Interatheriinae is an extinct subfamily of interatheriids that consisted of notoungulates dating from the Early

Eocene The Eocene ( ) is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (Ma). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene'' comes ...

(

Casamayoran The Casamayoran () age is a period of geologic time (50.0–48.0 Ma) within the Early Eocene epoch of the Paleogene, used more specifically within the South American land mammal age (SALMA) classification. It follows the Itaboraian and precedes th ...

SALMA) to the

Early Pliocene Early may refer to: Places in the United States * Early, Iowa, a city * Early, Texas, a city * Early Branch, a stream in Missouri * Early County, Georgia * Fort Early, Georgia, an early 19th century fort Music * Early B, stage name of Jamaican d ...

(

Montehermosan The Montehermosan age is a period of geologic time (6.8–4.0 Mya (unit), Ma) within the Miocene and Pliocene epochs of the Neogene used more specifically with South American Land Mammal Ages. It follows the Huayquerian and precedes the Chapadmalal ...

SALMA). The subfamily includes the genera '' Archaeophylus'', '' Argyrohyrax'', ''

Boleatherium ''Boleatherium'' is an extinct genus of interatheriid notoungulate that lived from the Early to Middle Miocene of what is now Argentina. Fossils of this genus have been found in the Cerro Boleadoras Formation, the formation which this genus w ...

'', '' Brucemacfaddenia'', '' Caenophilus'', '' Choichephilum'', '' Cochilius'', '' Eopachyrucos'', '' Federicoanaya'', '' Interatherium'', '' Juchuysillu'', ''

Miocochilius ''Miocochilius'' is an extinct genus of small Notoungulata, notoungulate mammals (typotheria, typotheres) native to South America. The genus lived during the Miocene, Middle Miocene epoch (Laventan in the South American land mammal age, SALMA cla ...

'', '' Neoicochilus'', '' Patriarchus'', ''

Proargyrohyrax ''Proargyrohyrax'' is an extinct genus of Interatheriinae, interatheriine Notoungulata, notoungulates that lived from the Early to Middle Oligocene in what is now Argentina. Fossils of this genus have been found in the Sarmiento Formation of Argen ...

'', '' Progaleopithecus'', ''

Protypotherium ''Protypotherium'' is an extinct genus of Notoungulata, notoungulate mammals native to South America during the Oligocene and Miocene epoch (geology), epochs. A number of closely related animals date back further, to the Eocene. Fossils of ''Prot ...

'', and '' Santiagorothia''. They were small to medium sized interatheres, and when compared to the other subfamily, Notopithecinae, interatheriines are found to occupy an advanced, derived position in the family. Material was copied from this source, which is available under a Creative Commons Attribution 4.0 International License

Description

Interatheriines were generally small to medium-sized interatheriids, and rarely exceeded the size of a

groundhog The groundhog (''Marmota monax''), also known as the woodchuck, is a rodent of the family Sciuridae, belonging to the group of large ground squirrels known as marmots. A lowland creature of North America, it is found through much of the Easte ...

. Compared with the other representatives of the suborder

Typotheria Notoungulata is an extinct order of ungulates that inhabited South America from the early Paleocene to the end of the Pleistocene, living from approximately 61 million to 11,000 years ago. Notoungulates were morphologically diverse, with forms re ...

, interatheriiness were mainly characterized by certain dental features, including the absence of roots in the anterior

incisors Incisors (from Latin ''incidere'', "to cut") are the front teeth present in most mammals. They are located in the premaxilla above and on the mandible below. Humans have a total of eight (two on each side, top and bottom). Opossums have 18, wher ...

. The

skull The skull, or cranium, is typically a bony enclosure around the brain of a vertebrate. In some fish, and amphibians, the skull is of cartilage. The skull is at the head end of the vertebrate. In the human, the skull comprises two prominent ...

s of interatheriines were usually equipped with full dentition. The best-known forms include ''

'', which was long-legged and vaguely rabbit-like in terms of appearance, and '' Interatherium'', which was short-legged and weasel-like in terms of appearance, both from the Early Miocene. Other well-known genera are '' Cochilius'', akin to the previous ones, and the bizarre ''

'', equipped with long two-toed legs, presumably an extreme adaptation to running.

Taxonomy

The subfamily Interatheriinae was established in 1887 by

Florentino Ameghino Florentino Ameghino (born Giovanni Battista Fiorino Giuseppe Ameghino; September 19, 1853 – August 6, 1911) was an Argentine naturalist, paleontologist, anthropologist and zoologist, whose fossil discoveries on the Argentine Pampas, especial ...

. The Interatheriinae subfamily includes the most derived interatheriids, the most derived of which include ''

'', '' Caenophilus'', '' Choichephilum'', '' Cochilius'', '' Interatherium'', '' Juchuysillu'', ''

'', and ''

''. According to Vera ''et al.'' 2017, the Interatheriinae is defined as "the most recent common ancestor of '' Eopachyrucos pliciferus'' and ''Interatherium robustum'', and all of its descendants". The following cladogram of the Interatheriinae is based on Vera ''et al.'' 2017.

References

{{Taxonbar, from=Q33139823 Typotheres Paleogene mammals of South America Neogene mammals of South America Mammal subfamilies Ypresian first appearances Zanclean extinctions