Camelidae

Camelidae Temporal range: 50–0  Ma PreꞒ Ꞓ O S D C P T J K Pg N Middle Eocene – Holocene
A Bactrian camel walking in the snow
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Artiodactyla
Suborder:	Tylopoda
Superfamily:	Cameloidea
Family:	Camelidae Gray, 1821
Type genus
Camelus
Subfamilies
†Poebrodontinae †Poebrotheriinae †Miolabinae † Stenomylinae †Floridatragulinae Camelinae
Current range of camelids, all species

Camelids are members of the biological

.

Characteristics

Camelids are large, strictly

applications.

Camelids do not have hooves; rather, they have two-toed feet with toenails and soft foot pads (

Camelids are behaviorally similar in many ways, including their walking gait, in which both legs on the same side are moved simultaneously. While running, camelids engage a unique "running pace gait" in which limbs on the same side move in the same pattern they walk, with both left legs moving and then both right, which ensures that the fore and hind limb will not collide while in fast motion. During this motion, all four limbs momentarily are off the ground at the same time.[7] Consequently, camelids large enough for human beings to ride have a typical swaying motion.

Dromedary camels, bactrian camels, llamas, and alpacas are all induced ovulators.^[8]

The three Afro-Asian camel species have developed extensive adaptations to their lives 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.^[9]

Comparative table of the seven extant species in the family Camelidae:

Species	Image	Natural range	Weight
Camelus
Bactrian camel (Camelus bactrianus)		Central and Inner Asia (entirely domesticated)	300 to 1,000 kg (660 to 2,200 lb)
Dromedary or Arabian camel (Camelus dromedarius)		South Asia and Middle East (entirely domesticated)	300 to 600 kg (660 to 1,320 lb)
Wild Bactrian camel (Camelus ferus)		China and Mongolia	300 to 820 kg (660 to 1,800 lb)
Lama
Llama (Lama glama)		(domestic form of guanaco)	130 to 200 kg (290 to 440 lb)
Guanaco (Lama guanicoe)		South America	about 90 to 120 kg (200 to 260 lb)
Alpaca (Lama pacos)		(domestic form of vicuña)	48 to 84 kg (106 to 185 lb)
Vicuña (Lama vicugna)		South American Andes	35 to 65 kg (77 to 143 lb)

Evolution

Camelid Lamini Lama L. glama L. guanicoe V. vicugna V. pacos Camelini Camelus C. bactrianus C. dromedarius †Camelops ⊞ C. kansanus C. hesternus C. minodokae ⊟

A family tree indicating different species within the Camelidae family[10]

Camelids are unusual in that their modern distribution is almost the inverse of their area of origin. Camelids first appeared very early in the evolution of the even-toed ungulates, around 50 to 40 million years ago during the middle Eocene,^{[citation needed]} 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.^[6][11]

The family diversified and prospered, with the two living tribes, the

, which survived until the middle Pleistocene.

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, and possibly as a result of changing environmental conditions after the last ice age, or a combination of these factors. Three species groups survived - the dromedary of northern Africa and southwest 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. Camelids were domesticated by early Andean peoples,^[12] and remain in use today.

Fossil camelids show a wider variety than their modern counterparts. One North American genus, Titanotylopus, stood 3.5 m at the shoulder, compared with about 2.0 m for the largest modern camelids. Other extinct camelids included small, gazelle-like animals, such as Stenomylus. Finally, a number of very tall, giraffe-like camelids were adapted to feeding on leaves from high trees, including such genera as Aepycamelus and Oxydactylus.^[6]

Whether the wild Bactrian camel (Camelus ferus) is a distinct species or a subspecies (C. bactrianus ferus) is still debated.^[13][14] The divergence date is 0.7 million years ago, long before the start of domestication.^[14]

Scientific classification

Vicugna vicugna

)

Family Camelidae

• †Subfamily Poebrotheriinae
• †Subfamily Miolabinae
• †Subfamily
  Stenomylinae
• †Subfamily Floridatragulinae
• Subfamily Camelinae
  • Tribe Lamini
    • Genus: Lama
      • Llama, Lama glama
      • Guanaco, Lama guanicoe
      • Alpaca, Lama pacos
      • Vicuña, Lama vicugna
    • Genus: Hemiauchenia
      • †Hemiauchenia macrocephala
      • †Hemiauchenia minima
      • †Hemiauchenia blancoensis
      • †Hemiauchenia vera
      • †Hemiauchenia paradoxa
    • Genus Palaeolama
      • †
        Palaeolama mirifica
  • Tribe Camelini
    • Genus: Camelus
      • Bactrian camel, Camelus bactrianus
      • Dromedary, Camelus dromedarius
      • Wild Bactrian camel, Camelus ferus
      • †
        Camelus moreli
      • †Camelus sivalensis
      • †Camelus knoblochi
    • Genus: Camelops
      • †
        Camelops hesternus
    • Genus: Paracamelus
      • †Paracamelus gigas

Phylogeny

Extinct genera

Genus name	Epoch	Remarks
Aepycamelus	Miocene	Tall, s-shaped neck, true padded camel feet
Aguascalientia[24]	Earliest Miocene	A small, primitive, narrow-snouted floridatraguline camel
Camelops	Pliocene-Pleistocene	Large, with true camel feet, hump status uncertain
Eulamaops	Pleistocene	From South America
Floridatragulus	Early Miocene	An unusual species of camel with a long snout
Hemiauchenia	Miocene-Pleistocene	A North and South American lamine genus
Megacamelus	Miocene-Pleistocene	The largest species of camelid
Megatylopus	Miocene-Early Pleistocene	Large camelid from North America
Oxydactylus	Early Miocene	The earliest member of the "giraffe camel" family
Palaeolama	Pleistocene	A North and South American lamine genus
Poebrotherium	Oligocene	This species of camel took the place of deer and antelope in the White River Badlands.
Procamelus	Miocene	Ancestor of extinct Titanolypus and modern Camelus
Protylopus	Late Eocene	Earliest member of the camelids
Stenomylus	Early Miocene	Small, gazelle-like camel that lived in large herds on the Great Plains
Stevenscamelus[24]	Late Eocene	Long-snouted primitive relative of Floridatragulus
Titanotylopus	Miocene-Pleistocene	Tall, humped, true camel feet

References

External links

Wikimedia Commons has media related to Camelidae.

Wikispecies has information related to Camelidae.

• Pictures of camelid species