A new study found that the remains of Homo floresiensis, fossilized bones of a previously unknown human species, actually belong to modern humans with Down syndrome, and not to a new species of human beings.
The remains were found in October of 2004 in the Flores Island of Indonesia. Since it did not match any known human relics before, scientists thought that they might be from an unknown species of human.
A detailed assessment by an international team of scientists suggested that the relics do not belong to a new species, but to a human being who developed abnormally.
The new designation of the Homo florensiensis was called LB1, and further analysis showed that the remains could be from someone with Down syndrome. The strongest evidence of this theory was the comparison of the cranial volume. LB1 only had 380 milliliters of cranial volume and was one-third smaller than the cranial volume of an average human being. The reconstruction of the species' gait using its thighbones also revealed that the creature's height was 3.5 feet.
"The difference is significant, and the revised figure falls in the range predicted for a modern human with Down syndrome from the same geographic region," said Robert B. Eckhardt, lead author of the study and a professor of developmental genetics and evolution from Penn State.
Down syndrome was one of the most commonly observed development-related problems for modern humans.
"When we first saw these bones, several of us immediately spotted a developmental disturbance," said Eckhardt, "but we did not assign a specific diagnosis because the bones were so fragmentary. Over the years, several lines of evidence have converged on Down syndrome."
Further details of the study were published in the Aug.5 issue of Proceedings of the National Academy of Sciences.
