''Martinmiguelia'' 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 ...

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

, belonging to the family

Leontiniidae Leontiniidae is an extinct family comprising eighteen genera of notoungulate mammals known from the Middle Eocene (Mustersan) to Late Miocene (Huayquerian) of South America South America is a continent entirely in the Western Hemisphe ...

. It lived during the Middle

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

, and its fossil remains were found in

South America South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...

Description

This animal is only known from skull and mandible remains, and it probably shared similarities with later and better known leontiniids, such as ''

Scarrittia ''Scarrittia'' is an extinct genus of hoofed mammal of the family Leontiniidae, native to South America during the Oligocene, Late Oligocene epoch (Deseadan in the South American land mammal age, SALMA classification). Description ''Scarritt ...

''. It was smaller-sized than those derived genera, approximately the size of a

sheep Sheep or domestic sheep (''Ovis aries'') are domesticated, ruminant mammals typically kept as livestock. Although the term ''sheep'' can apply to other species in the genus ''Ovis'', in everyday usage it almost always refers to domesticated s ...

. ''Martinmiguelia'' was characterized by an archaic dental formula, with a complete dentition (three incisors, one canine, four premolars and three molars) and a quasi-absence of diastema, except for small spaces around the small-sized canines. The molars and premolars were low-crowned (brachydont), a primitive condition for leontinnids. The upper incisors were canine-like and possessed labial girdles, and the second upper incisor was larger than the others.

Classification

''Martinmiguelia fernandezi'' was first described in 1995, based on fossils found in the Casa Grande Formation, in the

Jujuy Province Jujuy is a province of Argentina, located in the extreme northwest of the country, at the borders with Chile and Bolivia. The only neighboring Argentine province is Salta to the east and south. Geography There are three main areas in Jujuy: * ...

Argentina Argentina (), officially the Argentine Republic ( es, link=no, República Argentina), is a country in the southern half of South America. Argentina covers an area of , making it the second-largest country in South America after Brazil, th ...

, in terrains dated from the

Mustersan The Mustersan age is a period of geologic time (48.0–42.0 Ma) within the Eocene epoch of the Paleogene, used more specifically within the South American land mammal age (SALMA) classification. It follows the Casamayoran and precedes the Divisade ...

(Middle

). ''Martinmiguelia'' is considered to be one of the oldest and most basal members of the family Leontiniidae, a group of heavy

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 ...

s with massive builds. It was related with the Eocene genus '' Coquenia'', and with the

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...

genus '' Elmerriggsia''.

Bibliography

*M. Bond and G. M. López. 1995. Los Mamíferos de la Formación Casa Grande (Eoceno) de la Provincia de Jujuy, Argentina. Ameghiniana 32(3):301-309 *J. E. Powell, M. J. Babot, D. A. García López, M. V. Deraco, and C. Herrera. 2011. Eocene vertebrates of northwest Argentina: annotated list. In J. Salfity, R. A. Marquillas (eds.), Cenozoic Geology of the Central Andes of Argentina 349–370 *B. J. Shockey, J. J. Flynn, D. A. Croft, P. Gans, and A. R. Wyss. 2012. New leontiniid Notoungulata (Mammalia) from Chile and Argentina: comparative anatomy, character analysis, and phylogenetic hypotheses. American Museum Novitates 3737:1-64 Toxodonts Eocene mammals of South America Paleogene Argentina Fossils of Argentina Fossil taxa described in 1995 Prehistoric placental genera {{paleo-mammal-stub