Homo erectus: an overview of the extinct early human species

The name of the genus Homo is derived from Latin homo [ˈhɔmoː], German 'Mensch'. The species name erectus is derived from Latin erigere ('to raise up'). Homo erectus thus means 'the erect man'.

The first three fossils, Trinil I to III, discovered by Eugène Dubois in 1891/92 and known as Java Man, had initially been named by Dubois as Anthropopithecus erectus ('erect man-ape'), derived from ancient Greek ἄνθρωπος anthropos, German 'man' and Greek. πίθηκος, Old Greek pronounced píthēkos ('monkey'). In 1894, Dubois changed the generic name to Pithecanthropus erectus ('erect ape-man') in a technical paper, describing the species as a transitional form that had led to modern humans. In giving this name, Dubois took up a suggestion that Ernst Haeckel had recommended in 1863, when he had described a hypothetical transitional form between man and ape and called it Pithecanthropus.

In 1944, Theodosius Dobzhansky published the paper On species and races of living and fossil man, in which he argued that there had been only a single, variant species of Hominini at any time. In 1950, Ernst Mayr, in a lecture at the Cold Spring Harbour Symposium on Quantitative Biology, supported Dobzhansky's assumptions and convinced paleoanthropologists to assign all presumed human ancestors discovered in the meantime to the genus Homo and in future to refrain from naming individual finds with a genus and species name; instead, such fossils should be named according to their origin (for example, Sterkfontein find instead of "Plesianthropus" for Mrs. Ples). This had the consequence that the fossils designated as Pithecanthropus erectus were also renamed again, that according to the international rules for zoological nomenclature the species name erectus was retained and that the three fossils discovered by Eugène Dubois are now the type specimens of Homo erectus.

Holotype of Homo erectus are three fossils recovered by Eugène Dubois on the Indonesian island of Java: a cranium discovered in October 1891 with a prominent, continuous transverse bulge of the frontal bone above the root of the nose ("over-eye bulge"), collection number Trinil II; a completely preserved femur (Trinil III) discovered in August 1892, similar in shape and structure to the femur of anatomically modern humans, which Dubois interpreted as an indication that its owner moved similarly upright to modern humans; and a large molar tooth (Trinil I) already discovered in August 1891.

However, the tooth and skullcap were initially interpreted by Dubois as a fossil of a non-hominin ape, because Dubois believed they were similar to recent chimpanzees. He therefore initially assigned the find to the new species Anthropopithecus erectus; Anthropopithecus was the generic name of chimpanzees at the time.

The three fossils discovered by Eugène Dubois were considered at the time to be the first finds of fossils of the Hominini outside Europe and at the same time the oldest discovered from this clade up to that time. Due to the fact that they were found at the edge of a former body of water, the dating of the bones is problematic; according to current knowledge, the skullcap is thought to be about one million years old. However, the skullcap has so few characteristic features that it cannot be reliably compared with other fossils. The assignment of the molar tooth to the genus Homo, on the other hand, is not considered certain today, and the femur is interpreted by some researchers as belonging to anatomically modern humans (Homo sapiens).

The first description in Dubois' publication Paleontologische onderzoekingen op Java is dated in the original to the year 1892, which is why the full name of the species is usually Homo erectus DUBOIS, 1892; if, however, the publication was not published until 1893, as occasionally claimed, the species would have to be named Homo erectus DUBOIS, 1893.