Fossils of the Olteţ
A European valley
yields clues about
early human migration
Owl monkey skull. Photos provided.
On their last day in Romania, after two-and-a-half weeks at the “Emil Racoviţă” Institute of Speleology in Bucharest, Claire Terhune and her colleagues found a file cabinet in one of the rooms where they were working. There was a label on the front of the cabinet: “Oltenia.”
Hmm, thought Terhune, that’s interesting.
“We didn’t have time to go through the whole cabinet,” she said. “We had to catch our flight.”
Terhune, an assistant professor of anthropology in the J. William Fulbright College of Arts and Sciences, has one foot in the present and one in the ancient past. As a biological anthropologist, she studies bones and primate anatomy. Her work will help doctors and dentists understand how different skeletal components of the jaw are correlated, how pathologies such as arthritis develop, and how anatomical changes occur during the lifetime of an individual, be it human or chimpanzee.
But other, related work might explain how and when early humans migrated from Africa to Europe.
Claire Terhune’s work includes making models of the teeth of early humans to better understand their diet. Here she is collecting data at the American Museum of Natural History. Photo provided.
A Study to Chew On
Despite medical advances over the past century, science has yet to fully explain the complex mechanisms at work within the temporomandibular joint, which connects the jaw to the skull. This fact is even more remarkable when one considers how much we use this joint.
Talking, eating, yawning or anything done with the mouth or jaw depends on the health of the temporomandibular joint. Humans in particular seem to experience a lot of problems with it. Some estimates suggest that as many as 75 percent of adults will experience signs or symptoms, such as jaw
popping, of pathologies in the joint. In primates, the pathologies often lead to an arthritic joint, yet little research has been done regarding which primate species experience these arthritic changes and how often this occurs.
Terhune and colleagues at Johns Hopkins School of Medicine and Marquette University received a $219,000 grant from the National Science Foundation to study the anatomy and function of the temporomandibular joint in 16 closely related primate species, including humans. Their study focuses on how teeth, jaw and related joints work together as a chewing system and how these components are affected by aging and abnormal changes.
Terhune’s work may help explain these pathologies and inform clinical studies of dental problems in humans.
“We’re trying to provide a more complete picture of the anatomical interrelationships of this complex system,” she said. “We hope to show how changes occur during the lifetime of an individual, but also how primate species differ from each other in these changes. By changes, we mean both normal and pathological dental wear, as well as normal and abnormal, or arthritic, changes.”
Comparing these closely related primate species, Terhune and her colleagues will also look for similarities in the degree of evolutionary change over time. They will pay particular attention to shapes and pathologies and how or if they vary in relation to each other.
“For example, do you always see dental pathologies, such as tooth loss or abscesses, occurring with osteoarthritis in the temporomandibular joint? This is the kind of question we’re asking,” she said.
In the course of their work, Terhune and her colleagues will build a large database of 3-D models of primate skulls and teeth. After they’ve published their results, their models will be made freely available to anthropological and biomedical researchers.
“Sharing data this way is really valuable for pushing research forward,” Terhune said. “Researchers who may not otherwise have the resources to collect these data can use them for their own work, and we can ultimately decrease wear and tear on museum collections.”
An Amazing Valley
Since 2012, Terhune and several American and Romanian colleagues have spent a chunk of their summers in Romania, poring over fossil specimens at the massive Emil Racoviţă Institute, or exploring farms and tiny communities of the Olteţ River Valley. For researchers like her – paleontologists and anthropologists studying the many facets of human and primate evolution – the Olteţ River Valley is a goldmine.
Ancient fossils line the valley. It is one of Eastern Europe’s most fossil-rich areas for sites dating to the early Pleistocene, a geological sub-epoch that started roughly million years ago and ended 781,000 years ago. The valley’s most famous site, Grănceanu, which dates back about 1.8 million years, is a tremendously rich deposit including thousands of bones of fossil mammals and vertebrates. Extinct species found at Grănceanu include mammoths, saber-toothed cats and the prehistoric ancestors of giraffes, giant deer, horses, rhinos, wolves, bears, hyenas and primates similar to today’s baboons.
Scientists discovered the site in the 1960s. Or, as Terhune explained, the site found them.
“At the height of communism in Eastern Europe, agriculture increased in this area,” she said. “As a result, so did deforestation. When this happened, combined with the local geology, landslides increased. Many of these landslides uncovered these fossil deposits.”
Searching for Migration Clues
At Grănceanu or one of the other Olteţ sites – already discovered or not – Terhune and others hope to find clues that might answer one of the big questions anthropologists have been asking for decades: How and when did early humans, arriving from Africa, “disperse,” or migrate, into Europe? Scientists have confirmed the presence of human ancestors in Spain about 1.4 million years ago, but so far they have not found evidence of hominins in Eastern or Central Europe dating back that far.
This void begets many migration theories, says Terhune. Did early humans reach the site in Spain by crossing the Strait of Gibraltar? Could they have island-hopped from Tunisia to Sicily and then Italy? Or, did they access the Balkan Peninsula in Eastern Europe by walking from Egypt through the Middle East and Turkey?
Terhune creates highly accurate digital models of skulls and other specimens with a blue LED scanner.
“We’re trying to build a better understanding of the paleo-environments in Europe at this time,” Terhune says. “Grănceanu and these other sites are so important, because this is the exact area through which early humans would have had to travel to reach Western Europe from Africa, via the present-day Middle East.”
Though they would exult at the discovery of actual fossils of early humans, Terhune and her colleagues would settle for other evidence, such as stone tools that would have been used for cutting meat off bones, or indirect evidence of hominins in the form of cut marks on bones.
“So we’re also asking what type of animals might these early humans have encountered when they moved into this area,” she said. “Would the presence of some types of animals have made it less likely for them to be successful in their migration?”
Unfortunately for Terhune and her team, the fossils discovered and collected from the Olteţ Valley in the 1960s had not been given much attention for the past few decades. Furthermore, all records describing the specimens were lost. This essentially meant they needed to start from scratch organizing and cataloguing specimens, just to see what they had.
Additionally, changes in how fossil species are recognized over the past 50 years suggested they might need to reanalyze some specimens to make sure they were correctly identified.
At the Emil Racoviţă Institute, Terhune and her colleagues have worked together on the existing Grănceanu collection. They have “bagged, tagged and preliminarily described as many specimens as we could.” They’ve unpacked and sorted large “grab-bags” of fossils, identified specimens and matched them to the correct species and part of the skeleton. Her team has also taken detailed measurements and photos of teeth, molded teeth for microwear and sampled them for isotopic analysis.
All of these analyses will help them figure out which species the fossils belong to and what type of foods those animals ate during their lifetime. For significant specimens, such as partly intact skulls, Terhune has used a blue LED scanner to create highly accurate digital models (the original fossils have to stay in Romania.) These models can be used for later analysis or as the basis for printing replicas using a three-dimensional printer.
Terhune and her colleagues found a treasure trove of documents in an old cabinet, including hand-drawn sketches of fossil beds.
What’s In That Cabinet?
In September 2016, Terhune and her colleagues received a $30,000 grant from the National Science Foundation to conduct additional fossil surveys in the Olteţ River Valley, which is roughly 125 miles west of Bucharest.
“So we know the fossils are there,” she says. “Until now, we just haven’t had the time or resources to look for them properly.”
The award provides seed money for researchers to assess the feasibility of anthropological research that relies on factors that are difficult to assess but may have great payoffs. If successful, the award and work it supports could lead to more funding.
The success of future Olteţ fossil surveys might depend on the other reason Terhune looks forward to returning to Romania. After the landslides and the discovery of Grănceanu in the 1960s, experts from the “Emil Racoviţă” Institute investigated and excavated the site. Fossils were recovered and stored at the institute. Scholarly publications about the site flourished in the 1970s, ’80s and into the ’90s, but, for various reasons – mostly political and related to the Ceaușescu regime – access to the fossils was limited. All documentation from the site excavation notes, geological information and a list of the fossils was thought to have been lost. Until last summer.
“Oltenia,” the word written on label on the file cabinet Terhune and her colleagues found last summer, refers to the region surrounding the Olteţ River Valley. The cabinet contained a treasure trove of documents – photographs, diagrams, drawings and maps of the Oltenia sites.
When she realized what they’d found, Terhune immediately dropped to the floor and started paging through documents.
But she ran out of time.
Terhune and others hope that one of the Olteţ sites will produce the big find: fossils or tools or even cut marks that prove the existence of human ancestors in this area more than a million years ago.