Marco Rustioni

Last Glacial mammals in South America: a new scenario from the Tarija Basin (Bolivia)

The chronology, sedimentary history, and paleoecology of the Tarija Basin (Bolivia), one of the richest Pleistocene mammalian sites in South America, are revised here based on a multidisciplinary study, including stratigraphy, sedimentology, geomorphology, paleontology, isotope geochemistry, and 14C geochronology. Previous studies have indicated a Middle Pleistocene age for this classic locality. We have been able to obtain a series of 14C dates encompassing all the fossil-bearing sequences previously studied in the Tarija Basin. The dated layers range in age from about 44,000 to 21,000 radiocarbon years before present (BP), indicating that the Tarija fauna is much younger than previously thought. Glacial advances correlated to marine isotopic stages (MIS) 4 and 2 (ca. 62 and 20 ka BP, respectively) are also documented at the base and at the very top of the Tarija–Padcaya succession, respectively, indicating that the Bolivian Altiplano was not dry but sustained an ice cap during the Last Glacial Maximum. The results of this multidisciplinary study enable us to redefine the chronological limits of the Tarija sequence and of its faunal assemblage and to shift this paleontological, paleoclimatological, and paleoecological framework to the time interval from MIS 4 to MIS 2.

Cesi, an early Middle Pleistocene site in the Colfiorito Basin (Umbro-Marchean Apennine), central Italy

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.

Miocene Vertebrate remains from Scontrone, National Park of Abruzzi, Central Italy

In the outskirts of Scontrone, in the National Park of Abruzzi, the uppermost beds of marine sequence outcrops have yielded fossil remains of reptiles (crocodiles and chelonians) and continental mammals (a carnivore and perhaps four artiodactyls). The vertebrate-bearing sediments are tentatively dated to the Tortonian or Messinian. Artiodactyls point to a relationship with the Early Pliocene endemic fauna of the Gargano promontory, thus raising an intriguing problem of Late Neogene paleogeography.RiassuntoI termini superiori di una serie marina che affiora nei pressi di Scontrone, nel Parco Nazionale degli Abruzzi, hanno restituito resti tossili di rettili (coccodrilli e cheloni) e mammiferi (un carnivoro e forse quattro artiodattili). I livelli a vertebrati sono al momento attribuiti al Tortoniano-Messiniano. Gli artiodattili indicano una relazione con la fauna endemica del Pliocene inferiore del promontorio del Gargano, sollevando cosi un interessante problema di paleogeograiia del tardo Neogene.

Taphonomic analysis of Tapirus arvernensis remains from the lower valdarno (Tuscany, central Italy)

The present investigation describes the taphonomic evidence that can be observed on the remains of two Tapirus arvernensis individuals, a prime-aged adult and a juvenile, recovered at Casenuove (Empoli), in the Lower Valdarno marine Pliocene sediments. The spatial arrangement of the bones on the fossiliferous surface suggests the action of one or two currents, and seems to agree with the tentative reconstruction of the shoreline at the Early-Mid-Pliocene transition. Reference to the biology and ethology of presently living Asian tapirs leads to interpret the two individuals as a female, presumably at its first breeding experience, and its cub.

A Multidisciplinary Approach to the Analysis of Multifactorial Land Mammal Colonization of Islands

A highly debated question that engages paleontologists, zoogeographers, and zoologists is how terrestrial mammals colonize islands. The questions oversimplification and the subjective and partial responses to it have led to reductionist models. Insular faunas and fossil assemblages result from a complex interaction of geological, biological (in a broad sense), climatic, eustatic, taphonomic, and historical processes. Insular assemblages and their accompanying variables should be investigated on a case-by-case basis. In this article, we discuss not only common misconceptions and their potential origins but also the key issues that should be addressed when dealing with the colonization of islands by land mammals. We call for the implementation of multi- and interdisciplinary research programs and teamwork, involving paleontological, geological, and stratigraphic information; climatological factors; sea-level evolution; sampling and analytical biases; ecological, physiological, taphonomic, and environmental factors; behavioral characters and ecological preferences; genetics; phylogeography; densities of colonizing populations; and historical reports of human-mediated faunal introductions.

The genus Ursus in Eurasia: dispersal events and stratigraphical significance

On the basis of the results of former studies by the present authors five main groups of bears are recognized: Ursus gr. minimus - thibetanus (black bears), Ursus gr. etruscus (etruscan bears), Ursus gr. arctos (brown bears), Ursus gr. deningei - spelaeus (cave bears) and Ursus gr. maritimus (white bears). Black bears seem to have disappeared from Europe during the Late Pliocene, immigrated again at the beginning of the Middle Pleistocene, and definitively died out in Europe at the beginning of the Late Pleistocene. Etruscan bears occur more or less contemporaneously in the southern areas of Europe and Asia during the Late Pliocene. The Asian branch apparently became extinct at the end of this period, while the European stock survived, giving rise to more advanced representatives during the Early Pleistocene. Brown bears seem to have originated in Asia. This group dispersed widely in holoarctic areas diversifying into a great number of varieties. They reached Europe presumably at the very end of the Early Pleistocene. The arrival of brown bears in Europe is a crucial event, which approximately coincides with the great faunal turnover which marks the Early-Middle Pleistocene transition. Brown bears replaced the etruscan bears, typical of the Villafranchian faunal assemblages, and gave rise to the cave bear line. Cave bears were very successful in Europe during the Middle and Late Pleistocene and disappeared at the end of the last glaciation or even at the very beginning of the Holocene. White bears presumably originated from northern Eurasian brown bear populations during the Late Pleistocene.

L’orso fossile di Senèze (Francia meridionale)

L’orso di Seneze e qui riferito al ceppo degli orsi neri dell’Eurasia. Viene messa in discussione 1a coerenza dell’associazione faunistica per 1a presenza di alcuni elementi tardo pliocenici e di alcuni tardo villafranchiani, fra i qualiHippopotamus cf.antiquus. Anche la posizione stratigrafica e controversa. Alla luce di cio, l’orso di Seneze potrebbe rappresentare l’ultima testimonianza di questo gruppo in Europa oppure una presenza isolata nel Pleistocene inferiore.The bear from Senèze is here referred to the black bear stock of Eurasia. The coherency of the faunal assemblage is discussed, in the light of the occurrence of late Pliocene and several Late Villafranchian elements, among whichHippopotamus cf.antiquus. The stratigraphical position is also controversial. In accordance with this, the black bear from Senèze could represent either the last occurrence of this stock in Europe, or an isolated presence during the Early Pleistocene.RiassuntoL’orso di Senèze è qui riferito al ceppo degli orsi neri dell’Eurasia. Viene messa in discussione 1a coerenza dell’associazione faunistica per 1a presenza di alcuni elementi tardo pliocenici e di alcuni tardo villafranchiani, fra i qualiHippopotamus cf.antiquus. Anche la posizione stratigrafica è controversa. Alla luce di ciò, l’orso di Senèze potrebbe rappresentare l’ultima testimonianza di questo gruppo in Europa oppure una presenza isolata nel Pleistocene inferiore.

A Miocene cervid from the torrente Morra sequence (Collesalvetti, Pisa Italy)

A well preserved fossil left tibia of artiodactyl was recently found along Torrente Morra, in the surroundings of Collesalvetti (15 Kms South of Pisa). The bone is embedded in Upper Messinian deltaic sediments which outcrop patchily in the area. The specimen can be referred to a primitive cervid and shows morphological characters and proportions very close to those of the tibiae of extant roe deer, Capreolus capreolus . The find is particularly significant because continental mammals have never been reported before from the Miocene deposits of this area. A possible reference to a primitive roe deer would be consistent with Late Miocene macrofloral and palynological evidence from this area, which attest to a transition from a subtropical forested environment to a temperate Mediterranean one.