialis survived this mass extinction, persisting on the Pacific coast of Pliocene Peru for a few million more years.^[19] Furthermore, crocodyloids would recolonize South America via the AfricanCrocodylus in the early Pliocene,^[15] whereas gryposuchines would only re-appear in the fossil record six million years later, as"Ikanogavialis"papuensis, in the Late Pleistocene/Holocene marine sediments of theWoodlark Island, in theSolomon Sea. Separated by a geographical barrier of at least 10,000 km, this gavialoid had presumably reachedMelanesia in a similar fashion asBrachylophus andLapitiguana iguanas, being carried by Pacific oceanic currents. Found in association withdugongs andsea turtles,"Ikanogavialis" papuensis was a marine animal like its ancestors, a 2-3 meter long coastal piscivore so far known only fromMurua. Like other Pleistocene gharials, the species was presumably hunted to extinction by humanity.^[20]

• Gavialidae
• Paleogene crocodylomorphs
• Neogene crocodylomorphs
• Prehistoric reptiles of South America
• Chattian first appearances
• Paraphyletic groups

• Articles with short description
• Short description is different from Wikidata
• Articles with 'species' microformats