Paula Bona | Universidad Nacional de La Plata (original) (raw)

Papers by Paula Bona

Journal of Vertebrate Paleontology

Publicación Electrónica de la Asociación Paleontológica Argentina

Resumen. El Museo de La Plata tiene una larga trayectoria en el estudio de los reptiles fósiles c... more Resumen. El Museo de La Plata tiene una larga trayectoria en el estudio de los reptiles fósiles continentales, representada por dinosaurios, cocodrilos, tortugas y escamados. Sus estudios se remontan hacia finales del siglo XIX, motorizados por los estudios pioneros de Florentino Ameghino, Santiago Roth, Richard Lydekker y Arthur Smith Woodward, principalmente. Durante la primera mitad del siglo XX los estudios de formas continentales son saltuarios, destacándose los aportes de Friedrich von Huene y Ángel Cabrera. En la década de 1960 se produjeron dos hechos singulares. Por un lado, las expediciones a Patagonia lideradas por Rodolfo Casamiquela, generando conocimientos sobre la herpetofauna mesozoica, y depositando los especímenes en las colecciones del Museo de La Plata. Por otro lado, la visión de Rosendo Pascual, profesor y jefe de la División Paleontología de Vertebrados, quién a finales de esa década, incentiva a jóvenes postulantes al estudio sobre anfibios, reptiles y aves, conformándose la primera promoción de paleoherpetólogos con títulos académicos y especialidades temáticas: Ana María Báez en anuros, Zulma Brandoni de Gasparini en crocodiliformes y Eduardo P. Tonni en aves. Todos ellos dejaron escuela, la que se advierte claramente en las camadas de discípulos que aún trabajan en esos clados. A comienzos del siglo XXI se establecen líneas de investigación derivadas del legado de Gasparini, basadas en el estudio de la anatomía, las relaciones filogenéticas y la paleobiología de arcosaurios continentales. Las mismas tienen foco en los pseudosuquios y dinosaurios sauropodomorfos, lideradas por Paula Bona, Julia Desojo y Alejandro Otero, todos con lugar de trabajo permanente en la institución.

Fil: Bona, Paula. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Divis... more Fil: Bona, Paula. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; ArgentinaFil: Barrios, Francisco. Museo Municipal Carmen Funes. Plaza Huincul; ArgentinaFil: Gasparini, Zulma. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; Argentin

Morphological studies of the braincase and cranial endocast of fossil crocodylians, especially ga... more Morphological studies of the braincase and cranial endocast of fossil crocodylians, especially gavialids, are scarce. Here, we present a detailed description of the neuroanatomy of Gryposuchus neogaeus from the Miocene of Argentina, based on CT scans. The cranial endocast is sub-horizontal and the angle formed between the mid-brain and the hind-brain is poorly marked. When compared with Gavialis gangeticus, the mid-brain of G. neogaeus is relatively shorter, although the distribution of cranial nerves is similar. In the floor of the endocranial cavity, posterior to the dorsum sellae, there is a median foramen that leads into a canal that runs anteroventrally through the basisphenoid to penetrate the posterior wall of the pituitary fossa (open foramen for the basilar artery?). The same structure is present in G. gangeticus, but is absent in other living crocodylians, suggesting a potential synapomorphy of Gavialoidea. The pneumaticity of the skull roof and the lateral branches of the...

The Anatomical Record, 2022

The lower jaw of early tetrapods is composed of several intramembranous ossifications. However, a... more The lower jaw of early tetrapods is composed of several intramembranous ossifications. However, a tendency toward the independent reduction of the number of bones has been observed in the mandible of mammals, lepidosaurs, turtles, crocodiles, and birds. Regarding archosaurs, the coronoid and prearticular bones are interpreted to be lost during the evolution of stem-birds and stem-crocodiles, respectively, but the homology of the post-dentary bones retained in living pseudosuchians remains unclear. Here, we combine paleontological and embryological evidence to explore in detail the homology of the crocodylian post-dentary bones. We study the mandible embryogenesis on a sample of 71 embryos of Caiman and compare this pattern with the mandibular transformations observed across pseudosuchian evolution. In the pre-hatching ontogeny of caimans, at least five intramembranous ossification centers are formed along the margins of the internal mandibular fenestra (perifenestral centers) and, subsequently, merge to form the coronoid (three intramembranous centers), angular (one intramembranous center), and articular (one intramembranous and one chondral center). In the fossil record, an independent prearticular is lost around the base of Mesoeucrocodylia (optimized as reappearing in Thalattosuchia if they are placed within Neosuchia), and the coronoid is apomorphically lost in notosuchians. The integration of embryological and paleontological data indicates that most perifenestral centers are involved in the origin of the prearticular of non-mesoeucrocodylian pseudosuchians. These centers are rearranged during the evolution to contribute to different post-dentary bones in mesoeucrocodylians bolstering the idea that the coronoid and the articular of Crocodylia are not completely homologous to those of other diapsids.

Phylogenetic taxon-character matrix used in the cladistic analysis

Biogeographic taxon-area matrix used in the biogeographic analysis

Herpetological Journal

Caiman is one of the five extant genera of alligatorid crocodylians. While several quantitative a... more Caiman is one of the five extant genera of alligatorid crocodylians. While several quantitative and qualitative studies exist on morphological variation in the genus, little is known about ontogenetic effects. Here, we quantify ontogenetic variation in morphology for Caiman yacare and C. latirostris in a phylogenetic context. A linear regression analysis on twelve skull measurements of C. yacare and C. latirostris against a measure of size (the first axis of a PCA of all variables) showed high correlation coefficients (r 2=0.89– 0.99) and negative allometry. Eight allometric trajectories showed common slopes at different intercepts, reflecting a common ontogenetic pattern of morphological growth fixed early in ontogeny. The anterior width of the snout and the posterior width of the skull table are suitable to discriminate between the two species. The relationship between snout width and snout length is isometric in C. latirostris while it is negatively allometric in C. yacare. These...

Revista Ciencias Morfológicas, 2014

Presentamos el primer estudio sobre la disparidad craneana en C. yacare y C. latirostris utilizan... more Presentamos el primer estudio sobre la disparidad craneana en C. yacare y C. latirostris utilizando un análisis de morfometría geométrica en dos dimensiones. Se fotografiaron cráneos de distintos estadios ontogenéticos en vista dorsal y palatal. Se establecieron 28 landmarks en vista dorsal y 27 en vista palatal y se digitalizaron usando TPSUtil y TPSDig. Para el análisis se utilizó Morpho J. Para evaluar el cambio de forma en cada especie se realizó una regresión de las coordenadas de landmarks contra el logaritmo del centroide. Se compararon las trayectorias ontogenéticas y se hizo un análisis de componentes principales para identificar los componentes de variación. En vista dorsal no hubo diferencias entre las trayectorias ontogenéticas; sí en vista ventral. Los especímenes se separaron en relación al primer componente principal. En vista dorsal, respecto de C. latirostris, C. yacare presenta un cráneo y hocico alargado y angosto, órbitas angostas, gran concavidad del borde lateral a la altura de la sutura maxilo-yugal y menor concavidad del borde posterior de la tabla craneana. En vista ventral, C. yacare presenta un cráneo, hocico, alas pterigoideas y fenestras suborbitarias alargados y angostos y un desplazamiento medial del contacto cuadrado/cuadrado-yugal y del contacto anterolateral entre maxilares y palatinos.

Cretaceous Research, 2020

Abstract Araripesuchus (Uruguaysuchidae) is a Gondwanan mesoeucrocodylian genus that includes sev... more Abstract Araripesuchus (Uruguaysuchidae) is a Gondwanan mesoeucrocodylian genus that includes several species, distributed in the Cretaceous of Niger (A. wegeneri and A. rattoides), Madagascar (A. tsangatsangana), Brazil (A. gomesii), and Argentina (A. patagonicus and A. buitreraensis). The two Argentinean species came from different localities of the lower Cenomanian of Patagonia. Here, we present a complete cranial description of A. buitreraensis and explore its phylogenetic relationships, based on new as well as previously reported specimens. We studied the skulls of eight specimens of A. buitreraensis, almost all represented by partial cranium and mandible, adding new autapomorphies to the original diagnosis of this taxon. A comparison between the new specimens also reveals some discrepant features, which are interpreted as ontogeny or as intraspecific variation. We present revised scorings of several uruguaysuchid species (A. buitreraensis, A. gomesii, and Uruguaysuchus aznarezi) from a published morphological dataset and conduct a phylogenetic analysis to test the phylogenetic position of A. buitreraensis. As in resent phylogenetic proposals, this taxon was recovered as the basalmost member of a clade, which clusters all uruguaysuchids from South America. A revision of the diagnosis and a new phylogenetic definition of Uruguaysuchidae is also presented.

data matrix of Eusuchia used in the cladistic analysi

Melanosuchus niger Spix is distributed throughout the Amazon River basin today. The extinct Melan... more Melanosuchus niger Spix is distributed throughout the Amazon River basin today. The extinct Melanosuchus fisheri Medina from the late Miocene of Venezuela was erected based on two almost complete, but heavily deformed skulls (the holotype MCNC 243 and the referred specimen MCZ 4336), which show morphological differences from each other. The comparison indicates that only the holotype can be referred to Melanosuchus Gray. We propose MCZ 4336 is a representative of the caimanine Globidentosuchus brachyrostris Scheyer, Aguilera, Delfino, Fortier, Carlini, Sánchez, Carrillo-Briceño, Quiroz and Sánchez-Villagra. Although the taxonomy of M. fisheri is taken into question herein, the classification of the holotype still sustains the hypothesis that the genus is registered in South America since the late Miocene.Melanosuchus niger Spix se distribuye actualmente por toda la cuenca del Río Amazonas. La especie extinta Melanosuchus fisheri Medina del Mioceno tardío de Venezuela se erigió sobre...

Table of coordinates for cluster analysis

Contents: i) – Stratigraphic and geographic provenance of Protocaiman peligrensis ii) – Additiona... more Contents: i) – Stratigraphic and geographic provenance of Protocaiman peligrensis ii) – Additional anatomical information for Protocaiman peligrensis iii) – Phylogenetic relationships of Protocaiman peligrensis and other early caimanines iv) – Biogeographic analysis of early alligatorids v) – References

TPS file of landmark coordinates used in the geometric morphometric analysis

Caimanines are crocodylians currently restricted to South and Central America and the oldest memb... more Caimanines are crocodylians currently restricted to South and Central America and the oldest members are from lower Palaeocene localities of the Salamanca Formation (Chubut Province, Argentina). We report here a new caimanine from this same unit represented by a skull roof and partial braincase. Its phylogenetic relationships were explored in a cladistic analysis using standard characters and a morphogeometric two-dimensional configuration of the skull roof. The phylogenetic results were used for an event-based supermodel quantitative palaeobiogeographic analysis. The new species is recovered as the most basal member of the South American caimanines, and the Cretaceous North American lineage '<i>Brachychampsa</i> and related forms' as the most basal Caimaninae. The biogeographic results estimated north-central North America as the ancestral area of Caimaninae, showing that the Cretaceous and Palaeocene species of the group were more widespread than thought and be...

Roca Formation is a stratigraphic succession of marine and continental sediments that belongs to ... more Roca Formation is a stratigraphic succession of marine and continental sediments that belongs to Malargue Group, which was deposited from the Late Campanian to the Danian in the Neuquen Basin, western Argentina. Fossil vertebrates recovered at different outcroppings of this lithostratigraphic unit correspond to marine taxa. The turtle material studied here was collected from the lower section of Roca Formation (Maastrichtian?-Danian) in northeastern Lago Pelegrini (38o 40’ 06’’S, 67o 52’ 02’’ O), Rio Negro Province. Remains of carapace and plastron of continental turtles were assigned to indeterminate chelid pleurodires and to Yaminuechelys cf. maior (Staesche, 1929). This record of chelid turtles in Roca Formation confirms the existence of marine paleoenvironments with continental influence and represents the first record of Danian continental vertebrates in the Neuquen Basin

Cretaceous Research, 2017

Fil: Barrios, Francisco. Provincia de Neuquen. Ministerio de Energia, Ambiente y Servicios Public... more Fil: Barrios, Francisco. Provincia de Neuquen. Ministerio de Energia, Ambiente y Servicios Publicos. Direccion Provincial de Mineria. Museo Provincial de Ciencias Naturales Prof. ; Argentina. Consejo Nacional de Investigaciones Cientificas y Tecnicas; Argentina

Earth and Environmental Science Transactions of the Royal Society of Edinburgh, 2017