Paleoenvironmental and paleoclimatic proxies to the Early Pleistocene hominids of Barranco León D and Fuente Nueva 3 (Granada, Spain) by means of their amphibian and reptile assemblages

Abstract

Because most amphibians are water dependent and most reptiles are temperature dependent, the climatic and/or environmental parameters in their immediate environment mark their distribution. Accordingly, they can contribute to an understanding of microhabitats and microclimates within a larger landscape, such as the Guadix-Baza Basin in south-eastern Spain. The Early Pleistocene archaeological and paleontological sites of Barranco León D and Fuente Nueva 3, which are localized in both space and time in the Guadix-Baza Basin, have together yielded a diversified accumulation of herpetofauna that comprises at least 20 taxa of amphibians, chelonians, lizards and snakes. With the exception of the bufonid Bufo sp. ( viridis group) and the anguid lizard Dopasia, these two assemblages do not specifically differ from the extant herpetofauna of the Iberian Peninsula, making them suitable for use in paleoclimatic and paleoenvironmental reconstructions without the ecological uncertainties of extinct taxa. In this paper, mutual climatic range and habitat weighting methods are applied to amphibian and reptile assemblages in order to estimate quantitative data. The results indicate that during the late Early Pleistocene mean annual temperature and mean annual precipitation were higher than they are now on the south-eastern Iberian Peninsula. The contrast between summer and winter temperatures (i.e. continentality) was less pronounced, mainly due to warmer conditions during winter. Rainfall distribution indicates a considerable increase in precipitation in every season but summer, which was drier and consistent with the Mediterranean climate pattern. The terrestrial landscape was composed of open environments (mainly dry meadows, rocky-stony areas and Mediterranean scrubland), although there were some wet wooded areas. Water-linked amphibians and reptiles suggest the existence of a sunny permanent aquatic environment with banks made up of a movable ground. These results are compared with those for large mammals, small mammals and pollen analyses, yielding a scenario for the paleoclimatic and paleoenvironmental conditions that were in place during the Early Pleistocene in the Guadix-Baza Basin.