Proboscidea

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Proboscidea

[‚prō·bə′sid·ē·ə]
(vertebrate zoology)
An order of herbivorous placental mammals characterized by having a proboscis, incisors enlarged to become tusks, and pillarlike legs with five toes bound together on a broad pad.

Proboscidea

 

an order of mammals. The earliest representatives of the order Proboscidea were relatively small animals; later ones were larger, reaching a height of 4.5 m. The legs are long and columnar. The forelegs are five-toed, and the hind legs are four- or five-toed. The neck is short, and the head almost immovable. The highly developed upper lip and the nose concresce to form the movable proboscis, or trunk. In the earliest representatives the proboscis was very small or apparently absent. The dental system is characterized by the absence of canines (except in Moeritherium) and first incisors. The highly developed second incisors (tusks) are marked by constant growth. The molars have broad chewing surfaces that are nodular or have transverse ridges, sometimes with plates. The teeth are formed from dentine and enamel; only in elephants and some mastodonts is cement deposited between the ridges or plates.

The oldest Proboscidea are known from Africa, where their remains have been found in Middle Eocene deposits. Proboscidea were subsequently widely distributed in Africa, Eurasia, and America. At present they are found only in Africa and South Asia. Most species inhabited tropical rain forests; some were apparently semi-aquatic. Only elephants were adapted to life in diverse environments—forests, forest steppes, steppes, and tundra. There are three suborders: Moeritherioidea, Elephantoidea, and Deinotherioidea. The first and third suborders are extinct.

Elephantoidea include three families: Gomphotheriidae, Mastodontidae, and Elephantidae. Extant species belong only to the last family.

REFERENCES

Osnovy paleontologii: Mlekopitaiushchie. Moscow, 1962.
Osborn, H. F. Proboscidea: A Monograph of the Discovery, Evolution, Migration and Extinction of the Mastodonts and Elephants of the World, vols. 1–2. New York, 1936–42.

V. E. GARUTT

References in periodicals archive ?
All of the discussants at this yearly forum doubtlessly would agree that the most awesome and important members of the Pleistocene fauna are the mastodonts and mammoths, huge proboscideans (elephant-like beasts) that were the dominant members of the terrestrial community of the time.
Beginning 50 million years ago, and as recently as the late Pleistocene, 10,000 or so years ago, proboscideans roamed the globe.
The current study adds to the fossil record two recently investigated proboscideans from Nogal, New Mexico.
Unlike archival readings, which indicate only how elephants resist human placings, this ecological rendition enables an engagement with the ways through which elephants create their own spaces, where their proboscidean ways, ends, doings can be reflected.
The fact most fossil proboscideans in Michigan have been excavated from former shallow basins of kettle bog sites attests to this hypothesis.
Mastodons were the predominant proboscidean of the Texas coastal plains, although mammoths, too, ranged widely over coastal areas; conversely, mammoths were more common than mastodons in central Texas (Fox et al.
Examples of supernumerary teeth have been reported for some extinct mammals (Lucas and Schoch, 1987) but not for extinct proboscideans.
LeConte (1858) presented a brief account of proboscidean fossil he encountered in Honduras to the Academy of Natural Sciences in Philadelphia during its meeting of February 2, 1858:
Kapp) provided an update on records of mastodont and mammoth localities (as well as other Pleistocene vertebrates) and, in doing so, posed several questions, including (1) Why were proboscidean sites in the state so abundant for such a short period of time (12,000 to 10,000 years ago), while other vertebrates were apparently so uncommon?
columbi because it is the only other element of a proboscidean besides the more easily identified fragment of cheek tooth.
By our count, there are at least 74 localities in Central America that have yielded proboscidean fossils, about 43 of which are well documented (Fig.