The Authors have elaborated four range charts of mammalian (large and micro), molluscs and fresh-water and brackish ostracodes faunas, for the selected Plio-Pleistocene fossiliferous localities of the Italy. A new Mammal Age (Aurelian) correlatable to late Middle and Late Pleistocene has been defined. Inside this age two Faunal Units (Torre in Pietra and Vitinia) have been defined as characteristic for Early and Middle Aurelian, while no gisements have been chosen for the late Aurelian. Biochronological units are calibrated on magnetostratigraphic and isotopic scales and by radiometric datings.

Near the village of Cesi, at the head of the Chienti River, in the Colfiorito Basin (Umbro-Marchean Apennines, central Italy), fluvio-lacustrine deposits have yielded mammal fossil remains. The results of a multidisciplinary investigation indicate that the vertebrate-bearing sediments date about 700 ka and accordingly provide a fossil assemblage for the Middle-Late Galerian. Palynological investigations carried out from sediments underlying the fossiliferous level suggest predominantly cold and dry conditions, whereas the fauna suggests a slight climatic amelioration towards cool and moist conditions in the uppermost part of the sequence. (C) 1997 by John Wiley & Sons, Ltd.

Paleontological, geomorphological and sedimentological investigations on the Cangahua Formation in the Interandean depression of Northern and Central Ecuador have provided information on the evolution of the Andean paleoenvironment during the Late Pleistocene. Pyroclastic and windblown sediments were deposited during cold and dry phases of the last glaciation, interrupted many times by the development of forest-steppe and steppe paleosoils during interstadials. An erosional phase which closed the Cangahua sedimentation was followed by the deposition of colluvial sediments, characterized by a high number of minor pedogenetic episodes. The colluviums are confidently referable to the Holocene. The upper part of the Cangahua Formation is rich in mammal fossils and is probably referable to the Last Glacial Maximum.The fossiliferous sequences suggest that mastodonts disappeared before mylodonts and equids. We hypothesize that the increased cold and aridity of the Last Glacial Maximum, which deeply affected the Cordillera, caused the extinction of most of the mega-fauna and the mastodonts seem to have been the most sensitive to the environmental degradation.The final history of South American mastodonts, represented by Haplomastodon and Stegomastodon, spans the latest Pleistocene and probably the earliest Holocene. Haplomastodon was dispersed in the highlands within the tropical belt and Stegomastodon in plains of the southernmost part of Brazil, in Paraguay, Uraguay, Argentine, central and northern Chile.Both Haplomastodon and Stegomastodon suffered the same negative effects of the Last Glacial Maximum when their habitats underwent intense desertifications under dry and cold conditions. They disappeared in a mosaic way in the course of the latest Pleistocene, the last representatives probably surviving in favorable restricted areas where however the considerably increased selective pressure was in the long run devastating. In our opinion the human impact was not a determinant in causing mastodont extinction. (C) 1997 Published by Elsevier Science Ltd.

The first lower molars of the endemic vole Microtus (Tyrrhenicola) henseli from caves, karst fissures, and bone breccias of eight Sardinian localities of Middle Pleistocene and Holocene age, and from one Holocene cave deposit of northern Corsica have been studied. The material, consisting of a total of 198 ml ’s, has been examined by means of morphometric methods, including multivariate techniques. A further prelimi­ nary analysis of the microstructural pattern of the enamel has been also carried out, on the basis of a small number of molars. The results of these analyses are fairly congruent. The morphological analysis has demonstrated the presence of correlations between some parameters (e. g., the length of the anteroconid complex and the anterior loop, or the elongation of T6 and the pinching of the neck) that strengthen the evolutionary signific­ ance of the observed trends, even though in the evaluation of the overall evolutionary level of each population it is necessary to realize that a certain degree of independence between the characters is present (mosaic distribution). The study of enamel microstruc­ ture has demonstrated the occurrence of great intraspecific variability that should be investigated in larger subsamples, but has also identified a general trend towards reduction of the tangential layer in the trailing edges, coupled with a reduction in thickness of the whole distal enamel walls of the dental triangles. On the basis of these results, the forms from the sites studied can be arranged in two main groups: a less derived group of Pleistocene forms from six localities, characterized by small size, a simpler and somewhat shorter anteroconid complex, and a broad neck, and a more derived group, composed of latest Pleistocene to early Middle Holocene samples, that includes forms with a more complex anteroconid, a more pronounced pinching of the neck, and a tendency towards larger size. The samples from the localities of Capo Figari and Grotta Dragonara show the least derived morphologies within the group of Pleistocene localities, with molars moderately differentiated in a microtine direction as concerns the pattern of enamel microstructure, while in this group the samples from Monte San Giovanni and Bonaria display intermediate characters. In the group including the Holocene forms, with more derived morphology and a reduced layer of tangential enamel and thinner trailing edges, the sample from the Corsican site of Fontaneddu is distinct in having highly derived features coupled with a slightly less elongated anteroconid complex. The evolutionary data resulting from our study may be useful for a more detailed biochronological subdivision of the Corsica-Sardinia faunal complexes, and suggest that a marked increase in evolutionary rates should have occurred at the end of the Pleistocene, possibly due to environmental changes related to climatic factors and to the impact of human civilization on the endemic mammal community.