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 ...
litoptern
Litopterna (from "smooth heel") is an extinct order of South American native ungulates that lived from the Paleocene to the Pleistocene-Holocene around 62.5 million to 12,000 years ago (or possibly as late as 3,500 years ago), and were also pres ...
that lived during the Early Miocene, in what is now
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 ...
. Fossils have been found in the
Sarmiento Formation
The Sarmiento Formation (Spanish language, Spanish: ''Formación Sarmiento''), in older literature described as the Casamayor Formation, is a geological formation in Chubut Province, Argentina, in central Patagonia, which spans around 30 million y ...
of Argentina.
Description
This animal may have been vaguely similar to a small
horse
The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 mi ...
, and, even if it is only known from incomplete fossils, it is possible to hypothesize on its appearance thanks to the comparison with its better-known relatives, such as ''
Thoatherium
''Thoatherium'' (meaning "active swift-beast") is an extinct genus of litoptern mammals from the Early Miocene of Argentina. Fossils of the genus have been found in the Santa Cruz Formation in Argentina.Proterotherium'' and '' Diadiaphorus''. Compared to the latter, ''Prolicaphrium'' was more basal, especially regarding its
molars
The molars or molar teeth are large, flat tooth, teeth at the back of the mouth. They are more developed in mammal, mammals. They are used primarily to comminution, grind food during mastication, chewing. The name ''molar'' derives from Latin, '' ...
: the six primary denticles were well developed and independent. The last molar had a reduced posterior lobe both in its external and internal parts. ''Prolicaphrium'' was also characterized by a skull with very elongated nasal bones pointing forward, to the contrary of the previously mentioned genera.
Classification
''Prolicaphrium'' is a member of the
Proterotheriidae
Proterotheriidae is an extinction, extinct family of Litopterna, litoptern ungulates known from the Eocene-Late Pleistocene of South America. Members of the group were small-medium sized cursorial Herbivore, herbivores with brachydont Tooth, teet ...
, a family of litopterns with a build vaguely evocative of small horses. The genus ''Prolicaphrium'' was first described in 1902 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 ...
, based on fossil remains from Early Miocene terrains of
Patagonia
Patagonia () is a geographical region that includes parts of Argentina and Chile at the southern end of South America. The region includes the southern section of the Andes mountain chain with lakes, fjords, temperate rainforests, and glaciers ...
, and it was considered to belong to an animal ancestral of the also Early Miocene genus '' Licaphrium'' (now considered a synonym of '' Anisolophus''. Ameghino described two species : the type species, ''Prolicaphrium specillatum'', and the better known ''P. spectabile''.A third species described by Ameghino, ''P. festinum'', was later attributed to a new genus, '' Licaphrops'' (a junior synonym of ''
Lambdaconus
''Lambdaconus'' is a genus of proterotheriidae, proterotheriid from the Oligocene, Late Oligocene to Early Miocene of Argentina. The type species is ''L. suinus'', named in 1897 by Ameghino, with referred species including ''L. lacerum'', named a ...
''), while ''P. sanalfonensis'', initially described in 1997 and coming from the Middle Miocene of
Colombia
Colombia, officially the Republic of Colombia, is a country primarily located in South America with Insular region of Colombia, insular regions in North America. The Colombian mainland is bordered by the Caribbean Sea to the north, Venezuel ...