''Ilchunaia'' is an extinct

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of sebecid

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 Me ...

Fossil A fossil (from Classical Latin , ) is any preserved remains, impression, or trace of any once-living thing from a past geological age. Examples include bones, shells, exoskeletons, stone imprints of animals or microbes, objects preserve ...

s have been found from the

Divisadero Largo Formation __NOTOC__ Divisadero may refer to: Places Mexico * Divisadero, Chihuahua, a town on the Ferrocarril Chihuahua al Pacífico (Copper Canyon railroad) * Divisaderos, Sonora United States * Divisadero Street, in San Francisco * Divisadero Street, ...

Argentina Argentina, officially the Argentine Republic, is a country in the southern half of South America. It covers an area of , making it the List of South American countries by area, second-largest country in South America after Brazil, the fourt ...

dating back to the

Late Eocene The Priabonian is, in the International Commission on Stratigraphy, ICS's geologic timescale, the latest age (geology), age or the upper stage (stratigraphy), stage of the Eocene epoch (geology), Epoch or series (stratigraphy), Series. It spans ...

,''Ilchunaia''
at

Fossilworks Fossilworks was a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database, a large relational database assembled by hundreds of paleontologists from around the world. History Fossilworks was cr ...

.org and a locality in

Mendoza, Argentina Mendoza (), officially the City of Mendoza (), is the capital of the Provinces of Argentina, province of Mendoza Province, Mendoza in Argentina. It is located in the northern-central part of the province, in a region of foothills and high plain ...

dating back to the

Oligocene The Oligocene ( ) is a geologic epoch (geology), epoch of the Paleogene Geologic time scale, Period that extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that defin ...

. Little material is known from the genus, with only the anterior portion of the skull being present to study (the

holotype A holotype (Latin: ''holotypus'') is a single physical example (or illustration) of an organism used when the species (or lower-ranked taxon) was formally described. It is either the single such physical example (or illustration) or one of s ...

has since been lost).

Taxonomy

The placement of ''Ilchunaia'' within Sebecosuchidae has been questioned in the past, and many recent phylogenetic analyses have shown the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

to be entirely

paraphyletic Paraphyly is a taxonomic term describing a grouping that consists of the grouping's last common ancestor and some but not all of its descendant lineages. The grouping is said to be paraphyletic ''with respect to'' the excluded subgroups. In co ...

, with members most likely being basal

sebecosuchia Sebecosuchia (meaning "Sobek crocodiles") is an extinct group of mesoeucrocodylian crocodyliforms that includes the families Sebecidae and Baurusuchidae. The group was long thought to have first appeared in the Late Cretaceous with the baurusu ...

ns ancestral to the

baurusuchids Baurusuchidae is a Gondwanan Family (biology), family of mesoeucrocodylians that lived during the Late Cretaceous. It is a group of terrestrial hypercarnivorous crocodilians from South America (Argentina and Brazil) and possibly Pakistan. Baurusu ...

.Ortega, F., Gasparini, Z., Buscalioni, A. D., and Calvo, J. O. (2000). A new species of ''Araripesuchus'' (Crocodylomorpha, Mesoeucrocodylia) from the Lower Cretaceous of Patagonia (Argentina). ''Journal of Vertebrate Paleontology'' 20:57–76.

References

External links

Ilchunaia
in the

Paleobiology Database The Paleobiology Database (PBDB) is an online resource for information on the distribution and classification of fossil animals, plants, and microorganisms. History The Paleobiology Database originated in the NCEAS-funded Phanerozoic Marine Pale ...

{{Taxonbar, from=Q9007983 Sebecidae Eocene crocodylomorphs Eocene reptiles of South America Tinguirirican Divisaderan Paleogene Argentina Fossils of Argentina Fossil taxa described in 1946 Prehistoric pseudosuchian genera