''Cachiyacuy'' is an

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 ...

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

caviomorph Caviomorpha is the rodent infraorder or parvorder that unites all New World hystricognaths. It is supported by both fossil and molecular evidence. The Caviomorpha was for a time considered to be a separate order outside the Rodentia, but is now a ...

known from the Loreto of

Peru , image_flag = Flag of Peru.svg , image_coat = Escudo nacional del Perú.svg , other_symbol = Great Seal of the State , other_symbol_type = Seal (emblem), National seal , national_motto = "Fi ...

. It contains two species: the type species ''C. contamanensis'' and ''C. kummeli''.

Description

All ''Cachiyacuy'' specimens were collected in the CTA-27 Locality (or Maquía locality), from the uppermost part of the Yahuarango Formation, dating to the latest

Lutetian The Lutetian is, in the geologic timescale, a stage or age in the Eocene. It spans the time between . The Lutetian is preceded by the Ypresian and is followed by the Bartonian. Together with the Bartonian it is sometimes referred to as the Midd ...

stage of the late Middle Eocene, about 41

million years ago The abbreviation Myr, "million years", is a unit of a quantity of (i.e. ) years, or 31.556926 teraseconds. Usage Myr (million years) is in common use in fields such as Earth science and cosmology. Myr is also used with Mya (million years ago). ...

. The type species ''C. contamanensis'' is known from 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 ...

MUSM 1871, a right second molar and from some referred teeth including MUSM 1870, MUSM 1872, MUSM 1873, MUSM 1874, MUSM 1875, MUSM 1876, MUSM 1877, MUSM 1878, MUSM 1879 and MUSM 1880. Its body mass estimated at 80–120 gram. The second species ''Cachiyacuy kummeli'' is known from the

MUSM 1882, a left first molar and from some referred teeth including MUSM 1881, MUSM 1883, MUSM 1885, MUSM 1886, MUSM 1887 and MUSM 1888. It was a tiny rodent, approximately 30% smaller than ''C. contamanensis'' as its body mass estimated at 30–40 gram. A cladistic analysis found ''Cachiyacuy'' to be monophyletic and one of the

basalmost In phylogenetics, basal is the direction of the ''base'' (or root) of a rooted phylogenetic tree or cladogram. The term may be more strictly applied only to nodes adjacent to the root, or more loosely applied to nodes regarded as being close to th ...

and the oldest known caviomorph (the other being '' Canaanimys'' from the same locality).

Etymology

''Cachiyacuy'' was first named by Pierre-Olivier Antoine, Laurent Marivaux, Darin A. Croft, Guillaume Billet, Morgan Ganerød, Carlos Jaramillo, Thomas Martin, Maëva J. Orliac, Julia Tejada, Ali J. Altamirano, Francis Duranthon, Grégory Fanjat, Sonia Rousse and Rodolfo Salas Gismondi in

2012 File:2012 Events Collage V3.png, From left, clockwise: The passenger cruise ship Costa Concordia lies capsized after the Costa Concordia disaster; Damage to Casino Pier in Seaside Heights, New Jersey as a result of Hurricane Sandy; People gather ...

and 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 ...

is ''Cachiyacuy contamanensis''. The generic name is derived from ''Cachiyacu'', name of a local River, and ''cuy'', Quechua for "guinea pig". The

specific name Specific name may refer to: * in Database management systems, a system-assigned name that is unique within a particular database In taxonomy, either of these two meanings, each with its own set of rules: * Specific name (botany), the two-part (bino ...

of the type species is named after the geographical provenance of the specimens, close to the city of Contamana. The specific name of ''C. kummeli'' honors the

geologist A geologist is a scientist who studies the solid, liquid, and gaseous matter that constitutes Earth and other terrestrial planets, as well as the processes that shape them. Geologists usually study geology, earth science, or geophysics, althou ...

Bernhard for describing extensively for the first time the Cachiyacu section in the 1940s.

References

{{Taxonbar, from=Q1949631 Hystricognath rodents Eocene rodents Eocene mammals of South America Divisaderan Paleogene Peru Fossils of Peru Fossil taxa described in 2012