Fig 1.
Locations of Graecopithecus-bearing exposures.
Digital elevation map of a, Attica (Greece) and b, Upper Thrace (Bulgaria) with main structural units indicated. The positions of the geological maps of Pyrgos Vassilissis, Pikermi and Azmaka (see Fig 2) are indicated. c, Digital elevation map of the Balkan Peninsula.
Fig 2.
Geological maps of the regions around the studied localities.
a, Map of the Pikermi area (Mesogea Basin, Attica, Greece) modified after ref. 31. Sampling points (black stars). PV3 –Pikermi valley 3 (new excavation of Theodorou 2010 = old excavation of Gaudry 1855–1860, Woodward and Skoufos 1901, Abel 1911–1912), PV1 –Pikermi valley 1 (new excavation of Theodorou 2009), Chomateri (old excavations of Symeonidis & Bachmayer 1972–1980). Blue lines represent measured sections along the Megálo Réma rivulet. b, Map of the Pyrgos Vassilissis area (Athens Basin, Attica, Greece) modified after ref. 28, 32. The position of the type locality of Graecopithecus freybergi is indicated by a black star. c, Map of the Azmaka area (3 km north of Chirpan, Upper Thrace Basin, Bulgaria). The location where the Graecopithecus tooth was found in the Azmaka quarry is indicated by a black star.
Fig 3.
Field photographs of the Pikermi and Rafina formations.
a-d, Red Conglomeratic Member of the Pikermi Formation along the Megálo Réma rivulet. a, Red aeolian silts and conglomeratic levee of a dominant debris-flow from the upper part of the PV1 section. b, Lenticular shaped, dominant (‘doubled’) debris-flow, middle of PV3 section. c, Same debris-flow as b with undulating surface. d, Same debris-flow as b and c, with projecting cobbles (length of hammer 35 cm). e-g, Transition from the Red Conglomeratic Member to the Chomateri Member of the Pikermi Formation in the northern former clay pit Chomateri. e, Section Chom-A (northern view) with slight dip of sediments to the south-east. The transition between members is indicated by an arrow. f, Same as e, with channel-fill trains at the base of the Chomateri Member. g, view to the east of laterally continuous channel-fill trains. h, Chomateri Member of the Pikermi Formation in the southern former clay pit Chomateri. Section Chom-B showing the prominent 2.2-m-thick calcic palaeosol (E-Btk-Bk soil horizons) at the base (Btk and Bk horizons deeply rooted by macro-rhizolithes), overlain by faint and dominant fluvial channel-fill trains. i, j, Upper part of the Rafina Formation. i, Lacustrine marls and limestones with organic-rich interlayers (arrow). j, Planorbis shells from marl horizons.
Fig 4.
Upper Miocene sediments of southern Attica.
a, Simplified stratigraphic column of the Pikermi and Rafina formations (profile of the Rafina Formation according to[40]), sedimentary facies development, and correlation to chronostratigraphy, alkenone-based eastern Mediterranean Sea Surface Temperatures[41], and insolation seasonality at 40°N[28]. Grey bars and numbers represent Mediterranean sapropel layers (dark grey–prominent sapropel, light grey–distinct sapropel) of the Tortonian type section at Monte dei Corvi[42]. Blue arrow indicates intense cooling during the latest Tortonian. b-d, Typical outcrop views of the upper Rafina Formation platy limestones (b, height of image = 1.5 m), alluvial sandstones of the Chomateri Member (c, height of image = 1 m), and red silt with debris-flow of the Red Conglomeratic Member (d, height of image = 2 m). For further details see Fig 3.
Fig 5.
Palaeomagnetic results from each studied section.
a-i, Representative results of stepwise thermal (alternating field) demagnetization experiments on orthogonal vector endpoint diagrams[44] for samples from the (a-e) Pikermi, (f) Rafina and (g-i) Ahmatovo formations. Open (closed) symbols represent projection onto the vertical (horizontal) plane. g, Great circle trend of demagnetization results. Grey lines indicate proposed linear fits of the respective component (component name in grey letters). Steps are in °C (except f, where steps are in milliTesla). j-m, Stereographic equal-area projections of component mean directions of (j-l) Pikermi and (m) Ahmatovo formations for indicated components (Pikermi). Overall mean directions (with 95% confidence intervals) are also shown except for (l) component C. k, Grey marked samples are excluded from the reversals test. l Distribution of directions for component C fails a test of randomness[45], where R is lower than R0, which indicates a random distribution. m, GC indicates that the direction was obtained from the intersection of two remagnetization great circles.
Fig 6.
Plot of virtual geomagnetic pole (VGP) latitude versus stratigraphic height for the Pikermi sections and the Ahmatovo section (AZM).
The column to the left of each VGP latitude plot indicates the polarity interpretation, where black (white) corresponds to normal (reversed) polarity. Grey areas indicate intervals with uncertain polarity. Crossed intervals were not sampled. GC represents the VGP latitude obtained from the intersection of two remagnetization great circles.
Fig 7.
Mammalian fossils from Pyrgos Vassilissis.
a, b, Hippotherium brachypus skull fragment (AMPG 2). a, Right lateral view; b, ventral view. c-e, Tragoportax macedoniensis, skull of female individual (AMPG 19a). c, Dorsal view; d, left lateral view (the red outline indicates the basal cross-section of the left horn-core); e, occlusal view of the left toothrow.
Table 1.
Mammal taxa recovered from Pyrgos Vassilissis.
Fig 8.
Stratigraphy and chronology of Upper Miocene sections from Attica and Upper Thrace.
Bio-magnetostragraphic correlation of Upper Miocene sections from Attica (Pyrgos Vassilissis[9], Chomateri A and B, Pikermi Valley 1 and 3, Rafina) and Upper Thrace (Azmaka) and astronomical tuning of the Pikermi Formation to insolation seasonality at 40°N (I40°N 21June−I40°N 21Dec of the astronomical solution La04[28]). The orbitally tuned dominant (d) and faint (f) debris flows and fluvial channels are indicated. Black stars represent Graecopithecus-levels, dashes (small dots) indicate palaeomagnetic (palaeobotanic) sampling horizons and numbered stars denote horizons of fossil excavations within the Pikermi Formation undertaken by major museums or collections (1 and 2 represent the classical Pikermi levels), 1 –Gaudry 1855 (partim), 1860 (Muséum National d'Histoire Naturelle, Paris), Abel and Skoufos 1912 (Naturhistorisches Museum Wien, University of Athens), 2 –Gaudry 1855, Woodward and Skoufos 1901 (British Museum of Natural History, London, University of Athens), 3 –Theodorou 2009 ff. (University of Athens), 4 –Symeonidis & Bachmayer 1972–1978 (University of Athens, Naturhistorisches Museum Wien), 5 –Symeonidis & Bachmayer 1979–1980 (University of Athens, Naturhistorisches Museum Wien), 6 –v. Freyberg, Paraskevaidis 1944 ff. (University of Erlangen, University of Athens).
Fig 9.
Grain-size and -texture and U-Pb geochronology of detrital zircon grains.
a, Grain-size distribution (GSD) of siltstone samples (n = 97) of the Pikermi Formation. Each GSD is coloured according to its dominant end-member (blue–EM1, magenta–EM2, yellow–EM3, green–EM4). b, SEM image of a siltstone sample (Red Conglomeratic Member, CA 2.75) with angular grains and adhering particles (for texture documentation see Fig 10). c, Combined binned frequency and probability density distribution plots of U-Pb LA-ICP-MS ages of detrital zircon grains from sample CA 2.75. d, SEM image of a ‘giant’ detrital zircon (sample CA 2.75) with a typical surface shaped by aeolian abrasion.
Fig 10.
Silt grain texture and aeolian zircons from the studied sediments.
a-f, Raster Electron Microscope images of silica precipitation surfaces (SPS), solution pits (SP), upturned plates (UP), flat cleavage faces (FCF), and adhering particles (AP). Samples a, PV3–0.4, b, PV3–0.4, c, PV1 0.5, d, PV3–0.4, e, Pyrgos Vassilissis, and f, CA 2.75. g, Detrital zircon (CA 2.75 m) affected by chemical corrosion (etching) before transportation.
Fig 11.
End-members of grain-size distributions from the studied sediments.
a, Factor loadings (solid lines) of end-members of grain-size distributions obtained using EMMAgeo[57] for 97 samples of the Pikermi Formation (Mesogea Basin). The dashed lines represent Gaussian fits to the main modes and are referred to as simplified EM spectra (summarized in S11 Table). b, Same factor loadings, plotted on a micrometer scale. c, Relative contributions of EMs to each sample from the Pikermi Formation. For better visibility, the curves are shifted vertically, using the EM index p as an offset. d, e, Explained variance of the original grain-size data from the Pikermi Formation by the EM model based on four end members (solid lines). d, At the level of grain-size (Eq. 4a in S1 Text), e, with respect to samples (Eq. 4b in S1 Text). When EM p = 4 is omitted from the model (i.e., pmax = 3, dashed lines), the mean variance at the sample level of 93% is practically not affected, while the mean variance at the grain-size level drops from 72% to 59%, resulting in an overall drop in total explained variance from 83% to 77%.
Fig 12.
Mineral dust and vegetation of the Pikermi formation and Pyrgos (red crosses).
Upper panel–dust mass accumulation rate (DMAR) and total soluble salt (TSS) chemistry. a, Ca/Cl and b, Na/Ca concentration ratios in the leachate indicate change from Ca2+ to Na+ and Cl- dominance. Low Na/Ca and high Ca/Cl ratios (140, not shown) for Pyrgos suggest leached conditions. c, Cl/Br molar ratios point to contributions from both marine-based and evaporitic sodium chlorides (red line–marine Cl/Br ratio of 655,[23]). Concentrations of (d) soluble SO42- and (e) Na+ in the samples indicate that halite and gypsum dominate TSS during the earliest Messinian. f, TSS reaches its highest concentrations at 7.18 Ma. g, DMAR is quantified for the proportion of silt <30 μm. Lower panel–phytolith indices and charcoal abundance. h, Climatic index (Ic) specifies the relative proportions of C4 and C3 grasses and i, the humidity-aridity index (Iph) represents the relative proportion of C4-grass sub-families Panicoideae and Chloridoideae. j, Tree cover density index (D/P) is the ratio between woody dicotyledons and grass phytoliths. k, Woody cover index describes the relative abundance of globular (woody dicotyledon) phytoliths. l, Water-stress index quantifies aridity by the relative percentage of silicified bulliform cells. m, Micro-charcoal abundance is given in 103 particles per gram dry-weight.
Fig 13.
Phytoliths, pollen and micro-charcoal particles.
a-l, Phytolith types used in this study. a, Bilobate, b, cross, c, fan-shape, d, trapeziform short cell, e, globular echinate, f, globular granulate, g, globular psilate, h, parallelepiped elongate, i, point-shape/acicular, j, rondel, k, saddle, l, trapeziform polylobate. m-t, Pollen from sample CA 2.75 (Pikermi Formation; black bar represents 10 μm). m, Pinus, n, Ericipites, o, Chenopodiaceae, p, Caryophyllacae, q, Asteraceae, r, Malvaceae, s, Alnipollenites, t, Poaceae. u-x Charcoal particles from sample CA 2.75 in the size-range between 30 and 150 μm (black bar represents 30 μm).