A tiny bone fragment could provide crucial information about the fate of Amelia Earhart, the legendary pilot who disappeared 73 years ago while flying over the Pacific Ocean in a record attempt to fly around the world at the equator.
Collected on Nikumaroro, an uninhabited tropical island in the southwestern Pacific republic of Kiribati, the bone has raised the interest of The International Group for Historic Aircraft Recovery (TIGHAR), which has long been investigating the Earhart mystery, as it may be from a human finger.
The phalax was found together with other artifacts during a month-long expedition last June to the tiny coral atoll believed to be Earhart's final resting place.
"At first we assumed it was from the turtle whose remains we found nearby. Indeed, sea turtles have finger bones in their flippers. But further research suggests it could also be human," Ric Gillespie, executive director of TIGHAR, told Discovery News.
TIGHAR's investigations and theories challenge the assumption that Earhart's twin-engined Lockheed "Electra" crashed in the ocean when running out of fuel on July 2, 1937.
Their findings, along with historical reconstructions of Earhart's disappearance and the futile massive search that followed, are detailed in "Finding Amelia," a Discovery Channel documentary that airs Saturday at 8 p.m. ET/PT on The Discovery Channel.
"After 22 years of rigorous research and 10 grueling expeditions, we can say that all of the evidence we have found on Nikumaroro is consistent with the hypothesis that Earhart and her navigator Fred Noonan landed and eventually died there as castaways," Gillespie said.
Indeed, a number of artifacts unearthed on the uninhabited island provide strong circumstantial evidence for a castaway presence.
Science news from NBCNews.com
Among the most interesting features are the remains of small fires with birds and fish bones, giant clams that had been opened like a New England oyster, empty shells laid out as if to collect rain water, pieces of a pocket knife, pieces of rouge and the broken mirror from a woman's compact, and pre-war American bottles with melted bottoms that had once stood in a fire as if to boil drinking water.
Discovered near turtle remains on the island's remote southeast end, in an area called the Seven Site, where campsite and fire features were also found, the mysterious tiny finger bone is one of the most promising pieces.
Initially, Gillespie and his team did not pay much attention to the tiny fragment, assuming it belonged to the turtle. It was only when archaeologist Tom King catalogued the turtle bones that questions began to arise.
"We discovered that the turtle remains consisted only of parts of the carapace and plastron (the shell and underbelly). There were no limb bones. If whoever brought the turtle to the Seven Site didn't bring the legs, how did a phalanx get there?" said Gillespie.
Densely vegetated in shrubs known as Scaevola frutescens, the Seven Site site is where the partial skeleton of a castaway was found in 1940.
Recovered by British Colonial Service Officer Gerald Gallagher, human remains were described in a forensic report and attributed to an individual "more likely female than male," "more likely white than Polynesian or other Pacific Islander," "most likely between 5 feet 5 inches and 5 feet 9 inches in height." Unfortunately the bones have been lost.
Gillespie believes that many of the bones might have been carried off by crabs, suggesting an unmerciful end for Earhart.
However, parts of the skeleton not found in 1940 may still remain at the site.
"We know that none of the hand bones of the castaway were found in 1940. Could that bone be a human finger?" Gillespie said.
Forensic anthropologist Karen Ramey Burns, a specialist in the identification of human remains, examined the phalanx. She could not say with certainty that it was or was not human.
"Human and turtle phalanges are easily distinguishable when they are whole and complete. The problem with that bone is the fragmentation and disintegration. Many key morphological details are not visible," Burns told Discovery News.
The mystery will be soon solved when the finger bone is examined at the Molecular Science Laboratories at Oklahoma University in Norman, Okla.
"Whether or not the phalanx bone yields human DNA, there is a sufficient preponderance of circumstantial evidence to continue our research with hope and determination," Gillespie said.
© 2012 Discovery Channel