First palynologic record of the Cretaceous La Yesera Formation (Salta Group), northwestern Argentina

Thirty-four taxa were documented from six palynologically productive samples of the La Yesera Formation (Brealito and Don Bartolo Members) in the Pucará locality (Salta Province, northwestern Argentina). In the Brealito Member, aquatic species (mainly freshwater algae) dominate the palynofl ora, while terrestrial species are represented by trilete spores (mainly Anemiaceae) and gymnosperm pollen grains. In the Don Bartolo Member, Classopollis spp. dominate most of the assemblages, trilete Anemiaceae spores constitute half of the total counts in one of the assemblages and a unique angiosperm species (Tricolpites variabilis) was found in two assemblages. Ephedra-type pollen grains (three genera and six species) appear in both members, although in low abundance. The results support previous sedimentology studies that indicate a perennial lake environment at the time of deposition of the Brealito Member, with evidence for dry seasonality in the Don Bartolo Member. The inferred regional paleoclimate is subtropical with arid conditions. Considering the stratigraphic ranges of selected species and the sedimentology data, an Albian/Cenomanian age is suggested for the unit.Trinta e quatro táxons foram registrados a partir de seis amostras palinológicas provenientes da Formação La Yesera (membros Brealito e Don Bartolo), na localidade Pucará, Província de Salta, noroeste da Argentina. No Membro Brealito, predominam as espécies aquáticas, principalmente de algas de água doce; as espécies terrestres estão representadas por esporos triletes, principalmente de Anemiaceae e por grãos de pólen de gimnospermas. No Membro Don Bartolo, os grãos de pólen Classopollis spp. dominam a maioria das assembleias, embora numa das amostras, metade das contagens totais é constituída por esporos triletes de Anemiaceae e, uma única espécie de angiospermas (Tricolpites variabilis) foi encontrada em duas assembleias. Grãos de pólen do tipo Ephedra, com três gêneros e seis espécies, aparecem em baixa abundância em ambos os membros. Estes resultados corroboram estudos sedimentológicos anteriores e indicam ambiente lacustre perene, no momento da deposição do Membro Brealito, com evidência de sazonalidade seca para a Membro Don Bartolo. O paleoclima regional inferido é subtropical árido. Considerando os intervalos estratigráfi cos de espécies selecionadas e os dados sedimentológicos, é sugerida idade Albiano/Cenomaniano para a unidade estudada.Fil: Narvaez, Paula Liliana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Pramparo, Mercedes Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Provincia de Mendoza. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales. Universidad Nacional de Cuyo. Instituto Argentino de Nivología, Glaciología y Ciencias Ambientales; ArgentinaFil: Sabino García, Ignacio Federico. Tecpetrol S. A.; Argentin

Sedimentología y vertebrados fósiles de la Formación Santa Cruz (Mioceno temprano) en Lago Posadas, suroeste de Patagonia, Argentina

Lago Posadas se ubica al pie de los Andes Patagónicos Australes, en el suroeste de Argentina, donde la Formación Santa Cruz (FSC) del Mioceno temprano muestra afloramientos potentes y lateralmente continuos. Esta región ha sido escasamente explorada en relación con sus vertebrados fósiles desde los primeros esfuerzos de J.B. Hatcher en 1898-99. En esta contribución, se presentan estudios sedimentológicos y paleontológicos con el fin de reconstruir los ambientes deposicionales y la fauna de vertebrados asociada. Los datos sedimentológicos sugieren que el registro sedimentario comienza con depósitos marinos-estuarinos restringidos, que gradan a depósitos de planicies de inundación y canales fluviales. Dichas planicies, ocasionalmente interrumpidas por canales arenosos, muestran colores rojizos dominantes, pobre a moderado desarrollo de paleosuelos, abundantes depósitos de desbordes y ausencia de restos vegetales, lo cual sugiere depositación en ambientes oxigenados de bajo gradiente, con altas tasas de sedimentación. Las tendencias estratigráficas verticales son tenues, lo que indicaría cambios ambientales menores durante la depositación. Las direcciones de paleocorrientes, la composición de areniscas y la reconstrucción paleogeográfica indican que la acumulación de la FSC estuvo asociada al levantamiento Andino contemporáneo. Los vertebrados fósiles analizados son el resultado del esfuerzo propio de colecta y de colecciones de museos. La asociación faunística incluye 31 taxa: 28 mamíferos y tres aves. Los mamíferos pertenecen a los grupos principales registrados en otras áreas en la FSC (metaterios, xenartros, notoungulados, litopternos, astrapoterios y roedores) y permiten asignar una edad Santacrucense sensu lato a la fauna de la FSC de Lago Posadas. Son necesarias revisiones taxonómicas de varios taxa para mejorar el significado bioestratigráfico de esta asociación. La combinación del registro de arborícolas, ramoneadores y frugívoros por un lado, y mamíferos pastadores y ñandúes por el otro, plantearía la presencia tanto de árboles como de ambientes abiertos. Los frugívoros, entre los consumidores primarios, y el nicho de los consumidores secundarios, se encuentran subrepresentados debido a sesgos en el tamaño de los fósiles como en el tamaño del muestreo. El registro sedimentológico y paleontológico de la FSC en Lago Posadas sugiere que el ascenso de los Andes Patagónicos Australes ha actuado como un control primario sobre la subsidencia y el aporte de sedimentos, y ha otorgado características distintivas a las localidades subandinas. Sin embargo, los cambios climáticos previamente postulados, están pobremente registrados en este estudio.Lago Posadas is located at the foot of the Southern Patagonian Andes, in southwestern Argentina, where the early Miocene Santa Cruz Formation (SCF) shows thick and laterally continuous exposures. This region has been scarcely explored for fossil vertebrates since the first efforts by J.B. Hatcher in 1898-99. In this contribution, we performed sedimentologic and paleontological studies in order to reconstruct depositional environments and the associated fossil vertebrate fauna. Sedimentologic data suggest that the sedimentary record begins with restricted marine-estuarine deposits grading upward to fluvial floodplains and fluvial channels. Extensive floodplains, occasionally interrupted by low-sinuosity, sand-dominated channels, show dominant reddish coloration, moderate to low paleosol development, abundant crevasse splay sandstones and lack of vegetal remains, suggesting deposition in a low gradient, oxygenated setting under elevated sedimentation rates. Vertical stratigraphic trends are subtle, suggesting little paleoenvironmental changes during deposition of the whole SCF in this region. Paleocurrent directions, sandstone composition and paleogeographic reconstructions all indicate that deposition of the SCF was strongly associated to the contemporaneous uplift of the Andes. Fossil vertebrates analyzed are the result of our collecting effort and revision of museum collections. The faunal assemblage includes 31 taxa: 28 mammals and three birds. Mammals belong to the main groups recorded in other areas of the SCF (metatherians, xenarthrans, notoungulates, litopterns, astrapotheres and rodents). The assemblage allows a Santacrucian Age sensu lato assignment for the fauna at Lago Posadas. Taxonomic revisions of several taxa are necessary to further adjust the biostratigraphic significance of this association. The combined record of arboreal, browser and frugivores, on one side, and grazer mammals and rheas, on the other, suggest the presence of both trees and open environments. Frugivores, among primary consumers, and the secondary consumers guild are under-represented due to sample and fossil remain size biases. The sedimentologic and paleontological record of the SCF in Lago Posadas suggests that the uplift of the Southern Patagonian Andes acted as a primary control on basin subsidence and sediment supply, providing a special signature for sub-andean localities. However, previously registered climatic changes are poorly recorded in this study.Fil: Cuitiño, José Ignacio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico de Geología y Paleontología; ArgentinaFil: Vizcaíno, Sergio Fabián. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata; ArgentinaFil: Bargo, María Susana. Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas; Argentina. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. División Paleontología Vertebrados; ArgentinaFil: Aramendía, Inés. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Centro Nacional Patagónico. Instituto Patagónico para el Estudio de los Ecosistemas Continentales; Argentin

Mid-Mesozoic leaves from near Ida Bay, southern Tasmania, Australia

Several leaf specimens from a locality in southern Tasmania are described. They are assigned to Coniopteris websterii sp.nov., Cladophlebis indica (Oldham & Morris) Sahni & Rao, Pachypteris sp. cf. indica (Oldham & Morris) Bose & Roy, Otozamites sp., Pterophyllum? sp. and Conites sp. The specimen of Olozamiles sp. is also partially petrified and, thus, gives some indication of its internal tissues. These genera and species suggest a mid-Mesozoic, rather than a Tertiary, age for this locality

Malignant melanoma of the urethra: a rare histologic subdivision of vulvar cancer with a poor prognosis

Malignant melanoma of the urethra is a rare tumour that is difficult to diagnose and treat, resulting in a poor prognosis. In this paper, we present the case of a 65-year-old woman who was referred to a gynaecologist because of a urethral mass that mimicked a caruncle. The tumour was removed by local excision, and a pathological analysis revealed a malignant melanoma. Distal urethrectomy was performed after three months with no evidence of residual tumour. There was no evidence of disease at a six-year followup. In this paper, we compare the epidemiology, treatment, staging, and prognosis of vulvar cancer in general to malignant melanoma of the vulva in particular

The Paleozoic and Mesozoic vertebrate record of Venezuela: An overview, summary of previous discoveries and report of a mosasaur from the La Luna Formation (Cretaceous)

Most reports of Paleozoic and Mesozoic vertebrates from Venezuela are anecdotical, with few detailed descriptions of mostly ‘fish' groups. Synapsids (e.g., mammals) are totally unknown, and dinosaurs are only reported from the La Quinta Formation. At least 14 formally recognized geological formations contain fossil vertebrates, most from the Central and Western parts of the country. In the Devonian there is a significant contrast between the vertebrates of Venezuela and Colombia and those of more southern parts of South America. Marine reptiles are present in a few localities in western Venezuela, and are very fragmentary, with one exception. A mosasaur from the Cretaceous La Luna Formation, reported here for the first time, is the most complete vertebrate (tetrapod) from the Cretaceous of Venezuela, and includes a partial skull and a few postcranial remain

Burdigalian deposits of the Santa Cruz Formation in the Sierra Baguales, Austral (Magallanes) Basin: Age, depositional environment and vertebrate fossils

Indexación: Web of Science; Scielo.ABSTRACT. A succession of marine and continental strata on the southern flank of Cerro Cono in the Sierra Baguales, northeast of Torres del Paine, can be correlated with stratigraphic units exposed along the southern border of the Lago Argentino region in Santa Cruz Province, Argentina. These include the Estancia 25 de Mayo Formation and the basal part of the Santa Cruz Formation. The lithological correlation is also confirmed by detrital zircon ages (maximum age of 18.23±0.26 Ma) and a rich assemblage of terrestrial vertebrate fossils, biostratigraphically equivalent to a postColhuehuapian, pre-Santacrucian South American Land Mammal Age (SALMA) fauna, suggesting a range of 19 to 17.8 Ma. Similar ages have been obtained from the basal part of the Santa Cruz Formation at Estancia Quién Sabe in southwestern Argentina, supporting the assumption of a regional continuity between these deposits. A measured lithostratigraphic column is presented and the depositional environment is interpreted as a coastal plain with small, meandering rivers and ephemeral floodplain lakes. The sedimentation coincides with intensified uplift of the Patagonian Andes during the ‘Quechua Phase’ of Andean tectonism, which is reflected by a change in paleocurrent directions from northwest to east-northeast. Keywords: Burdigalian, Santa Cruz Formation, Santacrucian SALMA, ‘Notohippidian’ fauna, Meandering rivers.RESUMEN. Una sucesión de estratos marinos y continentales en el flanco meridional del cerro Cono, en la sierra Baguales, al noreste de Torres del Paine, se correlaciona con estratos al sur de la región de lago Argentino en la Provincia de Santa Cruz, República Argentina. Estas unidades incluyen la Formación Estancia 25 de Mayo y la parte basal de la Formación Santa Cruz. La correlación litológica es, además, confirmada por datación de circones detríticos (edad máxima de 18,23±0,26 Ma) y un variado ensamble de vertebrados fósiles terrestres de edad post-Colhuehuapense a pre-Santacrucense en la escala de Edades Mamífero Sudamericanas (EMAS), con un rango temporal de entre 19 a 17,8 Ma. Edades similares han sido reportadas para la parte basal de la Formación Santa Cruz, en estancia Quién Sabe, en el suroeste de Argentina, ratificando la continuidad regional entre estos depósitos. Se presenta una columna estratigráfica y se interpreta el ambiente de depositación como una llanura costera con pequeños ríos sinuosos y lagos efímeros. La edad de sedimentación coincide con el solevantamiento de los Andes Patagónicos durante la 'Fase Quechua', lo que se ve reflejado por un cambio en la dirección de las paleocorrientes desde el noroeste hacia el este-noreste.http://ref.scielo.org/csxwd

The Four Phases of Plant-Arthropod Associations in Deep Time

Vascular-plant hosts, their arthropod herbivores, and associated functional feeding groups are distributed spatiotemporally into four major herbivore expansions during the past 420 m.y. They are: (1) a Late Silurian to Late Devonian (60 m.y.) phase of myriapod and apterygote, hexapod (perhaps pterygote) herbivores on several clades of primitive vascular-plant hosts and a prototaxalean fungus; (2) a Late Mississippian to end-Permian (85 m.y.) phase of mites and apterygote and basal pterygote herbivores on pteridophyte and basal gymnospermous plant hosts; (3) a Middle Triassic to Recent (245 m.y.) phase of mites, orthopteroids (in the broadest sense) and hemipteroid and basal holometabolan herbivores on pteridophyte and gymnospermous plant hosts; and (4) a mid Early Cretaceous to Recent (115 m.y.) phase of modern-aspect orthopteroids and derived hemipteroid and holometabolous herbivores on angiospermous plant hosts. These host-plant and herbivore associations are mediated by seven functional feeding groups: a) external foliage feeding, b) piercing-and-sucking, c) boring (Phase 1 origins); d) galling, e) seed predation, f) nonfeeding oviposition (Phase 2 origins); and leaf mining (early Phase 3 origin). Within about 20 m.y. of each herbivore expansion, there is a biota that expresses the nearly full spectrum of later plant-arthropod associations. These four associational phases may be linked to the paleoclimatologic variables of greenhouse/icehouse cycles and atmospheric O2 and CO2 levels by uncertain causes, although some relationship probably is present. The 7 functional feeding groups persist through most of the sampled interval but harbor host-plants and arthropod herbivores that are spatiotemporally ephemeral. Poor understanding of associations in Phases 1 to 3 is attributed to disproportionate focus on the angiosperm and holometabolan insect associations of Phase 4

Primeiro registro de madeira de annonaceae para o neógeno da América do Sul, Bacia do Amazonas, Brasil

The relief of the regions of Manaus and Itacoatiara,Central Amazon, is supported by Neogene siliciclastic rocks, boundedat the base and top by lateritic paleosols and covered by quaternary sedimentarydeposits from the Solimões-Amazon river system. This unitis informally assigned to the Novo Remanso Formation, consists ofusually reddish and ferruginized sandstones, conglomerates and pelites,with few identified fossil records, a fact that has hindered its stratigraphicposition, and the paleoenvironmental reconstruction of the lastphase of the Amazon Basin settling. This study describes, for the firsttime, the occurrence of fossil wood in outcroppings of the left bank ofthe Amazon River, where anatomical and morphological data has enabledits characterization to the species level. Thus, the data marks therecord of the Annonaceae in South America, as well as the depositionalprocesses related to incorporation of organic material in the sandylayer and the fossilization processes that allowed its preservation. In anunprecedented way, this study has described Duguetiaxylon amazonicumnov. gen and sp. and provided information on the anatomical andsystematic character, as well as data on plant-insect interaction, and abetter understanding of the family.O relevo das regiões de Manaus e Itacoatiara, na Amazônia Central, é suportado por rochas siliciclásticas neogênicas, delimitadas na base e no topo por paleossolos lateríticos e cobertas por depósitos sedimentares quaternários do sistema fluvial Solimões-Amazonas. Essa unidade é informalmente atribuída à Formação Novo Remanso, constituída geralmente de arenitos avermelhados e ferruginizados, conglomerados e pelitos, com poucos registros fósseis identificados, fato que tem impedido sua posição estratigráfica e a reconstrução paleoambiental da última fase do assentamento da Bacia Amazônica. Este estudo descreve, pela primeira vez, a ocorrência de madeira fóssil em afloramentos da margem esquerda do Rio Amazonas, onde dados anatômicos e morfológicos possibilitaram sua caracterização ao nível da espécie. Assim, os dados marcam o registro de Annonaceae na América do Sul, bem como os processos deposicionais relacionados à incorporação de material orgânico na camada arenosa e os processos de fossilização que permitiram sua preservação. De modo sem precedentes, este estudo descreve Duguetiaxylon amazonicum nov. gen e sp. e fornece informações sobre as características anatômicas e sistemáticas, bem como dados sobre a interação planta-inseto e melhor compreensão da família.Fil: Amaral Soares, Emilio Alberto. Universidade Federal Do Amazonas; BrasilFil: Cabral Kloster, Adriana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Gnaedinger, Silvia Cristina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Centro de Ecología Aplicada del Litoral. Universidad Nacional del Nordeste. Centro de Ecología Aplicada del Litoral; ArgentinaFil: Riker, Silvio Roberto. Serviço Geológico Do Brasil; BrasilFil: Da Cruz Lima, Felipe José. Serviço Geológico Do Brasil ; BrasilFil: Motta, Marcelo Batista. Serviço Geológico Do Brasil; Brasi

A new sauropod titanosaur from the Plottier Formation (Upper Cretaceous) of Patagonia (Argentina)

This paper presents a new titanosaur sauropod, collected from levels of reddish clays assigned to the Plottier Formation (Coniacian-Santonian). The holotype of Petrobrasaurus puestohernandezi gen. et. sp. nov. is a disarticulated specimen, from which teeth, cervical, dorsal and caudal vertebrae, sternal plates, metacarpals, femora, tibia, a fragment of ilium, pubis, haemal arches, and cervical and dorsal ribs have been preserved. This period is of particular interest because it saw the definitive isolation of the vertebrate faunas of Patagonia, with the separation of South America from the rest of Gondwana, a process that had begun during the Early Cretaceous. Although some of the characters observed in Petrobrasaurus gen. nov. suggest a relationship with the South American clade Lognkosauria, this new sauropod is regarded as Titanosauria incertae sedis until a more profound analysis of the Titanosauria that in which it is included is undertaken