''Kuttanacaiman'' is a

monotypic In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nom ...

of extinct

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 f ...

represented by 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 specime ...

''Kuttanacaiman iquitosensis''. ''Kuttanacaiman'' lived in what is now the Amazon basin during the Middle Miocene, approximately 13 million years ago (Ma). The species was named in 2015 on the basis of one nearly complete skull and a second partial skull from the

Pebas Formation The Pebas Formation is a lithostratigraphic unit of Miocene age, found in western Amazonia. The formation extends over , including parts of Brazil, Peru, Ecuador and Colombia.Wesselingh et al., 2006 It is interpreted as representing the deposits ...

near Iquitos, Peru. ''K. iquitosensis'' is characterized by a short, rounded snout and blunt teeth at the back of its jaws that were likely adapted to crushing freshwater bivalves. Its estimated total body length is . Kuttanacaiman size

Etymology

The genus name comes from the

Quechua Quechua may refer to: *Quechua people, several indigenous ethnic groups in South America, especially in Peru *Quechuan languages, a Native South American language family spoken primarily in the Andes, derived from a common ancestral language **So ...

word ''kuttana'', meaning "grinding or crushing machine", and its species name honors the Iquitos native peoples.

Habitat

''Kuttanacaiman'' lived in Amazonia at a time before the

Amazon River Basin The Amazon basin is the part of South America drained by the Amazon River and its tributaries. The Amazon drainage basin covers an area of about , or about 35.5 percent of the South American continent. It is located in the countries of Bolivi ...

was established; in its place was a massive wetland, called the Pebas Mega-Wetland System, that covered an approximate area of over in a

drainage basin A drainage basin is an area of land where all flowing surface water converges to a single point, such as a river mouth, or flows into another body of water, such as a lake or ocean. A basin is separated from adjacent basins by a perimeter, ...

east of the still forming

Andes The Andes, Andes Mountains or Andean Mountains (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long, wide (widest between 18°S – 20°S ...

, which at the time were experiencing rapid uplift in certain parts. ''Kuttanacaiman'' coexisted with six other

crocodylian 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 ...

species, including two other caiman species with crushing dentitions: ''

Gnatusuchus pebasensis ''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 ...

'' and ''

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 ...

''. Shells belonging to the bivalve genus '' Pachydon'' form thick fossil beds in the Pebas Formation and may have been a food source for ''Kuttanacaiman'' and these other caimans in swamps and marshes.

Taxonomy

phylogenetic analysis In biology, phylogenetics (; from Greek φυλή/ φῦλον [] "tribe, clan, race", and wikt:γενετικός, γενετικός [] "origin, source, birth") is the study of the evolutionary history and relationships among or within groups o ...

published in 2015 indicates that ''Kuttanacaiman'' is one of the most basal members of the clade

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 fr ...

. Other basal caimanines such as ''Gnatusuchus'' and ''

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 l ...

'' also possess crushing teeth, suggesting that this type of dentition was ancestral for the clade. Later caimanines, including most living species in the 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 f ...

'', have more generalized dentitions, but some species such as ''C. wannlangstoni'' and '' C. latirostris'' seem to have re-evolved crushing dentitions. Below is a

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 ...

showing this evolutionary pattern, with crushing-dentition caimanine species in bold:

References

{{Taxonbar, from=Q20071778 Miocene crocodylomorphs Miocene reptiles of South America Mayoan Laventan Colloncuran Friasian Neogene Peru Fossils of Peru Fossil taxa described in 2015 Prehistoric pseudosuchian genera