New material of Alierasaurus ronchii (Synapsida, Caseidae) from the Permian of Sardinia (Italy), and its phylogenetic affinities

New characters of the giant caseid Alierasaurus ronchii are described here based on material recovered from the type locality in the Permian deposits of Cala del Vino Formation (Sardinia NW) and additional preparation of the previously collected material. All new described osteological elements are characterized by the same state of preservation and, given the absence of double elements and the total compatibility in absolute size, the new material can be attributed without doubt to the holotypic individual of A. ronchii. Highly diagnostic material includes a caudal neural spine with a broad bifid distal termination. This represents a synapomorphy characterizing the more derived caseids, thus fully confirming the attribution of the Sardinian specimen to Caseidae. Also the other vertebral material and newly collected ribs show a typical caseid structure, fully consistent with the previously published material. Despite the highly partial nature of Alierasaurus, the taxon was included in a recent phylogenetic analysis of caseids to investigate its phylogenetic position within the monophyletic Caseasauria. Alierasaurus falls as the sister taxon of Cotylorhynchus, and is autapomorphic in the general construction of MT-IV and proximal phalanx IV-I. The absolute size of the newly recovered material confirms a gigantic body size for Alierasaurus, comparable, if not greater, to that of the huge North American species Cotylorhynchus hancocki (up to 6 m in length). Such gigantic adult body size, closely correlated to its herbivorous lifestyle, must have been selected during evolution of caseids, leading to substantial advantages in terms of fitness

Generi e metro in Sofocle. Analisi di alcuni casi esemplari

Il lavoro risulta strutturato in tre macro-sezioni, organizzate sulla base dei due generi lirico-corali che costituiscono il focus della tesi e a ognuno dei quali \ue8 dedicata una sezione; queste, a loro volta, sono precedute da una lunga introduzione di carattere storico-metodologico, nella quale si stabiliscono le linee-guida della ricerca. La sezione introduttiva si propone di riprendere sinteticamente la storia degli studi relativamente a tre percorsi che costituiscono il presupposto metodologico del lavoro di tesi: la storia del concetto di genere letterario nella Grecia antica; i limiti e le finalit\ue0 di una ricerca intertestuale, che metta a dialogo la tragedia attica del V sec. a.C. e la produzione lirica arcaico-classica; la validit\ue0 e l\u2019utilit\ue0 di un\u2019analisi metrico-ritmica dei canti tragici in un\u2019ottica che, attraverso un approccio semantico all\u2019interpretazione metrica, guarda all\u2019intersezione di generi lirici sul piano performativo. A proposito di quest\u2019ultimo punto, vengono prese in considerazione delle problematiche molto discusse nel dibattito critico degli ultimi decenni: come decidere quale partitura metrica \ue8 la pi\uf9 affidabile (opposizione fra i difensori della colometria tr\ue0dita e i sostenitori del contrario)? Quale rapporto esisteva fra il testo, il metro, il ritmo e la musica e cosa si pu\uf2 trarre dai primi due in assenza degli altri elementi? Delle altre due macro-sezioni, la prima si concentra sui \u2018canti iporchematici\u2019 nella produzione drammatica di Sofocle e si suddivide nei seguenti capitoli: un\u2019introduzione al genere iporchematico, che ripercorre le fonti e i frammenti superstiti per definire le caratteristiche del genere e i possibili metri in esso impiegati; l\u2019analisi di Soph. Ai. 693-718; l\u2019analisi di Soph. Trach. 205-224, seguita da alcuni confronti con altri tre corali drammatici (Eur. El. 585-595; Ar. Thesm. 953-1000; Eur. Ba. 1153-1167); l\u2019analisi di tre canti sofoclei che, per diversi aspetti, possono essere ritenuti fortemente \u2018mimetici\u2019 e forse eseguibili secondo \u2018modalit\ue0 iporchematiche\u2019 (Soph. El. 1384-1397; OC 1044-1095; OC 1447-1499); l\u2019analisi di tre scene corali di ricerca nelle tragedie di Sofocle, di per s\ue9 estremamente mimetiche (Soph. Ai. 866-878; Phil. 201-218; OC 118-168). La terza e ultima sezione si occupa di due stasimi tragici che presentano alcuni stilemi formali propri dell\u2019epinicio: essa \ue8 composta rispettivamente da un\u2019introduzione al canto di vittoria, relativa al suo impianto formale e al suo uso in tragedia; dall\u2019analisi di Eur. El. 859-879 (con un raffronto finale con il frammento di epinicio composto da Euripide per Alcibiade); dall\u2019analisi di Soph. Trach. 633-662 (corredata da confronti testuali con i precedenti corali della medesima tragedia e altri brani di poeti lirici e di Euripide).This dissertation is structured into three macro-sections, two of which linked to a specific choral lyric genre (the main focus of these analyses) and preceded by a historical and methodological introduction, where the guidelines of this research are fully outlined. The first section aims at briefly synthetize the history of studies about three paths that constitute the methodological premise of this research: the concept of \u2018literary genre\u2019 in ancient Greece; the limits and goals of intertextuality, especially concerning the relationship between fifth-century Attic tragedy and archaic and classical choral lyric production; the validity and benefit of a textual analysis of tragic songs that focusses on metre and rhythm, using these elements as heralds of meaning, thus looking at the intersections of literary genres from a performative perspective. About this last point, many problems are taken into consideration, problems that were discussed in the critical debate so far: how to choose the \u2018more reliable\u2019 metrical pattern (the current debate around ancient colometry)? In what kind of relationship where the text, the metrical pattern, the rhythm and the music and what can we say starting from the two former in lack of the latter elements? The second section revolves around the so-called \u2018hyporchematic songs\u2019 in Sophocles\u2019 drama and it consists of these chapters: an introduction to the hyporchematic genre, where the sources and fragments are used in order to retrieve the main features of the lyric genre and the most recurrent metres; the analysis of Soph. Ai. 693-718; the analysis of Soph. Trach. 205-224, followed by three comparisons with other dramatic songs (Eur. El. 585-595; Ar. Thesm. 953-1000; Eur. Ba. 1153-1167); the analysis of three Sophoclean choral songs which can be considered strongly \u2018mimetical\u2019 for different reasons, and thus could have been performed in a \u2018hyporchematical way\u2019 (Soph. El. 1384-1397; OC 1044-1095; OC 1447-1499); the analysis of three choral research-scenes in the tragedies of Sophocles, that are strongly mimetic "per se" (Soph. Ai. 866-878; Phil. 201-218; OC 118-168). The third and last section aims to analyse two tragic stasima where some writing styles typical of the victory ode are implied and it does so in three chapters: an introduction to the epinician genre, its formal features and its employment in tragedy; the analysis of Eur. El. 859-879 (with a final comparison with a fragment of the epinician ode composed by Euripides for Alcibiades); the analysis of Soph. Trach. 633-662 (followed by textual comparisons with the previous choral parts of the same tragedy and other lyric and Euripidean fragments)

Subfossil tooth of a dwarf Hippopotamus (Mammalia, Artiodactyla) from the Holocene of the Berivotra ouctrops (Mahajanga Basin, NW Madagascar), with remarks on the distribution of the genus in the island

We report the presence of subfossil dwarf hippopotamuses from the neighbourhood of Berivotra (Mahajanga Basin, NW Madagascar), based on an isolated premolar of Hippopotamus, tentatively referred to H. madagascariensis Guldberg, 1882 or H. lemerlei Grandidier, 1868, two of the three species of the genus known in the Malagasy fossil record. Dwarf hippopotamuses from Madagascar are Holocenic, concentrated on the central upland and near the SW coast, with the exception of a single site on the East coast. Their presence and distribution in the N is poorly documented. The new finding, in a locality about 50 km E-SE to the city of Mahajanga, represents the innermost fossil site respect to the present coast line from the NW of the island, and increases the areal distribution of the genus in the Mahajanga Province

Semiaquatic adaptations in a giant predatory dinosaur

Mysterious dinosaur a swimmer? Dinosaurs are often appreciated for their size and oddity. In this regard, the North African carnivorous theropod Spinosaurus , with its huge dorsal sail and a body larger than Tyrannosaurus rex , has long stood out. This species also stands out because of its history. The unfortunate loss of the type specimen during World War II left much of what we know about Spinosaurus to be divined through speculation and reconstruction. Ibrahim et al. now describe new fossils of this unusual species. They conclude it was, at least partly, aquatic, a first for dinosaurs. Science , this issue p. 1613 </jats:p

Comparative 3D analyses and palaeoecology of giant early amphibians (Temnospondyli: Stereospondyli)

Macroevolutionary, palaeoecological and biomechanical analyses in deep time offer the possibility to decipher the structural constraints, ecomorphological patterns and evolutionary history of extinct groups. Here, 3D comparative biomechanical analyses of the extinct giant early amphibian group of stereospondyls together with living lissamphibians and crocodiles, shows that: i) stereospondyls had peculiar palaeoecological niches with proper bites and stress patterns very different than those of giant salamanders and crocodiles; ii) their extinction may be correlated with the appearance of neosuchians, which display morphofunctional innovations. Stereospondyls weathered the end-Permian mass extinction, re-radiated, acquired gigantic sizes and dominated (semi) aquatic ecosystems during the Triassic. Because these ecosystems are today occupied by crocodilians, and stereospondyls are extinct amphibians, their palaeobiology is a matter of an intensive debate: stereospondyls were a priori compared with putative living analogous such as giant salamanders and/or crocodilians and our new results try to close this debate.Peer ReviewedPostprint (published version

The oldest ceratosaurian (Dinosauria: Theropoda), from the Lower Jurassic of Italy, sheds light on the evolution of the three-fingered hand of birds

The homology of the tridactyl hand of birds is a still debated subject, with both paleontological and developmental evidence used in support of alternative identity patterns in the avian fingers. With its simplified phalangeal morphology, the Late Jurassic ceratosaurian Limusaurus has been argued to support a II–III–IV digital identity in birds and a complex pattern of homeotic transformations in three-fingered (tetanuran) theropods. We report a new large-bodied theropod, Saltriovenator zanellai gen. et sp. nov., based on a partial skeleton from the marine Saltrio Formation (Sinemurian, lowermost Jurassic) of Lombardy (Northern Italy). Taphonomical analyses show bone bioerosion by marine invertebrates (first record for dinosaurian remains) and suggest a complex history for the carcass before being deposited on a well-oxygenated and well-illuminated sea bottom. Saltriovenator shows a mosaic of features seen in four-fingered theropods and in basal tetanurans. Phylogenetic analysis supports sister taxon relationships between the new Italian theropod and the younger Early Jurassic Berberosaurus from Morocco, in a lineage which is the basalmost of Ceratosauria. Compared to the atrophied hand of later members of Ceratosauria, Saltriovenator demonstrates that a fully functional hand, well-adapted for struggling and grasping, was primitively present in ceratosaurians. Ancestral state reconstruction along the avian stem supports 2-3-4-1-X and 2-3-4-0-X as the manual phalangeal formulae at the roots of Ceratosauria and Tetanurae, confirming the I–II–III pattern in the homology of the avian fingers. Accordingly, the peculiar hand of Limusaurus represents a derived condition restricted to late-diverging ceratosaurians and cannot help in elucidating the origin of the three-fingered condition of tetanurans. The evolution of the tridactyl hand of birds is explained by step-wise lateral simplification among non-tetanuran theropod dinosaurs, followed by a single primary axis shift from digit position 4 to 3 at the root of Tetanurae once the fourth finger was completely lost, which allowed independent losses of the vestigial fourth metacarpal among allosaurians, tyrannosauroids, and maniraptoromorphs. With an estimated body length of 7.5 m, Saltriovenator is the largest and most robust theropod from the Early Jurassic, pre-dating the occurrence in theropods of a body mass approaching 1,000 Kg by over 25 My. The radiation of larger and relatively stockier averostran theropods earlier than previously known may represent one of the factors that ignited the trend toward gigantism in Early Jurassic sauropods