''Xenorhinotherium'' is an

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 macraucheniine macraucheniids, native to northern South America during the

Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

and

Holocene The Holocene () is the current geologic time scale, geological epoch, beginning approximately 11,700 years ago. It follows the Last Glacial Period, which concluded with the Holocene glacial retreat. The Holocene and the preceding Pleistocene to ...

epoch, closely related to ''

Macrauchenia ''Macrauchenia'' ("long llama", based on the now-invalid llama genus, ''Auchenia'', from Greek "big neck") is an extinct genus of large ungulate native to South America from the Pliocene or Middle Pleistocene to the end of the Late Pleistocene. I ...

'' 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 ...

. The

type species In International_Code_of_Zoological_Nomenclature, 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 spe ...

is ''X. bahiense''.''Xenorhinotherium''
at

Fossilworks Fossilworks was a portal which provides query, download, and analysis tools to facilitate access to the Paleobiology Database, a large relational database assembled by hundreds of paleontologists from around the world. History Fossilworks was cr ...

.org

Taxonomy

Some authors have proposed that the genus ''Xenorhinotherium'' a synonym of ''Macrauchenia'', though this has not been widely accepted. The name ''Xenorhinotherium'' means "Strange-Nosed Beast" and ''bahiense'' refers to the Brazilian state of

Bahia Bahia () is one of the 26 Federative units of Brazil, states of Brazil, located in the Northeast Region, Brazil, Northeast Region of the country. It is the fourth-largest Brazilian state by population (after São Paulo (state), São Paulo, Mina ...

, where the first fossils were found. ''Xenorhinotherium'' was a rather derived representative of the

Macraucheniidae Macraucheniidae is a family in the extinct South American ungulate order Litopterna, that resembled camelids. They had three functional digits on the fore and hind feet, as well as elongate necks. The family is generally divided up into two sub ...

, a group of litopterns with camel-like appearances. Probably derived from lower Miocene forms such as '' Cramauchenia'' and '' Theosodon'', this animal probably closely related to the large macraucheniids of the

Pliocene The Pliocene ( ; also Pleiocene) is the epoch (geology), epoch in the geologic time scale that extends from 5.33 to 2.58Pleistocene The Pleistocene ( ; referred to colloquially as the ''ice age, Ice Age'') is the geological epoch (geology), epoch that lasted from to 11,700 years ago, spanning the Earth's most recent period of repeated glaciations. Before a change was fin ...

, such as ''

'' and '' Windhausenia''. Below is a phylogenetic tree of the

, based on the work of McGrath ''et al''. 2018, showing the position of ''Xenorhinotherium''.

Characteristics

''X. bahiense'' was a

megafauna In zoology, megafauna (from Ancient Greek, Greek μέγας ''megas'' "large" and Neo-Latin ''fauna'' "animal life") are large animals. The precise definition of the term varies widely, though a common threshold is approximately , this lower en ...

herbivore A herbivore is an animal anatomically and physiologically evolved to feed on plants, especially upon vascular tissues such as foliage, fruits or seeds, as the main component of its diet. These more broadly also encompass animals that eat ...

that probably looked very much like ''

'', weighing about . In life, ''X. bahiense'' would have vaguely resembled a tall, humpless camel with three toes on each foot and either a

saiga The saiga antelope (, ''Saiga tatarica''), or saiga, is a species of antelope which during antiquity inhabited a vast area of the Eurasian steppe, spanning the foothills of the Carpathian Mountains in the northwest and Caucasus in the southwes ...

-like

proboscis A proboscis () is an elongated appendage from the head of an animal, either a vertebrate or an invertebrate. In invertebrates, the term usually refers to tubular arthropod mouthparts, mouthparts used for feeding and sucking. In vertebrates, a pr ...

or a

moose The moose (: 'moose'; used in North America) or elk (: 'elk' or 'elks'; used in Eurasia) (''Alces alces'') is the world's tallest, largest and heaviest extant species of deer and the only species in the genus ''Alces''. It is also the tal ...

-like nose.

Pictographs A pictogram (also pictogramme, pictograph, or simply picto) is a graphical symbol that conveys meaning through its visual resemblance to a physical object. Pictograms are used in systems of writing and visual communication. A pictography is a wri ...

from the Serranía de La Lindosa

rock formation A rock formation is an isolated, scenic, or spectacular surface rock (geology), rock outcrop. Rock formations are usually the result of weathering and erosion sculpting the existing rock. The term ''rock Geological formation, formation ...

of Guaviare,

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 ...

, show what might possibly be ''Xenorhinotherium'' with three toes and a trunk, though the claims are highly controversial, and it is uncertain whether they even date to the last Ice Age. Paired δ¹³C and δ¹⁸O measurements from fossils in the Brazilian Intertropical Region indicate that ''X. bahiense'' was primarily a browser. These findings are supported by its hypsodonty index.

Distribution

Fossils of ''Xenorhinotherium'', dating from the

Late Pleistocene The Late Pleistocene is an unofficial Age (geology), age in the international geologic timescale in chronostratigraphy, also known as the Upper Pleistocene from a Stratigraphy, stratigraphic perspective. It is intended to be the fourth division ...

to the Early Holocene, have been found in the states of

, the Jandaíra Formation of

Rio Grande do Norte Rio Grande do Norte (, , ) is one of the states of Brazil. It is located in the northeastern region of the country, forming the northeasternmost tip of the South American continent. The name literally translates as "Great Northern River", refe ...

, and

Minas Gerais Minas Gerais () is one of the 27 federative units of Brazil, being the fourth largest state by area and the second largest in number of inhabitants with a population of 20,539,989 according to the 2022 Brazilian census, 2022 census. Located in ...

in modern Brazil, and also in

Venezuela Venezuela, officially the Bolivarian Republic of Venezuela, is a country on the northern coast of South America, consisting of a continental landmass and many Federal Dependencies of Venezuela, islands and islets in the Caribbean Sea. It com ...

, in the localities of Muaco, Taima-Taima and Cuenca del Lago. Though not known from other countries, computer modelling suggests that the habitat in the western

Andean The Andes ( ), Andes Mountains or Andean Mountain Range (; ) are the longest continental mountain range in the world, forming a continuous highland along the western edge of South America. The range is long and wide (widest between 18°S ...

slopes of Colombia,

Ecuador Ecuador, officially the Republic of Ecuador, is a country in northwestern South America, bordered by Colombia on the north, Peru on the east and south, and the Pacific Ocean on the west. It also includes the Galápagos Province which contain ...

, and

Peru Peru, officially the Republic of Peru, is a country in western South America. It is bordered in the north by Ecuador and Colombia, in the east by Brazil, in the southeast by Bolivia, in the south by Chile, and in the south and west by the Pac ...

would have been suitable for this animal, particularly in areas that have not been extensively excavated yet. A 2025 study suggested that ''Xenorhinotherium'' survivied until the Holocene around 3,493–4,217 years cal.

Before Present Before Present (BP) or "years before present (YBP)" is a time scale used mainly in archaeology, geology, and other scientific disciplines to specify when events occurred relative to the origin of practical radiocarbon dating in the 1950s. Because ...

(BP), based on a radiocarbon dated specimen found in Brazil.

References

Bibliography

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Taxonomy

Characteristics

Distribution

References

Bibliography

Further reading