Equidae

(redirected from equid)
Also found in: Dictionary, Thesaurus, Medical, Wikipedia.

Equidae

[′ēk·wə‚dē]
(vertebrate zoology)
A family of perissodactyl mammals in the superfamily Equoidea, including the horses, zebras, and donkeys.

Equidae

 

a family of the order Perissodactyla. It comprises three subfamilies with approximately 20 genera, including extinct genera (such as Hyracotherium, Anchitherium, Mesohippus, Miohippus, Merychippus, Hipparion, and Pliohippus) and the only surviving genus, Equus.

The family comprises animals varying greatly in appearance and structure. With the exception of the most ancient (Eocene) representatives, equids are well-proportioned animals, with long legs and a very developed large third toe encased in a hoof; the second and fourth toes are greatly reduced (they are absent in modern equids). The facial part of the skull is greatly elongated. The cheek teeth are hypsodont and grow as they wear down. The equids evolved so as to adapt to fast running in open spaces and eating coarse vegetation. During the evolutionary process, the legs lengthened, the joints straightened, the middle toe enlarged, and the side toes gradually reduced. The face lengthened as the molars grew larger, and the premolars acquired a molar-like appearance and a complex folded chewing surface.

The history of the family Equidae has been well studied in North America, where they lived from the early Eocene epoch to the late Pliocene epoch. In the eastern hemisphere, in different geological periods there existed representatives of the family that were not linked to one another evolutionarily. The ancestors of the modern equids came to the eastern hemisphere from North America in the late Pliocene epoch, and in different parts of their vast area of distribution gave rise to different groups of modern equids. The history of the family’s development studied in detail by V. O. Kovalevskii is a classic example of research into the specific evolutionary paths of a large group of animals.

REFERENCES

Kovalevskii, V. O. Sobranie nauchnykh trudov, vol. 2. Moscow, 1956.
Osnovy paleontologii: Mlekopitaiushchie. Moscow, 1962.
Simpson, G. G. Horses. New York, 1951.

B. A. TROFIMOV

References in periodicals archive ?
Merriam coined the term "Equitarian" for his cause, built grass-roots support for the effort and then brought the Equitarian idea to the AAEP, which in 2010 formed the Equitarian Task Force to improve the health and welfare of working equids worldwide through promotion of education, direct aid, and organizational leadership and collaboration.
MacDonald (1960) identified six equid taxa from Mission that include Hypohippus sp.
org), >800,000 equids (horses, mules, and donkeys) are present on the Arabian Peninsula, but their role as putative MERS-CoV animal reservoirs has not been investigated.
Phase Equid Sheep/goat Gazelle Hare Canis Fox Upper phase 123 1 539 31 36 11 % mammal NISP 16.
Previous fossil records suggested this group was part of an ancient lineage from North America but the DNA showed these unusual forms were part of the modern radiation of equid species," Orlando said.
According to Dr Canan Cakirlar, the archaeozoologist of the project, it was probably from the long bone of a large mammal such as a bovid or an equid.
Faunal remains included a substantial proportion of herded sheep, with significant quantities of hunted aurochs and equid and a small number of deer.
Pieces of an equid were found in close association with the bones of two humans in a pit in a cemetery of the Late Antique period in west-central France.
With the exception of Phase 1a, equid remains were recovered from all phases of occupation at Begash.
More common are remains of a smaller, more gracile equid with hemionine features, most likely Equus altidens.
A fragment of equid tibia found with a Mousterian assemblage in a rockshelter in the Crimean peninsula is carefully examined.
The kunga equid is generally accepted as an onager-donkey cross, a type of 'mule', which preceded the appearance of the horse in Mesopotamia and was both stronger and faster than the only other available transport equid, the donkey.