London, April 1 (ANI): A recently unearthed human skull, dating back to 500,000 years, shows signs of a disorder that might have caused mental retardation, which offers the earliest evidence that ancestors of Homo sapiens did not abandon young with severe birth defects.
According to a report in New Scientist, the skeleton belonged to a five to 12-year-old child who suffered from craniosynostosis.
The rare congenital condition occurs when two of the flat bones that make up the skull fuse together along their margins too early during fetal development, hindering brain growth.
Spanish researchers discovered the first pieces of the skull near Atapuerca, Spain, in 2001, but they only recently pieced enough of it together to make a conclusive diagnosis.
"We were sure we had evidence of a real pathology," said Ana Gracia, a palaeoanthropologist at Complutense University in Madrid, who led the new study. "It's obvious - you only have to look at the cranium," she added.
The child suffered from a form of craniosynostosis that occurs in about 1 in every 200,000 children.
He or she was a member of the species Homo heidelbergensis, - early humans that lived in Europe up to 800,000 years ago and may have given rise to Neanderthals.
The discovery marks the earliest example of a human skeleton with signs of a physical deformity that that might have made the individual dependent on others for survival.
Most animals, including primates, sacrifice or abandon young born with crippling deformities, according to Gracia.
"It's impossible to know whether the child suffered from any cognitive problems, but he or she would undoubtedly have looked different from family and friends," she said.
According to Erik Trinkaus, a paleoanthropologist at Washington University in Saint Louis, Missouri, "The obvious conclusion is that this child was being helped by other members of the social group." (ANI)