extinct
Extinction is the termination of an organism by the death of its Endling, last member. A taxon may become Functional extinction, functionally extinct before the death of its last member if it loses the capacity to Reproduction, reproduce and ...
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 ...
of
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
The Miocene ( ) is the first epoch (geology), geological epoch of the Neogene Period and extends from about (Ma). The Miocene was named by Scottish geologist Charles Lyell; the name comes from the Greek words (', "less") and (', "new") and mea ...
to the Middle 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 ...
and
Chile
Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...
.
Description
This animal is only known from fragmentary remains, mainly from its teeth, and was probably similar to its relative '' Adiantoides''. It was a small animal with generalist teeth, but it had some unusual characteristics. The crown of its teeth was higher than in ''Adiantoides'', and the lower
premolar
The premolars, also called premolar Tooth (human), teeth, or bicuspids, are transitional teeth located between the Canine tooth, canine and Molar (tooth), molar teeth. In humans, there are two premolars per dental terminology#Quadrant, quadrant in ...
s were more molariform. The second lower
incisor
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 ...
and the lower
canine
Canine may refer to:
Zoology and anatomy
* Animals of the family Canidae, more specifically the subfamily Caninae, which includes dogs, wolves, foxes, jackals and coyotes
** ''Canis'', a genus that includes dogs, wolves, coyotes, and jackals
** Do ...
had three lingually directed ridges, forming two closed basins. The first three premolars had two ridges, while the fourth premolar was completely molariform.
Classification
''Adianthus bucatus'' was first described in 1891 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 a single tooth of enigmatic shape, perhaps coming from the so-called "''
Notohippus
''Notohippus'' is an extinct genus of notoungulate mammal from the Early Miocene (Santacrucian in the SALMA classification) Santa Cruz Formation, Río Bote, Argentina. Subsequently, Ameghino described a mandible with teeth as a new species, ''Adianthus patagonicus''; however, those remains were later attributed to a different genus, '' Proheptaconus''.Ameghino, F. (1894). ''Enumération synoptique des espèces de mammifères fossiles des formations éocènes de Patagonie''. Imp. de PE Coni é hijos.
Chicago In 1991, a new species of ''Adianthus'', ''A. godoyi'', was described by Richard Cifelli from the Galera Formation of
Chile
Chile, officially the Republic of Chile, is a country in western South America. It is the southernmost country in the world and the closest to Antarctica, stretching along a narrow strip of land between the Andes, Andes Mountains and the Paci ...
, preserving a more complete skeleton, including postcranial remains.
''Adianthus'' is the eponymous genus of the
Adianthidae
Adianthidae is an extinct family of litopterns that existed from the Middle Eocene (Mustersan) to the Early Miocene (Santacrucian).
Description
Adianthids were actively mobile herbivores. They were small in size when compared to most litopterns ...
, a family of small-sized litopterns with a characteristic dentition. ''Adianthus'', despite being little known, seems to have been one of the more specialized members of the family.R. L. Cifelli and M. F. Soria. 1983. Systematics of the Adianthidae (Litopterna, Mammalia). American Museum Novitates 2771:1-25