The Graecopithecus freybergi hominin; the oldest human ancestor?

Humans and chimpanzees split from their last common ancestor several hundred thousand years earlier than believed, according to Prof. Böhme and co-authors.

Their findings, published in the journal PLoS ONE, also indicate that the split of the human lineage occurred not in Africa, but in the Eastern Mediterranean.

“Present-day chimpanzees are humans’ nearest living relatives. Where the last chimp-human common ancestor lived, however, is a central and highly debated issue in paleoanthropology,” Prof. Böhme and co-authors said.

“Scientists have assumed up to now that the lineages diverged 5-7 million years ago and that the first pre-humans developed in Eastern Africa.”

“According to the 1994 theory of French paleoanthropologist Yves Coppens, climate change in the region could have played a crucial role.

“Our discovery outlines a new scenario for the beginning of human history,” added co-author Professor David Begun, from the University of Toronto.

“While great apes typically have two or three separate and diverging roots, the roots of Graecopithecus converge and are partially fused — a feature that is characteristic of modern humans, early humans and several pre-humans including Ardipithecus and Australopithecus,” Prof. Böhme said.

“The lower jaw of Graecopithecus freybergi has additional dental root features, suggesting that the species might belong to the pre-human lineage.”

“We were surprised by our results, as pre-humans were previously known only from sub-Saharan Africa,” said co-author Jochen Fuss, a PhD student at the University of Tübingen.

“Furthermore, Graecopithecus freybergi is several hundred thousand years older than the oldest potential pre-human from Africa, the 6-7 million-year-old Sahelanthropus tchadensis from Chad.”

The team dated the sedimentary sequence of the Graecopithecus fossil sites in Greece and Bulgaria with physical methods and got a nearly synchronous age for both fossils: 7.24 and 7.175 million years before present.

“This dating allows us to move the human-chimpanzee split into the Mediterranean area,” Prof. Begun said.

“It is at the beginning of the Messinian, an age that ends with the complete desiccation of the Mediterranean Sea,” Prof. Böhme said.

“The findings call into question one of the most dogmatic assertions in paleoanthropology since Charles Darwin, which is that the human lineage originated in Africa,” Prof. Begun said.

(Source: http://www.sci-news.com/othersciences/anthropology/graecopithecus-freybergi-hominin-04888.html)

Scientists analyzing 7.2 million-year-old fossils uncovered in modern-day Greece and Bulgaria suggest a new hypothesis about the origins of humankind, placing it in the Eastern Mediterranean and not — as customarily assumed — in Africa, and earlier than currently accepted. The researchers conclude that Graecopithecus freybergi represents the first pre-humans to exist following the split from the last chimpanzee-human common ancestor.

(Source: https://www.sciencedaily.com/releases/2017/05/170523083548.htm)

The hominid species includes humans and their fossil ancestors as well as some of the great apes. The specimens concerned are a lower jaw found in Greece (above photo) and a tooth discovered in Bulgaria.

After detailed analyses, the research team concluded that Graecopithecus was a pre-human species hitherto unknown. For example, the dental roots were, for the most part, fused – a feature that is characteristic of humans and their extinct relatives. Great apes usually have separate dental roots.

After analyzing the sediments from which the fossils had been retrieved, the research team dated the lower jaw to 7.175 million years and the tooth to 7.24 million years ago. That makes the two specimens older than than the hitherto oldest known pre-human from Africa, Sahelanthropus, which is dated to about 6 to 7 million years ago.

The “East Side Story,” according to which pre-humans originated in Africa, was now called into question by the European “North Side Story,” said Böhme during the presentation of the study’s findings in Tübingen. “I now expect frantic reactions, I expect a lot of dissent,” she said.

She intends to corroborate her theory, including with analyses of “El Graeco’s” nourishment. In addition, she plans to look for further clues pointing to the evolution of pre-humans beyond Africa – in Iran, Iraq and, possibly, Lebanon.

“The split of humankind’s hominid ancestors from the great apes is badly documented,” says Jean-Jacques Hublin, head of the Human Evolution department at the Leipzig-based Max-Planck-Institute for Evolutionary Anthropology, who is not involved with the study.

“This is not the first time that researchers have suggested the occurrence (of those ancestors) in southern Europe’s extensive fossil record.”

(Source: https://www.dw.com/en/study-the-oldest-pre-human-could-originate-from-europe-not-africa/a-39004699)

Great ape dental roots diverge (usually split into two or three segments), but the roots of El Graeco converge and are partially fused, a human characteristic also found in Australopithecus, for example. Converged roots are not found in the chimpanzee line. One conclusion is that human and chimp ancestors separated earlier than the 7 million years that is commonly thought.

“We believe the split between the ancestors of chimps and humans was created in the eastern Mediterranean,” Bohme says.

Finding two Graecopithecus fossils in the Mediterranean region means precisely nothing about the prevalence of this species throughout Asia and southern Europe. But Bohme shoots down the suggestion that theoretically, the beast could have also thronged Africa. When El Graeco lived, the uncrossable wasteland of the Sahara lay between habitable parts of Africa and the Mediterranean.

Geologists have long known that the Sahara Desert “came and went” – now it’s here, but there were times in the history of the Earth that North Africa was a paradise, rich in rivers and fauna. Not in El Graeco’s time, though. Both Graecopithecus fossils were found in sediment rich in dust that had blown in from the Sahara.

According to the scientists’ data, the population north of the Sahara evolved into hominins, says Bohme. No fossil ape remains from 7 or 8 million years ago have been found (at least not yet) in Africa, but she speculates that the southern crowd stuck below the Sahara became Pan, the genus that includes the chimps and bonobos.

There is also a circumstantial case for El Graeco being the precursor of humans, not apes. At the time, Graecopithecus was living in arid savannah conditions, says Bohme.

“The climate conditions were arid. There were very few trees and the environment was very dusty, similar to the environments in the central Asian deserts or the African Sahel. From what we know about great apes, none can live in the savannah environment,” she explains.

In other words, El Graeco lived in the sort of harsh environment that requires special biology or special metabolism – and/or culture – for survival, she suggests. Again that argues for primitive man, not ape.

Yet more evidence backing a Mediterranean origin of man is Ouranopithecus, which existed throughout the eastern Mediterranean some 9 million years ago, and which could theoretically have been the ancestor of El Graeco. Ouranopithecus was found in Greece and seems related to fossils found in Turkey and Iran. There are no known African fossil hominins from that time. “All the African hominin fossils are younger,” Bohme said.

So, if we hominins originated in the Mediterranean region, how and when did our forefathers migrate to Africa?

“Later, perhaps half million years after El Graeco, the Sahara Desert disappeared again. It was probably quite a humid period,” says Bohme. Fossil river beds indicate massive flows of water, including in today’s arid Libya. Lake Chad existed and was high enough to overflow. In short, the area was inviting and the man-apes, either El Graeco itself or its descendent, moved southward into this lovely landscape. The earliest-known African hominid is a good 200,000 years later than our Graeco: Sahelanthropus tchadensis.

(Source: https://www.haaretz.com/archaeology/evolution-of-man-began-in-eastern-mediterranean-not-africa-1.5475961)

Abstract Two Late Miocene hominoids are known from Greece. The first, Graecopithecus freybergi , is known by a single mandible with the worn m2 from the locality of Pyrgos Vassilissis, near Athens. The other, Ouranopithecus macedoniensis , is known from Axios Valley and Chalkidiki (Macedonia, Greece) by a partial skull and a set of maxillary and mandibular remains. Some authors consider these two hominoids as synonyms and in the present article a detailed comparison of them is given. The morphology and size of the symphysis, the more robust mandible, the more open dental arcade of Ouranopithecus distinguishes it clearly from Graecopithecus . Moreover, the incompleteness of the mandible of Graecopithecus with the doubtful morphology and size, the limited material and the uncertain geological age of the locality cannot allow precise and clear comparisons with the rest extant and extinct hominoids. Thus in our opinion there are not enough data to support the similarity, and therefore, the synonymy of the two genera. The Pyrgos mandible must remain as a separate and isolated genus with one species, which only includes this sole mandible.

(Source: “The Late Miocene hominoids Ouranopithecus and Graecopithecus . Implications about their relationships and taxonomy”, by George D. Koufos, Louis de Bonis)

Abstract Dating fossil hominids and reconstructing their environments is critically important for understanding human evolution. Here we date the potentially oldest hominin, Graecopithecus freybergi from Europe and constrain the environmental conditions under which it thrived. For the Graecopithecus-bearing Pikermi Formation of Attica/Greece, a saline aeolian dust deposit of North African (Sahara) provenance, we obtain an age of 7.37–7.11 Ma, which is coeval with a dramatic cooling in the Mediterranean region at the Tortonian-Messinian transition. Palaeobotanic proxies demonstrate C4-grass dominated wooded grassland-to-woodland habitats of a savannah biome for the Pikermi Formation. Faunal turnover at the Tortonian-Messinian transition led to the spread of new mammalian taxa along with Graecopithecus into Europe. The type mandible of G. freybergi from Pyrgos (7.175 Ma) and the single tooth (7.24 Ma) from Azmaka (Bulgaria) represent the first hominids of Messinian age from continental Europe. Our results suggest that major splits in the hominid family occurred outside Africa.

The Late Miocene was a time of major hominine radiation (African apes and humans), but when, where, and why lineages split is debated intensely. Recent discoveries with potential hominin (humans and their non-ape ancestors) affinities in Greece (Attica) and Bulgaria (Upper Thrace) raise questions about the age and origin of these candidate pre-humans and the environmental conditions under which they thrived in Europe. Exact dating of Graecopithecus and reconstruction of its habitats in Attica and Upper Thrace may, therefore, shed new light on the debate on hominin origins.

The type mandible of Graecopithecus freybergi was found in the Athens Basin of southern Attica near Pyrgos Vassilissis Amalias, an area that is today largely overbuilt by the rapidly growing Greek capital. To resolve the site stratigraphy it is necessary to study the adjacent Mesogea Basin, which preserves the famous bone accumulations of Pikermi, which have been excavated for nearly 180 years and are displayed in museums worldwide. Both the Athens and the Mesogea basins developed during the Late Miocene by activation of a major detachment fault, which separates carbonates of the Internal Hellenides from Mesozoic metamorphic rocks. The thick continental basin deposits consists of coarse grained alluvial fan sediments (e.g. debris-flows) and palustrine and lacustrine sediments (coal, platy limestones), with deposition starting during the early Tortonian. The second Graecopithecus fossil, a single tooth, derives from Upper Miocene sediments at Azmaka in the Upper Thrace Basin. This basin is formed by Neogene extension and is filled by the fluvial Ahmatovo Formation, at the base of which the hominid tooth was found.

Biochronological age constraints for the Pikermi and Ahmatovo formations are derived from their exceptionally rich large mammal record, documented from more than ten accumulation horizons. The middle Turolian fauna of the classical Pikermi levels is considered to be close in age to the Tortonian-Messinian boundary. In contrast, the mammalian faunas of Azmaka, Chomateri-1, and Pyrgos imply a post-Pikermi age because they contain new immigrants such as the proboscidian Anancus (for the former two localities) and higher evolutionary stages in several ungulate lineages compared to the classical Pikermi fauna. In particular, most of the mammal taxa of Pyrgos are different from Pikermi. Beside a different giraffe species, a new grazing bovid appears, and the hipparion Hippotherium brachypus is morphologically distinct from those at Pikermi. Most importantly, the boselaphine bovid Tragoportax macedoniensis links Pyrgos with younger (Messinian) localities of the Balkans. The post-Pikermian newcomers have no discernible affinities to African faunas; their biogeographic relationships are inferred to be eastern Mediterranean.

On the basis of orbital tuning of the Pikermi Formation and the bio-magnetostratigraphy of Azmaka, Graecopithecus can be dated to 7.24 Ma (tooth from Azmaka) and 7.18–7.17 Ma (type mandible from Pyrgos) and is, thus, of earliest Messinian age. The levels that contain a classical Pikermi mammal fauna can now be dated to between 7.33 and 7.29 Ma. Therefore, the transition from the Pikermi to post-Pikermi fauna appears to coincide with the Tortonian-Messinian boundary.

For the first time we demonstrate that C4 grasses were the dominant herbaceous element of the Pikermi Formation. Our habitat reconstruction suggests fire-prone woody grasslands and woodlands within a savannah biome for Pikermi and Pyrgos and, thus, provides unambiguous evidence for the early environmental conjectures of Gaudry. Given the potential hominin nature of Graecopithecus freybergi, our habitat reconstruction for the Pikermi Formation further supports the “Savannah Hypothesis” put forward to explain earliest hominin emergence. Analysis of both potential hominin sites indicates that Graecopithecus inhabited different habitats, be it open braided-river landscapes in Azmaka, or the wooded grassland of Pyrgos.

The Tortonian-Messinian transition in the Mediterranean appears to represent a period of significant environmental and climatic changes. During the latest Tortonian (~7.4–7.25 Ma) C4 grass ecosystems progressively penetrate the Balkan Peninsula and constitute the environment of the mammal fauna of Pikermi, which contradicts earlier assumptions. The classical Pikermi fauna is terminated at the beginning of the Messinian (7.25–7.10 Ma) by a significant faunal turnover (post-Pikermi turnover), accompanied by massive increase of Saharan dust and salt accumulation with profound effects on soil salinity and nutrition.

Our results reveal formerly unrecognized Mediterranean environmental changes during the Tortonian-Messinian transition, which provide important constraints for the evolution of Graecopithecus freybergi. At the Tortonian-Messinian boundary (7.25 Ma), water-stress levels increased and wildfire frequency decreased, which can be interpreted as increasing aridification. Rather than representing a local phenomenon, aridification occurred on a larger scale. We demonstrate that aeolian dust accumulation was widespread at the northern Mediterranean coast and that large amount of salt-laden mineral dust and marine-based aerosols were blown from dried lake beds in North Africa toward Europe, where ~30-m-thick red silts were deposited in southern Greece and southern France. We relate this dust accumulation to progressive late Tortonian Mediterranean aridification and cooling, which started at around 7.4 Ma and culminated during the earliest Messinian, when Mediterranean Sea surface temperature dropped by about 7°C to values comparable to the present-day.

Our dating of Graecopithecus and the taxonomy of its accompanying large mammals indicate that, during culmination of cooling at the base of the Messinian, the post-Pikermi turnover replaced part of the Pikermi fauna. Several newcomers like the elephantoid Anancus or the boselaphid Tragoportax macedoniensis have Asian affinities and we hypothesize that Eastern Mediterranean aridification played an important role in the westward shift of their habitats. Graecopithecus, as part of this new post-Pikermi fauna, lived in a warm-temperate and dusty environment unlike any other known hominid (except for our own genus). Graecopithecus predates by several hundred thousand years the next youngest candidate hominin Sahelanthropus, which occupied the southern Saharan tropics after its earliest Messinian desertification. Given the potential hominin affinity of Graecopithecus, our results suggest that the Pan-Homo split predated the Messinian and that the chimpanzee–human last common ancestor thrived in the Mediterranean region.

(Source: “Messinian age and savannah environment of the possible hominin Graecopithecus from Europe”, by Madelaine Böhme , Nikolai Spassov, Martin Ebner, Denis Geraads, Latinka Hristova, Uwe Kirscher, Sabine Kötter, Ulf Linnemann, Jérôme Prieto, Socrates Roussiakis, George Theodorou, Gregor Uhlig, Michael Winklhofer)

Abstract The split of our own clade from the Panini is undocumented in the fossil record. To fill this gap we investigated the dentognathic morphology of Graecopithecus freybergi from Pyrgos Vassilissis (Greece) and cf. Graecopithecus sp. from Azmaka (Bulgaria), using new μCT and 3D reconstructions of the two known specimens. Pyrgos Vassilissis and Azmaka are currently dated to the early Messinian at 7.175 Ma and 7.24 Ma. Mainly based on its external preservation and the previously vague dating, Graecopithecus is often referred to as nomen dubium. The examination of its previously unknown dental root and pulp canal morphology confirms the taxonomic distinction from the significantly older northern Greek hominine Ouranopithecus. Furthermore, it shows features that point to a possible phylogenetic affinity with hominins. G. freybergi uniquely shares p4 partial root fusion and a possible canine root reduction with this tribe and therefore, provides intriguing evidence of what could be the oldest known hominin.

Within the intensively studied field of early hominin evolution, a crucial question is the split of our own clade from the Panini. Over the last decades the fossil record of potential early hominins increased with taxa such as Ardipithecus, Orrorin and Sahelanthropus. Recent molecular data propose a divergence time of Pan and Homo between 5 and 10 Ma and Langergraber et al. propose an age of at least 7–8 Ma. These estimations largely coincide with the evidence obtained from the fossil record across Africa and Eurasia.

In the present study, we define ‘hominoid’ as ‘apes’; ‘hominid’ as ‘great apes and humans’; ‘hominine’ as ‘African apes and humans’; and ‘hominin’ as ‘humans and their non-ape ancestors’. Currently, the fossil record reveals three Miocene candidates with potential hominin affinity. Ardipithecus kadabba is dated to between 5.2 and 5.8 Ma. It is more primitive than Ardipithecus ramidus and may not belong to the same genus, but it does show hominin affinities such as evidence of bipedalism and canine reduction. Orrorin tugenensis is dated to ~5.8–6.0 Ma and shows an upright posture. Sahelanthropus tchadensis is dated to ~6–7 Ma and provides several derived cranial and dental features that suggest hominin affinity. Lebatard et al. propose an age of 7.2–6.8 Ma for Sahelanthropus. We do not consider this age determination to be reliable given the circumstances of the provenance of the skull and the relatively low accuracy of the method.

The overwhelming effort to reconstruct hominin origins have been focused on the African continent. However, ancestral lineages remain largely unknown. A crucial problem in identifying ancestral lineages is the prevalence of homoplasy and the relative lack of derived morphological features that reduces the phylogenetic resolution around lineage divergence.

In this study, we propose based on root morphology a new possible candidate for the hominin clade, Graecopithecus freybergi from Europe. Graecopithecus is known from a single mandible from Pyrgos Vassilissis Amalia (Athens, Greece) and possibly from an isolated upper fourth premolar (P4) from Azmaka in Bulgaria. A new age model for the localities Pyrgos Vassilissis and Azmaka, as well as the investigations on the fauna of these localities confirms that European hominids thrived in the early Messinian (Late Miocene, 7.25–6 Ma) and therefore existed in Europe ~ 1.5 Ma later than previously thought. This, and recent discoveries from Çorakyerler (Turkey), and Maragheh (Iran) demonstrate the persistence of Miocene hominids into the Turolian (~8 Ma) in Europe, the eastern Mediterranean, and Western Asia.

The type mandible of G. freybergi was found in 1944 by von Freyberg, who mistook it for the cercopithecid Mesopithecus. In the first description by von Koenigswald the mandible was identified as a hominid. Some authors have concluded, based on external morphology and in particular the apparently thick enamel and large molars, that another hominid from Greece, Ouranopithecus (9.6–8.7 Ma), could not be distinguished from Graecopithecus, thus synonymizing the former with the latter. Other authors have consistently maintained a genus level distinction between Ouranopithecus (northern Greece) and Graecopithecus (southern Greece), based on the argument that the Pyrgos specimen is insufficiently well preserved to diagnose a taxon (nomen dubium) or based on anatomical arguments.

Here, we provide a detailed description of the Pyrgos and Azmaka specimens by using μCT based analyses and 3D visualisations. For the first time, their internal structures are examined in order to reveal previously unknown characters in root and pulp canal morphology. Additionally, previously described features are re-assessed and a new diagnosis of G. freybergi is given. Thereby, we address the taxonomic validity of G. freybergi and further, raise the possibility of a hominin affinity.

G. freybergi is only known from one mandible and possibly the tooth from Azmaka. This compares with a relatively large number of Ouranopithecus specimens. Ouranopithecus has been synonymised with Graecopithecus by some. Others emphasize the dentognathic differences between both taxa, but regard the Pyrgos specimen as largely uninformative due to its poor surface preservation and vague dating. The new data provided here support previous conclusions that Ouranopithecus and Graecopithecus differ in significant numbers of characters more than adequate to recognize two different taxa with probable generic differences. Beside shared characters between G. freybergi and O. macedoniensis (thick enamel, m2 crown dimension, symphyseal shape), both taxa differ in the dental arch, which is shorter and narrower in G. freybergi. The width (BL) and length (MD) of the m2 crown is within the range of female O. macedoniensis, but it is broader relative to the mandibular robusticity. The BL width of m2 approximates the breadth of the mandibular corpus at this position. Hence, the mandible of G. freybergi is very gracile compared to O. macedoniensis and other Miocene and Pliocene hominids, as already suggested by von Koenigswald and Martin & Andrews. Generally, the mandibular corpus breadth in hominids show only minor sex differences, but is of taxonomic significance. The breadth of female and male O. macedonienis mandibles are closer to one another than either is to G. freybergi. Thus, the considerable lower breadth in G. freybergi strongly suggests a taxonomic difference.

The inter-genus variability among extant great apes is low, but large between great apes and humans.

Both individuals from Azmaka and Pyrgos show the same evolutionary trend in upper and lower teeth respectively. Accordingly, we assign the Azmaka specimen to cf. Graecopithecus sp.

G. freybergi differs from extant great apes (Pan, Gorilla, Pongo) in its thickly-enamelled teeth. It differs from the similar sized P. troglodytes in its absolutely longer dental roots of m2 and m3, but shows comparable c to m1 root lengths. G. freybergi differs from most hominids (e.g. Sivapithecus, Ouranopithecus, australopiths, early Homo) in its gracile mandibular corpus. Its corpus height is within the lower range of female O. macedoniensis, but its breadth is lower. It can be further distinguished from O. macedoniensis by its narrow dental arc. G. freybergi differs from O. macedoniensis in its root configuration, having two-rooted lower premolars including a partially fused p4-root and a reduced number of pulp canals.

G. freybergi is a hominid in the size range of female chimpanzees based on dentognathic size.

The hominin record shows different levels of p4 root fusion, although separated roots are common as well. However, p4 root fusion never occurs in Miocene non-hominins, suggesting that this feature in Graecopithecus is a hominin synapomorphy. Accordingly, the most parsimonious interpretation of the phylogenetic position of Graecopithecus is that it is a hominin, although we acknowledge that the known sample of fossil hominin root configurations is too small for definitive conclusions.

In earlier studies, a relationship of European hominids to the African hominins is proposed. Taken at face value, the derived characters of Graecopithecus (p4 root morphology and possibly canine root length) may indicate the presence of a hominin in the Balkans at 7.2 Ma. In many publications, de Bonis, Koufos and colleagues have proposed that Ouranopithecus, from northern Greece and more than 1.5 million years older, is a hominin. Other researchers have interpreted the similarities between Ouranopithecus and australopithecines as homoplasies. It is possible that the similarities between Graecopithecus and Ardipithecus and some australopithecines are also homoplasies. However, as stated before the premolar root number is less functionally constrained than megadonty and enamel thickness, and thus, potentially more useful for phylogeny reconstruction. Graecopithecus has reduced root morphology yet heavy mastication and megadontia, suggesting a de-coupling of root and molar function. In contrast, larger roots, large teeth and thicker enamel together contribute to a functional complex shared with australopithecines, which is evoked as the mechanism accounting for the homoplastic appearance of hard object feeding adaptations in Ouranopithecus and australopithecines.

Therefore, we submit that the dental root attributes of Graecopithecus suggest hominin affinities, such that its hominin status cannot be excluded. If this status is confirmed by additional fossil evidence, Graecopithecus would be the oldest known hominin and the oldest known crown hominine, as the evidence for the gorillin status of Chororapithecus is much weaker than the hominin status of Graecopithecus. More fossils are needed but at this point it seems likely that the Eastern Mediterranean needs to be considered as just as likely a place of hominine diversification and hominin origins as tropical Africa.

(Source: “Potential hominin affinities of Graecopithecus from the Late Miocene of Europe”, by Jochen Fuss, Nikolai Spassov, David R. Begun, Madelaine Böhme)

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