''Ancylocoelus'' 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 ...

mammal Mammals () are a group of vertebrate animals constituting the class Mammalia (), characterized by the presence of mammary glands which in females produce milk for feeding (nursing) their young, a neocortex (a region of the brain), fur or ...

, belonging to the order

Notoungulata 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 ...

. It lived during the Late

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 ...

, in what is today

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

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 genus is only known from cranial remains, but comparison with some of its better-known relatives such as '' Leontinia'' indicates that it was an heavily shaped animal, vaguely similar to an hornless, smaller and slender

rhinoceros A rhinoceros (; ; ), commonly abbreviated to rhino, is a member of any of the five extant species (or numerous extinct species) of odd-toed ungulates in the family Rhinocerotidae. (It can also refer to a member of any of the extinct species o ...

. The skull was short and tall, with low-crowned (brachydont) premolars and molars. ''Ancylocoelus'' was approximately 1.70 meters long and 70 centimeters high at the withers. Compared to other, more basal forms, ''Ancylocoelus'' lacked both its upper and lower canines, and its first lower premolar.

Classification

''Ancylocoelus'' was first described in 1894 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, especially ...

, based on fossil remains found in

. 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 ''Ancylocoelus frequens''. A few years later Ameghino described two other species, ''A. lentus'' and ''A. minor''. ''Ancylocoelus'' was a member of 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 ...

, a group of Notoungulates with heavy shapes, typical of the South American Oligocene. It was closely related to ''Leontina'' and ''

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 ...

''.

Bibliography

*F. Ameghino. 1894. Sur les oiseaux fossiles de Patagonie; et la faune mammalogique des couches à Pyrotherium. Boletin del Instituto Geographico Argentino 15:501-660 *F. Ameghino. 1897. Mamiferos Cretaceos de la Argentina. Segunda contribucion al conocimiento de la fauna mastologica de las capas con restos de Pyrotherium. Boletin Instituto Geografico Argentino 18:406-521 *F. Ameghino. 1901. Notices préliminaires sur des ongulés nouveaux des terrains crétacés de Patagonie reliminary notes on new ungulates from the Cretaceous terrains of Patagonia Boletin de la Academia Nacional de Ciencias de Córdoba 16:349-429 *B. J. Shockey. 2005. New leontinidids (Class Mammalia, Order Notoungulata, Family Leontiniidae) from the Salla beds of Bolivia (Deseadan, Late Oligocene). Bulletin of the Florida Museum of Natural History 45(4):249-260 *A. M. Ribeiro, G. M. López, and M. Bond. 2010. The Leontiniidae (Mammalia, Notoungulata) from the Sarmiento Formation at Gran Barranca, Chubut Province, Argentina. In R. H. Madden, A. A. Carlini, M. G. Vucetich, R. F. Kay (eds.), The Paleontology of Gran Barranca: Evolution and Environmental Change through the Middle Cenozoic of Patagonia 170–181 {{Taxonbar, from=Q23000919 Toxodonts Oligocene mammals of South America Paleogene Argentina Fossils of Argentina Fossil taxa described in 1894 Taxa named by Florentino Ameghino Prehistoric placental genera Golfo San Jorge Basin Sarmiento Formation