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A 24,500-year-old skeleton found in Portugal shows Neandertals and early modern humans intermixed and produced children, said Erik Trinkaus, Ph.D., professor of anthropology in Arts and Sciences. Trinkaus is the principal paleontologist examining a 4-year-old child's skeleton that was excavated from the Abrigo do Lagar Velho, near Leiria, Portugal, about 90 miles north of Lisbon.
Radiocarbon dating recently confirmed the age of the skeleton, indicating the child lived 4,000 years after the time that Neandertals and early modern humans coexisted on the Iberian Peninsula, said Trinkaus, a renowned paleontologist who has written several books and numerous articles on Neandertals and early modern humans. The discovery challenges the commonly held theory that the Neandertals were not direct ancestors of modern humans.
"This find tells us what it means to be human," said Trinkaus, who is working with João Zilhão, Portugal's director of antiquities and head of the excavation team. "Many people like to distance themselves categorically from Neandertals. This skeleton, which has some characteristics of Neandertals and others of early modern humans, demonstrates that early modern humans and Neandertals were not all that different. They intermixed, interbred and produced children."
Trinkaus believes the child -- likely a boy -- was not the isolated offspring of one Neandertal and early modern human couple. "This is not a unique love child," he said. "This skeleton shows that the results of admixture were in the population 4,000 years after the generally recognized transition from Neandertals to early modern humans in southern Iberia. The age of the skeleton indicates this child was the result of an already extensively mixed population."
The skeleton is the first archaeological find demonstrating characteristics of both Neandertals and early modern humans, Trinkaus said. The child's stocky trunk and short leg bones are similar to those of the Neandertals, while its prominent chin and modest-sized front teeth are similar to those of early modern humans. Other aspects of the skull and features of the arms and pelvis show a mosaic or blend of Neandertal and early modern human features, the pattern seen in individual hybrids between modern species.
The Lagar Velho find also presents the first evidence of Paleolithic burial practices in southern Iberia. The skeleton was found with an ornamental shell and was heavily stained with red ochre, indicating a wrap around the body. These practices are commonly associated with contemporaneous ritual burials of early modern humans from elsewhere in Europe. Scientists have debated the extent to which Neandertals practiced cultural rites, including ritual burial, or whether such rituals originated with early modern humans, who are thought to have had more elaborate technological and sociocultural systems.
Members of the Portuguese Institute of Archaeology originally discovered the Lagar Velho child's left-hand and forearm bones in November in the Lapedo Valley. An extensive amount of earth had been removed from the site several years earlier, exposing Upper Paleolithic deposits. An archaeological team led by Zilhão then began removing what turned out to be a nearly complete skeleton.
In January, Trinkaus flew to Portugal to begin conducting the paleontological analysis of the bones. The skeleton is now at the Portuguese National Archaeological Museum in Lisbon, where an international team of specialists, including Trinkaus, will be analyzing it in the years to come.
"This find refutes strict replacement models of modern human origins -- that early modern humans evolved in Africa about 100,000 years ago and then spread and wiped out the Neandertals without interbreeding," Trinkaus said. "While the replacement adherents argue that Neandertals became extinct about 30,000 years ago, and, therefore, were not ancestors of modern humans, the Lagar Velho find would indicate a transition period in which both populations interbred, leading to the descent of modern humans."
Trinkaus said that in Spain and Portugal the spread of early modern humans was very late, compared to the transition elsewhere in Europe. "While the fossil record is scant, previous finds have indicated Neandertals endured in the cul-de-sac of Iberia 5,000 to 10,000 years after they had been replaced or absorbed elsewhere in Europe," he said.
Using DNA evidence, some scientists have argued that Neandertals and early modern humans were different species, and, thus, that modern humans did not descend from Neandertals. While the first evidence of archaic human ancestors dates back more than 4 million years, the genus Homo evolved 2.5 million years ago. Homo erectus, who used advanced tools and fire, appeared about 2 million years ago and evolved into Neandertals (beginning about 200,000 years ago) and other late archaic human groups in different geographical regions. Early modern humans evolved from one or more groups of these late archaic humans.
Commonly associated with a protruding brow and stocky build, Neandertals often are characterized as a less sophisticated and less intelligent species than the more graceful and intelligent early modern humans.
"The Lagar Velho child demonstrates that through interbreeding, Neandertals could have contributed to the ancestral line of modern humans," Trinkaus said. "Yes, we are unique and special, but we are not all that different from our ancestors."