WASHINGTON (Reuters) - Scientists examining the jawbone of a saber-toothed, mammal-like beast that prowled Tanzania 255 million years ago have come across a remarkable fossil rarity: one of the oldest-known tumors.

A histological thin section of the gorgonopsid lower jaw of a saber-tooth mammal-like beast that prowled Tanzania 255 million years ago, taken near the top of the canine root showing the cluster of small circles, indicative of compound odontoma. Courtesy of Chistian Sidor/Megan Whitney/Handout via REUTERS

University of Washington researchers on Thursday described a benign tumor composed of miniature tooth-like structures they found embedded next to the root of the creature’s enlarged canine tooth while studying an unrelated aspect of the jaw.

The animal was a member of an extinct group of four-legged carnivores called gorgonopsians that mixed mammal-like and reptile-like traits. They reached up to 10 feet (3 meters) long and appeared early in the evolutionary lineage that led to mammals. The jawbone came from one of the smaller gorgonopsian species.

Gorgonopsians were among the top predators of their time, thriving from about 270 million to 252 million years ago when they were wiped out during Earth’s worst mass extinction at the end of the Permian Period. Their demise came roughly 20 million years before the first dinosaurs.

When the researchers sliced into the mandible fossil from Tanzania’s Ruhuhu Valley, they found a benign dental tumor called a compound odontoma that grows within the gums or other jaw soft tissues. When people get one, surgery is sometimes used to remove it.

“There was no indication that there was a tumor in this jaw. It looked normal before we cut it open. It was pure luck that we found the tumor,” University of Washington paleobiologist Megan Whitney said.

Until now, this type of tumor was known only in mammals, including some Ice Age fossils tens of thousands of years old. The new discovery shows such a tumor existed in mammal ancestors that lived tens of millions of years before the first mammals appeared.

Tumors, malignant and benign, typically involve soft tissue, and rarely fossilize.

“Ancient tumors generally need to affect hard parts such as bones and teeth in order to be preserved in the fossil record,” University of Washington paleobiologist Christian Sidor added.

This tumor included hard enamel and dentin.

Few tumor fossils are older. A 300-million-year-old fish was found with a tumor and a 350-million-year-old armored fish has an apparent tumor that some dispute.

“Fossils allow us to understand the evolution of diseases in deep time and have the potential to provide clues as to the causes of diseases that afflict humans,” Whitney said.

The research appears in the Journal of the American Medical Association Oncology. </s> University of Washington researchers on Thursday described a benign tumor composed of miniature tooth-like structures they found embedded next to the root of the creature's enlarged canine tooth while studying an unrelated aspect of the jaw.

The animal was a member of an extinct group of four-legged carnivores called gorgonopsians that mixed mammal-like and reptile-like traits. They reached up to 10 feet (3 meters) long and appeared early in the evolutionary lineage that led to mammals. The jawbone came from one of the smaller gorgonopsian species.

Gorgonopsians were among the top predators of their time, thriving from about 270 million to 252 million years ago when they were wiped out during Earth's worst mass extinction at the end of the Permian Period. Their demise came roughly 20 million years before the first dinosaurs.

When the researchers sliced into the mandible fossil from Tanzania's Ruhuhu Valley, they found a benign dental tumor called a compound odontoma that grows within the gums or other jaw soft tissues. When people get one, surgery is sometimes used to remove it.

"There was no indication that there was a tumor in this jaw. It looked normal before we cut it open. It was pure luck that we found the tumor," University of Washington paleobiologist Megan Whitney said.

Until now, this type of tumor was known only in mammals, including some Ice Age fossils tens of thousands of years old. The new discovery shows such a tumor existed in mammal ancestors that lived tens of millions of years before the first mammals appeared.

"Ancient tumors generally need to affect hard parts such as bones and teeth in order to be preserved in the fossil record," University of Washington paleobiologist Christian Sidor added.

Few tumor fossils are older. A 300-million-year-old fish was found with a tumor and a 350-million-year-old armored fish has an apparent tumor that some dispute.

"Fossils allow us to understand the evolution of diseases in deep time and have the potential to provide clues as to the causes of diseases that afflict humans," Whitney said.

The research appears in the Journal of the American Medical Association Oncology. </s> A super-thin slice of the ancient gorgonopsid lower jaw fossil revealed the compound odontoma. Photo by Megan Whitney/Christian Sidor/University of Washington

SEATTLE, Dec. 8 (UPI) -- Researchers from the University of Washington have discovered the earliest evidence of a compound odontoma, a benign tumor made up of tiny tooth-like structures typically found growing in the gums.

Odontoma -- which are painful and typically surgically removed from the mouths of humans. -- are well known among mammals. Until now, however, the earliest evidence of the benign tumor came from ice age fossils.

The newest odontoma evidence was discovered in the 255 million-year-old lower jaw fossil of a gorgonopsid, a mammal predecessor. Scientists recalled the discovery in a new paper, published this week in the Journal of the American Medical Association Oncology.

"Until now, the earliest known occurrence of this tumor was about one million years ago, in fossil mammals," Judy Skog, program director in the National Science Foundation's Division of Earth Sciences, said in a news release. "The discovery suggests that the suspected cause of an odontoma isn't tied solely to traits in modern species, as had been thought."

Gorgonopsians fit beneath the umbrella of a larger group of animals called synapsids. Today, the only living synapsids are mammals.

"To understand when and how our mammalian features evolved, we have to study fossils of synapsids like the gorgonopsians," explained Megan Whitney, lead author and UW biology graduate student.

Synapsids are sometimes called reptile-mammals, as they posses features unique to both animal groups. Whitney and fellow graduate student Larry Mose were trying to study the similarities among the teeth of gorgonopsians, reptiles and mammals when they discovered the toothy mass.

"At first we didn't know what to make of it," said Whitney. "But after some investigation we realized this gorgonopsian had what looks like a textbook compound odontoma." </s> Distinctive mammalian traits, such as endothermy (warm-bloodedness), a muscular diaphragm, large brain size, fur, and a highly specialized dentition, including diphyodonty, prismatic enamel, and a functionally regionalized tooth row (heterodonty), are the product of more than 300 million years of evolutionary divergence from reptiles and other tetrapods.1 The sequence and timing of these adaptations are captured in the fossil record of premammalian synapsids (Figure 1), but an understanding of the evolutionary context of mammalian disease, including cancer, remains elusive. We report the first instance, to our knowledge, of a tumor in a 255-million-year-old mammalian forebear and comment on the implications for establishing the phylogenetic and physiological conditions under which such pathologic features first arose.

Methods

Fossil thin-sectioning protocol is well established, and the resultant data are an increasingly significant tool in understanding the physiologic mechanisms and evolution of extinct animals.2 Despite the relative abundance of gorgonopsian fossils, few histologic observations have been made of their jaws. The anterior right dentary of a gorgonopsian was prepared by embedding the specimen in a clear polyester resin. Thin (approximately 2 cm) wafers of the embedded specimen were cut using a precision slow-speed saw and then mounted onto glass slides. Sections were ground to a final thickness of approximately 100 µm using a variable-speed grinder and polisher. The root of the lower canine and associated pathological tissues were examined and imaged under regular and cross-polarized light.

Institutional review board approval was waived for this study because no live specimens were used.

Results

Histologic sections present ectopic toothlike structures that were not apparent from the external morphologic features of the mandible (Figure 2). The lesions are located adjacent to the labial edge of the functional canine root, and each resembles a miniature tooth with an internal cavity, dentine as evidenced by the presence of tubules, and a thin outer covering of enamel. Up to 8 lesions of varying diameter (approximately 0.3-3.9 mm) can be observed on an individual slide, with consecutive slides revealing that their shape and arrangement change along the apical-cervical axis of the canine root. Apically, the lesions are circular and cluster around the mesial edge of the canine root. Incursion of the lesions into the root of the canine coincides with the loss of cementum and dentine in the latter. Moving cervically, the masses erode even further into the functional tooth root. Midroot, some of the lesions lose their circular cross-sectional shape and become more amorphous, although continuing to maintain similar tissues and tissue boundaries. Near the cervical region of the canine root, the lesions slightly retreat from their incursion and penetrate further into the bone of the jaw. At this cervical end, the pathologic features return to a circular cross-section and cluster together.

Discussion

Histologic examination reveals that this ancient condition closely resembles compound odontoma.3 In humans, compound odontoma is characterized by fully differentiated enamel and dentine organized into miniature teeth that can cause resorption of the functional tooth root,3 all of which mirror our paleohistologic observations. Odontomas are the most common odontogenic tumors,3 but their cause is poorly understood. Interestingly, odontomas have been reported in a handful of fossil mammals up to a few million years old4,5 but were previously unknown in deep premammalian evolutionary history. Recognition of odontoma in such a distant relative of humans suggests that this condition is unlikely related to characteristics of mammalian dentition or physiologic features but rather evolved much earlier in vertebrate evolution. More broadly, the fossil record has the potential to provide an evolutionary context for modern pathologic features6 by disassociating traits that co-occur in modern species.

Back to top Article Information

Corresponding Author: Megan Whitney, MSc, Department of Biology, University of Washington, PO Box 351800, Seattle, WA 98195 (megwhit@uw.edu).

Published Online: December 8, 2016. doi:10.1001/jamaoncol.2016.5417

Author Contributions: Ms Whitney and Dr Sidor had full access to all the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.

Study concept and design: Whitney, Sidor.

Acquisition, analysis, or interpretation of data: All authors.

Drafting of the manuscript: All authors.

Critical revision of the manuscript for important intellectual content: All authors.

Obtained funding: Sidor.

Administrative, technical, or material support: Sidor.

Study supervision: Sidor.

Conflict of Interest Disclosures: None reported.

Funding/Support: This research was supported by grant EAR 1337569 from the National Science Foundation (Dr Sidor) and a University of Washington Mary Gates Research Fellowship (Mr Mose).

Role of the Funder/Sponsor: The funding sources had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and the decision to submit the manuscript for publication.

Disclaimer: The views in this article are those of the authors and do not represent official positions of the University of Washington. </s> Researchers have claimed that a broken skull found from a cave in Greece is the oldest modern human fossil ever found outside Africa, The Guardian reported.

The partial skull was discovered in the Apidima cave on the Mani peninsula in southern Greece and is estimated to be at least 2,10,000 years old, becoming the oldest known modern human fossil in Europe.

A second skull found in the Grecian cave belonged to a Neanderthal who lived 1,70,000 years ago, according to a new study published in Nature. Researchers believe that finding both skulls in the same cave illustrate that early humans migrated in multiple stages out of Africa rather than a single event, CNN reported. Southeast Europe is considered to be a major migration corridor out of Africa.

“Our results indicate that an early dispersal of Homo sapiens out of Africa occurred earlier than previously believed, before 2,00,000 years ago,” said Katerina Harvati, the director of paleoanthropology at the University of Tübingen in Germany. “We’re seeing evidence for human dispersals that are not just limited to one major exodus out of Africa.” Harvati is among the authors of the study.

The skulls were discovered in 1978 when the National and Kapodistrian University of Athens was conducting research, according to CNN. They were found in a block of broken fragments of rock and fossil cemented together and wedged between the walls of the Apidima Cave.

The skulls were stored in a museum in Athens, but received little attention as they were damaged and incomplete. The second skull, which retains a face, was studied the most and identified as Neanderthal, according to The Guardian. The first skull, consisting only of the back of the skull, was largely ignored,

Harvati and her colleagues took CT scans of the fossils and created virtual 3D reconstructions. The models were then compared with skulls from various ancient Homo sapiens, Neanderthals and modern humans. The researchers found that the partial skull closely matched that of a modern human. </s> In the late 1970s, two fossilized human crania were discovered in the Apidima cave in southern Greece. Researchers were somewhat befuddled by the remains; they were incomplete and distorted, for one, and had been found without any archaeological context, like stone tools. But because the skulls had been encased in a single block of stone, experts assumed they were the same age and of the same species—possibly Neanderthals.

Now, a bombshell study published in Nature posits that one of the crania, dubbed “Apidima 1,” in fact belonged to an early modern human that lived 210,000 years ago. The report has been met with skepticism by some experts, but if its conclusions are correct, Apidima 1 represents the oldest Homo sapiens fossil in Europe by some 160,000 years.

For the past 40-odd years, Apidima 1 and the other cranium, “Apidima 2,” have been held at the University of Athen’s Museum of Anthropology. Scientists there recently reached out to Katerina Harvati, director of paleoanthropology at the Eberhard Karls University of Tübingen, to see if she would be interested in taking a fresh look at the skulls, reports Maya Wei-Haas of National Geographic.

Harvati and a team of colleagues analyzed the remains using cutting-edge techniques. First, they CT-scanned both fossils and generated 3D reconstructions in an attempt to get a better picture of what the skulls looked like. Though it had been badly damaged over the centuries, Apidima 2 is the more complete fossil; it includes the facial region, and the new models affirmed previous research indicating that the specimen belonged to a Neanderthal. Apidima 1 consists of just the back of the crania, but the team’s reconstructions and analyses revealed something surprising: the fossil’s features were consistent not with those of Neanderthals, but with those of modern humans.

Tellingly, the Apidima 1 fossil lacks a “chignon,” the distinctive bulge at the back of the skull that is characteristic of Neanderthals. The posterior of the skull is also rounded, which “is considered to be a uniquely modern human feature that evolved relatively late,” Harvati tells Ed Yong of the Atlantic. And when the team dated the fossils by analyzing the radioactive decay of trace uranium in the specimens, they got another shock. Apidima 2 was found to be around 170,000 years old, which is consistent with the age of other Neanderthal fossils in Europe. But Apidima 1 was dated to 210,000 years ago, making it by far the oldest Homo sapiens fossil found on the continent.

“I couldn’t believe it at first,” Harvati tells Yong, “but all the analyses we conducted gave the same result.”

This discovery may add a wrinkle to the commonly accepted timeline of modern humans’ dispersal from Africa and arrival in Europe. It is widely accepted that our species evolved in Africa—the oldest known Homo sapiens fossils were found in Morocco and date back 315,000 years ago—and first ventured out of the continent between 70,000 and 60,000 years ago. All the while, Neanderthals were evolving in Europe, genetically isolated from other hominid species. Homo sapiens are thought to have arrived on the scene around 45,000 years ago, interbreeding with Neanderthals and eventually emerging as the dominant species.

But the authors of the new study contend that their findings “support multiple dispersals of early modern humans out of Africa.” Given that no similarly old human fossils have been found in Europe, it is possible that Apidima 1 belonged to a population that could not compete with the continent’s resident Neanderthals, paleoanthropologist Eric Delson writes in a Nature article about the new paper. “Perhaps one or more times, the two species replaced each other as the main hominin group present in this region,” Delson adds.

There have been signs that other “failed” human groups were migrating out of Africa at a relatively early date. Last year, for instance, researchers announced the discovery of a 175,000 year old jawbone in Israel, which appeared to belong to a member of Homo sapiens. At the time, the specimen was hailed as “by far the oldest human fossil ever uncovered outside Africa.” Apidima 1 is even older, and “indicates that early modern humans dispersed out of Africa starting much earlier, and reaching much further, than previously thought,” the study authors write.

But not all experts are convinced. Melanie Lee Chang, an evolutionary biologist at Portland State University, tells Joel Achenbach of the Washington Post that Apidima 1 is an “outlier,” and that she is “not willing to sign on to all of [the researchers’] conclusions here.” And Juan Luis Arsuaga, a paleoanthropologist from the University of Madrid, tells National Goegraphic’s Wei-Haas that he is “astonished” by the team’s interpretation of the fossils. Arsuaga was part of a 2017 study that dated Apidima 2 to approximately 160,000 years ago.

“I cannot see anything suggesting that [Apidima 1] belongs to the sapiens lineage,” he says.

Even Chris Stringer, a co-author of the study and paleoanthropologist at London’s Natural History Museum, acknowledges in an email to Achenbach that the paper represents “challenging new find.”

“We don’t have the frontal bone, browridge, face, teeth or chin region, any of which could have been less ‘modern’ in form,” Stringer says, though he notes that Apidima 1 “certainly shows the high and rounded back to the skull that is typical only of H. sapiens.”

DNA analysis would certainly lend some clarity to this debate, but it isn’t always possible to extract DNA from ancient, decaying specimens. According to Delson, palaeoproteomics, or the analysis of ancient proteins preserved in fossils, might be the next best option; this technique was recently used to identify a fossil from a Siberian cave as belonging to a Denisovan.

“Proteins are composed of a sequence of amino acids, and this sequence is coded for in the genome,” Frido Welker, the author of that study explained at the time. “[A]ncient proteins survive longer than DNA, making them a suitable molecular alternative for evolutionary analyses in cases where ancient DNA does not survive.”

But for now, Delson maintains, studies like the one by Harvati and her team “provide our best handle on the complex history of our species and our close relatives as these populations dispersed out of Africa—from the early, unsuccessful dispersals to the migrations that eventually succeeded.” </s> A hominid species may have lived in what is now California as long as 130,000 years ago — turning the record of early humans in North America upside down, according to a provocative paper published Wednesday in the journal Nature.

Scientists say an archaeological site in San Diego County shows tell-tale evidence of human behavior: specifically, bones and teeth of an elephant-like mastodon that appear to have been smashed with rocks. Uranium-thorium dating puts the bones at 130,000 years old, researchers said.

“What makes sense to us, even though it’s out there, is the hypothesis that humans brought these rocks to the site, and that humans used these rocks to break bone,” lead researcher and paleontologist Thomas Deméré of the San Diego Natural History Museum said in a statement.

Combining insights from paleontology and archaeology, Deméré and his team believe that early humans used this site to break up mastodon bones.

“The bones and several teeth show clear signs of having been deliberately broken by humans with manual dexterity and experiential knowledge,” Dr. Steve Holen, director of research at the Center for American Paleolithic Research, said in a statement.

The team found no traces of human remain at the site.

If confirmed, the new signs of human activity would be 100,000 years earlier than the “broadly accepted date for the first occupation of the Americas,” said researcher John McNabb of the University of Southhampton.

“The CM (Cerutti Mastodon) site is, to our knowledge, the oldest in situ, well-documented archaeological site in North America and, as such, substantially revises the timing of arrival of Homo into the Americas,” researchers wrote.

The first Americans: Clues to an ancient migration by on YouTube

The southern California site was first discovered during routine construction work to expand a freeway in 1992. Brought in to excavate, paleontologists found hammerstones, stone anvils, and the skeleton of a single mastodon. They placed the site within the early late Pleistocene epoch, but struggled to put a precise date on it at the time.

Now, the researchers are calling for further archaeological investigation to help expand our knowledge of the earliest human presence on the continent.

“Until we find a skeleton, at this site or at a site of a comparable age in the Americas, it’s all open to speculation, and we just don’t know,” McNabb said. </s> Ancient tooth fossils found in Europe may represent a new chapter in the human origin story.

The fossils, which date back more than 7 million years, belonged to an ape-like creature named Graecopithecus freybergi, researchers hypothesized in two new papers. A lower jaw bone and upper premolar were found in Greece and Bulgaria, respectively.

The findings suggest that humans split off from great apes several hundred thousand years earlier than previously thought, according to research published this week in the journal PLOS ONE.

If true, that would mean the first pre-humans developed in Mediterranean Europe — not in sub-Saharan Africa, which is widely considered the birthplace of early humans.

Still, the studies alone aren't enough to rewrite the story of humankind's beginnings.

Outside experts say they are deeply skeptical of the research. They argue the evidence is still too thin to upend decades' worth of fossil and genetic discoveries in Africa.

"The new claims about Graecopithecus need to be treated with a good deal of caution," Darren Curnoe, an associate professor at the University of New South Wales Sydney, wrote in an opinion piece for The Conversation.

"I'm open to the idea that early humans lived beyond Africa, but Graecopithecus falls well short of proving it," he said.

Many researchers assume that human and ape lineages diverged some 5 to 7 million years ago. Charles Darwin initially surmised that humans evolved in Africa, because that's the home of humans' closest ape relatives, chimpanzees and gorillas.

The oldest potential pre-human, a 6- to 7-million-year old named Sahelanthropus, was found in present-day Chad. But the Graecopithecus — nicknamed "El Graeco" — may be even older, according to an international team of researchers.

The Bulgarian premolar dates back some 7.24 million years ago, and the Greek jaw fossil dates back 7.175 million years ago, they said.

The teams were led by Madelaine Böhme from the Senckenberg Center for Human Evolution and Palaeoenvironment in Germany and Nikolai Spassov from the Bulgarian Academy of Sciences.

Researchers used computer tomography to take cross-sections of the two fossils. They found the roots of premolars were widely fused, a feature that is characteristic of modern humans, early humans, and several pre-human ancestors. Great apes, by contrast, have two or three separate and diverging premolar roots.

The lower jaw fossil also had additional dental root features that suggested its owner belonged to the pre-human lineage.

"We were surprised by our results, as pre-humans were previously known only from sub-Saharan Africa," Jochen Fuss, a doctoral student at the University of Tübingen in Germany who conducted this part of the study, said in a press release.

But Curnoe, the skeptical professor, said studying just one feature — dental roots — on a small number of fossils wasn't enough to prove El Graeco was on Team Human, not Team Ape.

"While our place in the tree of life is now well established — chimpanzees being our closest relatives — the beginning of the human line millions of years ago continues to be shrouded in mystery," he noted. </s> A few fossilized bones from the back of a skull may prove that our species spread into Eurasia much earlier than previously suspected. A new study of the partial skull, which was excavated from Apidima Cave in southern Greece 40 years ago, suggests that the fossil is Homo sapiens and that it’s roughly 210,000 years old. That makes it the oldest member of our species ever found outside of Africa.

The fossil, known as Apidima 1, is likely the remains of a member of an early wave of humans who spread into Eurasia. Based on genetic studies and the fossil record, anthropologists think these early pioneers failed to gain a successful foothold and ended up being replaced by Neanderthals (for a while, at least).

A new look at an old skull

Archaeologists excavating Apidima Cave in the 1970s found the partial skull lodged in a chunk of breccia, just a few centimeters away from a broken and distorted Neanderthal skull called Apidima 2, which dated to 170,000 years old. For decades, archaeologists assumed Apidima 1 was a Neanderthal, too. But Eberhard Karls University of Tübingen paleoanthropologist Katerina Harvati and her colleagues recently took a second look at Apidima 1. The partial skull included just the right pieces of bone to reveal something important: the skull was rounded at the back—a feature that’s unique to Homo sapiens.

And according to uranium-series dating, the skull could be as much as 210,000 years old. That’s a few thousand years older than Misliya-1, the previous holder of the Oldest Human Outside Africa title (at 194,000 to 177,000 years old). It fits pretty well with the growing pile of evidence that the earliest humans (like many of our hominin relatives) spread farther and faster than anthropologists have previously given them credit for.

“We never imagined anything like this for this area, but in hindsight, it's not actually a very surprising result,” said Harvati. Evidence of Homo sapiens in Israel dates to at least 177,000 years ago, and southeastern Europe was probably an important route from the Levant into Europe and parts of Asia. “It’s not actually so unimaginable that some of these populations would have expanded their range to reach southeast Europe,” said Harvati.

Harvati and her colleagues CT scanned the bone so they could digitally reconstruct the broken, distorted pieces of skull, then performed statistical analysis of how its dimensions and shape compared to other fossil skulls from humans, Neanderthals, and even older hominins. Consistently, the analysis suggested that Apidima 1 was human.

But that’s not to say there won’t be some debate, especially about the fossil’s age. Most calcium carbonate rocks, minerals that precipitate out of flowing water, also contain some uranium. By looking at the ratios of uranium isotopes in a rock or fossil, geochemists can date when it formed. In this case, Harvati and her colleagues came up with several potential dates, some of which are much earlier than 210,000 years ago. Geochemist Rainer Grün of Griffith University says that those earlier dates are probably the product of uranium from the breccia deposit—where the partial skull ended up after being washed through the cave sometime after death—leaching into the fossil bone over time.

It’s pretty common for paleoanthropologists to re-analyze, re-date, and argue about fossils, especially when they’re the centerpiece of a superlative claim like this one. Although Apidima 1 isn’t that much older than Misliya-1, it’s the oldest Homo sapiens fossil in Europe by a margin of about 150,000 years, and that’s a significant claim. It’s probably reasonable to expect to hear more about Apidima 1 in the future, one way or another.

“It's a fantastic coincidence that you have two skulls together, 30cm (11.8 inches) apart,” said Grün. “In all of Greece, you have one more skull—that’s it—in that timeframe. It's a wonder of nature that you find the two together.” The human and the Neanderthal probably died around 40,000 years apart, in different places in the labyrinthine Apidima cave system. At some point, water flowing through the cave washed both skulls down into the same chamber. The uranium isotope ratios in Apidima 1 were different from the surrounding rock, suggesting that they started out in different places and formed at different times. The Neanderthal’s signature, meanwhile, was more similar to the surrounding breccia.

The result may offer an uncanny fossil snapshot of our complicated history with the Neanderthals. Genetic studies of Neanderthal DNA have suggested that those living in Europe sometime after 270,000 years ago met early waves of human migrants. Those encounters left traces of human alleles in Neanderthal genomes, in the same way that Neanderthals, in turn, left traces in our modern genomes. Harvati says that Apidima 1 may be part of that long-lost group of humans who mingled with Neanderthals and then, apparently, disappeared.

Genetic evidence suggests that non-African populations today all descend from the wave of humans who dispersed into the rest of the world between 70,000 and 50,000 years ago. Older waves of dispersal, humans who left tools and bones at sites like Misliya, Qafzeh, and Skhul Caves in Israel, seem to have faded away without leaving descendants behind. And at several of those sites in Israel, the fossil record contains Homo sapiens remains in earlier layers, followed by Neanderthals in later ones. That suggests that somehow, Neanderthals temporarily replaced humans living in the area. Something similar likely happened to the first wave (or waves) of humans in Europe, as well.

“I would suspect that these were relatively small populations that made it all the way to Greece—for example, probably smaller than the source population in Israel, and of course ultimately from Africa,” said Harvati. Smaller groups would have been more vulnerable to local extinction. The first Homo sapiens may have arrived in the Levant and Europe to find Neanderthals already living there, and they co-existed for awhile before somehow dying out. Or perhaps the humans moved into unoccupied territory, only to later be edged out or absorbed by groups of Neanderthals migrating into the same region.

But for now, paleoanthropologists don’t know exactly what transpired between the two species, or why—just as they don’t know exactly why the Neanderthals went extinct around 40,000 years ago. They need more evidence to tackle those questions and to understand exactly when, where, and why our species began to explore the world outside Africa. That means looking for more fossils, of course, but it also means prying more information out of the fossil record that’s already sitting in museums and university collections.

“I think the questions that will be asked now are what caused this early dispersal? What enabled it in terms of land bridges or particular routes of dispersal? Were there any technological advances that enabled such a far geographic intrusion into Europe?” said Harvati. “And also why did they die out?”

Harvati and her colleagues plan to try to find ancient DNA and proteins in the skulls from Apidima Cave, though she admits she’s not optimistic because the fossils are so old and the site is in such a warm region. Heat seldom bodes well for DNA preservation.

Meanwhile, Greece, like much of southeastern Europe, hasn’t exactly been a hotspot for paleoanthropology—despite its geographic importance. That’s mostly because archaeology in the region has been more focused on much later periods of human history. Paleoanthropology has started to get more attention in recent years, though, and that may eventually yield more finds like Apidima 1.

“We did not suspect this, so it's possible that we will find [early human fossils] also elsewhere. It's possible that they reached further than we thought before,” said Harvati. We can only answer this by finding more evidence.”
University of Washington researchers report, in the peer-reviewed Journal of the American Medical Association Oncology, the discovery of an odontoma — a benign tumor — in the fossil of a 255-million-year old Tanzanian mammal-like saber-toothed gorgonopsia. This is one of the oldest-known tumors ever found.