346 research outputs found
A new species of Sangiorgioichthys (Actinopterygii, Semionotiformes) from the Kalkschieferzone of Monte San Giorgio (Middle Triassic; Meride, Canton Ticino, Switzerland)
No full textThe genus Sangiorgioichthys is one of the few Semionotidae known from the Middle Triassic. The type species S. aldae Tintori & Lombardo, 2007 has been found in Late Ladinian marine deposits of both the Italian and Swiss sides of Monte San Giorgio. A second species, S. sui López-Arbarello et al., 2011 described from the Pelsonian (Middle Anisian) of Luoping (Yunnan, South China) has extended the range of the genus both in time and space. A further species of Sangiorgioichthys, Sangiorgioichthys valmarensis n. sp., is described herein from the Late Ladinian Kalkschieferzone (Meride Limestone) of the Monte San Giorgio area, the same unit yielding the type species. Sangiorgioichthys valmarensis n. sp. differs from the already known species in number and arrangement of suborbitals, shape of the teeth and in shape and row number of the scales. The new species of Sangiorgioichthys increases the diversity of Semionotidae already in the Middle Triassic, indicating that the explosive radiation of Semionotidae during the Norian was preceded by a first phase of diversification during the Middle Triassic
Comment on “The vertebrates of the Anisian/Ladinian boundary (Middle Triassic) from Bissendorf (NW Germany) and their contribution to the anatomy, palaeoecology, and palaeobiogeography of the Germanic Basin reptiles” by C. Diedrich [Palaeogeography, Palaeoclimatology, Palaeoecology 273 (2009) 1–16]
No full textThe Middle Triassic vertebrates are proving to be very important witnesses of the post P/Tr crisis recovery, but also of the palaeobiology and paleogeography. The western Tethys (especially the Monte San Giorgio fossiliferous series) and the Germanic Basin are of particular interest as they show similar vertebrate assemblages in somewhat different environmental patterns and ages. Furthermore, the MSG specimens are usually complete and concentrated in different levels spanning from Late Anisian to Late Ladinian, while vertebrates of the Germanic basin often consist of scattered remains, sometimes gathered in bone-beds.
In the last years Diedrich proposed a number of restorations, concerning both organisms and palaeoenvironment. Very often his work does not consider other Authors’ papers, and a few concepts, such as the supposed ‘anatomic convergence’ between a sauropterigyan reptile and a mammal, appear scientifically unsound. In this comment the author points out some uncertain data and unproven conclusions in Diedrich’s pape
L’insicurezza stradale. Quando una politica pubblica diventa possibile e necessaria
No full textL'articolo prende in esame sia la situazione dell'incidentalità stradale che le politiche poste in essere per affrontare questo grave fenomeno sociale. Il caso italiano viene analizzato comparandolo con quellod egli altri paesi europei. Vengono analizzate alcune specifiche misure che si sono rivelati aprticoalrmente efficaci, quale l'obbligo di uso del casco e la patente a punti. Vengono infine esaminati alcuni casi di amministrazioni locali (Province di Bologna e Milano)
The Middle Triassic vertebrate levels in the Western tethys: are fossil fishes useful for biostratigraphy?
No full textLa sicurezza stradale. Quando una politica pubblica fa la differenza.
No full textIl volume analizza un fenomeno assai poco discusso nel contesto italiano, nonostante la sua rilevanza umana, sociale ed economica: quello dell'incidentalità stradale. Il fenomeno viene discusso nel contesto delle esternalità negative provocate dalla mobilità veicolare (inquinamenti, effetti relazionali, sociali ed urbanistici). Dopo aver presentato l'entità del fenomeno comparando l'Italia ad altri paesi, in particolare europei, vengono prese in esame le cause dei sinistri. Il volume quindi presenta le politiche pubbliche adottate per contrastare il fenomeno (fra cui la patente a punti), anche qui in un'ottica comparata prendendo in considerazione i paesi che hanno ottenuto i risultati più significativi nella riduzione degli incidenti enl perseguire l'obbiettivo indicato dall'Unione Europea di dimezzare gli incidenti e ele loro conseguenze entro il 2010
Feeding specialization in Late Triassic fishes
No full textThe ichthyofauna of the Zorzino Limestone represents an important proof of the richness and variety
reached by bony fishes during the Norian and, at the same time, it testifyies the beginning of the faunal
transition which will be realized during the Jurassic. The thousands of specimens and the extraordinary quality
of preservation found in the fossiliferous levels of this unit allowed, in the last years, not only to follow such a
crucial moment in the evolution of vertebrates, but also to reconstruct the mode of life and the trophic
adaptations reached by the different groups, living in the depositional basins. As evidence of this peculiar
evolutionary period, the large predators at the highest trophic levels are still represented by ’primitive’ basal
actinopterygians; on the contrary, the most derived neopterygians specialized in durophagy, a trophic niche
previously almost unexploited by actinopterygians. Within the main trophic categories, anyway, we can find
different morphological specializations, which probably allowed the fishes to exploit most of the available
trophic resources
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
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