An undiscovered lineage of Homo sapiens may have existed, according to a bone found in France's Grotte du Renne cave. The bone was removed from the cave many years ago; it was a hip bone known as an ilium.

With Neanderthal remains, the cave is regarded as one of Europe's most remarkable Paleolithic locations. Archaeological studies have been conducted at the Grotte du Renne cave for many years, revealing strata of historical value. The cave's higher strata represent the period when anatomically modern humans (AMHs) lived there, while the lower layers represent the time when Neanderthals lived there. The team found a stratum in between that points to the coexistence of both hominid species.

One of the three bones that make up the human pelvis, the ilium, was found to belong to a newborn (AR-63) whose morphology required careful examination in order to compare it to that of 32 recently deceased people who died during the perinatal period (the period just after birth) and to two Neanderthals in order to explore their morphological variation.

The bone, which was found to be from a newborn child, was neither fully anatomically Neanderthal nor totally modern human. Researchers found that it had a different shape from modern infant bones and other Neanderthal baby bones. Because of this, it can be inferred that the bone belongs to a different lineage of Homo sapiens that differs just slightly from AMHs.

Our findings show that newborns with anatomically modern ilia differ from Neanderthal ilia in terms of morphology. Even though AR-63 slightly deviates from recent variability, it differs from Neanderthals in several ways. According to the researchers' report, "We propose that this is because it descended from an early modern human lineage, whose morphology differs slightly from that of current humans.

The research group also suggests that diffusion might have produced the stone tools discovered in the Châtelperronian techno-cultural complex layer of the cave. According to this hypothesis, Neanderthals adapted and maybe changed the tools to fit their particular needs after AMHs produced them. During the time that Neanderthals and AMHs coexisted in diverse regions of Europe, this hybridization may have taken place.

The study, which was published in the journal Scientific Reports, advances our knowledge of human evolution and the intricate relationships that have existed between various hominid species. Additional investigation at the Grotte du Renne cave and other archeological sites may reveal more information on the evolution of Homo sapiens.