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FIRST SKELETAL REMAINS OF HELVETICOSAURUS FROM THE MIDDLE TRIASSIC ITALIAN OUTCROPS OF THE SOUTHERN ALPS, WITH REMARKS ON AN ISOLATED TOOTH
Get PDFThe enigmatic marine reptile Helveticosaurus zollingeri, from the Middle Triassic Besano Formation of Monte San Giorgio, is known from three specimens found in Swiss territory. This paper describes the first skeletal remains of this taxon recovered from the corresponding Italian outcrops of Besano (Varese). An isolated tooth assigned to the same taxon and coming from the San Salvatore Dolomite, Rasa di Varese (Varese), is also redescribed herein. The skeletal remains have been CT scanned to inspect the preserved morphology of the bones hidden below the surface; CT data also allowed the identification of an associated ammonoid which has been crucial to determine the stratigraphic position of the studied material. The redescription of the tooth has been helped by a digital model of the specimen obtained through photogrammetry. With the additional new data obtained from the two specimens, the first skeletal reconstruction of Helveticosaurus is provided. This is followed by a phylogenetic test of the taxon, assessing its position among marine Triassic diapsids. Finally, in the light of recent studies we discuss the swimming mode and the possible ecological niche occupied by the animal: we suggest a distinction between the function of forelimbs and hindlimbs, and a distinction between different swimming styles likely performed by Helveticosaurus, depending on the speed of movements
Evidence of large theropods from the Middle Jurassic of the Mahajanga basin, NW Madagascar, with implications for the ceratosaurian pedal ungual evolution.
No full textTwo large theropod remains from the Middle Jurassic (Isalo IIIb, Bathonian) of the Mahajanga Basin, NW Madagascar, are here described. They consist of a large tooth crown and a pedal ungual. The tooth is similar to the teeth of some basal tetanuran theropods, but we cautiously refer it to Theropoda incertae sedis. The pedal ungual, pertaining to a close relative of the abelisauroids but not to a member of the Abelisauroidea, shows that non-abelisauroid ceratosaurian theropods were present in the Middle Jurassic of Madagascar and provides new insight into the evolution of the ceratosaurian pedal unguals. Both remains reveal the large body size attained by the Middle Jurassic Malagasy theropods
New findings reveal that the Middle Triassic ichthyosaur Mixosaurus cornalianus is the oldest amniote with a dorsal fin
Get PDFTwo excellently preserved specimens of Mixosaurus cornalianus from the Anisian layers of the Middle Triassic
Formazione di Besano, with soft parts associated with well-articulated skeletal elements, revealed the presence in this
species of a dorsal fin and of a well-developed, triangular dorsal lobe of the caudal fin, both stiffened by an array of
fibre bundles, as in Jurassic fast-swimming ichthyosaurs. This finding testifies that efficient swimming exaptations were
already present in some Middle Triassic ichthyosaurs. Mixosaurus is then the oldest amniote so far known that developed
a dorsal fin. The preservation of the fin shapes, scaleless skin, and three-dimensional dermal fibres is remarkable,
allowing observation of their microstructure, and ruling out any artefactual interpretation. Stomach contents indicate
that both specimens preyed upon cephalopods and small fishes. An internal organ, possibly a tract of the intestine, is also
preserved in one specimen, which represents the first documented case in the ichthyosaurs of the Besano Formation, and
a rarity in the fossil record of the clade
First sauropod bones from Italy offer new insights on the radiation of Titanosauria between Africa and Europe.
No full textHere we describe the first sauropod skeletal remains from the Italian peninsula that also represent the
earliest record of titanosaurs in Southern Europe. Scattered bones, including an almost complete anterior
caudal vertebra, were found in Cretaceous (AptianeAlbian) marine deposits, some 50 km East of Rome.
The vertebra shows a bizarre and perhaps unique orientation of the zygapophyseal articular facets that
renders their interpretation problematic. Phylogenetic retrofitting tests support the placement of the
Italian titanosaur among basal lithostrotians. Palaeobiogeographic analysis based on the resulting
phyletic relationships suggests an Afro-Eurasian route for the ancestors of the Italian titanosaur, a scenario
compatible with the palaeogeographic evolution of the Italian microplates during the Cretaceous.
Together with previously recorded titanosaurian-like ichnites from a Cenomanian locality in Latium, this
new find suggests a quite long emersion for the Apenninic carbonate platform. We suggest that the
Italian titanosaur was member of a population that crossed the western Tethys Sea through a “filtering
bridge” composed of a chain of ephemeral islands and peninsulae, known as Periadriatic (Adria) carbonate
platforms, that connected sporadically Africa and Europe since the Early Cretaceous
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Get PDFWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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