Last month, a small fragment of bone was discovered in Denisova Cave in Siberia which turned out to belong to a human hybrid named Denny, who had a Denisovan father and Neanderthal mother, and now four new hominin bones have been found inside this cave, leaving scientists to ponder whether these may be bones of Denny’s relatives.

According to Nature, the discovery of these four new bones has come about through further investigation to find more hominins, which researchers have been doing by wading through numerous animal bones. Archaeologist Samantha Brown of Germany’s Max Planck Institute for the Science of Human History (MPI-SHH) explained that “we get very, very excited” whenever there is a new discovery like these hominin bones.

In this case, the new hominin bones from Denisova Cave measure 26-millimeters in length, and Brown noted that no matter how many new bones like this are discovered, they are all equally important.

“They’re all so important — every one we find really contributes to our understanding of the record.”

While archaeologists usually don’t have too much difficulty in spotting the difference between animal bones and those of ancient humans, in cases where the remains are either very small or have crumbled, there is frequent difficulty in identifying the remains. According to the University of Oxford’s Tim Higham, small pieces of bones like these are oftentimes the most frequent discovery in places like Denisova Cave.

Researchers who uncovered an ancient-human hybrid last month - who had a Neanderthal mother and Denisovan father - have discovered more hominin bones from the same cave. https://t.co/uTqTCX1BP2 — Nature News & Comment (@NatureNews) September 21, 2018

Fortunately, molecular signals in these bone fragments are able to show archaeologists just which animal group they can be aligned with. By using zooarchaeology by mass spectrometry, also known as ZooMS, researchers are able to take collagen from bones and then finally break the collagen down into peptides. By looking at these peptides, researchers can then learn whether they belong to a hominin or some other animal.

It was through ZooMS that the hybrid Denny was first identified, and his bone was the first to be found to be a hominin by using this method. Since the discovery of the human hybrid with the Denisovan father and Neanderthal mother, archaeologists excitingly found four further hominin bones from Denisova Cave through this technique.

As to whether these bones may be relatives of Denny’s, Higham explained that it is absolutely possible.

“Anything’s possible. Nothing surprises me in this field anymore.”

Palaeoanthropologist Chris Stringer, from the Natural History Museum in London, admits that he would love to discover bones from a first-generation hybrid that springs from either a Denisovan or a Neanderthal and a modern human.

“What we’d love to have is a first-generation hybrid of a modern human and a Neanderthal, and a modern human and a Denisovan. Those could be there, waiting to be discovered.”

With the discovery of four new hominin bones from Denisova Cave in Siberia, it remains to be seen whether these bones will turn out to be relatives of the human hybrid Denny.