Huilatherium
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''Huilatherium'' is an extinct
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 ...
of leontiniid, a group of hoofed mammals 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 ...
, that comprises other
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 ...
n ungulate families that evolved in parallel with some mammals of the Northern hemisphere. The leontiinids were a family of herbivorous species comprising medium to large browsers, with relatively short skulls and robust limbs, somewhat similar to their relatives, the best known toxodontids.


Etymology

The name ''Huilatherium'' means "Beast from Huila".


Description

''Huilatherium'' was discovered in
Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...
, at the Konzentrat-Lagerstätte of
La Venta La Venta is a pre-Columbian archaeological site of the Olmec civilization located in the present-day Mexican state of Tabasco. Some of the artifacts have been moved to the museum "Parque - Museo de La Venta", which is in nearby Villahermosa, ...
in the Honda Group of Huila. So far, only a single species is known, ''H. pluriplicatum''. This species was initially described based in a left
maxilla The maxilla (plural: ''maxillae'' ) in vertebrates is the upper fixed (not fixed in Neopterygii) bone of the jaw formed from the fusion of two maxillary bones. In humans, the upper jaw includes the hard palate in the front of the mouth. The t ...
ry deciduous teeth of a juvenile, which was reported by Jane Colwell in 1965 as a possible leontiinid, to which she applied the scientific name of ''Laventatherium hylei'' ("beast of La Venta"), but since she made her description in a master's thesis and it was never published, the authors Villarroel and Guerrero Díaz ignored this report and described the material again, this time as ''Huilatherium''.Villarroel, C. y Guerrero Díaz, J. 1985. Un nuevo y singular representante de la Familia Leontiniidae? (Notoungulata, Mammalia) en el Mioceno de La Venta, Colombia. ''Geología Norandina'' 9: 35-40. Despite being named after ''Laventatherium'', this is the official name since the former does not satisfy the rules of the
International Commission on Zoological Nomenclature The International Commission on Zoological Nomenclature (ICZN) is an organization dedicated to "achieving stability and sense in the scientific naming of animals". Founded in 1895, it currently comprises 26 commissioners from 20 countries. Orga ...
for publication of scientific names. ''Huilatherium'' lived during the
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 ...
and
Laventan The Laventan ( es, Laventense) age is a period of geologic time (13.8 to 11.8 Ma) within the Middle Miocene epoch of the Neogene, used more specifically within the SALMA classification in South America. It follows the Colloncuran and precedes ...
stages of the
South American land mammal age The South American land mammal ages (SALMA) establish a geologic timescale for prehistoric South American fauna beginning 64.5 Mya (unit), Ma during the Paleocene and continuing through to the Late Pleistocene (0.011 Ma). These periods are referre ...
s (SALMA), from approximately 16 to 11.8 Ma.''Huilatherium''
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 ...
.org


Paleobiology

Later descriptions of the species reported additional material from adult individuals: other
skull The skull is a bone protective cavity for the brain. The skull is composed of four types of bone i.e., cranial bones, facial bones, ear ossicles and hyoid bone. However two parts are more prominent: the cranium and the mandible. In humans, the ...
fragments, more teeth and some postcranial pieces, showing that it was an animal of up to , one of the largest of its kind living in the middle Miocene, about 12 million of years (in the
Laventan The Laventan ( es, Laventense) age is a period of geologic time (13.8 to 11.8 Ma) within the Middle Miocene epoch of the Neogene, used more specifically within the SALMA classification in South America. It follows the Colloncuran and precedes ...
SALMA The South American land mammal ages (SALMA) establish a geologic timescale for prehistoric South American fauna beginning 64.5 Ma during the Paleocene and continuing through to the Late Pleistocene (0.011 Ma). These periods are referred to as a ...
), being specially notable for being the last and most specialized known member of his family.Villarroel, C., y Coldwell Danis, J. 1997. A New leontiniid notoungulate. En: R.F. Kay, R.H. Madden, R.L. Cifelli y J.J. Flynn (eds.), ''Vertebrate Paleontology in the Neotropics. The Miocene Fauna of La Venta, Colombia''. Smithsonian Institution Press, Washington, D.C. pp. 303-318. In the leontiinids, there is a gradual trend towards specialization of the teeth, where this is going developing more the incisors and appears a conspicuous
diastema A diastema (plural diastemata, from Greek διάστημα, space) is a space or gap between two teeth. Many species of mammals have diastemata as a normal feature, most commonly between the incisors and molars. More colloquially, the condition ...
. In ''Huilatherium'', the canine teeth are very reduced in size, reducing the number of anterior
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, whe ...
s and developing tusk-like incisors. These features indicate a close relationship to '' Taubatherium paulacoutoi'', a genus from 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 ...
of
Tremembé Formation Tremembé is a municipality in the state of São Paulo in Brazil. It is part of the Metropolitan Region of Vale do Paraíba e Litoral Norte. The population is 47,714 (2020 est.) in an area of 191.09 km². The elevation is 560 m. A shr ...
in
Brazil Brazil ( pt, Brasil; ), officially the Federative Republic of Brazil (Portuguese: ), is the largest country in both South America and Latin America. At and with over 217 million people, Brazil is the world's fifth-largest country by area ...
with which form a separate
clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...
from other species of the family,Deraco, García López y Poweell. Relaciones filogenéticas del leontínido ''Coquenia bondi'' Deraco et al. (Mammalia: Notoungulata) del Eoceno del noroeste argentino. ''Resúmenes de las XXIV Jornadas Argentinas de Paleontología de Vertebrados, San Rafael, Mendoza, Argentina''. Mayo, 2009. that are primarily known from sites of
Paleogene The Paleogene ( ; British English, also spelled Palaeogene or Palæogene; informally Lower Tertiary or Early Tertiary) is a geologic period, geologic period and system that spans 43 million years from the end of the Cretaceous Period million yea ...
in
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 ...
and this indicate how this family was displaced to the tropical north of South America as the climate changes contribute to the disappearing of the woodland environments on which they depended to live.


References


External links


Website of the Museum of Paleontology of the University of California about La Venta, including photos of ''Huilatherium''
{{Taxonbar, from=Q5904741 Toxodonts Miocene mammals of South America Colloncuran Laventan Neogene Colombia Fossils of Colombia Honda Group, Colombia Fossil taxa described in 1985 Prehistoric placental genera