Evolution of Teeth and Quadrate in Non-avian Theropoda (Dinosauria: Saurischia), with the Description of Torvosaurus Remains from Portugal

Theropods form a highly successful and morphologically diversified group of dinosaurs that gave rise to birds. They include most, if not all, carnivorous dinosaurs, yet many theropod clades were secondarily adapted to piscivory, omnivory and herbivory, and theropods show a large array of skull and dentition morphologies. This work aims to investigate aspects of the evolution of theropod dinosaurs by analyzing in detail both the anatomy and ontogeny of teeth and quadrates in non-avian theropods, and by studying embryonic and adult material of a new species of theropod. A standardized list of terms and notations for each anatomical entity of the tooth, quadrate, and maxilla is here proposed with the goal of facilitating descriptions of these important cranial and dental elements. The distribution of thirty dental characters among 113 theropod taxa is investigated, and a list of diagnostic dental characters is proposed. As an example, four isolated theropod teeth from the Lourinhã Formation (Kimmeridgian‒Tithonian) of Portugal are described and identified based on a cladistic analysis performed on a data matrix of 141 dentition-based characters coded in 60 taxa. Two shed teeth are referred to an abelisaurid, providing the first record of Abelisauridae in the Jurassic of Laurasia and the one of the oldest records of this clade in the world, suggesting a possible radiation of Abelisauridae in Europe well before the Upper Cretaceous. The consensus tree resulting from this phylogenetic analysis, the most extensive on theropod teeth, indicates that theropod teeth provide reliable data for identification at approximately family level, and this method will help identifying theropod teeth with more confidence. A detailed description of the dentition of Megalosauridae is also provided, and a discriminant analysis performed on a dataset of numerical data collected on the teeth of 62 theropod taxa reveals that megalosaurid teeth are hardly distinguishable from other theropod clades with ziphodont dentition. This study highlights the importance of detailing anatomical descriptions and providing additional morphometric data on teeth with the purpose of helping to identify isolated theropod teeth. In order to evaluate the phylogenetic potential and investigate the evolutionary transformations of the quadrate, a phylogenetic morphometric analysis as well as a cladistic analysis using 98 discrete quadrate related characters were conducted. The quadrate morphology by its own provides a wealth of data with strong phylogenetic signal, and the phylogenetic morphometric analysis reveals two main morphotypes of the mandibular articulation of the quadrate linked to function. As an example, six isolated quadrates from the Kem Kem beds (Cenomanian) of Morocco are determined to be from juvenile and adult individuals of Spinosaurinae based on phylogenetic, morphometric, and phylogenetic morphometric analyses. Morphofunctional analysis of the spinosaurid mandibular articulation has shown that the posterior parts of the two mandibular rami displaced laterally when the jaw was depressed due to a mediolaterally oriented intercondylar sulcus of the quadrate. Such lateral movement of the mandibular ramus was possible due to a movable mandibular symphysis in spinosaurids, allowing the pharynx to be widened. A new species of theropod from the Lourinhã Formation of Portugal, Torvosaurus gurneyi, is erected based on a right maxilla and an incomplete caudal centrum. This taxon supports the mechanism of vicariance that occurred in the Iberian Meseta during the Late Jurassic when the proto-Atlantic was already well formed. A theropod clutch containing several crushed eggs and embryonic material is also assigned to this new species of Torvosaurus. Investigation on the maxilla ontogeny in basal tetanurans reveals that crown denticles, elongation of the anterior ramus, and fusion of interdental plates appear at a posthatchling stage. On the other hand, maxillary pneumaticity is already present at an embryonic stage in non-avian theropods.

Analysis of metabolic flux distributions in relation to the extracellular environment in Avian cells

Continuous cell lines that proliferate in chemically defined and simple media have been highly regarded as suitable alternatives for vaccine production. One such cell line is the AG1.CR.pIX avian cell line developed by PROBIOGEN. This cell line can be cultivated in a fully scalable suspension culture and adapted to grow in chemically defined, calf serum free, medium [1]–[5]. The medium composition and cultivation strategy are important factors for reaching high virus titers. In this project, a series of computational methods was used to simulate the cell’s response to different environments. The study is based on the metabolic model of the central metabolism proposed in [1]. In a first step, Metabolic Flux Analysis (MFA) was used along with measured uptake and secretion fluxes to estimate intracellular flux values. The network and data were found to be consistent. In a second step, Flux Balance Analysis (FBA) was performed to access the cell’s biological objective. The objective that resulted in the best predicted results fit to the experimental data was the minimization of oxidative phosphorylation. Employing this objective, in the next step Flux Variability Analysis (FVA) was used to characterize the flux solution space. Furthermore, various scenarios, where a reaction deletion (elimination of the compound from the media) was simulated, were performed and the flux solution space for each scenario was calculated. Growth restrictions caused by essential and non-essential amino acids were accurately predicted. Fluxes related to the essential amino acids uptake and catabolism, the lipid synthesis and ATP production via TCA were found to be essential to exponential growth. Finally, the data gathered during the previous steps were analyzed using principal component analysis (PCA), in order to assess potential changes in the physiological state of the cell. Three metabolic states were found, which correspond to zero, partial and maximum biomass growth rate. Elimination of non-essential amino acids or pyruvate from the media showed no impact on the cell’s assumed normal metabolic state.

Developmental and paleontological insights into skull bone homology and evolution

The Gallus gallus (chicken) embryo is a central model organism in evolutionary developmental biology. Its anatomy and developmental genetics have been extensively studied and many relevant evolutionary implications have been made so far. However, important questions regarding the developmental origin of the chicken skull bones are still unresolved such that no solid homology can be established across organisms. This precludes evolutionary comparisons between this and other avian model systems in which skull anatomy has evolved significantly over the last millions of years.(...)