Testing the persistence of Carcharodontosauridae (Theropoda) in the Upper Cretaceous of Patagonia based on dental evidence

The deposits corresponding to the Upper Cretaceous Neuquén and San Jorge Gulf basins from northern and central Patagonia have provided two of the most complete sequences of terrestrial vertebrate faunas of all Gondwanan landmasses. Among the carnivorous components, the carcharodontosaurid theropods appeared as common elements during the Early Cretaceous and the earliest Late Cretaceous in northern and central Patagonia. Although recorded mostly in the lower Turonian, isolated teeth suggest their presence in younger strata in northern and central Patagonia, reaching the clade in the region as late as the early Maastrichtian. Here, we verify the assignment of such isolated teeth previously identified as belonging to Carcharodontosauridae from the Upper Cretaceous strata of northern and central Patagonia. Using three different methods, namely a cladistic analysis performed on a dentition-based data matrix, and discriminant and cluster analyses conducted on a large dataset of theropod crown measurements, we assign a tooth from Candeleros Formation to carcharodontosaurid theropods and teeth from Cerro Lisandro, Bajo Barreal, Portezuelo, Plottier and Allen formations to abelisaurid theropods. These new reappraisals provide additional evidence about the extinction of Carcharodontosauridae in South America at about the late Turonian–earliest Coniacian as part of a general faunistic turnover event, with the last clear evidence of this lineage in Patagonia coming from the early–middle Turonian.Fil: Meso, Jorge Gustavo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Juárez Valieri, R. D.. Gobierno de la Provincia de Río Negro. Ministerio de Turismo, Cultura y Deporte. Secretaría de Cultura; ArgentinaFil: Porfiri, Juan Domingo. Museo del Desierto Patagónico; Argentina. Universidad Nacional del Comahue. Museo de Ciencias Naturales; Argentina. Universidad Nacional del Comahue. Facultad de Ingeniería; ArgentinaFil: Da Silva Correa, Samuel Aparecido. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; ArgentinaFil: Martinelli, Agustín Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Casal, G. A.. Universidad Nacional de la Patagonia "San Juan Bosco"; ArgentinaFil: Canudo, J. I.. Universidad de Zaragoza; EspañaFil: Poblete, F.. Museo del Desierto Patagónico; ArgentinaFil: Dos Santos, D.. Museo del Desierto Patagónico; Argentina. Universidad Nacional del Comahue. Museo de Ciencias Naturales; Argentina. Universidad Nacional del Comahue. Facultad de Ingeniería; Argentin

The dinosaurs: miths and truths

Tema del mesLos dinosaurios han sido entre los vertebrados terrestres, uno de los grupos que mayor interés han despertado dentro de la sociedad. Con ellos, han surgido numerosas historias, leyendas, mitos y verdades. La mente humana a partir de un nuevo descubrimiento crea nuevos conceptos que en algunos casos son correctos y en otros no son más que producto de la propia imaginación. Por ello, los científicos trabajan arduamente para poder dilucidar muchas de estas incógnitas. Las investigaciones paleontológicas que se llevan adelante en cada rincón de nuestro planeta han permitido descubrir nuevas especies de vertebrados que amplían el conocimiento de faunas extintas hace miles de años. Sin embargo, muchas de estas teorías, para la ciencia aún siguen siendo un gran misterio, otras son solo mitosThe dinosaurs are, between the terrestrial vertebrates, one of the groups that greater interest have waked up within the society. In this way, numerous histories, legend, myths and truths have arisen. The human mind from a new finding creates new concepts that in some cases are correct and in others they are not more than product of the imagination. For this reason, the scientists work arduously to be able to explain many of these mysteries. The paleontological investigations that take ahead in each corner of our planet have allowed to discover new species of vertebrates that extend the knowledge of extinct faunas does thousands of years. Each new finding allows to develop new theories on these beings of the Mesozoic Era confirming or refuting previous theories. Nevertheless, many of these theories, for science still continue being a great mystery, others are only myth

Sitios de Interés Geológico de la República Argentina

Fil: Calvo, Jorge Orlando. Centro Paleontológico Lago Barreales, Universidad Nacional del Comahue, Proyecto Dino; Argentina.Fil: Porfiri, Juan Domingo. Centro Paleontológico Lago Barreales, Universidad Nacional del Comahue, Proyecto Dino; Argentina.Fil: Sánchez, María Lidia. Departamento de Geología, Universidad Nacional de Río Cuarto; Argentina.Fil: Heredia, Susana. CONICET – Instituto de Geología, Facultad de Ciencias Exactas, Físicas y Naturales, Universidad Nacional de San Juan; Argentina.Neuquén, en los últimos 15 años, ha adquirido gran significado a nivel paleontológico debido a sus numerosos e importantes hallazgos y sitios fósiles; por esta razón, hoy se la conoce como «Tierra de Dinosaurios». No es para menos, ya que en rocas cretácicas continentales se encontraron los restos del dinosaurio carnívoro y del dinosaurio herbívoro más grandes del mundo. Uno de los más importantes yacimientos fosilíferos de Neuquén es el denominado Proyecto Dino, donde actualmente se ubican las instalaciones del Centro Paleontológico Lago Barreales (CePaLB) dependiente de la Universidad Nacional del Comahue. Este yacimiento posee gran cantidad de restos fósiles del período Cretácico: peces, plantas, tortugas, cocodrilos, pterosaurios, dinosaurios herbívoros de diversos grupos y dinosaurios carnívoros como Unenlagia paynemili y Megaraptor namunhuaiquii. En pocas palabras, estamos frente a un ecosistema casi completo de un momento de la Era Mesozoica. Todos estos materiales proceden de la Formación Portezuelo del Grupo Neuquén. Esta formación junto con la Formación Plottier, que la suprayace, se generaron en ambientes fluviales de baja a mediana energía. La geología, paleontología y geomorfología se unen en este sitio para brindar al turista un capítulo del libro de la historia, donde la interpretación y la lectura la realizan los profesionales y los conocimientos obtenidos son volcados al visitante

Evolution of the carnivorous dinosaurs during the Cretaceous: The evidence from Patagonia

Patagonia has yielded the most comprehensive fossil record of Cretaceous theropods from Gondwana, consisting of 31 nominal species belonging to singleton taxa and six families: Abelisauridae, Noasauridae, Carcharodontosauridae, Megaraptoridae nov. fam., Alvarezsauridae, and Unenlagiidae. They provide anatomical information that allows improved interpretation of theropods discovered in other regions of Gondwana. Abelisauroids are the best represented theropods in Patagonia. They underwent an evolutionary radiation documented from the Early Cretaceous through to the latest Cretaceous, and are represented by the clades Abelisauridae and Noasauridae. Patagonian carcharodontosaurids are known from three taxa (Tyrannotitan, Giganotosaurus and Mapusaurus), as well as from isolated teeth, collected from Aptian to Cenomanian beds. These allosauroids constituted the top predators during the mid-Cretaceous, during which gigantic titanosaur sauropods were the largest herbivores. Megaraptorans have become better documented in recent years with the discovery of more complete remains. Megaraptor, Aerosteon and Orkoraptor have been described from Cretaceous beds from Argentina, and these taxa exhibit close relationships with the Aptian genera Australovenator, from Australia, and Fukuiraptor, from Japan. The Gondwanan megaraptorans are gathered into the new family Megaraptoridae, and the Asiatic Fukuiraptor is recovered as the immediate sister taxon of this clade. Although megaraptorans have been recently interpreted as members of Allosauroidea, we present evidence that they are deeply nested within Coelurosauria. Moreover, anatomical information supports Megaraptora as more closely related to the Asiamerican Tyrannosauridae than thought. Megaraptorans improve our knowledge about the scarcely documented basal radiation of Gondwanan coelurosaurs and tyrannosauroids as a whole. Information at hand indicates that South America was a cradle for the evolutionary radiation for different coelurosaurian lineages, including some basal forms (e.g., Bicentenaria, Aniksosaurus), megaraptorans, alvarezsaurids less derived than those of Laurasia, and unenlagiids, revealing that Gondwanan coelurosaurs played sharply differing ecological roles, and that they were taxonomically as diverse as in the northern continents. The unenlagiids represent an endemic South American clade that has been recently found to be more closely related to birds than to dromaeosaurid theropods. Analysis of the theropod fossil record from Gondwana shows the highest peak of origination index occurred during the Aptian–Albian and a less intense one in the Campanian time spans. Additionally, peaks of extinction index are recognized for the Cenomanian and Turonian–Coniacian time spans. In comparison, the Laurasian pattern differs from that of Gondwana in the presence of an older extinction event during the Aptian–Albian time-span and a high origination rate during the Cenomanian time-bin. Both Laurasian and Gondwanan theropod records show a peak of origination rates during the Campanian.Fil: Novas, Fernando Emilio. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Agnolin, Federico. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; Argentina. Fundación de Historia Natural Félix de Azara; ArgentinaFil: Ezcurra, Martin Daniel. Ludwig Maximilians Universitat; Alemania. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Porfiri, Juan Domingo. Universidad Nacional del Comahue. Centro Paleontológico Lago Barreales; 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

A new and well-preserved early-diverging abelisaurid (theropoda: ceratosauria: abelisauroidea) from the early late cretaceous of northern patagonia

Abelisaurid theropods were the most diverse and abundant medium-sized to large-bodied carnivorous dinosaurs in many Gondwanan and European paleoecosystems during the Late Cretaceous, frequently occupying the apex predator niche in these environments. Although several derived abelisaurids (e.g., the Patagonian brachyrostrans Ekrixinatosaurus novasi, Skorpiovenator bustingorryi, Viavenator exxoni, Aucasaurus garridoi, and Carnotaurus sastrei and the Madagascan majungasaurine Majungasaurus crenatissimus) are represented by well-preserved skeletons, earlier-diverging members of the clade (e.g., the African Kryptops palaios and Rugops primus) are known from much less complete material. Consequently, the early evolutionary history of Abelisauridae remains poorly understood. Here we report a new taxon of medium-sized (body length ~5 m) basal abelisaurid collected from an exposure of the lowermost Upper Cretaceous (Cenomanian) Candeleros Formation in an area known as Aguada Pichana near the town of Añelo in Neuquén Province, northern Patagonia, Argentina. The new form is known from two individuals, one of which is represented by a largely complete, partially articulated skeleton (including much of an articulated skull and multiple teeth plus dorsal, sacral, and caudal vertebrae, dorsal ribs, hemal arches, a scapula, the forelimb lacking the manus, the pelvis, and several hind limb elements); the second individual is known only from a partial skull (consisting of the maxilla, lacrimal, jugal, quadratojugal, quadrate, pterygoid, ectopterygoid, palatine, and dentary with teeth). Notable osteological features include: (1) maxilla with 14 tooth positions (as in Carnotaurus and some generically unidentified abelisaurids but 3–5 fewer than in Rugops, Skorpiovenator, and Majungasaurus); (2) lacrimal with prominent anterior process; (3) postorbital with ‘inflated’ dorsal terminus and suborbital flange; (4) anterior caudal transverse processes with well-developed anterior projection at distal end; (5) humerus and metatarsals proportionally slender, recalling those of non-abelisaurid abelisauroids; and (6) radius and ulna ~34% length of humerus (proportionally longer than in Aucasaurus, Carnotaurus, and Majungasaurus). Phylogenetic analysis using two independent datasets recovers the new Candeleros form as a basal (i.e., non-brachyrostran, nonmajungasaurine) abelisaurid. As such, the new taxon is herein regarded as the earliest-branching abelisaurid that is known from the greater part of the skeleton.Fil: Lamanna, Matthew. Carnegie Museum Of Natural History; Estados UnidosFil: Porfiri, Juan Domingo. Universidad Nacional del Comahue; ArgentinaFil: Dos Santos, Domenica. Universidad Nacional del Comahue; ArgentinaFil: Juarez Valieri, Ruben Dario. Universidad Nacional del Comahue; ArgentinaFil: Gandossi, Paolo. Progetto Argendino, Bergamo; ItaliaFil: Baiano, Mattia Antonio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Patagonia Norte. Instituto de Investigación en Paleobiología y Geología; Argentina. Provincia del Neuquén. Municipalidad de Plaza Huincul. Museo "Carmen Funes"; Argentina79th Annual Meeting of Society of Vertebrate PaleontologyBrisbaneAustraliaSociety of Vertebrate Paleontolog