Discovery of Ancient Fossils Suggest Early Human Diversity

The recent discovery of ancient fossils in northern Laos suggests that early modern humans were physically quite diverse, according to a new study.

In 2009 and late 2010, respectively, an ancient human skull and a jawbone were found a few meters away in a cave known as Tam Pa Ling in the Annamite Mountains of present-day Laos.

The skull is the oldest modern human fossil found in Southeast Asia, and pushed back the date of modern human migration through the region by as much as 20,000 years. It revealed that early humans who migrated to the islands and coasts of Southeast Asia after migrating out of Africa also traveled inland much earlier than previously thought, some 46,000 to 63,000 years ago.

Meanwhile, unlike the skull, the ancient jaw fossil - dating back to around the same age - is unique in that it has both modern and archaic human traits.

"In addition to being incredibly small in overall size, this jaw has a mixture of traits that combine typical modern human anatomy, such as the presence of a protruding chin, with traits that are more common of our archaic ancestors like Neanderthals - for example, very thick bone to hold the molars in place," University of Illinois anthropology professor Laura Shackelford, who led the study, explained in a press release.

Although remarkable, this combination of archaic and modern human traits is not unusual, according to researchers. Other ancient human fossils from Africa, Eastern Europe and China also exhibit this blend of characteristics.

"Some researchers have used these features as evidence that modern humans migrating into new regions must have interbred with the archaic populations already present in those regions," Shackelford said. "But a more productive way to look at this variation is to see it as we see people today - showing many traits along a continuum."

The findings, published in the journal PLOS ONE, add to the growing evidence that very early modern humans migrating and settling in eastern Asia were extremely diverse in their physical appearance.

This research also directly follows another study that suggests that the diversity in human body size that we see today emerged earlier than scientists previously thought.

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