Primates, hominoids and hominidsFirst of all we are going to place ourselves on the taxonomic plane. The genus Homo sapiens is part of the order primates , which are characterized among other things by having hands and feet with five fingers, opposable thumb – except for our foot, which has lost that ability -, nails instead of claws, stereoscopic vision , and a larger cranial volume. Within the primate order, we are located in the Hominoidea superfamily, which is divided into the Hominidae family (ours), and the Pongidae family, which includes orangutans, gorillas and chimpanzees.
In search of the missing linkAlthough the term ‘ missing link ‘ is no longer in use, it reflects well that man’s search to find the first hominid, that common ancestor between humans and chimpanzees. We know that our lineage separated between 5 and 7 million years ago and there are several aspirants to fill the position of the oldest hominid. The most prominent are Sahelanthropus tchadensis , Orrorin tugenensis and the genus Ardipithecus , which is the most widely accepted in the scientific community.
AustralopithecusFor a long time, the scientific community considered that specimens of the extinct genus Australopithecus could be the longed-for missing link. Today we know that, although they are phylogenetically related to humans, they are not the common ancestor, and that this one goes back in time almost twice as long as the time that separates humans and Australopithecus. This genus has a range of antiquity that goes from 4.2 to 2.5 million years and within it there are seven described species, although there is still no scientific consensus on some.
Lucy, the primitive starThe most famous species is undoubtedly Australopithecus afarensis , and its star individual is Lucy , found in 1974 in the Afar desert, in Ethiopia. The importance of this fossil lies in the fact that Lucy had characteristics that made her very different from anything that had been excavated up to then, and at that time it was the oldest known skeleton . Its discoverers, aware that they had found something important, celebrated it in style, and say that the song Lucy in the sky by the Beatles was played repeatedly during the celebration. As already mentioned, today we know that Lucy was not the ‘missing link’, but she is surely the best known fossil remnant in the world, a kind of primitive star.
‘Paranthropus’This name means ‘next to man’: after the Australopithecus , there was a branch into two groups: the genus Homo and the genus Paranthropus , each with specific capacities to allow them to subsist in the environment in which they moved. This genus preserves some Australopithecus traits such as the reduced cranial capacity in relation to body size and prognathism – very protruding jaws. One of the new features is the development of a very powerful chewing device that will allow them to take advantage of very hard plant resources.
‘Homo habilis’This species is considered the first human, which emerged in Africa and has the ability to manufacture its own tools (we are talking about Mode 1 or Olduvayense technology) and, in addition, mentally plan them, visualize them before making them. Its brain is larger than that of Australopithecus, it has a less developed chewing apparatus and a more rounded cranial shape. The first fossils of this species were discovered by the Leakeys in the Olduvai Gorge, in Tanzania , in 1962, although the report describing the findings was published two years later.
‘Homo erectus’About two million years ago, the first great human expansion took place and Homo habilis left Africa. Currently, the fossil individuals found in Asia are considered within H. erectus , while the specimens found in Africa that already have more evolved characteristics from H. habilis are included in the species H. ergaster . With this species there is already talk of a new technology: Mode 2 or Acheulean.
‘Homo georgicus’This species, whose description has not been without controversy, refers to finds made in Dmanisi, Georgia. The archaeological remains represent an intermediate evolutionary stage between Homo erectus sensu lato and H. habilis . It is 1.8 million years old, 1.5 meters tall, and is attributed Olduvayense or Mode 1 technology.
‘Homo antecessor’Recapitulating everything explained so far, it seems that new species with different geographical locations emerged from Homo habilis : H. erectus in Asia, H. ergaster in Africa, and H. antecessor and H. heilderbergensis in Europe. The discovery of H. antecessor occurred in the Atapuerca site in 1994 and represented a paradigm shift, although it was not, like all the great finds in this area, without controversy. Until that moment it was thought that the first inhabitants of Europe had arrived around 500,000 years ago , but in Atapuerca signs were being found that human occupation in this settlement was much older. The species was described in an article published in the journal Science in 1997 and tells us about a surprising mix of primitive and derived characters. They measured between 1.6 and 1.85 meters, weighed between 69 and 90 kilos and among the primitive features the dental apparatus stands out, which would link them with African specimens. They are credited with Mode 1 technology. Photo: replica of the incomplete skull from Gran Dolina
‘Homo heildelbergensis’We speak of the European lineage, and of a species that is very important for the understanding of human evolution, since it is the direct ancestor of Neanderthal man. There are fossils of H. heildelbergensis with dates between 600,000 and 400,000 years, such as Mauer’s jaw, and other more modern finds with chronologies between 400,000 and 200,000 years, among which are various fossils found in the Sima de the Bones (Atapuerca). They were humans with great physical corpulence and possessing a fining apparatus, although their communication would be quite different from what we have today.
‘Homo neanderthalensis’On neandertales been said and written, particularly following recent studies show that DNA, to the less punctually, hybridization occurred between H. neanderthalensis and H. sapiens . Both species coexisted for approximately 10,000 years of years on the European continent until the extinction of the Neanderthals, whose causes are still under debate. The intermarriage , nutritional deficits or competition with sapiens are some of the hypotheses being considered. In any case, it seems that the classic vision that described Neanderthals as individuals more similar to beasts than to humans is out of date. For more than 100,000 years they inhabited several continents of the planet and were able to adapt to very extreme conditions . With the Neanderthals, technological development also took an important step, and we already talked about Mode 3 or Mousterian.
‘Homo sapiens’Just as Homo neanderthalensis arose from H. heilderbergensis in Europe, H. sapiens arose on the African continent . Today we know that at least our species is almost 200,000 years old, as indicated by Louis Leakey’s find in Omo, southern Ethiopia, in 1967.
‘Homo floresiensis’The discovery of Homo floresiensis in 2003 broke with a pattern that had been a constant in all findings related to human evolution: the process led to larger and larger individuals with greater cranial capacity . But the one also baptized as ‘the Hobbit’ did not follow this pattern: a morphology more similar to Australopithecus but a very recent chronology, which would place it around 18,000 years, and with its own surprisingly advanced technology. Much has been discussed regarding the interpretation of these remains, and even many theories pointed out that it was not a species as such, but that its morphology was due to some pathology. However, there is increasing consensus in affirming that we would be dealing with an H. erectus that evolved and adapted to the conditions of the island, modifying its morphology due to an effect of insularity.
‘Homo naledi’Homo naledi is the last described species of the genus Homo , since the find took place in South Africa in 2013, and its discovery has broken many schemes. We speak of a mixture of human characteristics with others much more archaic, with a very human morphology but a reduced cranial capacity and closer to Australopithecus . To make matters worse, it seems that these individuals buried their dead , so they would have a kind of symbolic thinking, a characteristic that had always been attributed to larger volumes of brain.
Denisova ManWe are talking about the first hominid identified through the analysis of its genes, and its taxonomy is still under debate. We know that this species – or subspecies, there is still discussion – is related to both Homo sapiens and H. neanderthalensis , so its finding, in 2008 in the Denisova cave (Siberia), adds even more emotion to the panorama of the prehistory. Later, in 2019 , the remains of a jaw found on the Tibetan plateau were identified as belonging to this extinct species. The findings were published in the journal Nature and prove that Denisovans would have spread beyond Siberia. In addition, there is evidence that Denisovans hybridized both with us and with Neanderthals: some native peoples of Oceania, for example, have around 5% Denisovan genes. Photo: molar Denisova 4
‘Homo luzonensis’In 2007, a team of scientists found human-like remains on the island of Luzon, in the Philippines. After many years of study, in 2019 the description of this find was published: the remains would correspond to a new species of hominid, H. luzonensis , which lived on this island 67,000 years ago, and present an interesting mix of primitive and modern features . As with H. floresiensis , it is quite possible that the isolation caused by its insular habitat had led H. luzonensis to evolve along a very different path from H. sapiens and the other hominid species with which it coexisted on our planet.
Stories of PrehistoryAs we have already seen, human evolution is fascinating, as are the stories of the most relevant discoveries we have about our origins. In a very pleasant and easy-to-read way, David Benito manages to immerse us in this exciting world and feel ourselves in the shoes of the most famous paleoanthropologists when they came across those key findings that give us clues about the way of life of those who preceded us. ‘Histories of Prehistory’ is a reference work for any curious reader who wonders about our origins.