font settings

Font Size: Large | Normal | Small
Font Face: Verdana | Geneva | Georgia

Camelidae

(Family)

Overview

[ Back to top ]

Camelids are members of the biological family Camelidae, the only living family in the suborder Tylopoda. dromedaries, Bactrian camels, llamas, alpacas, vicu?as, and guanacos are in this group.

Camelids are even-toed ungulates: they are classified in the order Artiodactyla, along with pigs, hippopotamus, deer, giraffes, cattle, goats, antelope,and many others.

[ Back to top ]
Camelid feet lack functional hooves, the toe bones being embedded in a broad cutaneous pad[1]

Camelids are large animals with slender n ecks and long legs, and are strictly herbivorous. Camelids differ from true ruminants in a number of ways. Their dentition shows traces of vesitigial central incisors in the upper jaw, and the third incisors are developed into canine-like tusks. Camelids also have true canine teeth and tusk-like premolars which are separated from the molars by a gap. The musculature of the hind limbs differs from those of other ungulates by the fact that the legs are attached to the body at the top of the thigh only, rather than attached by skin and muscle from the knee downwards. Because of this, camelids have to lie down by resting on their knees with their legs tucked underneath the body.[1] They have a three-chambered rather than a four-chambered digestive tract, an upper lip that is split in two with each part separately mobile, and uniquely among mammals, elliptical red blood cells. They also have a unique type of antibodies lacking the light chain, in addition to the normal antibodies found in other mammals. These so-called heavy-chain antibodies are being used to develop single-domain antibodies with potential pharmaceutical applications.

They do not have hooves, rather a two-toed foot with toenails and a soft footpad (Tylopoda is Latin for "padded foot"). The main weight of the animal is borne by these tough, leathery sole-pads. The South American camelids, adapted to steep and rocky terrain, can move the pads on their toes to maintain grip.[2] Many fossil camelids were unguligrade and probably hooved, in contrast to all living species.[3]

The two Afro-Asian camel species have developed extensive adaptations to their life in harsh, near-waterless environments. Wild populations of the bactrian camel are even able to drink brackish water, and some herds live in nuclear test areas.[4]

Evolution

[ Back to top ]
Map of the world showing distribution of camelids, prior to modern introductions to Australia and elsewhere. Solid black lines indicate possible migration routes.

Camelids are unusual in that their modern distribution is almost a mirror-image of their origin. Camelids first appeared very early in the evolution of the even-toed ungulates, around 45 million years ago during the middle Eocene, in present-day North America. Among the earliest camelids was the rabbit-sized Protylopus, which still had four toes on each foot. By the late Eocene around 35 million years ago, camelids such as Poebrotherium had lost the two lateral toes, and were about the size of a modern goat.[3][5]

The family diversified and prospered but remained confined to the North American continent until only about 2 or 3 million years ago, when representatives arrived in Asia, and (as part of the Great American Interchange that followed the formation of the Isthmus of Panama) South America.

The original camelids of North America remained common until the quite recent geological past, but then disappeared, possibly as a result of hunting or habitat alterations by the earliest human settlers, but more likely as a result of changing environmental conditions after the last Ice Age. Three species groups survived: the dromedary of northern Africa and south-west Asia; the Bactrian camel of central Asia; and the South American group, which has now diverged into a range of forms that are closely related but usually classified as four species: llamas, alpacas, guanacos, and vicu?as.

Fossil camelids show a wider variety than their modern counterparts. One North American genus, Titanotylopus, stood 3.5 metres at the shoulder, compared with the approximately two metres of the largest modern camelids. Other extinct camelids included small, gazelle-like animals, such as Stenomylus. Finally, there were a number of very tall, giraffe-like camelids, adapted to feeding on leaves from high trees, including such genera as Aepycamelus, and Oxydactylus.[3]

Scientific classification

[ Back to top ]
A dromedary camel (Camelus dromedarius) in the Australian outback, near Silverton, New South Wales
South American vicu?a (Vicugna vicugna)

Phylogenetic tree

[ Back to top ]

Extinct genera of camelids

[ Back to top ]

The newly discovered giant Syrian camel is yet to be officially described.

n by resting on their knees with their legs tucked underneath the body.[1] They have a three-chambered rather than a four-chambered digestive tract, an upper lip that is split in two with each part separately mobile, and uniquely among mammals, elliptical red blood cells. They also have a unique type of antibodies lacking the light chain, in addition to the normal antibodies found in other mammals. These so-called heavy-chain antibodies are being used to develop single-domain antibodies with potential pharmaceutical applications.

They do not have hooves, rather a two-toed foot with toenails and a soft footpad (Tylopoda is Latin for "padded foot"). The main weight of the animal is borne by these tough, leathery sole-pads. The South American camelids, adapted to steep and rocky terrain, can move the pads on their toes to maintain grip.[2] Many fossil camelids were unguligrade and probably hooved, in contrast to all living species.[3]

The two Afro-Asian camel species have developed extensive adaptations to their life in harsh, near-waterless environments. Wild populations of the bactrian camel are even able to drink brackish water, and some herds live in nuclear test areas.[4]

Evolution

[ Back to top ]
Map of the world showing distribution of camelids, prior to modern introductions to Australia and elsewhere. Solid black lines indicate possible migration route s.

Camelids are unusual in that their modern distribution is almost a mirror-image of their origin. Camelids first appeared very early in the evolution of the even-toed ungulates, around 45 million years ago during the middle Eocene, in present-day North America. Among the earliest camelids was the rabbit-sized Protylopus, which still had four toes on each foot. By the late Eocene around 35 million years ago, camelids such as Poebrotherium had lost the two lateral toes, and were about the size of a modern goat.[3][5]

The family diversified and prospered but remained confined to the North American continent until only about 2 or 3 million years ago, when representatives arrived in Asia, and (as part of the Great American Interchange that followed the formation of the Isthmus of Panama) South America.

The original camelids of North America remained common until the quite recent geological past, but then disappeared, possibly as a result of hunting or habitat alterations by the earliest human settlers, but more likely as a result of changing environmental conditions after the last Ice Age. Three species groups survived: the dromedary of northern Africa and south-west Asia; the Bactrian camel of central Asia; and the South American group, which has now diverged into a range of forms that are closely related but usually classified as four species: llamas, alpacas, guanacos, and vicu?as.

Fossil camelids show a wider variety than their modern counterparts. One North American genus, Titanotylopus, stood 3.5 metres at the shoulder, compared with the approximately two metres of the largest modern camelids. Other extinct camelids included small, gazelle-like animals, such as Stenomylus. Finally, there were a number of very tall, giraffe-like camelids, adapted to feeding on leaves from high trees, including such genera as Aepycamelus, and Oxydactylus.[3]

Scientific classification

[ Back to top ]
A dromedary camel (Camelus dromedarius) in the Australian outback, near Silverton, New South Wales
South American vicu?a ( Vicugna vicugna)

Phylogenetic tree

[ Back to top ]

Extinct genera of camelids

[ Back to top ]

The newly discovered giant Syrian camel is yet to be officially described.

References

[ Back to top ]
  1. ^ a b Clutton-Brock, Juliet (1987). A Natural History of Domesticated Mammals. pp. 208. ISBN 0521346975. 
  2. ^ Fra nklin, William (1984). Macdonald, D.. ed. The Encyclopedia of Mammals. New York: Facts on File. pp. 512?515. ISBN 0-87196-871-1. 
  3. ^ a b c Savage, RJG, & Long, MR (1986). Mammal Evolution: an illustrated guide. New York: Facts on File. pp. 216?221. ISBN 0-8160-1194-X. 
  4. ^ Wild Bactrian Camels Critically Endangered, Group Says National Geographic, 3 December 2002
  5. ^ Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. pp. 274?277. ISBN 1-84028-152-9. 

External links

[ Back to top ]

Taxonomy

[ Back to top ]

The Family Camelidae is a member of the Superfamily Cameloidea. Here is the complete "parentage" of Camelidae:

The Family Camelidae is further organized into finer groupings including:

Genera

[ Back to top ]

Aepycamelus

Aepycamelus is an extinct genus of camelid, formerly called Alticamelus which lived during the Miocene 20.6-4.9 Ma existing for approximately 15.7 million years. [more]

Aguascalientia

[more]

Alforjas

[more]

Alticamelus

[more]

Auchenia

[more]

Blancocamelus

[more]

Blickomylus

[more]

Camelops

Camelops is an extinct genus of camels that once roamed western North America, where it disappeared at the end of the Pleistocene about 10,000 years ago. Its name is derived from the Greek ???e??? (camel) + (face), thus "camel-face." [more]

Camelus

A 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, and Bactrian camels are native to Central and East Asia. Both species have been domesticated; they provide milk and meat, and are working animals. [more]

Capricamelus

[more]

Cuyamacamelus

Delahomeryx

[more]

Eschatius

Floridatragulus

Gentilicamelus

Gigantocamelus

Hemiauchenia

Hesperocamelus

Lama

A Genus in the Kingdom Animalia. [more]

Llama

Megacamelus

Megatylopus

Michenia

Miolabis

Miotylopus

Nothokemas

Nothotylopus

Oxydactylus

Palaeolama

[more]

Paracamelus

Paralabis

Paramiolabis

Paratylopus

[more]

Pliauchenia

Poebrodon

Poebrotherium

Priscocamelus

Procamelus

Protolabis

Protomeryx

Pseudolabis

[more]

Rakomylus

Stenomylus

Tanymykter

Titanotylopus

Vicugna

Vicugna is a genus containing two South American camelids, the vicu?a and the alpaca. [more]

Vicuna

The vicu?a (Vicugna vicugna) 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. Vicu?as produce small amounts of extremely fine wool, which is very expensive because the animal can only be shorn every 3 years. When knitted together, the product of the vicu?a's fur is very soft and warm. It is understood that the Inca valued vicu?as for their wool, and that it was against the law for any but royalty to wear vicu?a garments. [more]

More info about the Genus Vicuna may be found here.

References

[ Back to top ]
  1. ^ a b Clutton-Brock, Juliet (1987). A Natural History of Domesticated Mammals. pp. 208. ISBN 0521346975. 
  2. ^ Franklin, William (1984). Macdonald, D.. ed. The Encyclopedia of Mammals. New York: Facts on File. pp. 512?515. ISBN 0-87196-871-1. 
  3. ^ a b c Savage, RJG, & Long, MR (1986). Mammal Evolution: an illustrated guide. New York: Facts on Fil e. pp. 216?221. ISBN 0-8160-1194-X. 
  4. ^ Wild Bactrian Camels Critically Endangered, Group Says National Geographic, 3 December 2002
  5. ^ Palmer, D., ed. (1999). The Marshall Illustrated Encyclopedia of Dinosaurs and Prehistoric Animals. London: Marshall Editions. pp. 274?277. ISBN 1-84028-152-9. 

Sources

[ Back to top ]
Last Revised: August 24, 2012
2012/08/24 13:26:39