1,720,958 research outputs found
The first multi-individual assemblage of a Mesozoic dinosaur from Italy: systematic, osteohistological and morphological re-evaluations of Tethyshadros insularis (Dinosauria: Ornithopoda)
No full textTethyshadros insularis Dalla Vecchia, 2009 was originally described as an insular, pygmy hadrosauroid closely related to hadrosaurids, based on a complete and articulated specimen from the Upper Campanian–Early Maastrichtian Liburnian Formation, northeastern Italy. Recent preparation of a second specimen (SC 57247) and additional information from a third skull (SC 57026) provide important new elements on the anatomy and systematics of this taxon. T. insularis was originally diagnosed on a mosaic of primitive and derived characters, the latter particularly present in the skull, such as a long anteorbital region due to elongated maxillae and nasal bones. SC 57247 represents a 20 % larger individual based on skull length, with more massive appendicular proportions. The skull is remarkably
shorter and brachyrostrine, features also present in SC 57026, displaying proportions more reminiscent of iguanodontoid-grade ornithischians rather than hadrosauromorphs. Histological thin sections from the ribs of SC 57247 indicate this larger individual is approaching somatic maturity, with the development of an incipient external fundamental system. After the reinterpretation of the holotype as pertaining to an immature individual, the systematic position of the taxon shifts more basally towards affinities with smallerbodied hadrosauroids, casting doubts on previous claims of insular dwarfism in this ornithopod dinosaur
Cranial anatomy of Acynodon adriaticus and extreme durophagous adaptations in Eusuchia (Reptilia: Crocodylomorpha)
Full text linkAcynodon adriaticus, a small eusuchian from the Late Cretaceous of Italy, is known for its well-preserved cranial and postcranial material. Despite its excellent preservation, many details remain hidden due to the physical overlap between the elements and matrix obliteration. We used Micro-CT scans to reveal previously overlooked anatomical features and describe in detail the cranial and dental anatomy of this taxon, shedding new light on its palaeoecology. The holotypic specimen, SC 57248, represents a mature individual exhibiting signs of hyperossification, developed ornamentation, and various pathologies, including jaw arthritis and a possible dental anomaly. Acynodon adriaticus exhibits significant durophagous adaptations, including a robust, brevirostrine skull optimized for powerful biting and stress-load capacity. Its specialized dentition, lacking caniniform teeth, features anterior chisel-like teeth and hypertrophic posterior molariforms with thick enamel, indicative of a diet specializing in hard-shelled prey. The dentition pattern, accelerated molariform replacement rate, and reduced orbit size suggest adaptations for durophagous foraging in turbid, densely vegetated aquatic environments. The paleoecological context during the Late Cretaceous, characterized by increased freshwater habitats and high invertebrate diversity, likely facilitated the evolution of such specialized traits in A. adriaticus. This small crocodylomorph likely foraged slowly in shallow, benthic environments, using its powerful bite to process mollusks and large arthropods. The study of A. adriaticus, along with comparisons with other crocodylomorphs and ecomorphologically similar taxa like Iharkutosuchus makadii and Gnatusuchus pebasensis, provides a valuable morphofunctional model for understanding the evolutionary pathways of extinct crocodylians to durophagy
Body-size evolution and biogeographic history in the Late Cretaceous European ‘archipelago’ enlightened by the first Italian multi-individual dinosaur locality
No full textThe latest Cretaceous Adriatic Carbonate Platform (AdCP) system in the paleo-Mediterranean area
stands as one of the most complex and debated topics related to the evolution of land vertebrates
in the area surrounding the Tethys Sea. Italy holds the sole Late Cretaceous dinosaur-dominated
site of the AdCP, namely the Villaggio del Pescatore locality (VdP). The VdP site was discovered
thirty years ago in the Late Cretaceous-Paleogene beds exposed near Duino Aurisina, northeastern
Italy, and produced, among fish, crustacean and plant remains, an exquisitely preserved skeleton of
the diminutive hadrosauroid Tethyshadros insularis. The type specimen was originally described as
a pygmy taxon, showing peculiar adaptations connected to insular conditions. This taxon is here reexamined
based on additional specimens from the type locality, making the site the first, multiindividual
dinosaur locality of Italy. Sole representative of the latest Cretaceous paleo-Mediterranean
archipelago, T. insularis offers unmatched data to infer environmentally-driven body-size trends in
non-avian dinosaurs. Histological analyses indicate juvenile features in the type specimen, whereas
a second, larger individual, was approaching somatic maturity. Consequently, we revised the former
description of the holotype, documenting the morphological variation in this taxon, and highlighting
the ontogenetically variable characters. Finally, we investigated the phylogenetic position of
Tethyshadros using a phylogenetic comparative framework, which combines ancestral state
reconstruction and multiple regime Ornstein-Uhlenbeck models. Such approach enables to evaluate
whether the evolution of body-size was following a significant and accelerated trend of reduction in
this clade, in order to further test the interpretation of this taxon as an ‘aberrant’, insular dwarf
There is more than meet the eyes: unfolding the diversity, age, and ecology of the Late Cretaceous Villaggio del Pescatore site (Trieste, Italy)
No full textThe Late Cretaceous Mediterranean archipelago, its geodynamic history, ecological diversity, paleogeography and faunal composition stand as one of the most complex and debated topics related to the evolution of the Tethys Ocean and its continental margins. We conducted a pilot project started in 2019, generating novel and unforeseen outcomes related to one of the most important fossil localities of Europe: the Villaggio del Pescatore site (VdP, Duino-Aurisina, Trieste, Italy). Although this locality has achieved notoriety for the exquisite preservation of its dinosaur-dominated fossil assemblage, the organization of historically neglected and newly re-evaluated data into a unified framework set the ground for a renewed understanding of this site. With more than 450 identifiable fossils (including fish, crocodilian, dinosaurs, pterosaurs, crustaceans, plant remains, invertebrates), microfossils (foraminifera, pollens, ostracods, cyanobacteria), ~200 thin sections for biostratigraphic analyses, more than 100 still unprepared specimens and other still found in situ, the VdP offers a unique, high-resolution window for qualitative and quantitative analyses, including a detailed redefinition of its age. New prospecting activities and extractive processes resulted in additional observations. We here reevaluate data presented in the literature as referring exclusively to a very restricted area of approximately 300 square meters of the quarry and document that less than 40% of the site has been so far mapped and support a continuous extension of fossil beds outside the main, protected area. From a sedimentologic perspective, the uniqueness of VdP is represented by sharp facies variations from open marine, shallow-water limestones to organic-rich rhythmites, which interbed with breccias that accumulated as underwater bodies of breccia by subaqueous, density-driven, sedimentary flows. Rhythmites and breccias are folded by slumping and deformed by wet-sediment normal fault. Slumps also raise questions concerning the taphonomy (preservation of land vertebrates in dysoxic to anoxic bottom waters from marginal-marine settings) as well as the interaction between different depositional settings (terrestrial-paralic–shallow marine). The outstanding example of ‘Bruno’ – the second, sub-complete Tethyshadros insularis extracted from the quarry – shows how the mesoscale folding has interested the fossil body harmoniously but maintaining most of its skeletal connections. Based on inventory and new field surveys, we estimate seven articulated skeletons preserved at the VdP site and possibly eleven individuals of T. insularis. Originally described as an insular, pygmy hadrosauroid closely related to hadrosaurids, based on a single specimen. T. insularis is here revised on the basis of multiple individuals, including histological samples, documenting previously unexpected ontogenetic trends and morphological variation in this taxon
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe 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
Full text link“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
Full text linkWe 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
Full text linkWe 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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