Fossil Record Life & Ecology Systematics Morphology

Artiodactyla: Systematics

The systematic relationships of artiodactyls are still being worked out; many early fossil artiodactyls are not easy to place in standard classifications. Artiodactyls have traditionally been classified according to the scheme outlined below.

Palaeodonta
Various primitive, extinct artiodactyl groups, mostly small in size. Includes the oreodonts. This is almost certainly a paraphyletic assemblage.
Suina
Includes Suidae (pigs and warthogs), Tayassuidae (peccaries), and Hippopotamidae (hippopotami), plus several extinct families. Characterized by a simple stomach, omnivorous diet, and relatively unspecialized teeth. The giant hippopotamus is the only aquatic artiodactyl, spending most of its time in water.
Tylopoda
Includes Camelidae (camels, llamas, alpacas, etc.) plus several extinct families. Extinct members of the Tylopoda had small hooves, but in living camels the hooves have been lost and replaced by pads. Living tylopods have a chambered stomach, albeit not as well developed as that seen in the Pecora.
Tragulina
Includes two genera: Hyemoschus, the African chevrotain, and Tragulus, the Asian "mouse deer." These are the smallest of all artiodactyls; the smallest species, the lesser Malay mouse deer, is only 40 cm long — no bigger than a rabbit.
Pecora
Includes most living artiodactyls, such as Giraffidae (giraffes and okapi), Cervidae (deer, elk, caribou, etc.), Bovidae (cows, buffalo, sheep, goats, antelope), Moschidae (musk deer), and Antilocapridae (American pronghorn "antelope" — which is not a true antelope) Typical pecorans have well-developed, four-chambered ruminant stomachs, and most have paired horns on the head.

DeerNet, at the University of Alberta, has a list of living ungulates, including photographs. And be sure to check out The Ultimate Ungulate.

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