Archaeologists have recovered 140,000-year-old Homo erectus bones from an extinct human species on the ocean floor in Southeast Asia, Live Science reported, citing four separate studies published last week in the journal Quaternary Environments and Human.

The bones were found amongst roughly 6,000 animal fossils which were recovered during a construction project off the Indonesian island of Java. It is the first time fossils have been located in the submerged areas of the Indonesian archipelago, which during the last ice age connected Java to Asia's mainland. The land, known as "drowned Sundaland," existed about 140,000 years ago.

Then, the water teemed with marine life such as river sharks, hippos, fish, and turtles, while the land was occupied by elephants, water buffalo, and the Stegodon, an elephant-like animal. The presence of Homo erectus bones on the site shows researchers that ancient human ancestors were taking ample advantage of the fertile hunting grounds. The remains suggest that Homo erectus was hunting for large game such as cow-like bovids, a strategy which is more commonly associated with relatively modern humans.

"The Madura Strait hominins may have developed this hunting strategy independently," lead author Harold Berghuis told Live Science. "But the other possibility is that we are looking at a kind of cultural exchange."

Based on fossil evidence, Berghuis and his team determined that Homo erectus survived on Java until they went extinct roughly 117,000 to 108,000 years ago. Homo sapiens, meanwhile, arrived in Southeast Asia about 77,000 years ago. Berghuis admitted that he always "dreamed" of finding a fossil belonging to a hominid species, but it wasn't until the final day of his excavation that he discovered one.

"It was already getting dark and I sat down to enjoy [the] sunset," he recalled. "And then, right beside me, lay this fossil that reminded me so much of the only Dutch Neanderthal. This is a well-known fossil in my country, dredged from the North Sea."

Berghuis examined the fossil, a skull fragment, and found that its brow ridge resembled that of Neanderthals and other ancient human species. He and his team later determined that the fragment belonged to an adult or adolescent Homo erectus. Another skull fragment was found, and although it was found to belong to an adolescent member of the society, researchers could not determine their cause of death. In total, Berghuis and his team analyzed 6,372 recovered fossils belonging to 36 separate species.