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I was born ten thousand years ago

Skull found in a river sambaqui in the Ribeira Valley reveals São Paulo

The first prehistoric inhabitants of the region known today as the state of São Paulo were here one or two thousands of years before used to be imagined – roughly ten thousand years ago, — and they were a singular people, with an identity still being constructed. They were half way between the man from the sea and the man from the forest. Strictly speaking, they were neither one nor the other, probably a hybrid of the two. Their social life emulated certain behaviors of coastal dwellers, but their physical traits, in some cases, were reminiscent of those who inhabited Brazil’s hinterland. It was perhaps a reflection of the geography that sheltered them: they used to live close to the banks of the watercourses of an environmental transition zone between the plateau and the coast, the valley of the River Ribeira do Iguape, in the south of the state of São Paulo, close to Paraná. The members of this culture, who were some dozens of kilometers distant from the sea, used to bury their dead and cover them with a thick layer of shells, bequeathing to posterity a kind of archeological vestige known as a sambaquis, typical of the populations from the coast.

Along the whole Brazilian coastline, in particular Santa Catarina, there are coastal sambaquis that sometimes spring up from the ground as hills of up to 30 meters in height, formed from an accumulation of mussels, oysters and cockles. Just in the Ribeira Valley, there is a significant quantity of fluvial sambaquis, although in a smaller number and far more modest dimensions than those from the seaside. The height of the river shell mounds comes to between 80 centimeters and one and a half meters. A new look at the people that constructed these fluvial sambaquis is beginning to take shape with the studies done in the last few years by archeologists, geophysicists and biologists from the University of São Paulo (USP), who are taking part in a thematic project financed by FAPESP.  The most spectacular detail of the work, which even used geophysical techniques to locate and to characterize the concentrations of snails in the inside of the archeological sites, the oldest skull found until now in São Paulo was discovered, with an age of roughly 9 thousand years, perhaps even a little more, according to the carbon 14 dating method. “The bones were from a burial located in a geological layer very close to the surface”, recalls archeologist Levy Figuti, from USP’s Archeology and Ethnology Museum (MAE), the coordinator of the project. “We didn’t think that it was so old.” Shells close to the buried skull were also dated and gave an age similar to that of the bones. Found about six years ago at an archeological site called Capelinha I, in the basin of the River Jacupiranga, the male skull was the object of a scientific article published in April this year in the American magazine Journal of Human Evolution.

The remains of the prehistoric inhabitant of the fluvial sambaquis, probably a hunter and gatherer of snails, are important for two reasons: the advanced age and particular anatomical traits. Before the discovery of the new skull, the most ancient record of the human presence in the Ribeira Valley (and in the state) went back 8 thousand years, in the form of skeletons and other archeological records found in the numerous coastal sambaquis of the region, held to be older than the fluvial shell mounds. Very well preserved, the Capelinha skeleton has, for the time being, changed this scenario. Can one then state hat the fluvial sambaquis are older than those of the coast and, consequently, their inhabitants came from the hinterland, established themselves first in the environs of the rivers, and only later, along the coast? Not yet, the researchers reply. “Some 10 thousand years ago, the coastal plain used to be larger, and the sea was a few kilometers further away than it is today”, Figuti ponders. “Since then, the tide has been rising, and it is possible that the older coastal sambaquis have been submersed by the ocean.” If the hypothesis is correct, it will never be known for sure whether they were older than the fluvial sambaquis.

Aside from the unexpected advanced age, the Capelinha man revealed more surprises. The skull belonged to an individual some 30 years old, of about 1.60 meters, who, unlike the typical sambaquis men from the coast and the majority of the inhabitants of Brazilian prehistory, did not have mongoloid (oriental) traits. “It was a gracile little individual”, comments biologist Sabine Eggers, from USP’s Biosciences Institute, another research from the team.

The measures and the format of his skull showed Negroid characteristics, similar to those found in the present-day Australian aborigines and Africans – and in Luzia, the famous skull of a young woman who lived 11 thousand years ago in the region of Lagoa Santa, in the environs of Belo Horizonte, regarded as the oldest fragment of a human skeleton in Brazil. The Capelinha man showed craniosynostosis, a genetic malformation characterized by the premature closing of the cranial sutures. The problem, though, did not alter the shape and the size of the bones. He also had lesions in the femur and in the clavicle, probably derived from great physical efforts. “The marks on the clavicle suggest that repetitive movements were carried out, such as swimming or the act of rowing”, Sabine points out. Whether originating from the coast or from the plateau, he seemed adapted to the aquatic environmental.

If he was similar to the Luzia, the Capelinha can only have come from the hinterland of the country, and not from the coast, right? It probably is. But the researchers do not know up to what point the Capelinha skull is representative of the first inhabitants of the river sambaquis of the whole Ribeira Valley. The fragment of a skeleton may have been an exception, and not the rule in the region. The team from USP found remains of about 60 individuals in fluvial sambaquis. Only one sixth of them were dated by carbon 14, and they were all more recent than the Capelinha man, with ages between 1,200 and 6 thousand years. The appearance of the Capelinha man shows some contradictory aspects. At first sight, the skull proves to be quite different from the bones taken from the prehistoric site of Moraes, in the basin of the River Juquiá, another stretch of the middle Ribeira Valley. With an age of around 5 thousand years, the skeletons from Moraes, the fluvial shell mound from which came fragments of 40 individuals, were similar to those of the typical mongoloid populations that lived in the same period in the coastal sambaquis in the Santos Lowlands. However, more detailed analyses suggest that the physical differences between the human remains of Capelinha and Moraes are not so great. That is to say, there are more doubts than certainties. “With our work, we have opened up the range of problems about the occupation of the region”, explains archeologist Paulo De Blasis, from MAE/USP.

Contact zone
The fluvial sambaquis in the south of São Paulo have been known since the beginning of the 20th century, but they began to be studied in a more systematic way only in the 1970s and 1980s. Rich in caves, like the famous Caverna do Diabo (The Devil’s Cave) in the municipality of Eldorado, the region attracts levies of speleologists, amateur and professional. For archeologists, the Ribeira Valley, particularly its middle portion, represents an opportunity for getting to know and studying the prehistoric peoples that settled in an area regarded as a link between the coast and the plateau, on the upper story of the Serra do Mar (Sea Ridge). A zone where different cultures came into contact and possibly left varied kinds of archeological vestiges. “The region may also have been an area of refuge for groups under demographic pressure”, Figuti says. The middle Ribeira Valley used to be a meeting point, due to its particular geography. Unlike the other rivers of São Paulo, which rise on the plateau and run to the west, the Ribeira do Iguape flows eastwards, on its way to the sea. In its course to the Atlantic, it crosses mountain ranges and cuts small valleys, forming diversified microenvironments, which work like natural bridges between the coast, hot, and the plateau, colder. Instead of the abrupt scarps of the Serra do Mar, which more separate than link the coast to the plateau, the Ribeira region shows a gentler relief that integrates the coastal zone with the mountainous one.

The researchers from USP studied 29 fluvial sambaquis from the Ribeira Valley. The majority of the archeological sites have a circular shape, which extends for an area of from 500 to 1,900 square meters and is known by the local population due to their typical heaps of land snails, shells from the Megalobulimus genus. The shell mounds are more frequent in some stretches of the valley, above all in the basin of the River Jacupiranga and in the municipality of Itaoca, and, on a smaller scale, in the basin of the River Juquiá. The chronology shown by this set of prehistoric sites led the researchers to speculate that the prehistory of the fluvial sambaquis can be provisionally divided into three periods. The first phase encompasses the two sites of the Jacupiranga basin, including Capelinha I, with ages between 8,500 and 9,200 years. The second would cover nine sites, scattered over the three stretches with a greater concentration of shell mounds. These sambaquis have an age of between 7 thousand and 3,500 years. The third stage would bring together seven sites, all from the Itaoca region. In these places, there are indications that the culture of the last sambaqui men from the rivers was present for only half a century, between 1,700 and 1,200 years ago. There are two intervals of time in which there are no records of fluvial sambaquis, between 8,500 and 7 thousand years and between 3,500 and 1,700 years. This does not mean to say that there were no inhabitants in the region in those days. According to the researchers, fresh excavations may fill in the information gaps.

The presence of shells in the fluvial sambaquis induces one to think that the diet of the prehistoric inhabitants of the middle Ribeira used to be based on mollusks and fish from the river. The impression may be false. There are no records of the mollusks being cooked, nor of their tops being broken to take out the meat. The snails may have been collected, as a priority, for the construction of funeral heaps.  “The sambaqui from Moraes may have been a site used only to perform burials, as a cemetery, and not as a dwelling place”, comments archeologist Claudia Regina Plens, who is doing a doctorate at MAE/USP. “In some cases, we discovered how the fluvial sambaqui men died, and not how they lived”, Figuti explains. Vestiges of several mammals, such as peccaries, deer, howling monkeys, pacas and armadillos, suggest that hunting may have been a more important source of food than fishing or gathering mollusks.

The so-called material culture of the prehistoric peoples of the middle Ribeira Valley mirrors the influence both of the plateau and of the coast in the construction of utensils, tools and weapons. A typical adornment would be a necklace made with dozens of perforated howler monkey canine teeth, sometimes found around the neck of the buried bodies. By the look of it, they used to put almost everything of these monkeys to good use. Marine versions of the ornament, with sharks’ teeth, also appear in some sites. Arrowheads made of flint, quartz and other materials showed that to hunt was necessary. Mammals’ teeth, and, less frequently, teeth of marine fish and rays were used as awls or tips for cutting. Bones from land animals were polished and turned into objects reminiscent of flutes, although their utility, unknown, may not have been of the most musical. Three fishhooks of some 5 centimeters in length, made with animal bones, were perhaps the most unusual artifacts recovered from the fluvial sambaquis. “We don’t usually find fishhooks, even in the coastal sambaquis”, Figuti explains. “What river fish could they catch with that?” The ancient inhabitants of the middle Ribeira Valley, perhaps the first São Paulo dwellers of prehistory, were different, a people neither all sea nor all land.

Gamma rays in archeology
For being small and less visible than the costal sambaquis, the fluvial shell mounds can be difficult to locate and to delimit. To lessen this problem, the researchers from the thematic project tested the efficiency of geophysical measurements, normally used to find ore, as a tool in the work of archeological prospecting. One of the techniques put to the test, gamma spectrometry, proved to be useful for discovering the heaps of shells that characterize the sambaquis. By this method, a sensor records, during one minute, the gamma radiation naturally emitted by the geological layers of the soil. “In mining, this kind of measure is used to look for uranium and thorium deposits”, claims Carlos Alberto Mendonça, from USP’s Astronomical and Geophysical Institute (IAG), who coordinated this part of the studies. Places with greater radiation may indicate the presence of minerals with these elements.

With the sambaquis, the opposite happens. Places with lower radiation tend to be rich in limestone, a clue that there should be a sambaqui there. After all, the shell of the mollusk is made up basically of calcium carbonate. Adopting gamma spectrometry worked out so well that it led to the discovery of a second shell mound, smaller than the main sambaqui, at the Capelinha archeological site. The researchers also tested other techniques to find archeological vestiges, such as measuring the magnetism of the soil, which could indicate the existence of prehistoric bonfires. But the results were not so encouraging.

The Project
Archeological and geophysical investigations of the fluvial sambaquis in the Ribeira do Iguape Valley, State of São Paulo (99/12684-2); Modality: Thematic Project; Coordinator: Levy Figuti – MAE-USP; Investment: R$ 254,359.74