Elephantidae

Elephantids are distinguished from more basal proboscideans like gomphotheres by their teeth, which have parallel lophs, formed from the merger of the cusps found in the teeth of more basal proboscideans, which are bound by cementum. In later elephantids, these lophs became narrow lamellae/plates, The number of lophs/lamellae per tooth, as well as the tooth crown height (hypsodonty) is greater in later species. Elephantids chew using a proal jaw movement involving a forward stroke of the lower jaws, different from the oblique movement using side to side motion of the jaws in more primitive proboscideans. The most primitive elephantid Stegotetrabelodon had a long lower jaw with lower tusks and retained permanent premolars similar to many gomphotheres, while modern elephantids lack permanent premolars, with the lower jaw being shortened (brevirostrine) and lower tusks being absent. {{gallery|File:Stegotetrabelodon molar.jpg {{gallery|Jumbo_size_comparison.jpg|Skeleton of an African bush elephant (Loxodonta africana) bull|M. trogontherii skeletal (cropped).png|Skeleton of a steppe mammoth (Mammuthus trogontherii) in front-on (without head) side-on and top-down views|Asian_elephant_size_comparison.jpg|Skeleton of an Asian elephant (Elephas maximus)|Palaeoloxodon_antiquus_size_comparison.png|Skeleton of a straight-tusked elephant (Palaeoloxodon antiquus) bull|Palaeoloxodon falconeri Size Comparison.svg == Ecology ==

Living female and juvenile elephants live in matriarchal (female-led) herds of related individuals, with males leaving these groups to live solitarily or in loose male bonding groups upon reaching adolescence around 14–15 years of age. Evidence has been found that extinct elephantids, including the most primitive elephantid, Stegotetrabelodon, also lived in herds based on footprint tracks. From around the age of 20, adult male elephants peridiodically enter a state of heightened aggression known as musth, where stronger males assert dominance over weaker males, on rare occasions breaking out into fights between rival males. and healed wounds to some straight-tusked elephant (Palaeoloxodon antiquus) skeletons may have been the result of fighting between rival males. The earliest elephantid, Stegotetrabelodon, was a mixed feeder to a grazer based on dental mesowear analysis. Modern elephants are browsers to mixed feeders. Some extinct elephantids, like Palaeoloxodon recki and the woolly mammoth, were dedicated grazers. ==Classification==

elephantid species, including Palaeoloxodon and mammoths, showing cross species hybridisation resulting in introgressive gene flow from African forest elephants into Palaeoloxodon, after Palkopoulou et al. 2018 's A comparative view of the human and animal frame, 1860 '' at the French Museum of Natural History Some authors have suggested to classify the family into two subfamilies, Stegotetrabelodontinae, which is monotypic, only containing Stegotetrabelodon, and Elephantinae, containing all other elephantids. Living species • Loxodonta (African) • L. africana African bush elephant • L. cyclotis African forest elephant • Elephas (Asiatic) • E. maximus Asian elephant • E. m. maximus Sri Lankan elephant • E. m. indicus Indian elephant • E. m. sumatranus Sumatran elephant • E. m. borneensis Borneo elephant Classification • Elephantidae • Subfamily Stegotetrabelodontinae • †Stegotetrabelodon (4 species) • Subfamily Elephantinae • †Primelephas (2 species) • Elephas (7+ species) • †Stegoloxodon (2 species) • Loxodonta (6 species) • †Palaeoloxodon (14+ species) • †Phanagoroloxodon (1 species) • †Mammuthus (10 species) • †Stegodibelodon (1 species) • †Selenetherium (1 species) ==Evolutionary history==

(bottom) to the modern day (top)During the Late Miocene, around 10-8 million years ago, the earliest members of the family Elephantidae emerged in Afro-Arabia, having originated from gomphotheres, most likely from members of the genus Tetralophodon. The earliest members of the 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. Mammoths then migrated 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. Palaeoloxodon became extinct as part of the Late Pleistocene extinctions, with mammoths only surviving in relict populations on islands around the Bering Strait into the Holocene, with their latest survival being on Wrangel Island, where they persisted until around 4,000 years ago. ==See also==