The oldest known snakes from the Middle Jurassic-Lower Cretaceous provide insights on snake evolution

The previous oldest known fossil snakes date from ∼100 million year old sediments (Upper Cretaceous) and are both morphologically and phylogenetically diverse, indicating that snakes underwent a much earlier origin and adaptive radiation. We report here on snake fossils that extend the record backwards in time by an additional ∼70 million years (Middle Jurassic-Lower Cretaceous). These ancient snakes share features with fossil and modern snakes (for example, recurved teeth with labial and lingual carinae, long toothed suborbital ramus of maxillae) and with lizards (for example, pronounced subdental shelf/gutter). The paleobiogeography of these early snakes is diverse and complex, suggesting that snakes had undergone habitat differentiation and geographic radiation by the mid-Jurassic. Phylogenetic analysis of squamates recovers these early snakes in a basal polytomy with other fossil and modern snakes, where Najash rionegrina is sister to this clade. Ingroup analysis finds them in a basal position to all other snakes including Najash.Fil: Caldwell, Michael Wayne. University of Alberta; CanadáFil: Nydam, Randall L.. Department Of Anatomy, Midwestern University, Glendale; Estados UnidosFil: Palci, Alessandro. South Australian Museum. Earth Sciences Section; AustraliaFil: Apesteguía, Sebastián. 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; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

A New Clevosaurid from the Triassic (Carnian) of Brazil and the Rise of Sphenodontians in Gondwana

The early evolution of lepidosaurs is marked by an extremely scarce fossil record during the Triassic. Importantly, most Triassic lepidosaur specimens are represented by disarticulated individuals from high energy accretion deposits in Laurasia, thus greatly hampering our understanding of the initial stages of lepidosaur evolution. Here, we describe the fragmentary remains of an associated skull and mandible of Clevosaurus hadroprodon sp. nov., a new taxon of sphenodontian lepidosaur from the Late Triassic (Carnian; 237–228 Mya) of Brazil. Referral to Sphenodontia is supported by the combined presence of a marginal dentition ankylosed to the apex of the dentary, maxilla, and premaxilla; the presence of ‘secondary bone’ at the bases of the marginal dentition; and a ventrally directed mental process at the symphysis of the dentary. Our phylogenetic analyses recover Clevosaurus hadroprodon as a clevosaurid, either in a polytomy with the Late Triassic to Early Jurassic Clevosaurus and Brachyrhinodon (under Bayesian inference), or nested among different species of Clevosaurus (under maximum parsimony). Clevosaurus hadroprodon represents the oldest known sphenodontian from Gondwana, and its clevosaurid relationships indicates that these sphenodontians achieved a widespread biogeographic distribution much earlier than previously thought.Fil: Hsiou, Annie S.. Universidade de Sao Paulo; BrasilFil: Nydam, Randall L.. Midwestern University; Estados UnidosFil: Simões, Tiago R.. University of Alberta; Canadá. Harvard University; Estados UnidosFil: Pretto, Flávio A.. Universidade Federal de Santa Maria; BrasilFil: Onary, Silvio. Universidade de Sao Paulo; BrasilFil: Martinelli, Agustín Guillermo. Universidade Federal do Rio Grande do Sul; Brasil. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Museo Argentino de Ciencias Naturales "Bernardino Rivadavia"; ArgentinaFil: Liparini, Alexandre. Universidade Federal de Sergipe; BrasilFil: Romo de Vivar Martínez, Paulo Rodrigo. Universidade Federal do Rio Grande do Sul; BrasilFil: Soares, Marina. Universidade Federal do Rio Grande do Sul; BrasilFil: Schultz, Cesar. Universidade Federal do Rio Grande do Sul; BrasilFil: Caldwell, Michael Wayne. University of Alberta; Canad

Reacquisition of the lower temporal bar in sexually dimorphic fossil lizards provides a rare case of convergent evolution

34 p.Introducción. Cuando se piensa en centros de atención de usuarios se hace efímero el cuidado de la calidad de los servicios, porque de ello, la población blanco permanece fiel al servicio que se brinda; por esto se hace necesario contar con modelos que permitan conocer la calidad de los mismos, ejemplo de eso es el modelo Service Quality (SERVQUAL), que para efectos de este artículo se pretende enfatizar en el valor que tiene su utilización. Objetivo. Visibilizar la importancia de la utilización del modelo SERVQUAL a partir de una revisión sistemática de la literatura de tipo cualitativa en el periodo 2010-2016. Métodos. Se realiza una revisión sistemática de literatura cualitativa por el tipo de objetivo de la misma, cuya búsqueda finaliza a los veintiocho (28) días del mes de octubre de 2017. Se toma como bases de datos Pubmed, ScienceDirect, SciELO, LILACS, Tripdata base, Cochrane, Google, Google Scholar y Grey Lit. Para evaluar la calidad de los artículos se utiliza dos parrillas, la CASPe y THE JOANNA BRIGGS INSTITUTE, teniendo en cuenta las palabras claves que aparecen a continuación. Resultados. Se realiza un análisis a cuatrocientos treinta y siete (437) artículos de los cuales se obtiene una total de veintinueve (29) artículos, donde se visibiliza que el Modelo SERVQUAL es una buena herramienta en evaluar calidad en comparación con otros modelos Conclusión. El modelo SERVQUAL, dentro de sus bases teóricas se puede destacar, calidad de servicio, calidad de servicios en salud, a partir de ello, se plantean sus dimensiones que sirven como indicadores: tangibles; confiabilidad; sensibilidad; aseguramiento y empatía, de las cuales se destaca esta última, seguida de la tangibilidad, según los reportado en la literatura en estudios que aplicaron el modelo.Introduction. Introduction. When it thinks about user like a service centers, care for the quality of services becomes ephemeral, because of this, the white population remains faithful to the service provided; For this reason, it is necessary to have models that allow to know the quality of the same, example of that is the Service Quality model (SERVQUAL), which for the purposes of this article is intended to emphasize the value of its use. Objective. To make visible the importance of the use of the SERVQUAL model based on a systematic review of the qualitative literature in the period 2010-2016. Methods. A systematic review of qualitative literature is performed by the type of objective of the same, whose search ends on twenty-eight (28) days of the month of October 2017. It is taken as databases Pubmed, ScienceDirect, SciELO, LILACS, Tripdata base, Cochrane, Google, Google Scholar and Gray Lit. To assess the quality of the articles, we use two grills, the CASPe and THE JOANNA BRIGGS INSTITUTE, taking into account the key words that appear below. Results. An analysis is made to four hundred and thirty-seven (437) articles of which a total of twenty-nine (29) articles are obtained, where it is visible that the SERVQUAL Model is a good tool in evaluating quality in comparison with other models. Conclusion. The SERVQUAL model, within its theoretical bases can be highlighted, quality of service, quality of health services, based on this, its dimensions are considered as indicators: tangible; reliability; sensitivity; assurance and empathy, of which the latter stands out, followed by tangibility, as reported in the literature in studies that applied the model

Tetrapodophis amplectus is not a snake: Re-assessment of the osteology, phylogeny and functional morphology of an Early Cretaceous dolichosaurid lizard

The origin of snakes remains one of the most contentious evolutionary transitions in vertebrate evolution. The discovery of snake fossils with well-formed hind limbs provided new insights into the phylogenetic and ecological origin of snakes. In 2015, a fossil from the Early Cretaceous Crato Formation of Brazil was described as the first known snake with fore- and hind limbs (Tetrapodophis amplectus), and was proposed to be fossorial, to exhibit large gape feeding adaptations (macrostomy) and to possess morphologies suggesting constriction behaviours. First-hand examination of T. amplectus, including its undescribed counterpart, provides new evidence refuting it as a snake. We find: a long rostrum; straight mandible; teeth not hooked zygosphenes/zygantra absent; neural arch and spines present and tall with apical epiphyses; rib heads not tubercular; synapophyses simple; and lymphapophyses absent. Claimed traits not preserved include: braincase/descensus parietalis; ‘L’-shaped nasals; intramandibular joint; replacement tooth crowns; haemal keels; tracheal rings; and large ventral scales. New observations include: elongate retroarticular process; apex of splenial terminating below posterior extent of tooth row; >10 cervicals with hypapophyses and articulating intercentra; haemapophyses with articulating arches; reduced articular surfaces on appendicular elements; rows of small body scales; and reduced mesopodial ossification. The axial skeleton is uniquely elongate and the tail with >100 vertebrae is not short as previously claimed, although overall the animal is small (∼195 mm total length). We assessed the relationships of Tetrapodophis using a revised version of the original morphological dataset, an independent morphological dataset, and these two datasets combined with molecular data. All four were analysed under parsimony and Bayesian inference and unambiguously recover Tetrapodophis as a dolichosaur. We find that Tetrapodophis shows aquatic adaptations and there is no evidence to support constricting behaviour or macrostomy.Fil: Caldwell, Michael Wayne. University of Alberta; CanadáFil: Rodrigues Simões, Tiago. Harvard University; Estados UnidosFil: Palci, Alessandro. Flinders University. College Of Science And Engineering.; Australia. South Australian Museum; AustraliaFil: Garberoglio, Fernando Fabio. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Fundación de Historia Natural Félix de Azara; Argentina. Universidad Maimónides. Centro de Ciencias Naturales, Ambientales y Antropológicas; ArgentinaFil: Reisz, Robert R.. University of Toronto; CanadáFil: Lee, Michael S. Y.. Flinders University. College Of Science And Engineering.; Australia. South Australian Museum; AustraliaFil: Nydam, Randall L.. Midwestern University; Estados Unido

New skulls and skeletons of the Cretaceous legged snake Najash , and the evolution of the modern snake body plan

Snakes represent one of the most dramatic examples of the evolutionary versatility of the vertebrate body plan, including body elongation, limb loss, and skull kinesis. However, understanding the earliest steps toward the acquisition of these remarkable adaptations is hampered by the very limited fossil record of early snakes. Here, we shed light on the acquisition of the snake body plan using micro-computed tomography scans of the first three-dimensionally preserved skulls of the legged snake Najash and a new phylogenetic hypothesis. These findings elucidate the initial sequence of bone loss that gave origin to the modern snake skull. Morphological and molecular analyses including the new cranial data provide robust support for an extensive basal radiation of early snakes with hindlimbs and pelves, demonstrating that this intermediate morphology was not merely a transient phase between limbed and limbless body plans.Fil: Garberoglio, Fernando Fabio. 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; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Apesteguía, Sebastián. 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; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Simões, Tiago R.. University of Alberta; CanadáFil: Palci, Alessandro. Flinders University. College Of Science And Engineering.; AustraliaFil: Gomez, Raul Orencio. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Ciencias Geológicas; Argentina. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Departamento de Biodiversidad y Biología Experimental; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Nydam, Randall L.. Midwestern University; Estados UnidosFil: Larsson, Hans C. E.. McGill University; CanadáFil: Lee, Michael S. Y.. Flinders University. College Of Science And Engineering.; AustraliaFil: Caldwell, Michael Wayne. University of Alberta; Canad

New records of eutherian mammals from the Goler Formation (Tiffanian, Paleocene) of California and their biostratigraphic and paleobiogeographic implications /

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