Macrauchenia was a long-necked and long-limbed, three-toed
South AmericaSouth 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...
n
ungulateUngulates are several groups of mammals, most of which use the tips of their toes, usually hoofed, to sustain their whole body weight while moving. They make up several orders of mammals, of which six to eight survive...
mammalMammals 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...
, typifying the order
LitopternaLitopterna is an extinct order of fossil hoofed mammals from the Tertiary period that displays toe reduction. Three-toed, and even a one-toed horselike form developed....
. The oldest fossils date back to around 7 million years ago, and
M. patagonica disappears from the fossil record during the late
PleistoceneThe Pleistocene is the epoch from 2,588,000 to 11,700 years BP that spans the world's recent period of repeated glaciations. The name pleistocene is derived from the Greek and ....
, around 20,000 years ago.
M. patagonica was the best known member of the family
MacraucheniidaeMacraucheniidae is a family in the Litopterna order of extinct South American ungulates. The recessed nasal bones of their skulls suggest that they may have had a small proboscis, or trunk. Their hooves were similar to those of rhinoceroses today, with a simple ankle joint and three digits on each...
, and is known only from
fossilFossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
finds in
South AmericaSouth 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...
, primarily from the Lujan Formation in
ArgentinaArgentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
. The original specimen was discovered by
Charles DarwinCharles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...
during the voyage of the
Beagle. In life,
Macrauchenia resembled a humpless camel with a short trunk, though it is not closely related to either camels or
proboscideaProboscidea is a taxonomic order containing one living family, Elephantidae, and several extinct families. This order was first described by J. Illiger in 1881 and encompasses the trunked mammals...
ns.
History
Macrauchenia appeared in the fossil record some 7 million years ago in South America (in the
MioceneThe 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...
epoch). It is likely that
Macrauchenia arose from either
TheosodonTheosodon is an extinct genus of litoptern mammal from the early Miocene of South America.Theosodon bore a superficial resemblance the modern guanaco, and was around in length. It had a long neck and tapir-like, three-toed feet...
or
Promacrauchenia.
NotoungulataNotoungulata is an extinct order of hoofed, sometimes heavy bodied mammalian ungulates which inhabited South America during the Paleocene to Pleistocene, living from approximately 57 Ma to 11,000 years ago.-Taxonomy:...
and
LitopternaLitopterna is an extinct order of fossil hoofed mammals from the Tertiary period that displays toe reduction. Three-toed, and even a one-toed horselike form developed....
were two ancient orders of ungulates which only occurred in South America. Many of these species became extinct through competition with invading North American ungulates during the
Great American InterchangeThe Great American Interchange was an important paleozoogeographic event in which land and freshwater fauna migrated from North America via Central America to South America and vice versa, as the volcanic Isthmus of Panama rose up from the sea floor and bridged the formerly separated continents...
, after the establishment of the
Central AmericaCentral America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
n land bridge. A few survivors of this invasion were the litopterns
Macrauchenia and
XenorhinotheriumXenorhinotherium , an extinct Brazilian genus in the family Macraucheniidae, was related to Macrauchenia patachonica of Patagonia.-Name:...
and the large notungulates
ToxodonToxodon is an extinct mammal of the late Pliocene and Pleistocene epochs about 2.6 million to 16,500 years ago. It was indigenous to South America, and was probably the most common large-hoofed mammal in South America at the time of its existence....
and
MixotoxodonMixotoxodon is an extinct genus of notoungulate of the family Toxodontidae which inhabited South America during the Pleistocene living from 1.8—0.30 Ma and existed for approximately ....
. These last original South American hoofed animals died out eventually at the time of the arrival of humans at the end of the Pleistocene, along with numerous other large animals on the American continent (such as American
elephantElephants are large land mammals in two extant genera of the family Elephantidae: Elephas and Loxodonta, with the third genus Mammuthus extinct...
s,
horseThe horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature into the large, single-toed animal of today...
s,
camelA camel is an even-toed ungulate within the genus Camelus, bearing distinctive fatty deposits known as humps on its back. There are two species of camels: the dromedary or Arabian camel has a single hump, and the bactrian has two humps. Dromedaries are native to the dry desert areas of West Asia,...
s,
saber-toothed catSaber-toothed cat or Sabre-toothed cat refers to the extinct subfamilies of Machairodontinae , Barbourofelidae , and Nimravidae as well as two families related to marsupials that were found worldwide from the Eocene Epoch to the end of the Pleistocene Epoch ,...
s and
ground slothGround sloths are a diverse group of extinct sloths, in the mammalian superorder Xenarthra. Their most recent survivors lived in the Antilles, where it has been proposed they may have survived until 1550 CE; however, the youngest AMS radiocarbon date reported is 4190 BP, calibrated to c. 4700 BP...
s). As this genus was the last of the litopterns, its extinction ended that line of mammals.
Anatomy
Macrauchenia had a somewhat
camelA camel is an even-toed ungulate within the genus Camelus, bearing distinctive fatty deposits known as humps on its back. There are two species of camels: the dromedary or Arabian camel has a single hump, and the bactrian has two humps. Dromedaries are native to the dry desert areas of West Asia,...
-like body, with sturdy legs, a long neck and a relatively small head. Its feet, however, more closely resembled those of a modern
rhinocerosRhinoceros , also known as rhino, is a group of five extant species of odd-toed ungulates in the family Rhinocerotidae. Two of these species are native to Africa and three to southern Asia....
, and had three hoofs each. It was a relatively large animal, with a body length of around 3 metres (9.8 ft).
One striking characteristic of
Macrauchenia is that, unlike most other mammals, the openings for nostrils on its skull were atop the head, leading some early scientists to believe that, much like a
whaleWhale is the common name for various marine mammals of the order Cetacea. The term whale sometimes refers to all cetaceans, but more often it excludes dolphins and porpoises, which belong to suborder Odontoceti . This suborder also includes the sperm whale, killer whale, pilot whale, and beluga...
, it used these nostrils as a form of snorkel. Soon after some more recent findings, this theory was rejected. An alternative theory is that the animal possessed a trunk, perhaps to keep dust out of the nostrils.
One insight into
Macrauchenias habits is that its ankle joints and shin bones may indicate that it was adapted to have unusually good mobility, being able to rapidly change direction when it ran at high speed. It is speculated that since Macrauchenia
lived in an environment much like the savannaA savanna, or savannah, is a grassland ecosystem characterized by the trees being sufficiently small or widely spaced so that the canopy does not close. The open canopy allows sufficient light to reach the ground to support an unbroken herbaceous layer consisting primarily of C4 grasses.Some...
s of modern-day Africa, it may have had a tawny coat to match the color of dried grass.
Macrauchenia
is known, like its relative, TheosodonTheosodon is an extinct genus of litoptern mammal from the early Miocene of South America.Theosodon bore a superficial resemblance the modern guanaco, and was around in length. It had a long neck and tapir-like, three-toed feet...
, to have had a full set of 44 teeth.
Diet and behavior
Macrauchenia
was an herbivore, likely living on leaves from trees or grasses. Carbon isotope analysis of M. patagonicas
tooth enamelTooth enamel, along with dentin, cementum, and dental pulp is one of the four major tissues that make up the tooth in vertebrates. It is the hardest and most highly mineralized substance in the human body. Tooth enamel is also found in the dermal denticles of sharks...
, as well as analysis of its
hypsodontHypsodont dentition is characterized by high-crowned teeth and enamel which extends past the gum line. This provides extra material for wear and tear. Some examples of animals with hypsodont dentition are cows, horses and deer; all animals that feed on gritty, fibrous material. The opposite...
y index (low in this case; i.e., it was
brachydontBrachydont is a type of dentition characterized by low-crowned teeth, as opposed to high-crowned, hypsodont teeth. Human teeth are brachydont.-External links:*http://animaldiversity.ummz.umich.edu/site/topics/mammal_anatomy/tooth_diversity.html...
), body size and relative
muzzleThe snout, or muzzle, is the protruding portion of an animal's face, consisting of its nose, mouth, and jaw.-Terminology:The term "muzzle", used as a noun, can be ambiguous...
width suggests that it was a mixed feeder, combining browsing on
C3 carbon fixation is a metabolic pathway for carbon fixation in photosynthesis. This process converts carbon dioxide and ribulose bisphosphate into 3-phosphoglycerate through the following reaction:...
foliage with grazing on
C4C4 carbon fixation is one of three biochemical mechanisms, along with and CAM photosynthesis, used in carbon fixation. It is named for the 4-carbon molecule present in the first product of carbon fixation in these plants, in contrast to the 3-carbon molecule products in plants. fixation is an...
grasses. Scientists believe that, because of the forms of its teeth,
Macrauchenia ate using its trunk to grasp leaves and other food. It is also believed that it lived in herds like modern-day
wildebeestThe wildebeest , also called the gnu is an antelope of the genus Connochaetes. It is a hooved mammal...
or
antelopeAntelope is a term referring to many even-toed ungulate species indigenous to various regions in Africa and Eurasia. Antelopes comprise a miscellaneous group within the family Bovidae, encompassing those old-world species that are neither cattle, sheep, buffalo, bison, nor goats...
, the better to escape predators.
Predators
When
Macrauchenia first arose, it would have been preyed upon by the largest of native South American predators, terror birds such as
AndalgalornisAndalgalornis was a genus of flightless predatory birds of the family Phorusrhacidae that lived in Argentina. The type and only species is A. steulleti....
, and carnivorous
marsupialMarsupials are an infraclass of mammals, characterized by giving birth to relatively undeveloped young. Close to 70% of the 334 extant species occur in Australia, New Guinea, and nearby islands, with the remaining 100 found in the Americas, primarily in South America, but with thirteen in Central...
s such as
ThylacosmilusThylacosmilus was a genus of sabre-toothed metatherian predators that first appeared during the Miocene. Remains of the animal have been found in parts of South America, primarily Argentina...
and
BorhyaenaBorhyaena is an extinct genus of South American metatherian, living between 20 and 15 million years ago.Borhyaena was a large, bear-like marsupial predator of up to long and with an estimated average weight of . A typical borhyaenid, it had flat feet and a heavy build...
. During the late
PlioceneThe Pliocene Epoch is the period in the geologic timescale that extends from 5.332 million to 2.588 million years before present. It is the second and youngest epoch of the Neogene Period in the Cenozoic Era. The Pliocene follows the Miocene Epoch and is followed by the Pleistocene Epoch...
/Early Pleistocene, the Panama Isthmus formed, allowing predators of
North AmericaNorth America is a continent wholly within the Northern Hemisphere and almost wholly within the Western Hemisphere. It is also considered a northern subcontinent of the Americas...
n origin, such as the puma, the
jaguarThe jaguar is a big cat, a feline in the Panthera genus, and is the only Panthera species found in the Americas. The jaguar is the third-largest feline after the tiger and the lion, and the largest in the Western Hemisphere. The jaguar's present range extends from Southern United States and Mexico...
and the
saber-toothed catSaber-toothed cat or Sabre-toothed cat refers to the extinct subfamilies of Machairodontinae , Barbourofelidae , and Nimravidae as well as two families related to marsupials that were found worldwide from the Eocene Epoch to the end of the Pleistocene Epoch ,...
,
Smilodon populator, to emigrate into South America and replace the native forms.
It is presumed that
Macrauchenia dealt with its predators primarily by outrunning them, or, failing that, kicking them with its long, powerful legs, much like modern-day
vicuñaThe vicuña or vicugna is one of two wild South American camelids, along with the guanaco, which live in the high alpine areas of the Andes. It is a relative of the llama, and is now believed to share a wild ancestor with domesticated alpacas, which are raised for their fibre...
or
camelA camel is an even-toed ungulate within the genus Camelus, bearing distinctive fatty deposits known as humps on its back. There are two species of camels: the dromedary or Arabian camel has a single hump, and the bactrian has two humps. Dromedaries are native to the dry desert areas of West Asia,...
s. Its potential ability to twist and turn at high speed could have enabled it to evade pursuers.
Fossil evidence
Macrauchenia was first discovered on 9 February 1834 at
Port St JulianPuerto San Julián, also known historically as Port St Julian, is a natural harbour in Patagonia in the Santa Cruz Province of Argentina located at . In the days of sailing ships it formed a stopping point, south of Puerto Deseado...
in
PatagoniaPatagonia is a region located in Argentina and Chile, integrating the southernmost section of the Andes mountains to the southwest towards the Pacific ocean and from the east of the cordillera to the valleys it follows south through Colorado River towards Carmen de Patagones in the Atlantic Ocean...
(Argentina) by
Charles DarwinCharles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...
, when
HMS BeagleHMS Beagle was a Cherokee-class 10-gun brig-sloop of the Royal Navy. She was launched on 11 May 1820 from the Woolwich Dockyard on the River Thames, at a cost of £7,803. In July of that year she took part in a fleet review celebrating the coronation of King George IV of the United Kingdom in which...
was surveying the port during the
voyage of the BeagleThe second voyage of HMS Beagle, from 27 December 1831 to 2 October 1836, was the second survey expedition of HMS Beagle, under captain Robert FitzRoy who had taken over command of the ship on its first voyage after her previous captain committed suicide...
. As a non-expert he tentatively identified the leg bones and fragments of spine he found as "some large animal, I fancy a
MastodonMastodons were large tusked mammal species of the extinct genus Mammut which inhabited Asia, Africa, Europe, North America and Central America from the Oligocene through Pleistocene, 33.9 mya to 11,000 years ago. The American mastodon is the most recent and best known species of the group...
". In 1837, soon after the
Beagle's return, the anatomist
Richard OwenSir Richard Owen, FRS KCB was an English biologist, comparative anatomist and palaeontologist.Owen is probably best remembered today for coining the word Dinosauria and for his outspoken opposition to Charles Darwin's theory of evolution by natural selection...
revealed that the bones including vertebrae from the back an neck were actually from a gigantic creature resembling a
llamaThe llama is a South American camelid, widely used as a meat and pack animal by Andean cultures since pre-Hispanic times....
or
camelA camel is an even-toed ungulate within the genus Camelus, bearing distinctive fatty deposits known as humps on its back. There are two species of camels: the dromedary or Arabian camel has a single hump, and the bactrian has two humps. Dromedaries are native to the dry desert areas of West Asia,...
, which Owen named
Macrauchenia patachonica. In naming it, Owen noted the original Greek terms Μακρος (large or long), and αυχην (neck) as used by
IlligerJohann Karl Wilhelm Illiger was a German entomologist and zoologist.Illiger was the son of a merchant in Brunswick. He studied under the entomologist Johann Hellwig, and later worked on the zoological collections of Johann Centurius Hoffmannsegg...
as the basis of
Auchenia as a generic name for the llama,
VicugnaThe vicuña or vicugna is one of two wild South American camelids, along with the guanaco, which live in the high alpine areas of the Andes. It is a relative of the llama, and is now believed to share a wild ancestor with domesticated alpacas, which are raised for their fibre...
and so on. The find was one of the discoveries leading to the
inception of Darwin's theoryThe inception of Darwin's theory occurred during an intensively busy period which began when Charles Darwin returned from the survey voyage of the Beagle, with his reputation as a fossil collector and geologist already established...
. Since then, more
Macrauchenia fossils have been found, mainly in Patagonia, but also in
BoliviaBolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...
,
ChileChile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...
and
VenezuelaVenezuela , 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...
.
Cultural references
Macrauchenia is featured in the episode "Saber-tooth" of the documentary
Walking with BeastsWalking with Beasts is a 2001 six-part television documentary miniseries, produced by the BBC in the United Kingdom, narrated by Kenneth Branagh. In North America it has been retitled Walking with Prehistoric Beasts, and the original Discovery Channel broadcast was narrated by Stockard Channing...
, and individuals are featured in the 2002 Blue Sky film
Ice AgeIce Age is a 2002 American computer-animated film created by Blue Sky Studios and released by 20th Century Fox. It was directed by Carlos Saldanha and Chris Wedge from a story by Michael J. Wilson. The story follows three Paleolithical mammals attempting to return a lost human baby to its parents...
and its sequel, the 2006 film
Ice Age: The MeltdownIce Age: The Meltdown, also known as Ice Age 2: The Meltdown or simply as Ice Age 2, is the 2006 sequel to the 2002 computer-animated film Ice Age. It was produced by Blue Sky Studios for 20th Century Fox, and premiered in Belgium on March 1, 2006...
. It was included in the simulation game
Zoo Tycoon: Complete CollectionZoo Tycoon: Complete Collection is a video game of the Zoo Tycoon series. The game is a compilation of Zoo Tycoon, Zoo Tycoon: Marine Mania and Zoo Tycoon: Dinosaur Digs...
as part of the Dinosaur Digs Theme Pack and in Wildlife Park 2: Crazy Zoo as a cloneable beast. The related genus
CramaucheniaCramauchenia is a member of the litoptern order of South American mammals. Cramauchenia was named by Florentino Ameghino. The name has no literal translation. Instead, it is an anagram of the name of a related genus Macrauchenia....
was named by
Florentino AmeghinoFlorentino Ameghino was an Argentine naturalist, paleontologist, anthropologist and zoologist.Born in Luján, son of Italian immigrants, Ameghino was a self-taught naturalist, and focused his study on the lands of the southern Pampas...
as a deliberate anagram of
Macrauchenia.
External links