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The 20th Century. A New Science: Human Paleontology

1.1. Introduction

The 19th century saw the recognition of the animal and simian origin of Homo sapiens, although not without difficulty, through thought experiments due to the lack of sufficient knowledge in both paleontology and reproductive biology. The long geological periods throughout the history of the Earth and its cooling, as described by Georges Buffon, made it possible to locate fossil and current species according to lineages, or phylums, and then to link these phylums together by looking for "intermediate" fossil species. In this phylogeny of multicellular organisms, which became vertebrates with the horizontal organization of chordates, the primate lineage can be distinguished by the verticalization of the neuraxis starting from the posterior cranial base, the reduction of prognathism and an encephalization that led to Homo sapiens, the most verticalized chordate. Verticalization was the guiding thread of the problem, and the bimania (meaning two-hands in Latin) linked to this verticality was then much more significant for anthropologists, along with encephalization, then bipedalism, which was not original, being common in gibbons as well as birds. Whatever one's opinion on the meaning of Man's place in the animal kingdom and the history of the Earth, verticalized anatomy has not left the place assigned to it by the history of animals since Aristotle. It remains the last point on the curve of this complexification/verticalization, which was accompanied by an increase in cognitive capacities.

For prehistorians and anthropologists, Homo sapiens is characterized by articulated language and symbolic behaviors manifested by the creation of objects unrelated to primary necessities. These activities concern ornaments, engravings, paintings and sculptures; as innovations that express values, significations, they are bearers of meaning. On the eve of 19th century, the oldest Homo sapiens skeletons were still rare, but they were already associated with these productions at prehistoric periods that had nothing in common with the Adamic tradition, still well anchored in the European culture that refused the idea of a simian origin. This filiation was defended at the Muséum national d'Histoire naturelle (French National Museum of Natural History, henceforth referred to as the Muséum) in 1802 by Jean-Baptiste Lamarck, Etienne Geoffroy Saint-Hilaire and his son Isidore Geoffroy Saint-Hilaire, but 70 years later, it did not find unanimous acceptance with an interesting and strong personality, the geophysicist, physician and anthropologist Armand de Quatrefages.

1.2. Human paleontology, a nascent science

A new prehistoric Homo sapiens skeleton was exhumed in 1872 on the lands of the Principality of Monaco, in Cavillon, in one of the Grimaldi caves. Everything pointed to a sepulchral context at levels as old as the Cro-Magnon shelter in Les Eyzies-de-Tayac (France), dating back nearly 30,000 years. The stakes were considerable because the remains carried a mantilla composed of more than 200 shells on its head, covered with red ochre and black hematite. The discovery attested to an already highly ritualized and symbolic relationship with death. The mastery of articulated language left little room for doubt. The excavations, however, did not have any means of guaranteeing its date. Prehistory was not yet a scientific discipline.

Armand de Quatrefages studied the Les Eyzies skeletons with his naturalist assistant, the doctor Ernest Hamy (1842-1902). Together they defined the Cro-Magnon race as "the second fossilized human race", the first being the "Canstadt race" or Neanderthal Man, which was limited to three specimens recognized as: Neanderthal, Gibraltar and La Naulette (see Volume 1). Their study was exocranial, the base of the skull was partially preserved on one of the three adult skulls, but its endocranial surface was not described because of its inaccessibility and there was no question of damaging the unique piece.

New fossils of European Neanderthals enriched the collections in 1886, with three individuals discovered in Belgium in the Spy cave (currently dated at 38,500 years) and especially in Croatia in 1899 in the Krapina cave, with nearly 900 fragmented human remains, nearly 80 individuals dated at 125,000 years old. Traces of anthropophagy would be confirmed.

The great novelty came from Asia with the discovery of fossils of monkeys and great apes, and above all that of a very ancient anthropomorph in Java which generated a great stir among anthropologists. The monkey fossils were collected in the powerful sedimentary deposits of the upper Indus basin called Siwaliks, composed of molasse deposited in the plain by the erosion of the Himalayan range during formation. In the northwestern Indian subcontinent, the deposits were slightly folded and formed the Potwar Plateau. The erosion and scarcity of vegetation gave access to numerous fossiliferous outcrops. Further east, these deposits formed the foothills of the Himalayas, strongly compressed by plate tectonics between India and Asia, sometimes to verticality. The outcrops became long narrow bands covered by tropical forest at low altitude and richer in thorny trees at high altitude. Prospecting conditions were thus limited by vegetation cover and by the small surface area of the fossiliferous layers that inclined rapidly in the depths. The Geological Survey of India (the geological service of the British Empire in India) organized the geological map of the subcontinent. In 1874, Richard Lydekker (1849-1915), a geologist trained at Trinity College, Cambridge (University of Cambridge) was commissioned to map Kashmir, north of the Potwar.

Lyddeker was prospecting the Siwaliks and collecting numerous fossils of vertebrates preserved in the Museum of Calcutta. Among these fossils was a fragment of a monkey's jawbone collected in 1879. Close to the gibbon, the geologist named it Paleopithecus sivalensis, then in 1886, he described a canine tooth which resembled that of an orangutan. It was the second fossil of a large anthropoid after the mandible of Dryopithecus. Henceforth, the Siwaliks became the cradle of the origin of Man. This perspective was in line with the deductions of Georges Cuvier who thought it was located somewhere in the Himalayan heights, based on paleoclimatic arguments linked to a rise in sea water on a planetary scale. For the high Himalayan peaks, global warming was to result in the melting of the glaciers and the consequent flooding of the plains by the powerful Himalayan rivers.

1.2.1. The Java erect ape-man, or the missing link, Pithecanthropus

Haeckel's anthropogeny placed the ancestors of the gibbon in the ancestral lineage of Man and predicted a fossil link that he named Pithecanthropus. Since gibbons and orangutans still live in Southeast Asia, Haeckel located the cradle of humanity between Sumatra, Java and Borneo. The probability of finding fossils of this "missing link" in Asia was therefore supported by this maxilla and canine discovered in sub-Himalayan India. Five years later, in 1891, paleoanthropology made a prodigious leap forward in time thanks to a Dutch doctor. Eugène Dubois (1858-1940) had recently defended his thesis in medicine, in 1884, and was soon appointed lecturer with the chair of Anatomy at the University of Amsterdam in 1886. He was neither an anthropologist nor a paleontologist, but he did intend to devote his free time to researching this Pithecanthropus. In 1887, he decided to leave Amsterdam to settle in Sumatra with his family, and joined the Royal Dutch Indian Army as a doctor.

Human paleontology was not yet a discipline; the Neanderthal skeleton and the Gibraltar skull had still not been described. Dubois went to the island of Java and prospected the ancient formations of a river, the Solo, on a paleontological site called Trinil. Between 1891 and 1892 many fossils were collected with the help of two engineers and some convicts. These fossils included two human molars and a human-like skull cap with a low vault and a strong bulge above the orbits. Subsequently, a perfectly preserved femur of modern appearance was collected about 15 m from the area. The skull base was missing and only the proximity justified the association of the femur and the skull cap. Dating went back to the Middle Pleistocene (500,000 years in 2020). Dubois published a description of the fossils in Java in 1894 (Dubois 1894), comparing the skull cap with a chimpanzee and decided to attribute the fossil to an extinct genus of Hominids, the Pithecanthropus, and to add the femur to define the species as erectus, in other words, the erect ape-man. Cranial capacity was estimated at 900 ml, while that of Homo sapiens is 1,350 ml on average, that of the orangutan is 320-340 ml and that of the gibbon is 82 ml (White 2007). On the strength of his discovery, Dubois traveled around Europe in 1895 to obtain the approval of anatomists. The monograph was read carefully by the most informed authorities, some 20 experts, and the conclusions were more in the realm of opinions, ranging from a giant gibbon to an extinct genus of intermediate hominin between Ape and Man. The Société d'Anthropologie de Paris appreciated the discovery and its implications. In January 1895, Léonce Manouvrier (1850-1927), a specialist in the physiology and anatomy of the human brain, presented his analysis and...