Small humanlike skeletons found in a cave on a remote Indonesian island were actually human, and their miniature features were probably due to nutritional deficiency, researchers in Australia have suggested.
Writing in the Proceedings of the Royal Society B: Biological Sciences, the scientists said these were more likely to be cretin offspring of normal mothers who suffered from iodine and other dietary deficiencies. Cretinism is a condition of severely stunted physical and mental growth due to a congenital deficiency of thyroid hormones.
Ever since the 18,000-year-old skeletons were found in Liang Bua on the Indonesian island of Flores, four years ago, anthropologists have debated whether or not they represented a previously unseen species of dwarf hominid — or merely a group of deformed humans. The newly published research opens an additional argument for the latter view.
"We believe they were Homo sapiens, but with this disorder ... cretins born without the thyroid gland," Peter Obendorf of the School of Applied Sciences at RMIT University in Melbourne told Reuters in a telephone interview. "The mothers would be iodine- and selenium-deficient, and would be exposed to certain plant food that would release cyanide into the body."
Obendorf said the fossils were found inland, where their communities were cut off from seafood, a key source of iodine.
They probably relied on bamboo shoots and certain tubers, which could have released cyanide into their bodies given the primitive cooking methods they were using.
These plants are still found in forests in Flores.
"When there's a drought, people utilize them. In modern times, they are cooked better," he said.
Initially, the fossils were classified as a new species called Homo floresiensis, considered an offshoot of Homo erectus. Based on measurements of the skulls and skeletons, scientists said the hominids stood about 3 feet (1 meter) tall and had brains roughly the size of grapefruits.
The fossils were quickly dubbed "Hobbits," referring to the diminutive inhabitants of Middle Earth in J.R.R. Tolkien's "Lord of the Rings" trilogy.
Some skeptics argued that the small size of the Flores skulls more likely resulted from a genetic condition known as microencephaly, characterized by a small head and short stature. Other scientists sought to put those doubts to rest by citing comparative measurements of skeletal dimensions.
Obendorf and his colleagues put forth a different argument against the designation of a new species, contending that the "Hobbits" were essentially modern humans affected by diet rather than genetics.
"We think the population was normal, but many of the women had goiter. In the middle of a drought, some were forced to eat unsuitable food ... and they had cretin children," Obendorf said.
The researchers said certain structures of the fossils, such as the arm bone, matched descriptions contained in medical literature of cretin skeletons found in Europe, especially Germany and Switzerland.
"The dwarf cretins in Europe have just the same structural rotation of the arm bone," Obendorf said.
This report includes information from Reuters and msnbc.com.