A revisit to the Early Pliocene site of Abla (Guadix-Baza Basin, southern Spain)

The Guadix-Baza Basin (southern Spain) displays one of the best continental records from the Late Miocene to the Middle Pleistocene in western Europe, with many localities of fossil small mammals in a quite complete and continuous stratigraphic sequence. The Late Miocene continentalization of the Guadix-Baza Basin was firstly mentioned in the 1980s based on the presumed presence of Hipparion gromovae granatensis at the site of Abla (Almería province). Subsequent discoveries of late Turolian deposits confirmed the Late Miocene continentalization of the basin. The interest in the Abla site led to a second sampling campaign to look for microvertebrate fossils, which proved successful. In this paper, a complete taxonomic study of the novel microvertebrate fauna from Abla is presented, providing updated information on the age of the locality. Representatives of the vertebrate families Cyprinidae, Alytidae, Anguidae, Soricidae, Cricetidae, and Muridae have been identified. The presence of Stephanomys specimens exceeding the size of latest Miocene-earliest Pliocene species allows us to correlate the Abla site with the Early Pliocene (Ruscinian), a younger age than initially stated. A qualitative paleoecological interpretation based on the herpetofauna suggests the dominance of open environments with presence of permanent water bodies during the deposition of the Abla site, under warmer and more humid climate conditions than today in the Guadix-Baza Basin. A revision of the Hipparion remains from this locality showed that the sample is closer to Hipparion fissurae than to the initially assigned species.