592 research outputs found

    DINOSAURIOS VIAJEROS

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    La Patagonia se caracteriza por ser una tierra mística y desconocida, llena de interrogantes. Con casi un millón de kilómetros cuadrados encierra un tesoro envidiable: los Dinosaurios. Esta tierra virgen, pura y llena de sorpresas es una ventaja que nos permitirá a futuro tener una alternativa al desarrollo de la región no sólo mediante el turismo de la naturaleza sino el turismo paleontológico y geológico. La exposición «Dinosaurios argentinos, gigantes de la Patagonia» ha recorrido diferentes ciudades del mundo mostrando la diversidad de estos animales extintos

    First record of a clupeomorph fish in the Neuquén Group (Portezuelo Formation), Upper Cretaceous of Patagonia, Argentina

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    AbstractA new genus and species of clupeomorph fish, Leufuichthys minimus, is described from the fluvial deposits of the Portezuelo Formation, Upper Cretaceous (Turonian–Coniacian) of the Neuquén Group, Patagonia, Argentina. It is a small-sized fish with an estimated body length up to 46mm. Among other characters, the new species shows the following: abdominal scutes; abdomen moderately convex; anal fin elongate-based; three uroneurals; two epurals; caudal fin bearing very elongate rays; and cycloid scales. Leufuichthys minimus gen. et sp. nov. shows a greater similarity with Kwangoclupea dartevellei, a clupeomorph described from a marine Cenomanian deposit of the Democratic Republic of Congo (Africa), mainly due to the presence of an elongate-based anal fin, bearing more than 20 fin-rays, differing from it by the presence of a not hypertrophied abdomen. As far as known, L. minimus gen. et sp. nov. is the first clupeomorph described in the Upper Cretaceous of Patagonia and represents one fortuitous preservation of an articulated fish in fluvial deposits

    Ossos de pterosauro da Formação Portezuelo (Cretáceo), Grupo Neuquén, Patagônia, Argentina

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    The Futalognko quarry, located 90km northwest of Neuquén city, Argentina, has yielded several fossil vertebrates. All come from the upper part of the Portezuelo Formation (Turonian-Early Coniacian) and include some pterosaur remains, the first ones from the Cretaceous strata of the Neuquén Group. The material consists of a proximal end of a large ulna (MUCPv-358), the proximal part of a wing-phalanx (MUCPv-359), and another ulna associated with a radius (MUCPv-600). All specimens are referred to the Pterodactyloidea, and possibly represent members of the Azhdarchoidea. Histological sections of the large ulna (MUCPv-358) indicate that it belonged to an animal that was still growing at time of death. Comparisons with more complete specimens indicate that MUCPv-358 represents an animal with a wingspan of six meters, making it the largest pterosaur known from Argentina.O jazigo Futalognko está situado 90km a noroeste da cidade de Neuquén, Argentina, e forneceu uma grande quantidade de vertebrados fósseis, todos da parte superior da Formação Portezuelo (Turoniano- Eoconiaciano). Dentre os exemplares recuperados encontram-se alguns exemplares de pterossauros indicando a primeira ocorrência deste grupo para as rochas cretácicas do Grupo Neuquén. O material está representado pela parte proximal de uma ulna de grandes proporções (MUCPv-358), a parte proximal de uma primeira falange alar (MUCPv-359), e uma segunda ulna associada com o rádio (MUCPv-600). Todos estes exemplares são referidos a Pterodactyloidea e possivelmente representam formas de Azhdarchoidea. Seções histológicas da ulna maior (MUCPv-358) indicam que ela representa um animal jovem que estava em fase de crescimento quando morreu. Comparações com outros exemplares mais completos sugerem que MUCPv-358 tenha pertencido a um pterossauro com uma abertura alar em torno de seis metros, fazendo dele o maior réptil voador coletado até o presente momento na Argentina

    Floresta dos Borbas, uma nova localidade com pistas de dinossauros na Bacia de Sousa, Paraíba, Brasil.

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    A new site with dinosaur tracks from the Sousa Basin, Lower Cretaceous of Northeast Brazil is presented. Floresta dos Borbas is the sixth dinosaur tracksite found in the Antenor Navarro Formation. Two theropod trackways are described as well as three sauropod tracks. The sauropod record in this region indicates a restriction to the northern portion of the basin, mostly found in the Antenor Navarro Formation and probably the basal portion of the Sousa Formation. A preliminary analysis indicates that the lower portion of the stratigraphic sequence that forms the Sousa Basin was deposited in a different paleoenvironmental condition than the upper part, being possibly more favorable for sauropods.Uma nova localidade com pistas de dinossauros da Bacia de Sousa, parte do complexo de bacias do Rio do Peixe, Cretáceo Inferior do Nordeste do Brasil, é apresentada. A região, conhecida como Floresta dos Borbas, forma a sexta localidade com pistas e pegadas de dinossauros encontrada na Formação Antenor Navarro. Duas pistas de terópodes e três pegadas de saurópodes são descritas. O registro de pegadas de saurópodes está restrito à parte norte da bacia, procedente da Formação Antenor Navarro e possivelmente à base da Formação Sousa. Uma análise ainda bastante preliminar sugere a existência de diferentes condições paleoambientais na base da seqüência estratigráfica que forma esta bacia, possivelmente mais favorável ao desenvolvimento de uma comunidade de saurópodos do que a parte superior

    A new species of Comahuesuchus Bonaparte, 1991 (Crocodyliformes: Notosuchia) from the Upper Cretaceous of Neuquén, Lake Barreales, Patagonia, Argentina

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    Abstract Notosuchian crocodyliforms were major components of the South American Cretaceous biota and, for over 125 years, paleontological fieldwork in this continent recovered several well-preserved fossils of these animals. They are largely recognized for terrestrial life and specialized feeding habits, frequently presenting bizarre taxa such as Comahuesuchus. A new species, Comahuesuchus bonapartei n. sp. (MUCPv 597; cast MN), is described from geological strata of Sierra Barrosa Formation (Upper Turonian) and Portezuelo Formation (Lower Coniacian) of Lake Barreales, Patagonia, Argentina. The new fossil comprises a right dentary bone that shares important and unique anatomical features with specimens of Comahuesuchus brachybuccalis, such as the presence of a well-marked shelf on the lateral surface of the bone; a flat, low, and wide mandibular symphysis; an enlarged, labiolingually compressed caniniform tooth at caudal position in the dentary; the presence of serrated mesial and distal carinae in the caniniform with a faceted labial surface, and the absence or extremely reduction in number of the postcaniniform dentition. C. bonapartei differs from C. brachybuccalis in having individual dentary alveoli, rather a dentition set in groove. Phylogenetic analyses support a sister-relationship between both species, which are well nested within notosuchians

    Population structure of eleven Spanish ovine breeds and detection of selective sweeps with BayeScan and hapFLK

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    The goals of the current work were to analyse the population structure of 11 Spanish ovine breeds and to detect genomic regions that may have been targeted by selection. A total of 141 individuals were genotyped with the Infinium 50 K Ovine SNP BeadChip (Illumina). We combined this dataset with Spanish ovine data previously reported by the International Sheep Genomics Consortium (N = 229). Multidimensional scaling and Admixture analyses revealed that Canaria de Pelo and, to a lesser extent, Roja Mallorquina, Latxa and Churra are clearly differentiated populations, while the remaining seven breeds (Ojalada, Castellana, Gallega, Xisqueta, Ripollesa, Rasa Aragonesa and Segureña) share a similar genetic background. Performance of a genome scan with BayeScan and hapFLK allowed us identifying three genomic regions that are consistently detected with both methods i.e. Oar3 (150–154 Mb), Oar6 (4–49 Mb) and Oar13 (68–74 Mb). Neighbor-joining trees based on polymorphisms mapping to these three selective sweeps did not show a clustering of breeds according to their predominant productive specialization (except the local tree based on Oar13 SNPs). Such cryptic signatures of selection have been also found in the bovine genome, posing a considerable challenge to understand the biological consequences of artificial selection.Publishe
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