Since their first appearance in the Middle Miocene, Western Eurasian Miocene hominoids were characterised by increasing levels of diversity and abundance, ranging from Spain to Pakistan, through France, Germany, Austria, Slovakia, Greece, Turkey and Georgia. As a consequence, during the Vallesian mammal stage, this region had a variety of fossil apes, including quadrupedal semiterrestrial forms (Griphopithecus), slender suspensory forest-dwellers (Dryopithecus), robust gorilla-like hominoids (Ouranopithecus or Graecopithecus) and arboreal pongids (Sivapithecus). Therefore, the Middle Miocene Eurasian hominoid radiation parallels the one observed in Africa in Pliocene times, which finally gave rise to bipedal hominids. However, this radiation was abruptly interrupted in early Late Miocene times, in the frame of the late Vallesian Crisis (9.6 to 9.3 Ma), an extinction event which affected most of the forest-adapted European faunas (Agustí & Moyà-Solà, 1990; Agustí et al., 1997). Testing the link between this set of events and the environmental changes that affected Europe in the Miocene is usually hampered by the absence of accurate datings of most of the localities bearing hominoid remains. However, recent magnetobio-stratigraphic progress in a number of Miocene basins and sections enables one to offer a more robust chronological background for the hominoid record in Europe and to test its correlation with the main palaeogeographic and palaeoenvironmental events which affected this continent.
The chronological framework
The Miocene hominoid record in Eurasia includes several species, based on sets of remains varying in quality from isolated dental remains to rather well documented cranial and post-cranial skeletal remains (Bonis et al., 1990; Begun, 1992; Moyà-Solà & Kohler, 1993, 1996; Alpagut et al., 1996; Andrews et al., 1996).