45,000-Year-Old Unknown Baby Bones of Present-Day Humans Discovered in Neanderthal Cave

　The bones of a 45,000-year-old baby, believed to be from a previously unknown early lineage of Homo sapiens, have been discovered in the Grotte du Renne in France.

　The cave has been found to contain numerous bones and artifacts that provide evidence of Neanderthal survival, but why were the bones of early homo sapiens found in this cave?

　Apparently, the baby bones were most likely of Neanderthal admixture.

Chaterperon culture found in the Rennes Cave

　The Rennes Cave (Rennes means reindeer in French), located in the Yonne department of the Burgundy-Franche-Comté region of France, is one of the most intriguing Paleolithic sites in Europe that has aroused the interest of experts.

　It was inhabited at the turn of the last millennium, when Homo sapiens replaced Neanderthals.

　A large number of stone tools representing the Chaterperon culture have been found in the cave.

　The Chaterperon culture was a Paleolithic culture that flourished in Western Europe between 36,000 and 32,000 years ago. In addition to stone tools, other artifacts such as ivory beads, animal teeth drilled into holes, and dwellings that may have been supported by mammoth tusks have been found.

photo by iStock

Until now, only Neanderthal remains have been unearthed in the Lenne Cave.

　However, the identity of the people who created this culture is unclear. Some say it was Neanderthal, while others believe it was our own culture.

　However, until now, the only bodies excavated in the Caves of Rennes have been those of Neanderthals. If so, is the Châteller-Peron culture still a Neanderthal culture?

　However, it has now been discovered that some of the bones found there belonged to early Homo sapiens babies.

Rennes Cave / image credit:WIKI commons

Bones of an Unknown Incipient Human Found in Neanderthal Cave

　The baby bones, thought to be from an early lineage of Homo sapiens, are from the ilium (part of the hip bone).

　When these bones were compared to those of two Neanderthal children and 32 modern human newborns, it is clear that the shape is very different from that of the Neanderthals.

　If anything, they are closer to those of modern humans. However, a closer look reveals that they are also different from modern humans' newborns.

The right iliac bone of a baby of an unknown present-day human (mirror image on the left), the left iliac bone of a Neanderthal child, and the left iliac bone of a Neanderthal child. c) Left iliac bone of a Neanderthal child / image credit:nature

Possible Neanderthal admixture.

　This suggests that the baby's bones may belong to a previously unknown early lineage of Homo sapiens.

　The discovery "changes our previous understanding of early human migration to Europe," said Mateja Heidinjak, an associate researcher at the Max Planck Institute for Evolutionary Anthropology in Germany, who led the study.

　The team says the unknown bone is most likely the child of Neanderthals, who lived in Eurasia at the turn of the Middle to Late Stone Age, between 41,000 and 45,000 years ago, when Neanderthals and modern humans migrated from Africa and lived in the same place. The Neanderthals lived in the same place as the present-day humans who migrated from Africa.

photo by iStock

　In the Bachokilo Cave in Bulgaria, three bones of a Homo sapiens male from about 45,000 years ago have been found to contain Neanderthal DNA.

　Perhaps this could be evidence that the present humans who migrated to Europe are more interbred with Neanderthals than previously thought.

　If so, then it may have been both Neanderthals and the present humans that fostered the Chaterperon culture.

　According to the research team, the Chaterperon culture may be a culture developed by two societies influencing each other.

　Incidentally, past research has also indicated that Homo sapiens and Neanderthals would have had a physical relationship. Ironically, this may have even been the cause of the Neanderthal's demise.

　The study was published in Scientific Reports (August 4, 2023).

References:Genome analysis reveals unknown ancient human migration in Europe / 45,000-Year-Old Baby In Neanderthal Cave Belonged To Unknown Human Lineage | IFLScience

Trilobites Survive Two Mass Extinctions and We Know Why. The Secret Lies in Their Body Structure

　The trilobite, a marine animal that is a symbol of paleontology, is an amazing creature that survived two mass extinctions and dominated the ancient seafloor for 300 million years.

　How could trilobites survive for so long in a time when the Earth's oxygen levels were so turbulent that they could change at any time?

　According to Spanish and American paleontologists, the clue lies in a variant of the trilobite, Aulacopleura koninckii.

　According to them, this trilobite was able to survive harsh environmental changes because it was able to cope with low oxygen levels by increasing the number of body segments.

A Strange Species of Trilobite with Different Number of Body Segments in Different Individuals

　During the period of about 300 million years, from the Cambrian period (about 520 million years ago) to the end of the Permian period, the ancient oceans were teeming with trilobites.

　This symbol of paleontology has lived on Earth much longer than dinosaurs, surviving even two mass extinctions.

　More than 20,000 species of trilobites are known, but their bodies have the same basic structure, divided into three parts: head, thorax, and tail plate. Most species also have a fixed number of body segments.

　Aulacopleura koninckii, however, is somewhat unique. It is unusual in that it has a third eye, but it is also unique in that the number of body segments varies from 18 to 22, depending on the individual.

Aulacopreura koninckii fossil / image credit:Nigel Hughes / University of California, Riverside.

　To realize the wonder of this, consider this.

　Humans have a fixed number of backbones, 24. This is "basically" the same for all people, no matter how short or tall they are. However, in Aulacopreura, the number varies from one individual to another.

　The question is why. Is there any advantage to having more body segments?

　A team of paleontologists from the Universidad Complutense de Madrid and the University of California, Riverside, is trying to answer that question.

Why can't more body segments be rounded to protect themselves?

　Modern-day sowbugs try to protect themselves by curling their bodies into a ball-like shape when exposed to danger. They keep their hard shells on the outside so that their weak point, their bellies, are not visible to their enemies.

　Trilobites can also defend themselves in the same way. In this ball-like posture, the tail snaps under the head to hide the soft parts.

　However, the 3D model created this time shows that in the case of Aulacopreura, the tail plate is too long to fit under the head, thanks to the increased body segments.

　The GIF below shows a young trilobite with the common body segments so that the underside of the head and tail plate fit snugly together when in a defensive posture. But this is not the case in Aulacopreura. Their tails stick out and they are unable to curl up completely.

image credit:Nigel Hughes - UCR

The Aulacopreura survived its harsh environment by increasing its body segments to allow for easier respiration.

　If this is the case, why would they increase their body segments at such a risk?

　What is noteworthy here is the "legs" that lie beneath the body segments. In fact, trilobite legs serve as gills. In other words, they are part of the respiratory apparatus.

　Therefore, the more body segments they have, the easier it is for them to breathe.

　Based on this, the research team believes that Aulacopreura may have been able to survive on the seafloor, where oxygen is scarce, by increasing the number of body segments.

　Dangerous predators cannot approach such an oxygen-poor environment. However, Aulacopreura may have been able to live there without running out of oxygen because of its extra gills.

　The trilobites may be teaching us that flexibility and the ability to adapt to the environment are necessary for survival in the harshest environments on earth.

References:Scientists discover how trilobites survived environmental change