Asian elephants share a closer common ancestry with mammoths (genus Mammuthus) than they do with African elephants (Loxodonta).[4] The oldest species attributed to the genus Elephas is E. nawataensis from the Late Miocene-Early Pliocene of Kenya, though the validity of this species and its relationship to Elephas has been doubted.[5] The oldest species widely attributed to the genus, Elephas ekorensis is known from the early-mid Pliocene (5–4.2 million years ago) of East Africa,[6] though the attribution of this species to Elephas has been questioned, due to a lack of shared morphological features with later Elephas species.[7] The oldest record of the genus outside of Africa is Elephas planifrons which is known from the Late Pliocene of the Indian subcontinent, around 3.6 million years ago.[8] However, the placement of Elephas planifrons within the genus has also been questioned.[9] The earliest fossils of the ancestor of the modern Asian elephant, Elephas hysudricus date to the beginning of the Pleistocene, around 2.6 million years ago, with remains found on the Indian subcontinent.[10] Modern Asian elephants had evolved from E. hysrudicus by the Late Pleistocene.[11]
The scientific name Elephas was proposed by Carl Linnaeus in 1758 who described the genus and an elephant from Ceylon.[12]
The genus is assigned to the proboscidean family Elephantidae and is made up of one living and seven extinct species:[13]
Elephas ekorensis – described from the Kubi Algi Formation, Turkana, Kenya,[13] dating to the Early Pliocene, one of the oldest species of the genus.[16]
Elephas kiangnanensis a species sometimes recognised from the Early-Middle Pleistocene of China.[21][22]
Elephas nawataensis a species of elephant known from the Late Miocene-Early Pliocene of Kenya, though other authors argue that this species is actually a synonym of Primelephas korotorensis.[5]
Elephas atavus? known from the Early Pleistocene of Africa, traditionally considered part of Elephas/Palaeoloxodon recki
^Eleftheria Palkopoulou; Mark Lipson; Swapan Mallick; Svend Nielsen; Nadin Rohland; Sina Baleka; Emil Karpinski; Atma M. Ivancevic; Thu-Hien To; R. Daniel Kortschak; Joy M. Raison; Zhipeng Qu; Tat-Jun Chin; Kurt W. Alt; Stefan Claesson; Love Dalén; Ross D. E. MacPhee; Harald Meller; Alfred L. Roca; Oliver A. Ryder; David Heiman; Sarah Young; Matthew Breen; Christina Williams; Bronwen L. Aken; Magali Ruffier; Elinor Karlsson; Jeremy Johnson; Federica Di Palma; Jessica Alfoldi; David L. Adelson; Thomas Mailund; Kasper Munch; Kerstin Lindblad-Toh; Michael Hofreiter; Hendrik Poinar; David Reich (2018). "A comprehensive genomic history of extinct and living elephants". Proceedings of the National Academy of Sciences of the United States of America. 115 (11): E2566–E2574. Bibcode:2018PNAS..115E2566P. doi:10.1073/pnas.1720554115. PMC5856550. PMID29483247.
^Linnaei, C. (1760). "Elephas maximus". Caroli Linnæi Systema naturæ per regna tria naturæ, secundum classes, ordines, genera, species, cum characteribus, differentiis, synonymis, locis. Vol. Tomus I. Halae Magdeburgicae: Ioannes Ioachimus Langius. p. 33.
^ abMaglio, V.J. (1973). "Origin and evolution of the Elephantidae". Transactions of the American Philosophical Society, Philadelphia Volume 63. American Philosophical Society, Philadelphia, pp. 149