On Tuesday, September 2, a message appeared on the websites of news agencies that the age of the most ancient representative of the genus Homo, also known as the “great man from Chad,” or Tumai, was determined incorrectly. The issue of dating the remains of Tumai is important for paleoanthropology, despite the fact that the relationship between the "prehuman from Chad" and a simple man has not yet been proven
Tumai's newest history began in 2001, when a team of scientists from different countries, led by Michel Brunet, discovered a skull in the Chad desert, combining "advanced" and primitive features. Excavations were carried out in the south of the Sahara Desert, 2.5 thousand kilometers from the Great Rift Valley - an area stretching from northern Syria to central Mozambique in East Africa. In the Great Rift Valley, a large number of fossil remains of hominids have been found, the family to which the most advanced primates and humans belong. Many archaeologists call this region of Africa "the cradle of humanity."
In addition to the skull itself, fragments of a jaw and several teeth were discovered at the excavation site, which is known as the site TM-266. Based on the analysis of these remains, showing an amazing mosaic of features characteristic of hominids and non-human apes, scientists have identified the creature they found as a separate species Sahelanthropus tchadensis of the family of hominids (Hominidae) and the genus Sahelanthropus. The skull of the "great man" was distinguished by a flattened shape and a small volume of the brain section - from 320 to 360 cubic centimeters. A brain of this size is typical of modern chimpanzees. Other than size, however, Tumai's and chimpanzee's skulls no longer share features. The remains of ancient chimpanzees, with which one could compare the found skull, have not yet been found.
Nevertheless, from the very moment of the discovery of the skull, which received the serial number TM 266-01-60-1, researchers were inclined to believe that Tumai is the ancient ancestor of Homo sapiens. Actually, the very name Tumai in the dialect of one of the peoples of Chad means "hope for life." Tumai Aborigines call babies born before the dry season.
Preliminary analysis showed that the age of the remains is about seven million years. This means that the evolutionary branches of the human and chimpanzee ancestors diverged two to three million years after S. tchadensis appeared.
These data violated the already imperfect order in the “pedigree” of a person. Before the discovery of Tumai, the oldest known hominid species were considered Australopithecines, whose remains were found in South and East Africa. Various varieties of Australopithecus were distributed between four and one and a half million years ago. Some of the characteristics found in Tumai were absent in the Australopithecines, who, if the "great man of Chad" was indeed a great man, must have been his descendants. Such "flickering" of signs called into question the logic of building the evolutionary chain of organisms, leading in the end to man.
One of the main features that distinguishes hominids from other primates is bipedalism, which is also known in the scientific literature as vertical bipedalism. In 2005, a group of specialists, including Brunet, reconstructed the alleged appearance of S. tchadensis using computer analysis. The scientists' article was published in the reputable scientific journal Nature. The resulting model clearly indicated that the "great man of Chad" walked on two legs. In addition, in their work, the scientists emphasized that the foramen magnum, located at the base of the skull (this hole is located at the place where the skull connects to the spine and the spinal cord passes through it) has an oval shape, characteristic of bipedal primates, and not round like chimpanzees.
A year later, the journal PaleoAnthropology published the work of another group of scientists who tended to believe that S. tchadensis was not only not a biped, but had nothing to do with hominids at all. The list of authors was headed by Milford Wolproff, who even before that doubted that the human and the "owner" of the TM 266-01-60-1 skull had anything in common. Based on the results of a comprehensive analysis of the remains (in particular, the study of the shape of the hole at the base of the skull) and computer reconstruction of colleagues, the scientists came to the conclusion that Tumai's skull was planted in the same way as in monkeys, which move on four limbs.
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After examining the teeth found next to the skull, Walproff and colleagues concluded that in their characteristics they most closely resemble the teeth of ancient canines, rather than monkeys or representatives of the genus Homo.
Both supporters and opponents of the recognition of S. tchadensis as a hominid agreed that in order to draw definitive conclusions, they lacked accurate data on the age of the remains. Until recently, dating of Tumai's skull, teeth and jaw was carried out on the basis of a study of the remains of other animals found nearby. In particular, at the excavation site, archaeologists discovered the remains of Libycosaurus petrochii, a mammal from the extinct Anthracotheriidae family (to which, for example, hippos and pigs of the Miocene belonged). The animals found in the TM-266 area became completely extinct about six million years ago. Accordingly, the "great man from Chad" was supposedly older than this age. This accuracy was insufficient even for archaeologists.
More accurate data were published in March 2008 in the journal Proceedings of the National Academy of Science. A team of scientists led by Brunet carried out radiocarbon analysis of soil samples where the skull TM 266-01-60-1 was found. This method of determining the age of the remains is considered reliable, since after death the bodies are usually quickly covered with soil. According to Brunet and colleagues, Tumai is between 6.8 and 7.2 million years old. These findings (assuming that S. tchadensis was indeed a human ancestor) prompts a reexamination of the theory that humans and chimpanzees split between four and five million years ago, based on genetic analysis. In fact, this is tantamount to a revolution in anthropology.
Unexpectedly, one of the discoverers of Tumai, a former colleague of Brune's Alain Beauvilain, spoke out against the revolution. In a paper published in the South African Journal of Science, the scientist explains why the use of radiocarbon analysis of the soil around the location of the TM 266-01-60-1 skull is inappropriate. Beauvilen's objections are based on the fact that Tumai was found in the desert. In addition to sharp temperature changes, deserts are characterized by strong winds, which could lead to a redistribution of soil layers. In addition, the relatively light skull may have been blown away from the original burial site. Another subject of criticism was the selection of soil samples for analysis. Bovilen calls him “amazing”. In his opinion, the soil samples used for the study do not give a complete picture of the surroundings of the remains. In an interview with AFP, Bovilen declined to answer a question about Tumai's relationship with hominids, stressing that his objections concern only the age of the discovered skull.
Unfortunately, in paleoarcheology, just as, for example, in history, even the most harmonious theory can fall apart due to the lack of the necessary evidence. And if in physics or astronomy one can hope that the missing facts will sooner or later be found or proved experimentally, then paleontologists can only look and hope that the remains so necessary for them could survive millions of years of rains, snowfalls, droughts, and one day they will be able to to explain everything.
Irina Yakutenko