Xenastrapotherium
Encyclopedia
Xenastrapotherium is an extinct genus
of astrapothere
, a type of hoofed herbivorous mammal
, native to South America
, which lived in the mid-Miocene
period, during the Laventan
stage. It is a member of the family Astrapotheriidae in the subfamily Uruguaytheriinae, large astrapotheres, equipped with a trunk-like nose and protruding teeth, similar to the elephants, but their tusks were the canine teeth, not the incisors. Xenastrapotherium (named after the Greek
word xenos "strange" add to the genus Astrapotherium, "lightning beast") was a genus widely distributed in northern South America, in contrast to other species of astrapotheres which lived in the area of the Southern Cone of the continent. It differed from other astrapotheres by having two lower incisor
s on each side of the jaw and the tusk
s have a pronounced longitudinal curvature, although their general shape and size are probably very similar to Astrapotherium, whose weight would be 900 to 1,500 kilogram
s, comparable to the current black rhino.
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
of astrapothere
Astrapotheria
Astrapotheria is an extinct order of South American hoofed animals. The history of this order is enigmatic, but it may taxonomically belong to Meridiungulata . In turn, Meridungulata is believed to belong to the extant superorder Laurasiatheria...
, a type of hoofed herbivorous mammal
Mammal
Mammals are members of a class of air-breathing vertebrate animals characterised by the possession of endothermy, hair, three middle ear bones, and mammary glands functional in mothers with young...
, native to South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
, which lived in the mid-Miocene
Miocene
The Miocene is a geological epoch of the Neogene Period and extends from about . The Miocene was named by Sir Charles Lyell. Its name comes from the Greek words and and means "less recent" because it has 18% fewer modern sea invertebrates than the Pliocene. The Miocene follows the Oligocene...
period, during the Laventan
Laventan
The Laventan age is a period of geologic time within the Miocene epoch of the Neogene used more specifically with South American Land Mammal Ages. It follows the Colloncuran and precedes the Mayoan age....
stage. It is a member of the family Astrapotheriidae in the subfamily Uruguaytheriinae, large astrapotheres, equipped with a trunk-like nose and protruding teeth, similar to the elephants, but their tusks were the canine teeth, not the incisors. Xenastrapotherium (named after the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...
word xenos "strange" add to the genus Astrapotherium, "lightning beast") was a genus widely distributed in northern South America, in contrast to other species of astrapotheres which lived in the area of the Southern Cone of the continent. It differed from other astrapotheres by having two lower incisor
Incisor
Incisors are the first kind of tooth in heterodont mammals. They are located in the premaxilla above and mandible below.-Function:...
s on each side of the jaw and the tusk
Tusk
Tusks are elongated, continuously growing front teeth, usually but not always in pairs, that protrude well beyond the mouth of certain mammal species. They are most commonly canines, as with warthogs, wild boar, and walruses, or, in the case of elephants and narwhals, elongated incisors...
s have a pronounced longitudinal curvature, although their general shape and size are probably very similar to Astrapotherium, whose weight would be 900 to 1,500 kilogram
Kilogram
The kilogram or kilogramme , also known as the kilo, is the base unit of mass in the International System of Units and is defined as being equal to the mass of the International Prototype Kilogram , which is almost exactly equal to the mass of one liter of water...
s, comparable to the current black rhino.
Species
Several species of Xenastrapotherium have been described, although none is known from complete remains; they are distinguished by features of their teeth and jaws, and their geographical and temporal distribution. The species currently recognized are:- X. christi (Stehlin, 1929): the first known species, originally classified by Stehlin (1929) as Astrapotherium christi, and later reclassified to the current genus. It was found in VenezuelaVenezuelaVenezuela , officially called the Bolivarian Republic of Venezuela , is a tropical country on the northern coast of South America. It borders Colombia to the west, Guyana to the east, and Brazil to the south...
near ZarazaZarazaZaraza was an experimental/industrial funeral doom band from Canada.-Biography:Formed in Montreal, Canada, in early 1993, Zaraza was born out of a meeting between newly arrived Polish immigrant Jacek and local Montreal industrial/noise artist Grzegorz Haus ov Doom, with the object of fully...
in the state of GuaricoGuáricoGuárico State is one of the 23 states of Venezuela. The state capital is San Juan de Los Morros. Guárico State covers a total surface area of 64 986 km² and, in 2007, had an estimated population of 745,100.-Municipalities and municipal seats:...
, based on a full lower jaw.
- X. kraglievichi (Cabrera, 1929): based on several teeth and some jaws, discovered in the area of La VentaLa Venta (Colombia)La Venta is a settlement between the modern Tolima Department and Huila Department, Colombia. Nearby, one of the richest Neogene fossil assemblages in the whole of South America is known...
(Group Honda, Villavieja formation) in the department of Huila, ColombiaColombiaColombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
, dating from the middle Miocene, about 13 to 11 million years. Distinguished by their lower tusks, which were more horizontal and rounded in cross-section. This species was contemporary with its great relative, GranastrapotheriumGranastrapotheriumGranastrapotherium is a genus of extinct ungulate mammal described from remains found in rocks of the Honda Group in the desert of Tatacoa in the departments of Huila and Tolima, in Colombia which comprise the fossil site of La Venta, where they surfaced several Miocene vertebrate remains...
.
- X. aequatorialis (Johnson & Madden, 1997): Based on a piece of right lower jaw, found in the Río Burgaya in the province of CañarCañar ProvinceCañar is a province in Ecuador. The capital is Azogues. At the time of census 2005 the province had a population of 221,045. It contains the 16th-century ruins of Ingapirca, the best-known Inca settlement in Ecuador and a product of their conquest of the indigenous Cañari.- Cantons :The province...
, EcuadorEcuadorEcuador , officially the Republic of Ecuador is a representative democratic republic in South America, bordered by Colombia on the north, Peru on the east and south, and by the Pacific Ocean to the west. It is one of only two countries in South America, along with Chile, that do not have a border...
, in the Biblián formation (Middle Miocene, 19 million years ago). Is distinguished by its molar with buccal and labial cingulumCingulum (tooth)In dentistry, cingulum refers to an anatomical feature of the anterior teeth . It refers to the portion of the teeth, occurring on the lingual or palatal aspects, that forms a convex protuberance at the cervical third of the anatomic crown. It represents the lingual or palatal developmental lobe...
, and the first molarMolarMolar may refer to:*Molar , the fourth kind of tooth in mammals*Molar , another name for the Spanish wine grape Listan Negro*Molar concentration, a unit of concentration, or molarity, of solutions equal to 1 mole per litre*Molar volume...
was lophodont and had roots. This species is older than the fossils of La Venta, contemporary with Astrapotheriinae like Astrapotherium, Astrapothericulus and Parastrapotherium.
- X. chaparralensis (Johnson & Madden, 1997): Another species known from Colombia, was found near to ChaparralChaparralChaparral is a shrubland or heathland plant community found primarily in the U.S. state of California and in the northern portion of the Baja California peninsula, Mexico...
in department of TolimaDepartment of TolimaTolima is one of the 32 departments of Colombia, located in the Andean region, in the center-west of the country. It is bordered on the north and the west by the department of Caldas; on the east by the department of Cundinamarca; on the south by the department of Huila, and on the west by the...
, in the Tuné formation (early Miocene). It is distinguished by its greater molar area, a high molar buccal cingulum, with canines very similar to those of X. kraglievichi.
- X. amazonense (Paula Couto, 1976): Based on a jaw fragments found in the vicinity of the river Breu, Pedra Pintada, BrazilBrazilBrazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
, also found it in the Fitzcarrald Arch in PeruPeruPeru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....
. It is distinguished by the large size of the third molar, compared to other species of Xenastrapotherium. Originally classified in its own genus, Synastrapotherium.