Hominid Evolution from Homo erectus to Modern Humans: Turkana Boy, Java Man, Peking Man and Dmanisi, Homo floresiensis, the Archaic Sapiens of Mauer, Kabwe, Jinniushan and Narmada, the Neanderthals, Anatomically Modern Humans from Omo to Lake Mungo, and the Out of Africa, Multiregional and Partial Replacement Hypotheses

Homo erectus is the first hominin with a body like ours — tall, long-legged, narrow-hipped, built for walking and running in open country — and the first to leave Africa. It appears in East Africa about 1.9 million years ago, reaches the Caucasus by 1.8 million and Java by about 1.6 million (some claim earlier), and survives in Java until perhaps 110,000 years ago. Its skull is long and low, with a thick vault, a heavy continuous brow ridge (supraorbital torus), a receding forehead, an angular occiput with a transverse torus, a keeled midline, the greatest breadth low on the skull, large jaws without a chin and a brain that grew from about 800 to about 1,100 cc over its span (mean about 900–1,000 cc). It is associated with the Acheulian handaxe (from 1.76 million years in Africa, though eastern Asian erectus mostly kept chopper-chopping tools — the "Movius line"), with the controlled use of fire (Zhoukoudian; Gesher Benot Ya'aqov in Israel at 790,000 years is the securest early evidence) and with big-game hunting or scavenging. Many workers separate the early African fossils as Homo ergaster and keep Homo erectus for the Asian populations; the syllabus uses erectus for all.

Between about 700,000 and 200,000 years ago the Middle Pleistocene fossils of Africa, Europe and Asia show brains of 1,100–1,300 cc, within the modern range, on skulls that keep erectus features — the brow ridge, the low vault, the chinless jaw. They were once lumped as "archaic Homo sapiens"; most workers now call them Homo heidelbergensis, after the Mauer mandible found in a sand pit near Heidelberg in 1907 and named by Otto Schoetensack in 1908 (about 600,000 years), a massive chinless jaw with small teeth. Europe adds Arago (France), Petralona (Greece), Steinheim and the Sima de los Huesos at Atapuerca (Spain, about 430,000 years, over 28 individuals, ancestral to Neanderthals). Africa's representative is Rhodesian Man or Broken Hill 1, the skull found by a miner, Tom Zwiglaar, at Kabwe in Zambia in 1921, with an enormous brow, a 1,280 cc brain and dental caries, now dated to about 300,000 years (Grün and others, 2020); Bodo (Ethiopia, 600,000 years) and Ndutu (Tanzania) join it. Asia's is Jinniushan in Liaoning, north-east China, a skeleton found in 1984 and dated about 260,000 years, with a large brain (about 1,400 cc) and a robust body, sometimes placed with Dali (Shaanxi, 1978) as an Asian archaic; the syllabus also lists Jinniushan under modern sapiens, but it is archaic. India's is Narmada Man: on 5 December 1982 Arun Sonakia of the Geological Survey of India found a calvarium (the skull roof, lacking the face) in the Middle Pleistocene boulder conglomerate of the Narmada at Hathnora, Sehore district, Madhya Pradesh, with Acheulian tools and extinct fauna (Stegodon, Bos namadicus, Hexaprotodon). Sonakia described it as Homo erectus narmadensis (1984); Kennedy and others (1991) re-examined it as an archaic Homo sapiens (evolved erectus / heidelbergensis grade), with a cranial capacity estimated at 1,200–1,400 cc, probably a female, and Sankhyan later reported clavicles and a rib from the same horizon. Its date is bracketed between about 250,000 and 150,000 years, though older estimates exist. It remains the only Middle Pleistocene hominin fossil from India.

The type specimen was found in 1856 by quarrymen in the Feldhofer cave of the Neander valley (Neandertal) near Düsseldorf and described by Fuhlrott and Schaaffhausen; William King named Homo neanderthalensis in 1864, the first fossil human species. Both spellings are correct: "Neanderthal" preserves the older German spelling of the valley, "Neandertal" the reformed one. The Neanderthals lived from about 400,000 (in full form from about 130,000) to about 40,000 years ago across Europe, the Near East (Tabun, Amud, Kebara, Shanidar in Iraq) and Central Asia (Teshik-Tash in Uzbekistan) as far as the Altai, in cold-steppe and interglacial conditions alike. Their skull is long, low and large — brains average about 1,450–1,500 cc, above the modern mean — with a rounded occipital "bun", a double-arched brow ridge, a mid-facial projection with large nose and cheeks swept back, retromolar gaps, a taurodont dentition and no chin; the body is short (about 1.65 m for males), stocky, barrel-chested and heavily muscled, with short distal limbs on the Bergmann–Allen pattern for cold. They made Mousterian tools by the Levallois technique, hunted large game at close quarters (healed fractures are common), used fire and pigment, buried their dead at La Chapelle-aux-Saints, La Ferrassie, Kebara and Shanidar, and cared for the injured (Shanidar 1, blind in one eye with a withered arm, lived to about forty). Marcellin Boule's 1911–13 reconstruction of the arthritic "Old Man" of La Chapelle-aux-Saints as a stooping brute set the popular image; it was corrected in the 1950s. On phylogenetic position, the older debate between "Neanderthal phase" (Hrdlička, 1927: ancestral to modern Europeans) and "pre-sapiens" (Boule, Vallois: a side branch) has been settled by genetics. Neanderthal mitochondrial DNA (Krings and Pääbo, 1997) lies outside modern variation; the nuclear genome (Green and others, 2010) and later genomes put the divergence from the modern human line at roughly 550,000–750,000 years ago, and showed that all present-day non-Africans carry about 1–2% Neanderthal DNA from admixture some 50,000–60,000 years ago. Denisovans, known from a finger bone and teeth in Denisova cave (Altai, 2010), were a sister group whose DNA survives at 3–5% in Papuans and Aboriginal Australians and in the Tibetan EPAS1 altitude allele; the "Denny" fragment (2018) was a Neanderthal–Denisovan first-generation hybrid. The Neanderthals are therefore a distinct lineage that interbred with, and was replaced by, modern humans.

Anatomically modern humans have a high, rounded, thin-walled skull with a vertical forehead, no continuous brow ridge, a small flat face tucked under the braincase, a chin, small teeth and a light, tall skeleton with long limbs; the brain averages about 1,350 cc. The oldest are African. Omo Kibish in southern Ethiopia yielded Omo I (modern) and Omo II (more archaic) to Richard Leakey's 1967 expedition; argon dating of the tuffs gave about 195,000 years in 2005 and about 233,000 years in 2022, making Omo I the oldest securely dated modern human. Herto in the Middle Awash (Homo sapiens idaltu, 160,000 years, 2003) and the Jebel Irhoud fossils of Morocco (about 300,000 years, redated 2017, with a modern face but an elongated braincase) show the modern form assembling across Africa. In Europe the classic Upper Palaeolithic finds are French: Cro-Magnon, a rock shelter at Les Eyzies in the Dordogne where Louis Lartet in 1868 found five skeletons with Aurignacian tools (about 28,000–30,000 years) — tall, long-headed, with broad short faces and rectangular orbits, the type of the "Cro-Magnon race" of older textbooks; Chancelade, near Périgueux, a Magdalenian burial found in 1888 (about 17,000 years), short-statured and once likened to the Inuit; and the Grimaldi caves near Menton on the Italian–French border, where the Grotte des Enfants burial of 1901 (a woman and a boy, Gravettian, about 25,000 years) was once made a "Negroid race" on the strength of prognathism now known to be post-mortem distortion. Asia is represented in the syllabus by Jinniushan, which is archaic (above); the modern Asian fossils are Zhoukoudian Upper Cave (about 30,000 years), Niah Cave in Borneo (about 40,000) and Tam Pa Ling in Laos. Australia's Lake Mungo in the Willandra Lakes of New South Wales gave Mungo Lady (LM1, 1969, Jim Bowler), the world's oldest known cremation, and Mungo Man (LM3, 1974), a burial sprinkled with red ochre, both now dated about 40,000–42,000 years: the earliest modern humans in Australia and proof of sea-crossing by then.

The Out of Africa (recent African origin, replacement) hypothesis holds that anatomically modern humans evolved in Africa between about 300,000 and 200,000 years ago, spread from it in one or more waves — the main one about 70,000–50,000 years ago — and replaced the archaic populations they met (Neanderthals, Denisovans, late erectus) without significant interbreeding. Its fossil case was made by Chris Stringer and Peter Andrews (1988) and its genetic case by Rebecca Cann, Mark Stoneking and Allan Wilson (1987), whose mitochondrial DNA tree of living peoples rooted in Africa about 200,000 years ago ("mitochondrial Eve"); Y-chromosome trees, the decline of genetic diversity with distance from Africa, and the African fossils from Jebel Irhoud to Omo support it. The Multiregional hypothesis, formulated by Milford Wolpoff, Alan Thorne and Wu Xinzhi (1984) and descended from Weidenreich's "polycentric" scheme, holds that Homo erectus populations across the Old World evolved into modern humans in parallel, connected by gene flow, so that regional features (shovel-shaped incisors in East Asia, the robust Australian skulls) have a continuity of a million years; it has no separate species and no replacement. The Partial Replacement (assimilation, hybridisation) hypothesis of Fred Smith, Günter Bräuer ("Afro-European sapiens") and Erik Trinkaus holds that modern humans did originate in Africa and spread, but interbred with the archaic populations rather than simply replacing them. The ancient genomes have decided the matter in favour of Out of Africa with a measurable admixture: about 1–2% Neanderthal ancestry in all non-Africans, 3–5% Denisovan in Oceanians, and traces of "ghost" archaics in some African populations. The Southern Coastal route through Arabia and India to Australia by about 50,000–65,000 years ago, the Toba super-eruption (74,000 years) and the Indian Middle Palaeolithic at Jwalapuram are the subcontinent's part in the story.