Elephas

Elephas is one of two surviving genera in the family of elephants, Elephantidae, with one surviving species, the Asian elephant, Elephas maximus. Several extinct species have been identified as belonging to the genus, extending back to the Pliocene or possibly late Miocene.

Description
Species of Elephas have distinct bossing of the parieto-occipital region of the skull. The premaxillae bones containing the tusks are tapered.

Evolutionary history
Relationships of living and extinct elephantids based on DNA, after Palkopoulou et al. 2018. Asian elephants share a closer common ancestry with mammoths (genus Mammuthus) than they do with African elephants (Loxodonta). 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. 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, though the attribution of this species to Elephas has been questioned, due to a lack of shared morphological features with later Elephas species.  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. However, the placement of Elephas planifrons within the genus has also been questioned. 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. Modern Asian elephants had evolved from E. hysrudicus by the Late Pleistocene.

Taxonomy
The scientific name Elephas was proposed by Carl Linnaeus in 1758 who described the genus and an elephant from Ceylon. The genus is assigned to the proboscidean family Elephantidae and is made up of one living and seven extinct species: The following Asian elephants were proposed as extinct subspecies, but are now considered synonymous with the Indian elephant:
 * Elephas maximus – Asian elephant
 * Elephas maximus indicus – Indian elephant
 * Elephas maximus maximus – Sri Lankan elephant
 * Elephas maximus sumatranus – Sumatran elephant
 * Elephas maximus borneensis – Borneo elephant, proposed but not yet recognized as valid
 * Elephas maximus sondaicus – Javan elephant †
 * Elephas maximus rubridens – Chinese elephant †
 * Elephas maximus asurus – Syrian elephant †

The following Elephas species are extinct: While formerly assigned to this genus, Elephas recki, the straight-tusked elephant E. antiquus and the dwarf elephants E. falconeri and E. cypriotes are now placed in the separate genus Palaeoloxodon, which is more closely related to African elephants. However, some material historically assigned to Elephas recki, such as Elephas recki atavus, may be closely related to true Elephas, rather than to Palaeoloxodon  "Elephas" celebensis is now placed in Stegoloxodon.
 * Elephas beyeri – dwarf elephant species described from fossil remains found in 1911 in Luzon, the Philippines by von Königswald
 * Elephas ekorensis – described from the Kubi Algi Formation, Turkana, Kenya, dating to the Early Pliocene, one of the oldest species of the genus.
 * Elephas hysudricus – described from fossil remains found in the Siwalik hills by Falconer and Cautley, 1845, thought to be the ancestor of the living Asian elephant.
 * Elephas hysudrindicus – a fossil elephant of the Pleistocene of Java and different from Elephas maximus sondaicus
 * Elephas planifrons - one of the oldest species, known from the Late Pliocene-Early Pleistocene of the Indian subcontinent.
 * Elephas platycephalus a species sometimes recognised from the Pleistocene of India
 * Elephas kiangnanensis a species sometimes recognised from the Early-Middle Pleistocene of China.
 * 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.
 * Elephas atavus? known from the Early Pleistocene of Africa, traditionally considered part of Elephas/Palaeoloxodon recki