A number of varieties of Homo are grouped into the broad category of archaic humans in the period that precedes and contemporary to the emergence of the earliest Early modern humans (Homo sapiens) around 300 ka. Omo-Kibish I (Omo I) from southern Ethiopia (196 ± 5 ka) and the remains from Jebel Irhoud in Morocco (about 315 ka) and Florisbad in South Africa (259 ka) are the earliest remains of Homo sapiens. The term typically includes Homo neanderthalensis (430+–25 ka), Denisovans, Homo rhodesiensis (300–125 ka), Homo heidelbergensis (600–200 ka), Homo naledi, Homo ergaster, and Homo antecessor.
Archaic humans had a brain size averaging 1,200 to 1,400 cubic centimeters, which overlaps with the range of modern humans. Archaics are distinguished from anatomically modern humans by having a thick skull, prominent supraorbital ridges (brow ridges) and the lack of a prominent chin.
Anatomically modern humans appear around 300,000 years ago in Africa, and 70,000 years ago (see Toba catastrophe theory), gradually supplanting the "archaic" human varieties. Non-modern varieties of Homo are certain to have survived until after 30,000 years ago, and perhaps until as recently as 12,000 years ago. Which of these, if any, are included under the term "archaic human" is a matter of definition and varies among authors. Nonetheless, according to recent genetic studies, modern humans may have bred with "at least two groups" of ancient humans: Neanderthals and Denisovans. Other studies have cast doubt on admixture being the source of the shared genetic markers between archaic and modern humans, pointing to an ancestral origin of the traits which originated 500,000–800,000 years ago.
Another group may also have been extant as recently as 11,500 years ago, the Red Deer Cave people of China. Chris Stringer of the Natural History Museum in London has suggested that these people could be a result of mating between Denisovans and modern humans. Other scientists remain skeptical, suggesting that the unique features are within the variations expected for modern human populations.