La diversidad de los dinosaurios carnívoros

Características, evolución y taxonomía de los dinosaurios terópodos cuyos fósiles fueron encotnrados en el actual territorio sudamericano, los que forman parte de un nutrido y variado grupo que habría habitado todas las tierras del planeta, incluida la Antártida.Fil: Canale, Juan Ignacio. Provincia del Neuquén. Municipalidad de Villa El Chocón. Museo Paleontológico "Ernesto Bachmann"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Dinosaur tracks at Cañadón de las Campanas and Villa El Chocón area (Late Cretaceous, Candeleros Formation), Patagonia, Argentina

Several locations are known along the coast of the Ezequiel Ramos Mexía Dam, Neuquén province in Northwestern Argentinian Patagonia, comprising one of the richest dinosaur-tracking areas in South America. In this contribution we study a total of 166 dinosaur footprints and 31 dinosaur trackways recorded at the base of the Candeleros Formation (Cenomanian) from a new tracksite - Cañadón de las Campanas - and other localities nearby the Villa El Chocón area. The dinosaur footprints identified correspond to six morphotypes assigned to two ichnotaxa and three others are left with open nomenclature: Bressanichnus patagonicus, cf Brontopodus isp. (Sauropodichnus giganteus), large U-shaped tridactyl footprints (Limayichnus major), medium-siz ed tridactyl footprints and smallsized tridactyl footprints. The ichnotaxa S. giganteus and L. major are considered nomen dubium. Particularly, B. patagonicus presents two morphologies at the posterior margin of the footprint (rounded and narrow) most likely related to varying gaits and/or changingbehavior. As a result, the herein presented ichnofauna is interpreted as produced by non-avian theropod of varied sizes (large sized = large U-shaped tridactyl footprints, medium to large size = B. patagonicus, medium size = medium-sized tridactyl footprints and small size = small-sized tridactyl footprint) and one large-sized sauropod dinosaur (cf. Brontopodus isp.).Fil: Krapovickas, Verónica. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Estudios Andinos "Don Pablo Groeber". Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Estudios Andinos "Don Pablo Groeber"; ArgentinaFil: Garrido, Alberto Carlos. Provincia de Neuquén. Ministerio de Energía, Ambiente y Servicios Públicos. Dirección Provincial de Minería. Museo Provincial de Ciencias Naturales Prof. "Dr. Juan A. Olsacher"; ArgentinaFil: Canale, Juan Ignacio. Provincia del Neuquén. Municipalidad de Villa El Chocón. Museo Paleontológico "Ernesto Bachmann"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Isolated theropod teeth associated with a sauropod skeleton from the Late Cretaceous Allen Formation of Río Negro, Patagonia, Argentina

The discovery of theropod shed teeth associated with sauropod remains is relatively common in Cretaceous deposits of Patagonia. However, only a handful of studies have thoroughly explored the phylogenetic affinities of the theropod dental material. Here, we describe and identify twelve theropod shed teeth associated with a partially complete skeleton of a titanosaur sauropod from the Allen Formation (middle Campanian?lower Maastrichtian; Upper Cretaceous) of Paso Córdoba, Río Negro, Argentina. Using three methods, namely a cladistic analysis performed on a dentition-based data matrix, and a discriminant and cluster analyses conducted on a large dataset of theropod teeth measurements, we identify three dental morphotypes which are confidently referred to abelisaurid theropods. Whether the morphotypes represent different abelisaurid subclades or different positional entities within the jaw of the same abelisaurid species, is unknown. Such an identification, nevertheless, provides additional evidence of abelisaurids feeding on sauropod carcasses. This study highlights the importance of using combined qualitative and quantitative methodologies to identify isolated theropod teeth, especially those that can provide direct information on feeding ecology.Fil: Meso, Jorge Gustavo. Universidad Nacional de Río Negro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Hendrickx, Christophe. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - Tucumán. Unidad Ejecutora Lillo; ArgentinaFil: Baiano, Mattia Antonio. Provincia del Neuquén. Municipalidad de Plaza Huincul. Museo "Carmen Funes"; Argentina. Universidad Nacional de Río Negro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Canale, Juan Ignacio. Universidad Nacional de Río Negro; Argentina. Provincia del Neuquén. Municipalidad de Villa El Chocón. Museo Paleontológico "Ernesto Bachmann"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Salgado, Leonardo. Universidad Nacional de Río Negro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Díaz Martínez, Ignacio. Universidad Nacional de Río Negro; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; Argentin

Osteohistological analyses reveal diverse strategies of theropod dinosaur body-size evolution

The independent evolution of gigantism among dinosaurs has been a topic of long-standing interest, but it remains unclear if gigantic theropods, the largest bipeds in the fossil record, all achieved massive sizes in the same manner, or through different strategies. We perform multi-element histological analyses on a phylogenetically broad dataset sampled from eight theropod families, with a focus on gigantic tyrannosaurids and carcharodontosaurids, to reconstruct the growth strategies of these lineages and test if particular bones consistently preserve the most complete growth record. We find that in skeletally mature gigantic theropods, weight-bearing bones consistently preserve extensive growth records, whereas non- weight-bearing bones are remodelled and less useful for growth reconstruction, contrary to the pattern observed in smaller theropods and some other dinosaur clades. We find a heterochronic pattern of growth fitting an acceleration model in tyrannosaurids, with allosauroid carcharodontosaurids better fitting a model of hypermorphosis. These divergent growth patterns appear phylogenetically constrained, representing extreme versions of the growth patterns present in smaller coelurosaurs and allosauroids, respectively. This provides the first evidence of a lack of strong mechanistic or physiological constraints on size evolution in the largest bipeds in the fossil record and evidence of one of the longest-living individual dinosaurs ever documented.Fil: Cullen, Thomas. Field Museum of National History; Estados Unidos. North Carolina State University; Estados Unidos. North Carolina Museum of Natural Sciences; Estados UnidosFil: Canale, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Confluencia; Argentina. Provincia del Neuquén. Municipalidad de Villa El Chocón. Museo Paleontológico "Ernesto Bachmann"; ArgentinaFil: Apesteguía, Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Confluencia; Argentina. Fundación de Historia Natural Félix de Azara; Argentina. Universidad Maimónides. Área de Investigaciones Biomédicas y Biotecnológicas. Centro de Estudios Biomédicos, Biotecnológicos, Ambientales y de Diagnóstico; ArgentinaFil: Smith, Nathan D.. Natural History Museum of Los Angeles County. Dinosaur Institute; Estados UnidosFil: Hu, Dongyu. Shenyang Normal University; República de China. Ministry of Natural Resources; República de ChinaFil: Makovicky, Peter J.. Field Museum of National History; Estados Unidos. University of Minnesota; Estados Unido

History of the “Ernesto Bachmann” Museum, from Villa El Chocón, Neuquén

El Chocón es un sitio clave en la historia de la paleoherpetología argentina, ya que la zona donde se ubica ha brindado importantes descubrimientos, incluyendo uno de los primeros hallazgos de un reptil fósil para Argentina a fines del siglo XIX. El Museo “Ernesto Bachmann” de Villa El Chocón es una institución que, si bien fue creada hace relativamente poco, logró conformar un equipo de trabajo estable que ha protagonizado importantes contribuciones al conocimiento de los vertebrados fósiles del Cretácico patagónico. En este trabajo, se realiza una breve reseña histórica de los registros paleoherpetológicos locales, así como de los principales actores involucrados, tanto en las tareas de desarrollo científico como las personas que impulsaron la creación del Museo y lo han sostenido en el tiempo.El Chocón is a key site in the history of Argentine paleoherpetology, since the area where it is located has provided important discoveries, including one of the earliest findings of a fossil reptile for Argentina at the end of the 19th century. The “Ernesto Bachmann” Museum of Villa El Chocón is an institution that -although it was created recently- has managed to form a stable work team that has made important contributions to the knowledge of fossil vertebrates from the Cretaceous of Patagonia. In the present work, a brief historical review of the local paleherpetological records is made as well as the main actors involved both in the scientific projects and creation and development of the Museum over time.Fil: Canale, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Confluencia; Argentina. Provincia del Neuquén. Municipalidad de Villa El Chocón. Museo Paleontológico "Ernesto Bachmann"; Argentin

Una ulna parcial de Pterosauria de la Formación Candeleros (Grupo Neuquén), Cretácico tardío de Argentina

The proximal portion of the left ulna of a pterosaur is described. The specimen comes from the Candeleros Formation (Cenomanian), Neuquén Group, at Cabo Alarcón, Neuquén province, Argentina. The analysis of this new specimen allows the re-interpretation of a previously described pterosaur tibia founded at Los Catutos locality, Neuquén (MOZ 2280 P) as a proximal ulna. The new material belongs to a medium-sized pterosaur, considerably larger than previously recorded pterosaurs from this geological unit. The analysis of correlation between ulnar length-pes length in well-known pterodactyloid pterosaurs shows that the new ulna matches well with the inferred size of the Pteraichnus isp. trackmaker recorded from the same formation.The proximal portion of the left ulna of a pterosaur is described. The specimen comes from the Candeleros Formation (Cenomanian), Neuquén Group, at Cabo Alarcón, Neuquén province, Argentina. The analysis of this new specimen allows the re-interpretation of a previously described pterosaur tibia founded at Los Catutos locality, Neuquén (MOZ 2280 P) as a proximal ulna. The new material belongs to a medium-sized pterosaur, considerably larger than previously recorded pterosaurs from this geological unit. The analysis of correlation between ulnar length-pes length in well-known pterodactyloid pterosaurs shows that the new ulna matches well with the inferred size of the Pteraichnus isp. trackmaker recorded from the same formation.Fil: Haluza, Alejandro. Provincia del Neuquén. Municipalidad de Villa El Chocón. Museo Paleontológico "Ernesto Bachmann"; ArgentinaFil: Canale, Juan Ignacio. Provincia del Neuquén. Municipalidad de Villa El Chocón. Museo Paleontológico "Ernesto Bachmann"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

Small-sized abelisaurid (Theropoda: Ceratosauria) remains from the Upper Cretaceous of northwest Patagonia, Argentina

A new abelisaurid theropod from the Cenomanian of Candeleros Formation (Neuquén Province, NW Patagonia, Argentina) is described. It includes an isolated frontal, partial pelvis, two fused sacral centra, femoral shaft, rib fragments, partial metatarsal II and shaft of metatarsal III. A paleohistological analysis shows that MMCh-PV 69 was somatically mature at time of death. The prevalence of relatively ordered intrinsic fibers in the primary bone indicates a relatively lower growth rate of MMCh-PV 69 compared with other abelisauroids, such as Aucasaurus garridoi. Phylogenetic analysis found MMCh-PV 69 as a basal abelisaurid, sister group of the node formed by Majungasaurinae and Brachyrostra. We estimated the body mass of MMCh-PV 69 in 240 kg, which makes it one of the smallest abelisaurids recorded. This new form adds to the extensive theropod fauna of the Candeleros Formation, probably the most diverse association of meat-eating dinosaurs recorded in a Cretaceous Formation from South America.Fil: Canale, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Provincia del Neuquén. Municipalidad de Villa El Chocón. Museo Paleontológico "Ernesto Bachmann"; ArgentinaFil: Cerda, Ignacio Alejandro. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Novas, Fernando Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales “Bernardino Rivadavia”; ArgentinaFil: Haluza, Alejandro. Provincia del Neuquén. Municipalidad de Villa El Chocón. Museo Paleontológico "Ernesto Bachmann"; Argentin

The first Cearachelyini (Pelomedusoides, Bothremydidae) turtle from the Upper Cretaceous of Patagonia, and an overview of the occurrence and diversity of Pelomedusoides in Patagonia

A new species of pelomedusoid turtle: Elkanemys pritchardi gen. et sp. nov. from Upper Cretaceous (Cenomanian) is described. The specimen MMCH-PV 73 outcrops at Lago Ezequiel Ramos Mexia, near El Chocón town, Río Negro Province, Argentina. The holotype is only represented by a partial carapace and plastron, which has been included in a cladistic analysis, resulting Elkanemys pritchardi as a member of Cearachelyini tribe of the clade Bothremydidae. This new taxon corresponds to the first record of a Bothremydidae in a Cretaceous horizon of Neuquén Basin. The results here presented highlight the diversity of Pelomedusoides in the Cretaceous of Patagonia allowing the inclusion of this area in further paleobiogeographic history of Bothremydidae clade.Fil: Maniel, Ignacio Jorge. Universidad Tecnologica Nacional. Facultad Reg.san Rafael. Instituto de Evolucion, Ecologia Historica y Ambiente. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mendoza. Instituto de Evolucion, Ecologia Historica y Ambiente.; Argentina. Museo Municipal de Historia Natural San Rafael - Unidad Asociada al CCT Mendoza; ArgentinaFil: de la Fuente, Marcelo Saul. Universidad Tecnologica Nacional. Facultad Reg.san Rafael. Instituto de Evolucion, Ecologia Historica y Ambiente. - Consejo Nacional de Investigaciones Cientificas y Tecnicas. Centro Cientifico Tecnologico Conicet - Mendoza. Instituto de Evolucion, Ecologia Historica y Ambiente.; Argentina. Museo Municipal de Historia Natural San Rafael - Unidad Asociada al CCT Mendoza; ArgentinaFil: Canale, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Provincia del Neuquén. Municipalidad de Villa El Chocón. Museo Paleontológico "Ernesto Bachmann"; Argentin

New rebbachisaurid cranial remains (Sauropoda, Diplodocoidea) from the Cretaceous of Patagonia, Argentina, and the first endocranial description for a South American representative of the clade

Here we report new rebbachisaurid material (MMCh-PV 71) recovered from the Candeleros Formation (Cenomanian) of northwest Patagonia, Argentina. The cranial remains consist of a partial braincase and a right quadrate. Fractures in the braincase exposed the endocranial cavity, allowing the first study of the brain and inner ear morphologies of a South American rebbachisaurid. The braincase and cranial endocast both exhibit traits similar to those observed in the Cretaceous rebbachisaurs Nigersaurus from Africa and Limaysaurus from Argentina, although in terms of osteology, the South American taxa are highly similar. The endocast of MMCh-PV 71 is more similar to that of Nigersaurus than to those of Diplodocus and Camarasaurus, suggesting some probable rebbachisaurid features such as the noteworthy presence of the flocculus. The overall morphology of the quadrate shows similarities with Limaysaurus and Nigersaurus. However, differences such as the broader posterior fossa and the shape and orientation of the head and the pterygoid process indicate that the new specimen could represent a distinct taxon.Fil: Paulina Carabajal, Ariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigaciones en Biodiversidad y Medioambiente. Universidad Nacional del Comahue. Centro Regional Universidad Bariloche. Instituto de Investigaciones en Biodiversidad y Medioambiente; ArgentinaFil: Canale, Juan Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Provincia del Neuquén. Municipalidad de Villa El Chocón. Museo Paleontológico "Ernesto Bachmann"; ArgentinaFil: Haluza, Alejandro. Provincia de Neuquén. Ministerio de Energía, Ambiente y Servicios Públicos. Dirección Provincial de Minería. Museo Provincial de Ciencias Naturales Prof. "Dr. Juan A. Olsacher"; Argentin

Osteology and phylogenetic relationships of Tyrannotitan chubutensis Novas, de Valais, VickersRich and Rich, 2005 (Theropoda: Carcharodontosauridae) from the Lower Cretaceous of Patagonia, Argentina

The theropod clade Carcharodontosauridae is a broadly distributed group of large allosauroid theropods. The carcharodontosaurids recorded in the Albian – Cenomanian of Gondwana are the youngest and most derived members of this clade. Tyrannotitan chubutensis, from the Cerro Castan˜o Member of Cerro Barcino Formation (Albian; Chubut Group), Central Patagonia, Argentina, is of prime interest among Gondwanan carcharodontosaurids as it represents the oldest record of the group. Here we offer a detailed osteological comparative description of the holotype and paratype of Tyrannotitan chubutensis together with a new diagnosis of the species. The new information results in a better understanding of this taxon and Carcharodontosauridae. Furthermore, a comparative study of the anatomy of the pectoral girdle of Giganotosaurus is reinterpreted as very similar to that of Tyrannotitan and Mapusaurus. We also present a phylogenetic analysis of Carcharodontosauridae that recovers Tyrannotitan as a derived carcharodontosaurid, being the sister group of the clade formed by Giganotosaurus and Mapusaurus, all nested in the clade Giganotosaurini.Fil: Canale, Juan Ignacio. Provincia del Neuquén. Municipalidad de Villa El Chocón. Museo Paleontológico "Ernesto Bachmann"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Novas, Fernando Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Pol, Diego. Museo Paleontológico Egidio Feruglio; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin