Proboscidea (; from Latin proboscis, from Ancient Greek προβοσκίς (proboskís) 'elephant's trunk') is a taxonomic order of Afrothere paenungulate mammals described by J. Illiger in 1811. It encompasses the elephants (family Elephantidae) and their extinct relatives. Three living species of elephant are currently recognised: the African bush elephant, the African forest elephant, and the Asian elephant. Extinct members of Proboscidea include the deinotheres, mastodons, gomphotheres, amebelodonts and stegodonts. The family Elephantidae also contains several extinct groups, including mammoths and Palaeoloxodon. Proboscideans include some of the largest known land mammals, with the elephant Palaeoloxodon namadicus and mastodon "Mammut" borsoni suggested to have body masses surpassing 16 tonnes (35,000 lb), rivalling or exceeding paraceratheres, the otherwise largest known land mammals in size. The largest living proboscidean is the African bush elephant, with a recorded maximum size of 4 meters (13.1 feet) at the shoulder and a weight of 10.4 tonnes (11.5 short tons). In addition to their enormous size, later proboscideans are distinguished by tusks and long, muscular trunks, which were less developed or absent in early proboscideans.
Evolution Over 180 extinct members of Proboscidea have been described. The earliest members of Proboscidea like Eritherium are known from the Paleocene of Africa, around 60 million years ago, the earliest proboscideans were much smaller than living elephants, with Eritherium having a body mass of around 3–8 kilograms (6.6–17.6 lb). By the late Eocene, some members of Proboscidea like Barytherium had reached considerable size, with an estimated mass of around 2 tonnes, while others like Moeritherium are suggested to have been semi-aquatic. A major event in proboscidean evolution was the collision of Afro-Arabia with Eurasia, during the Early Miocene, around 18-19 million years ago allowing proboscideans to disperse from their African homeland across Eurasia, and later, around 16-15 million years ago into North America across the Bering Land Bridge. Proboscidean groups prominent during the Miocene include the deinotheres, along with the more advanced elephantimorphs, including mammutids (mastodons), gomphotheres, amebelodontids (which includes the "shovel tuskers" like Platybelodon), choerolophodontids and stegodontids. Around 10 million years ago, the earliest members of the family Elephantidae emerged in Africa, having originated from gomphotheres. The Late Miocene saw major climatic changes, which resulted in the decline and extinction of many proboscidean groups such as amebelodontids and choerolophodontids. The earliest members of modern genera of Elephantidae appeared during the latest Miocene-early Pliocene around 6-5 million years ago. The elephantid genera Elephas (which includes the living Asian elephant) and Mammuthus (mammoths) migrated out of Africa during the late Pliocene, around 3.6 to 3.2 million years ago. Over the course of the Early Pleistocene, all non-elephantid probobscideans outside of the Americas became extinct (including mammutids, gomphotheres and deinotheres), with the exception of Stegodon. Gomphotheres dispersed into South America during this era as part of the Great American interchange, and mammoths migrating into North America around 1.5 million years ago. At the end of the Early Pleistocene, around 800,000 years ago the elephantid genus Palaeoloxodon dispersed outside of Africa, becoming widely distributed in Eurasia. By the beginning of the Late Pleistocene, proboscideans were represented by around 23 species. Proboscideans underwent a dramatic decline during the Late Pleistocene as part of the Late Pleistocene megafauna extinctions, with all remaining non-elephantid proboscideans (including Stegodon, mastodons, and the American gomphotheres Cuvieronius and Notiomastodon) and Palaeoloxodon becoming extinct, with mammoths only surviving in relict populations on islands around the Bering Strait into the Holocene, with their latest survival being on Wrangel Island around 4,000 years ago. The following cladogram is based on endocasts.
Morphology
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