Camelidae (Gray, 1821)
* Camelidae on Mammal species of the World.
Camelids are members of the biological family Camelidae, the only living family in the suborder Tylopoda. Camels, dromedaries, Bactrian Camels, llamas, alpacas, vicuñas, and guanacos are in this group.
Camelids are even-toed ungulates: they are classified in the order Artiodactyla. Other suborders of Artiodactyla include pigs, peccaries and hippos (suborder Suina) and the extraordinarily successful and diverse suborder Ruminantia (which includes cattle, goats, antelope and many others).
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. Many fossil camelids were unguligrade and probably hooved, in contrast to all living species.
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.
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.
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. 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 Vicuñas.
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.
The newly discovered giant Syrian Camel is yet to be officially described.
1. ^ a b Clutton-Brock, Juliet (1987). A Natural History of Domesticated Mammals. pp. 208. ISBN 0521346975.
Source: Wikispecies, Wikipedia: All text is available under the terms of the GNU Free Documentation License