A big-toothed human fossil discovered in the seafloor of Taiwan might be from a new primitive human species that is yet to be known.

The discovery of the fossil suggests that there were different families of extinct humans that lived side by side in Asia around 40,000 years ago before modern humans emerged. Some of the extinct human species named by scientists include the Neanderthals, Denisovans, Homo erectus (upright man) and the Homo floresiensis (Hobbit human) of Indonesia.

Now, another extinct human species might join that list.

The Taiwan fossil, dubbed Penghu 1, was found by a fisherman who sold the fossil to a local antique shop. A collector bought the fossil and gave it Taiwan's National Museum of Natural Sciences, according to Live Science.

The researchers examined the fossil and dated it between 10,000 and 190,000 years ago and said it might be from an adult due to its size. They were surprised to see that it has stronger and larger jaws compared to fossils unearthed from Java and Indonesia 11,700 years ago. They presume that it might be a new primitive species, but need to study further to prove that.

"We need other skeletal parts to evaluate the degree of its uniqueness," study co-author Yousuke Kaifu, a paleoanthropologist at Japan's National Museum of Nature and Science in Tokyo, told Live Science. "The question of species can be effectively discussed after those steps."

Another hypothesis is that Penghu 1 might be an interbreed with two extinct species since it quite resembles an ancient fossil found in Hexian, southern China.

"The available evidence at least does not exclude the possibility that they survived until the appearance of Homo sapiens in the region, and it is tempting to speculate about their possible contact," co-author Yousuke Kaifu, who is an associate professor in the Department of Biological Sciences at The University of Tokyo, told Discovery News.

Penghu 1 is the first Homo fossil found in Taiwan.

The study was published in the Jan. 27 issue of Nature Communications.