3 results on '"VON BACZKO, MARÍA BELÉN"'
Search Results
2. Anatomic revision and phylogenetic status of the family Ornithosuchidae (Archosauria: Pseudosuchia) from the Upper Triassic of Argentina and Scotland
- Author
-
von Baczko, María Belén and Desojo, Julia Brenda
- Subjects
PALAEONEUROLOGY ,PHYLOGENY ,ARCHOSAURIA ,TRIASSIC ,FILOGENIA ,PALEONEUROLOGIA ,PSEUDOSUCHIA ,ORNITHOSUCHIDAE ,ANATOMIA ,TRIASICO ,ANATOMY - Abstract
La presente tesis aborda un estudio anatómico, taxonómico y filogenético del clado Ornithosuchidae a fin de enriquecer el conocimiento del grupo y esclarecer las relaciones filogenéticas entre sus integrantes y con los demás grupos de arcosauriformes. En este estudio se realizó la descripción anatómica detallada del ornitosúquido argentino Riojasuchus tenuisceps y se desarrolló el primer estudio de su cavidad endocraneana realizado por medio de tomografías computadas identificando algunas de las estructuras que habrían conformado su encéfalo. Se realizó la descripción de nuevos materiales pertenecientes al ornitosúquido argentino Venaticosuchus rusconii. Por otra parte, se llevó a cabo una revisión taxonómica del ornitosúquido escocés Ornithosuchus “longidens” para poner a prueba su sinonimia con el taxón “Dasygnathoides (=Dasygnathus) longidens” tal y como fue propuesta por Walker (1964). Como resultado se reconoció al género y especie Dasygnathoides (=Dasygnathus) longidens como nomina dubia y se propuso regresar a la combinación nomenclatorial Ornithosuchus woodwardi designada por Newton (1894). A partir del estudio detallado de las tres especies de ornitosúquidos conocidas, se reexaminaron y corrigieron numerosas codificaciones de caracteres en la matriz de datos utilizada y se aportaron modificaciones de caracteres, nuevos caracteres y nuevos taxones para ampliar la misma. Como resultado del análisis filogenético se recuperó a Ornithosuchidae como un robusto grupo monofilético con altos valores de soporte nodal. Se identificó a Ornithosuchidae como el clado más basal dentro de Pseudosuchia. Sin embargo, no se obtuvo el elevado soporte presentado en trabajos previos, sino que la posición de Ornithosuchidae exhibió un comportamiento más inestable, pudiendo cambiar de su posición óptima en la base de Pseudosuchia a posicionarse en la base de Avemetatarsalia con tan solo un paso extra. Dentro de Ornithosuchidae, Ornithosuchus fue recuperado como taxón hermano de un clado formado por Riojasuchus y Venaticosuchus, como fuera propuesto por Baczko et al. (2014), viéndose a su vez reflejado en la distribución geográfica dispar de Ornithosuchidae. No obstante, se obtuvieron valores soporte aún mayores que los presentados por Baczko et al. (2014) para el nodo Riojasuchus + Venaticosuchus así como dos nuevas sinapormorfías para dicho nodo gracias al estudio detallado y a primera mano de todos los materiales de los ornitosúquidos conocidos. This thesis involves an anatomical, taxonomical and phylogenetic study of the clade Ornithosuchidae. Its aim is to enrich the knowledge of this group in an attempt to clarify its phylogenetic relationships with other arcosauriform groups and amongst the species it comprises. A detailed anatomical description of the Argentinean ornithosuchid Riojasuchus tenuisceps was carried out in this study as well as the first reconstruction of its endocranial cavity, which allowed identifying some of the structures of its encephalon. New cranial materials belonging to the Argentinean ornithosuchid Venaticosuchus rusconii were described. A taxonomic revision of the Scottish ornithosuchid Ornithosuchus “longidens” was carried out to test its synonymy with “Dasygnathoides (=Dasygnathus) longidens” as proposed by Walker (1964). As a result, the species and genre Dasygnathoides (=Dasygnathus) longidens were regarded as nomina dubia and the nomenclatural combination Ornithosuchus woodwardi was restored, as originally proposed by Newton (1894). Through the study of the three known species of ornithosuchids, several scorings and characters from chosen the data matrix were modified, and new characters and taxa were added to expand the matrix. From the resulting analysis, Ornithosuchidae was recovered as a robust monophyletic group with high nodal support. It was also identified as the most basal group within Pseudosuchia. However, the high nodal support recorded in previous publications was not recovered here, and Ornithosuchidae exhibited a more unstable behaviour, being able to change from its optimal position at the base of Pseudosuchia to the base of Avemetatarsalia with just one extra step. Within Ornithosuchidae, Ornithosuchus was recovered as a basal taxon, sister to a clade comprising Riojasuchus and Venaticosuchus, as proposed by Baczko et al. (2014), which is also reflected in the disjunct geographic distribution of Ornithosuchidae. Nontheless, the nodal values here obtained for the clade Riojasuchus + Veneticosuchus were even higher than those reported by Baczko et al. (2014), and two new synapomorphies were also recovered for that clade thanks to the detailed study of all knows ornithosuchid materials. Fil: von Baczko, María Belén. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina.
- Published
- 2017
3. The skull anatomy and cranial endocast of the pseudosuchid archosaur Prestosuchus chiniquensis from the Triassic of Brazil.
- Author
-
MASTRANTONIO, BIANCA MARTINS, VON BACZKO, MARÍA BELÉN, DESOJO, JULIA BRENDA, and SCHULTZ, CESAR L.
- Subjects
- *
SKULL , *ANATOMY , *TOP predators , *MAXILLA , *FOSSILIZATION - Abstract
Prestosuchus chiniquensis is the most famous "rauisuchian" described by Friedrich von Huene, eight decades ago, and several specimens have been assigned to this taxon since then. In the present contribution, we provide the first detailed description of a complete and very well preserved skull (including the braincase) assigned to Prestosuchus chiniquensis from the Dinodontosaurus Assemblage Zone of the Santa Maria Supersequence of southern Brazil. The detailed description of the skull of Prestosuchus chiniquensis, besides increasing the knowledge about this taxon, may help elucidate the taxonomic relationships of pseudosuchians even further, since most of the characters used in phylogenetic analyzes are cranial. The presence of the subnarial fenestra, a controvertial extra opening on the skull of "rauisuchians", is thoroughly discussed considering the evidence provided by this new specimen. We consider that the small slit-opening between the premaxilla and the maxilla in Prestosuchus chiniquensis, can not safely be considered a true fenestra, but indicates more likely the existence of some degree of cranial kinesis between these elements which can result in different relative positions of the bones after definitive burial and fossilization, so that the size and shape of this opening is taphonomically controlled. Complementarily, the digital reconstruction of its cranial endocast was developed both from the observation of the preserved braincase and from CT scan images, which resulted in obtaining the first endocast known for a "rauisuchian". The endocast of Prestosuchus chiniquensis exhibited some remarkable convergences with that of theropod dinosaurs, which could be a reflection of the similar niches they occupied, since "rauisuchians" were the top predators at the end of the Late Triassic, before the extinction of all non-crocodylomorph pseudosuchians. [ABSTRACT FROM AUTHOR]
- Published
- 2019
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.