Latest news with #Paleoanthropology
The Independent
09-07-2025
- Science
- The Independent
Two-million-year-old teeth unlock new secrets of ancient human relatives
For nearly a century, scientists have been puzzling over fossils from a strange and robust-looking distant relative of early humans: Paranthropus robustus. It walked upright, and was built for heavy chewing with relatively massive jaws, and huge teeth with thick dental enamel. It's thought to have lived between 2.25 million and 1.7 million years ago. Humans today have a diverse array of hominin distant relatives and ancestors from millions of years ago. The South African fossil record ranges from early hominins such as Australopithecus prometheus, A. africanus (Taung child), A. sediba and P. robustus, to early members of the genus Homo (H. erectus/ergaster, H. habilis), to later hominins such as H. naledi and Homo sapiens (humans). Fossils show how these early relatives evolved from as far back as A. africanus, 3.67 million years ago. They also document milestones in evolution, including the transition to walking on two legs, tool making and increased brain development. Ultimately, our species – Homo sapiens – appeared in South Africa 153,000 years ago. Fossils of P. robustus were first discovered in South Africa in 1938. But crucial questions remained. How much variation was there within the species? Were the size differences related to sex, or did they reflect the presence of multiple species? How was P. robustus related to the other hominins and early Homo? And what, genetically, made it distinct? Until now, answers to these questions have been elusive. As a team of African and European molecular science, chemistry and palaeoanthropology researchers, we wanted to find answers but we couldn't use ancient DNA to help us. Ancient DNA has been a game-changer in studying later hominins like Neanderthals and Denisovans but it doesn't survive well in Africa's climate because of its simple structure. We experienced a breakthrough when we decided to use palaeoproteomics – the analysis of ancient proteins. We extracted these from the enamel of the 2-million-year-old teeth of four P. robustus fossils from Swartkrans Cave in South Africa's Cradle of Humankind. Luckily, proteins that are millions of years old preserve well because they stick to teeth and bones and are not affected by the warm weather. One of these proteins tells us the biological sex of the fossils. This is how we found that two of the individuals were male and two were female. These findings open a new window into human evolution – one that could reshape how we interpret diversity in our early ancestors by providing some of the oldest human genetic data from Africa. From there, we can understand more about the relationships between the individuals and potentially even whether the fossils come from different species. More than one kind of Paranthropus? The protein sequences also revealed other subtle but potentially significant genetic differences. One standout difference was found in a gene which makes enamelin, a critical enamel-forming protein. We found that two of the individuals shared an amino acid with modern and early humans, chimpanzees and gorillas. The other two had an amino acid that among African great apes is, so far, unique to Paranthropus. What's even more interesting is that one of the individuals had both the distinct amino acids. This is the first documented time we can show heterozygosity (a state of having two different versions of a gene) in proteins that are 2 million years old. When studying proteins, specific mutations are thought to indicate different species. We were quite surprised to discover that what we initially thought was a mutation unique to Paranthropus robustus was actually variable within that group – some individuals had it while others did not. Again, this was the first time anyone had observed a protein mutation in ancient proteins (these mutations are usually observed in ancient DNA). We realised that instead of seeing a single, variable species, we might be looking at a complex evolutionary puzzle of individuals with different ancestries. This shows that combining analyses of morphology (the study of the form and structure of organisms) and the study of ancient proteins, we can create a clearer evolutionary picture of the relationships among these early hominin individuals. However, to confirm that P. robustus fossils have different ancestry, we will need to take samples of tooth enamel protein from more of their teeth. To do this, we plan to sustainably sample more P. robustus from other sites in South Africa where they've been found. Preserving Africa's fossil heritage Our team was careful to balance scientific innovation with the need to protect irreplaceable heritage. Fossils were sampled minimally, and all work followed South African regulations. We also involved local laboratories in the analysis. Many of the authors were from the African continent. They were instrumental in guiding the research agenda and approach from the early stages of the project. Doing this kind of high-end science on African fossils in Africa is an important step towards transformation and decolonisation of palaeontology. It builds local capacity and ensures that discoveries benefit the regions from which the fossils come. By combining data on molecules and morphology, our study offers a blueprint for future research – one that could clarify whether early hominins were more or less diverse than we've known.
The Independent
09-06-2025
- Health
- The Independent
Discovery of two-million-year-old teeth reveals secrets of ancient humans
The enamel that forms the outer layer of our teeth might seem like an unlikely place to find clues about evolution. But it tells us more than you'd think about the relationships between our fossil ancestors and relatives. In our new study, published in the Journal of Human Evolution, we highlight a different aspect of enamel. In fact, we highlight its absence. Specifically, we show that tiny, shallow pits in fossil teeth may not be signs of malnutrition or disease. Instead, they may carry surprising evolutionary significance. You might be wondering why this matters. Well, for people like me who try to figure out how humans evolved and how all our ancestors and relatives were related to each other, teeth are very important. And having a new marker to look out for on fossil teeth could give us a new tool to help fit together our family tree. Uniform, circular and shallow These pits were first identified in the South African species Paranthropus robustus, a close relative of our own genus Homo. They are highly consistent in shape and size: uniform, circular and shallow. Initially, we thought the pits might be unique to P. robustus. But our latest research shows this kind of pitting also occurs in other Paranthropus species in eastern Africa. We even found it in some Australopithecus individuals, a genus that may have given rise to both Homo and Paranthropus. The enamel pits have commonly been assumed to be defects resulting from stresses such as illness or malnutrition during childhood. However, their remarkable consistency across species, time and geography suggests these enamel pits may be something more interesting. The pitting is subtle, regularly spaced, and often clustered in specific regions of the tooth crown. It appears without any other signs of damage or abnormality. Two million years of evolution We looked at fossil teeth from hominins (humans and our closest extinct relatives) from the Omo Valley in Ethiopia, where we can see traces of more than two million years of human evolution, as well as comparisons with sites in southern Africa (Drimolen, Swartkrans and Kromdraai). The Omo collection includes teeth attributed to Paranthropus, Australopithecus and Homo, the three most recent and well-known hominin genera. This allowed us to track the telltale pitting across different branches of our evolutionary tree. What we found was unexpected. The uniform pitting appears regularly in both eastern and southern Africa Paranthropus, and also in the earliest eastern African Australopithecus teeth dating back around 3 million years. But among southern Africa Australopithecus and our own genus, Homo, the uniform pitting was notably absent. A defect … or just a trait? If the uniform pitting were caused by stress or disease, we might expect it to correlate with tooth size and enamel thickness, and to affect both front and back teeth. But it doesn't. What's more, stress-related defects typically form horizontal bands. They usually affect all teeth developing at the time of the stress, but this is not what we see with this pitting. We think this pitting probably has a developmental and genetic origin. It may have emerged as a byproduct of changes in how enamel was formed in these species. It might even have some unknown functional purpose. In any case, we suggest these uniform, circular pits should be viewed as a trait rather than a defect. A modern comparison Further support for the idea of a genetic origin comes from comparisons with a rare condition in humans today called amelogenesis imperfecta, which affects enamel formation. About one in 1,000 people today have amelogenesis imperfecta. By contrast, the uniform pitting we have seen appears in up to half of Paranthropus individuals. Although it likely has a genetic basis, we argue the even pitting is too common to be considered a harmful disorder. What's more, it persisted at similar frequencies for millions of years. A new evolutionary marker If this uniform pitting really does have a genetic origin, we may be able to use it to trace evolutionary relationships. We already use subtle tooth features such as enamel thickness, cusp shape, and wear patterns to help identify species. The uniform pitting may be an additional diagnostic tool. For example, our findings support the idea that Paranthropus is a 'monophyletic group', meaning all its species descend from a (relatively) recent common ancestor, rather than evolving seperatly from different Australopithecus taxa. And we did not find this pitting in the southern Africa species Australopithecus africanus, despite a large sample of more than 500 teeth. However, it does appear in the earliest Omo Australopithecus specimens. So perhaps the pitting could also help pinpoint from where Paranthropus branched off on its own evolutionary path. An intriguing case One especially intriguing case is Homo floresiensis, the so-called 'hobbit' species from Indonesia. Based on published images, their teeth appear to show similar pitting. If confirmed, this could suggest an evolutionary history more closely tied to earlier Australopithecus species than to Homo. However, H. floresiensis also shows potential skeletal and dental pathologies, so more research is needed before drawing such conclusions. More research is also needed to fully understand the processes behind the uniform pitting before it can be used routinely in taxonomic work. But our research shows it is likely a heritable characteristic, one not found in any living primates studied to date, nor in our own genus Homo (rare cases of amelogenesis imperfecta aside). As such, it offers an exciting new tool for exploring evolutionary relationships among fossil hominins.
The Sun
06-05-2025
- Science
- The Sun
Jaw of lost human cousin that's NOT Neanderthal found at bottom of sea with teeth intact & may only be 10,000 years old
THE mystery of a robust ancient jawbone with large teeth and what species it belongs to has baffled scientists since it was dredged up in the 2000s. But in a new study, scientists say the bone may belong to one of the most elusive of human ancestors - Denisovans. 4 4 Paleoanthropologists have long debated whether the bone came from a Homo erectus, an archaic Homo sapiens, or a Denisovan. The bone, known scientifically as Penghu 1, was netted by a fisherman from the floor of the Penghu Channel, about 15.5 miles off the west coast of Taiwan. A technique that analyses the amino acids and proteins in bones found that the individual it belonged to was male, and most similar to Denisovans. "The same technique can and is being used to study other hominin fossils to determine whether they too are Denisovans, Neanderthals or other hominin populations," study co-author Frido Welker, a molecular anthropologist at the University of Copenhagen, told Live Science. Denisovans are a long-extinct human relative who lived at the same time as Neanderthals and Homo sapiens. The species roamed Asia, from the chilly corners of Siberia to humid areas like Taiwan, during the Pleistocene era - between 2.6 million to 11,700 years ago. "It is now clear that two contrasting hominin groups – small-toothed Neanderthals with tall but gracile mandibles and large-toothed Denisovans with low but robust mandibles coexisted during the late Middle to early Late Pleistocene of Eurasia," the researchers wrote in the study published in Science. Denisovan fossils remain elusive, so the entire species is shrouded in mystery. Unlike Neanderthals, whose bones have been found throughout Europe and western Asia for more than a century, Denisovans are mostly known from DNA. Face of oldest direct human ancestor, which lived 3.8million years ago, revealed by scientists Only a handful of fossils have ever been found, most of which come from Denisova Cave in Siberia. Experts have struggled to identify new Denisovan skeletons without a large collection of fossils to compare to. Little is known, therefore, about where Denisovans lived and how they are related to humans. Animal bones found alongside the Penghu 1 suggest it may also be the youngest fragment of a Denisovan ever discovered - trumping the current title holder by 30,000 years. Researchers were unable to use traditional methods such as carbon-14 or uranium dating on the bones because it was waterlogged for so long. DNA extraction attempts also failed. However, Welker explained that animal bones found with the jawbone suggest two age ranges - either 10,000 to 70,000 years ago or 130,000 to 190,000 years ago. "If the specimen falls into the younger age range, it could potentially be the youngest Denisovan found to date," he said. Currently, the youngest Denisovan fossil, found on the Tibetan Plateau, is 40,000 years old. 4
