For the first time ever, an archaic fossil from our genus Homo has been discovered in Taiwan. Until now, ancient Asian hominins (that’s us and our ancestors) have mostly been found in China, Indonesia, and further west. That means this fossil, described in Nature Communications this week, will begin to fill a big geographical gap in the Asian fossil record.

While researchers aren't sure if it belonged to an unknown primitive species or one we know little about, it's starting to look like there were multiple evolutionary lineages in eastern Asia before anatomically modern humans arrived in the area around 40,000 years ago.

A team led by Chun-Hsiang Chang of Taiwan’s National Museum of Natural Science and Yousuke Kaifu of Japan’s National Museum of Nature and Science examined a fossil jawbone that was dredged from the bottom of the Penghu submarine channel 25 kilometers (15.5 miles) off the western shore of Taiwan by a fisherman's net. The area was part of the mainland during periods of low sea-level. The team was unable to date the jawbone directly, but it was discovered with the fossil of an extinct hyena, which indicated that it was younger than 450,000 years old. Most likely, the team believe, this Taiwanese archaic hominin—dubbed Penghu 1—lived recently, between 190,000 and 10,000 years ago. 

During the Pleistocene epoch that ended around 11,700 years ago, a range of ancient hominins had made their homes in Asia. Long-lived Homo erectus lived in Java and China, the “hobbit” Homo floresiensis occupied Indonesia, while Neanderthals and a mysterious human-relative called the Denisovans resided in parts of western Asia and Russia. This new robust lower jaw with large, primitive-looking teeth is similar in structure to a 400,000-year-old hominin fossil that likely belonged to Homo erectus, unearthed in Hexian in eastern China. However, "we need other skeletal parts to evaluate the degree of its uniqueness," Kaifu tells Live Science. "The question of species can be effectively discussed after those steps."

There’s a general trend that jaw and tooth sizes have reduced over time during Pleistocene Homo evolution, according to a news release. However, the new Taiwan mandible appears to be even more robust than chronologically older populations of Homo erectus from Java around 800,000 years ago as well as northern China from 750,000 to 400,000 years ago—suggesting a different evolutionary origin than that of what we consider classic Homo erectus.

And did they ever interact with our species? "The available evidence at least does not exclude the possibility that they survived until the appearance of Homo sapiens in the region,” Kaifu tells Discovery News. “And it is tempting to speculate about their possible contact.”