1,721,016 research outputs found
A preliminary study on the ornamentation patterns of ganoid scales in some mesozoic actinopterygian fishes
No full textGanoid scales are one of the most common remains of vertebrates in the fossil record of Paleozoic and Mesozoic. Their knowledge is important for the understanding of the paleobiology and evolution of actinopterygian fishes. The distinctive feature of these scales is the outermost shiny layer of ganoine, an hyper-mineralized enamel-like tissue. During the Mesozoic, ganoid scales show a great variety of shapes and very different patterns of ornamentation made of ganoine. The surface of scales may be from smooth to very ornamented, with a relief arranged in tubercles, ridges, grooves or a combination of them. Here we present a preliminary study on the squamation of some Mesozoic non-teleost actinopterygians in order to test the association between body shape and ganoine ornamentation. Using several morphological descriptors, we built an empirical morphospace to compare ganoid scales ornamentation. The use of a quantitative method to describe scales allows to test if there is a meaningful correlation between body shape and ganoine ornamentation in non-teleost actinopterygians. We found an important association between body shape and scale ornamentation in the taxa under investigation. In particular, deep-bodied fishes bear a more complex and variegate ornamentation than fusiform ones. This finding has important implications in our understanding of non-teleost actinopterygians paleobiology. Since swimming activity is a primary function for fish and this is performed by the body acting as an integrated unit, the correlation between body shape and ganoine ornamentation could be related to hydrodynamics. A quantitative test of this hypothesis, however, would be desirable
Functional morphology and mode of life of the Late Triassic placodont Psephoderma alpinum Meyer from te Calcare di Zorzino (Lombardy, Northern Italy).
No full textA new Lariosaurus from the Kalkschieferzone (Uppermost Ladinian) of Valceresio (Varese, Northern Italy)
No full textArchosaur (possibly theropod) teeth from the Norian (Late Triassic) of Lombardy (Northern Italy)
No full textNota sul ritrovamento di una vertebra di Ittiosauro (Leptpterygiidae indet.) del Giurassico Inferiore delle Cave di Arzo (Ticino Meridionale, Svizzera)
No full textPrimi Vertebrati fossili dalla Formazione di Cunardo (Ladinico Inferiore,Triassico Medio) della Valtravaglia (Varese)
No full textLa presenza dell’Uomo di Neandertal e nuovi dati dalla Caverna Generosa (scavi 2002 e 2003).
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Indices de fréquentation humaine dans les grottes à ours au Paléolithique moyen final. L'exemple de la Caverna Generosa dans les Préalpes lombardes, Italie
No full textAlready known like a palaeontological site for the study of Ursus spelaeus, Caverna Generosa also records ephemeral traces of human visits during the late Middle Palaeolithic. The cave opens at an altitude of 1450 m on the steep southern slope of the Monte Generoso Massif between the Lugano and the Como lakes and forms a complex group of narrow galleries and inner chambers. Sedimentological and palaeontological data and radiocarbon dates place both the cave-bear and the human frequentations in the first part of the isotopic stage 3 with climatic conditions shifting from cool and dry to more temperate and wet. Environment progressively changed from scarcely arboreal to arboreal-brush with small open spaces. Few flakes and Levallois flakes have been recovered scattered in the sediment and affected in most cases by intense postdepositional alteration. These items testify incursions of mousterian groups equipped with endproducts and radiolarite flakes struck from blocks provisioned at lower locations southwards. End-products, namely Levallois flakes, prove that lithic reduction sequences were spatiotemporally fractionated in the covered territory. Conversely, it cannot be excluded a priori that sublocal radiolarite has been chipped at the entrance of the cave or at the very close surroundings for extraction of rudimental tools for immediate use. It is worth to mention that the small chert slabs in the Moltrasio limestone which crop throughout the cave walls were totally ignored. Caverna Generosa can be viewed as a refugia-location used in function of more or less constrained factors strongly influenced by high-altitude and bioclimatic situations. This type of site might well be integrated within the seasonal movements of humans in the western Lombard Pre-Alps area.Connue comme un gisement paléontologique fortement fréquenté par l’ours des cavernes, la Caverna Generosa a livré au cours des recherches récentes des indices discrets de fréquentation anthropique rapportables au Paléolithique moyen final. La caverne s’ouvre à 1450 m d’altitude sur le versant méridional abrupt du massif du Monte Generoso, entre le Lac de Lugano et le Lac de Côme, et se présente comme un complexe de galeries étroites et de chambres internes. Les données sédimentologiques, paléontologiques et un ensemble de dates radiocarbone situent les fréquentations animales et humaines dans la première partie du stade isotopique 3. Elles témoignent du passage d’une phase climatique relativement froide et aride à une phase plus tempérée et humide, avec une transformation progressive des environnements, de faiblement arborés à arborés riches en arbustes et végétation de sous-bois avec de rares zones ouvertes. De rares éclats découverts dispersés et dans certains cas profondément altérés par des phénomènes post-dépositionnels témoignent d’une série d’incursions de Moustériens équipés d’objets achevés et de quelques blocs bruts en radiolarite prélevés à faible distance de la cavité. Les objets achevés démontrent une segmentation spatio-temporelle de la chaîne opératoire, alors qu’il n’est pas exclu que les blocs de radiolarite aient été travaillés à l’entrée du site ou à proximité pour obtenir des outils rudimentaires destinés à être utilisés immédiatement. Il convient de souligner le désintérêt total pour les plaquettes de silex contenues dans le Calcaire de Moltrasio, aux dépens duquel est creusée la cavité
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