Can I pull out this little bone?” Lisiane Müller, a biologist from the city of Petrópolis, points to a fragment held up by toothpicks on a still-buried skeleton. Bending over the excavation site for hours on end, she separates grains of sediment with a brush and pushes them into a plastic bottle cut open like a scoop. Brazilian archeologist André Strauss, a visiting professor at the University of Tübingen, Germany, confirms that it won’t be possible to continue the exhumation without removing the bone. Strauss is one of the leaders of a team averaging 25 volunteers from a range of specialty areas—and accents. Nothing happens at the archeological site without authorization from Strauss or his colleague, Rodrigo Elias de Oliveira, a dentist and bioanthropologist from the Laboratory for Human Evolutionary and Ecological Studies (LEEEH) at the University of São Paulo (USP). The setting is Lapa do Santo, a cave in the Lagoa Santa region in the state of Minas Gerais, which in recent years has proven to be an important center for mortuary rituals performed between 10,000 and 8,000 years ago, as described in a paper published in the journal Antiquity in December 2016 (see Pesquisa FAPESP Issue nº 247).
Before they are removed, all the finds must be positioned in space with the help of a topography instrument known as a total station, which provides coordinates along three axes. Every day, and before modifications are made in any part of the excavation, the team also makes a detailed photographic record of the progress achieved in exposing each group of bones. The photos are printed on-site and annotated with the observations made by the person in charge of each exhumation. Small red plastic squares positioned at several points at the burial site are also located, or plotted, and included in the photograph. This procedure subsequently helps the researchers to build a three-dimensional model of each skeleton.
The work is carried out with enormous care, and even solemnity, since any slip can represent thousands of years lost. To prevent damage to the bones, the researchers can walk around the excavation site only in stocking feet. But the more striking presence is that of the ancient inhabitants who were buried by their companions, such as the child who died at approximately eight years of age and was laid on its side, with legs folded and arms positioned between them. Seeing this skeleton up close, buried so carefully that it has remained in the same position for some 10,000 years, is an emotional experience. It is even more moving to observe that same level of care being exercised by a group so removed in time and provenance. In addition to the multi-accented Brazilians on-site, in 2016 the team also included two students from the University of Tübingen, María López Sosa from Mexico and Franziska Mandt from Germany.
The sensation of the expedition was the skeleton of a woman accompanied by tiny bones which, once exposed, proved to be from the skeleton of a fetus or a newborn. Oliveira was there for practically the entire day, removing sediment one grain at a time while he kept an eye on the other exhumations in progress. He notes that the woman was placed on her knees in the pit, with her body bent over her legs in the fetal position, probably with the trunk twisted so that, if she were still pregnant, her belly would lay sideways and not beneath her ribs. This, plus the stone that served as a grave marker, likely explains why the tiny skeleton was some distance away from the bones of the presumed mother.
Exhaustive precision
“I won’t find out whether it was a baby or a fetus until we examine this tooth in the lab,” the dentist explained when he found a fragment recovered thanks to the team’s exhaustive investigative practices. The sediment is removed with the help of a brush or a rubber bulb used for blowing, and then put through small kitchen strainers—the kind you hold over a cup to separate cream from boiling milk—with the help of a watering can, to separate out the smaller fragments. When a small container called a petisqueira, thought to contain nothing important, was brought back to the dentist, he plucked out the tooth with tweezers. But the analyses conducted back in São Paulo yielded an inconclusive result. “It’s quite typical of that era in regard to birth, with some margin of error, so it could be nearly end-of-term, or it could have been born,” he explains. The milk teeth begin to form between the second and third month of pregnancy.
In addition to strainers for the delicate material, much of the sediment removed from the excavation is filtered through a large screen hanging from a tripod, to separate out fragments that escaped screening by the brush. That job, which requires constant attention and a strong tolerance of the dust that fills the air, was often handled by Gabriel Francisco Pereira, a volunteer who lives in Lagoa Santa and “knows everything about the region,” according to Strauss, and Nina Hochreiter, who, soon after completing 50 years as a veterinarian, retired and began to devote herself to her passion for archeology. This was her fourth stint as a volunteer at Lapa do Santo.
While the team functions like an ant colony, with everyone handling a certain job and working collaboratively, Strauss takes notes on much of what happens, using a computer labeled “journal.” Its keyboard is covered in plastic film to help withstand the fine dust that is impossible to escape. There he reports everything that is done, as a public record. “It’s a guide to help us think about what to do next, and especially for when we’re back in São Paulo,” he explains. Another important reference is the video journal, made at the end of each day, when hundreds of parrots return squawking to their nests in the rock wall above the shelter. “There’s an impressive level of site control,” observes Rita Scheel-Ybert, an archeobotanist from Brazil’s National Museum at the Federal University of Rio de Janeiro (MN-UFRJ), during a visit. She says that the set of meticulous procedures at the site is a hallmark of the work being done there. “It’s because we’re lazy,” Strauss quips. In truth, the work flow, which includes a computerized management system he developed, enables the team to finish the field work with much of the material already curated, and the information computerized and easily recoverable from a database.
Click on the photos to see the captions
