Research: Potential Hominin Affinities of Graecopithecus from the Late Miocene of Europe

Μandible of the Graecopithecus freybergi Photo: Wolfgang Gerber, University of Tübingen.

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, the study published in PLOS says.

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 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 [1–3]. Recent molecular data propose a divergence time of Pan and Homo between 5 and 10 Ma [4] and Langergraber et al. [5] 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 [6, 7]. (…)

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) [38] and possibly from an isolated upper fourth premolar (P4) from Azmaka in Bulgaria [39] (Fig 1A and 1B). A new age model for the localities Pyrgos Vassilissis and Azmaka, as well as the investigations on the fauna of these localities [40] 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 [39]. 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 [41, 42].

 

Read the study here and here.