''Miocochilius'' is an extinct genus of small notoungulate mammals (

typotheres Typotheria is a suborder of the extinct mammalian order Notoungulata and includes five families: Archaeopithecidae, Campanorcidae, Interatheriidae, Mesotheriidae, and Oldfieldthomasiidae. CifelliCifelli, Richard L. 1993. The phylogeny of the nat ...

) native to South America. The genus lived during the

Middle Miocene The Middle Miocene is a sub-epoch of the Miocene Epoch made up of two stages: the Langhian and Serravallian stages. The Middle Miocene is preceded by the Early Miocene. The sub-epoch lasted from 15.97 ± 0.05 Ma to 11.608 ± 0.005 Ma (million y ...

epoch ( Laventan in the SALMA classification). The genus contains two described species, the type species ''M. anomopodus'' described in 1953 by Ruben Arthur Stirton and ''M. federicoi'', described and included in the genus by Darin A. Croft. Fossils of ''Miocochilius'' have been found at the Lagerstätte of La Venta in the

Honda Group is a Japanese public multinational conglomerate manufacturer of automobiles, motorcycles, and power equipment, headquartered in Minato, Tokyo, Japan. Honda has been the world's largest motorcycle manufacturer since 1959, reaching a product ...

of Colombia, where it is the most abundant mammal, the

of Bolivia (''M. federicoi'') and the Ipururo Formation in the

Ucayali Basin The Ucayali River ( es, Río Ucayali, ) is the main headstream of the Amazon River. It rises about north of Lake Titicaca, in the Arequipa region of Peru and becomes the Amazon at the confluence of the Marañón close to Nauta city. The city ...

of Peru. The typothere lived alongside a rich faunal assemblage comprising many other mammals, crocodylians, turtles and lizards.

Description

The genus ''Miocochilius'' was first described by Ruben Arthur Stirton in 1953, based on a nearly complete and numerous incomplete skeletons found in the Honda Group of Colombia.''Miocochilius''
at

Fossilworks Fossilworks is a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database The Paleobiology Database is an online resource for information on the distribution and classification of fossil animals ...

.orgStirton, 1953, p.265 The type species was named ''M. anomopodus''. More fossils of this species were found at La Venta and in the Ipururo Formation in Peru.''Miocochilius anomopodus''
at

.org The holotype specimen of the small typothere, a cursorial

insectivore A robber fly eating a hoverfly An insectivore is a carnivorous animal or plant that eats insects. An alternative term is entomophage, which can also refer to the human practice of eating insects. The first vertebrate insectivores wer ...

, had a cerebral hemisphere length of , canines of and a

cheekbone In the human skull, the zygomatic bone (from grc, ζῠγόν, zugón, yoke), also called cheekbone or malar bone, is a paired irregular bone which articulates with the maxilla, the temporal bone, the sphenoid bone and the frontal bone. It is s ...

of . The premaxilla measured . A second species, ''M. federicoi'', was described by Darin A. Croft in 2007 based on a maxilla found in the Honda Group of Bolivia.''Miocochilius federicoi''
at

.org The species

epithet An epithet (, ), also byname, is a descriptive term (word or phrase) known for accompanying or occurring in place of a name and having entered common usage. It has various shades of meaning when applied to seemingly real or fictitious people, di ...

refers to Federico Anaya, a scientist and field collector who has been instrumental in advancing vertebrate paleontology in Bolivia. ''M. federicoi'' differs from ''

Eopachyrucos ''Eopachyrucos'' is an extinct genus of interatheriid notoungulates that lived from the Middle Eocene to the Late Oligocene of Argentina and Uruguay. Fossils of this genus have been found in the Sarmiento Formation of Argentina and the Fray Ben ...

'', ''

Santiagorothia ''Santiagorothia'' is an extinct genus of interatheriid notoungulate. It lived during the Early Oligocene, and its fossils were discovered in Argentina and Chile. Description This animal was about the size of a large paca. It could reach 65 ...

'', ''

Proargyrohyrax ''Proargyrohyrax'' is an extinct genus of interatheriine 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 Argentina. Material was copied f ...

'', '' Archaeophylus'' and ''

Progaleopithecus ''Progaleopithecus'' is an extinct genus of interatheriid notoungulate that lived during the Late Oligocene of Argentina. Fossils of this genus have been found in the Agua de la Piedra, Deseado, and Sarmiento Formations of Argentina. Taxonomy ...

'' in having extremely high crowned teeth. The described species is differentiated from the Chasicoan to

Colloncuran The Colloncuran ( es, Colloncurense) age is a period of geologic time (15.5–13.8 Ma) within the Middle Miocene epoch of the Neogene, used more specifically within the SALMA classification in South America. It follows the Friasian and precedes ...

genus ''

Protypotherium ''Protypotherium'' is an extinct genus of notoungulate mammals native to South America during the Oligocene and Miocene epochs. A number of closely related animals date back further, to the Eocene. Fossils of ''Protypotherium'' have been found in ...

'' in having more open lingual enamel folds, variable presence of small median lobe on upper molars, and molars with more rounded distal lobes. The species also is different than ''

Argyrohyrax ''Argyrohyrax'' is an extinct genus of interatheriid notoungulate that lived during the Late Oligocene, of what is now Argentina and Bolivia. Description This animal may have vaguely resembled a medium-sized ground-dwelling rodent, such as ...

'' in the absence of fossettes on the upper molars. Compared to ''

Cochilius ''Cochilius'' is an extinct genus of interatheriid notoungulate that lived between the Late Oligocene and the lower Miocene in what is now Argentina. Description The skull and skeleton show features also found in other similar contemporary o ...

'' and the Colloncuran ''

Interatherium ''Interatherium'' is an extinct genus of interatheriid mammal from the Early to Middle Miocene (Colhuehuapian- Mayoan). Fossils have been found in the Santa Cruz, Collón Curá and Sarmiento Formations in Argentina.Fernández, M. (2015). Re ...

'', ''Miocochilius federicoi'' has a longer, low skull. The author inclined to describe the specimen as a separate genus, but finally included the species in ''Miocochilius''.Croft, 2007, p.284

Paleoecology

''Miocochilius'' shared its habitat with many other mammals, birds, reptiles and amphibians. The Colombian specimens were found in

fluvial In geography and geology, fluvial processes are associated with rivers and streams and the deposits and landforms created by them. When the stream or rivers are associated with glaciers, ice sheets, or ice caps, the term glaciofluvial or fluviog ...

claystone Mudrocks are a class of fine-grained siliciclastic sedimentary rocks. The varying types of mudrocks include siltstone, claystone, mudstone, slate, and shale. Most of the particles of which the stone is composed are less than and are too sm ...

s of the "Monkey Unit", El Líbano sands and clays, San Nicolas Unit, Upper Red Bed and the Baraya Volcanic Member of the Villavieja Formation and the Cerro Gordo Member of the

La Victoria Formation The Honda Group ( es, Grupo Honda, Tsh, Ngh) is a geological group of the Upper and Middle Magdalena Basins and the adjacent Central and Eastern Ranges of the Colombian Andes. The group, in older literature also defined as formation, is in its ...

of the Honda Group. Fossils of ''Miocochilius'', the most abundant mammal at La Venta,Croft, 2007, p.283 were found alongside the

primates Primates are a diverse order of mammals. They are divided into the strepsirrhines, which include the lemurs, galagos, and lorisids, and the haplorhines, which include the tarsiers and the simians (monkeys and apes, the latter including huma ...

'' Mohanamico hershkovitzi'', '' Neosaimiri fieldsi'' and ''

Stirtonia tatacoensis ''Stirtonia'' is an extinct genus of New World monkeys from the Middle Miocene (Laventan in the South American land mammal ages; 13.8 to 11.8 Ma). Its remains have been found at the Konzentrat-Lagerstätte of La Venta in the Honda Group of ...

'', the rodents '' Scleromys colombianus'', '' S. schurmanni'', '' Drytomomys aequatorialis'', '' Neoreomys huilensis'', '' Eodolichotis maddeni'', '' Rhodanodolichotis antepridiana'', '' Prodolichotis guerreroi'' and '' P. pridiana'', the ant eater ''

Neotamandua borealis ''Neotamandua borealis'' is an extinct species of anteater. Fossils were found in the Honda Group, Colombia, Honda Group at the Lagerstätte, Konzentrat-Lagerstätte of La Venta (Colombia), La Venta, Colombia. It was suggested to be an ancestor ...

'', the bat '' Notonycteris magdalenensis'', the pampatheriid '' Scirrotherium hondaensis'', other notoungulates '' Pericotoxodon platignathus'', '' Huilatherium pluripicatum'', the sea cow '' Potamosiren magdalenensis'', the sparassodonts '' Hondadelphys fieldsi'' and ''

Lycopsis longirostrus ''Lycopsis'' is an extinct genus of South American metatherian, that lived during the Miocene in Argentina and Colombia. History Although not named until 1927, Florentino Ameghino described a species now seen as synonymous with ''Lycopsis ...

'', the litoptern '' Megadolodus molariformis'' and the ground sloth '' Magdalenabradys confusum''. The assemblage also contained the crocodylians ''

Purussaurus neivensis ''Purussaurus'' is an extinct genus of giant caiman that lived in South America during the Miocene epoch, from the Friasian to the Huayquerian in the SALMA classification. It is known from skull material found in the Brazilian and Peruvian Amazon ...

'' and '' Charactosuchus fieldsi'', the caiman lizard '' Dracaena colombiana'', and the turtles '' Geochelone'' and ''

Podocnemis pritchardi ''Podocnemis'' is a genus of aquatic turtles, commonly known as South American river turtles, in the family Podocnemididae. The genus consists of six extant species occurring in tropical South America.

''.Interathere locality
at

.orgBaraya Volcanic Member
at

.orgEl Líbano sands and clays
at

.orgMonkey Unit
at

.orgUpper Red Bed
at

.orgLone Tree locality
at

.orgCerro Gordo
at

.orgToxodont locality
at

.org The fossils belong to the '' Xenastrapotherium kraglievichi''-'' Granastrapotherium snorki'' assemblage at La Venta.Goillot et al., 2011, p.339 Based on vegetational and grazer diversity analysis of the La Venta fauna, it has been suggested the ecosystem resembled more that of Africa and Asia than of the modern Neotropics.Kay & Madden, 1997, p.183 The Peruvian specimen was collected in a

conglomerate Conglomerate or conglomeration may refer to: * Conglomerate (company) * Conglomerate (geology) * Conglomerate (mathematics) In popular culture: * The Conglomerate (American group), a production crew and musical group founded by Busta Rhymes ** Co ...

, deposited in a storm-dominated coastal to fluvial

environment Environment most often refers to: __NOTOC__ * Natural environment, all living and non-living things occurring naturally * Biophysical environment, the physical and biological factors along with their chemical interactions that affect an organism or ...

, alternatively described as lacustrine and paludal,Castro Medina, 2010, p.58 at the Fitzcarrald Arch in the

Ucayali River The Ucayali River ( es, Río Ucayali, ) is the main headstream of the Amazon River. It rises about north of Lake Titicaca, in the Arequipa region of Peru and becomes the Amazon at the confluence of the Marañón close to Nauta city. The city of ...

basin of Amazonian Peru.Antoine, 2016, p.35 Other mammals found in the same location were the

toxodont Toxodontia. Retrieved April 2013. is a suborder of the meridiungulate order Notoungulata. Most of the members of the five included families, including the largest notoungulates, share several dental, auditory and tarsal specializations. The g ...

'' Pericotoxodon cf. platignathus'',

glyptodont Glyptodonts are an extinct subfamily of large, heavily armoured armadillos. They arose in South America around 48 million years ago and spread to southern North America after the continents became connected several million years ago. The best-kn ...

s '' Boreostemma'' and '' Parapropalaehoplophorus septentrionalis'', the

ground sloth Ground sloths are a diverse group of extinct sloths in the mammalian superorder Xenarthra. The term is used to refer to all extinct sloths because of the large size of the earliest forms discovered, compared to existing tree sloths. The Caribbe ...

Urumacotherium ''Urumacotherium'' (meaning "Urumaco beast") is an extinct genus of ground sloths of the family Mylodontidae. It lived from the Middle Miocene to the Early Pliocene of what is now Brazil, Peru and Venezuela. Classification ''Urumacotherium'' is ...

'' and rodent '' Drytomomys cf. aequatorialis''.IN-DTC-32, Ipururo Formation
at

.org The Bolivian species ''M. federicoi'' was discovered in fluvial silty claystones of the Honda Group, dated on the basis of ⁴⁰K/⁴⁰Ar analysis at 12.83 ± 0.11 Ma and 11.96 ± 0.11 Ma. The fossil was accompanied by a large variety of rodents, sparassodonts, litopterns, notoungulates and the glyptodonts '' Hapalops angustipalatus'', '' Hiskatherium saintandrei'' and '' Propalaehoplophorus andinus''.Quebrada Honda fauna
at

.org In total, 30 different genera of mammals are described from the Quebrada Honda fauna, while 68 genera were described at La Venta.Croft, 2007, p.287Croft, 2007, p.290

References

Bibliography

* * * * * * {{Taxonbar, from=Q3858658 Typotheres Miocene mammals of South America Laventan Neogene Bolivia Fossils of Bolivia Neogene Colombia Fossils of Colombia Honda Group, Colombia Neogene Peru Fossils of Peru Fossil taxa described in 1953 Prehistoric placental genera

Description

Paleoecology

See also

References

Bibliography