35 research outputs found

    Combined data analysis of fossil and living mammals: a Paleogene sister taxon of Placentalia and the antiquity of Marsupialia

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    The Cretaceous–Paleogene (KPg) boundary, one of Earth’s five major extinction events, occurred just before the appearance of Placentalia in the fossil record. The Gobi Desert, Mongolia and the Western Interior of North America have important fossil mammals occurring just before and after the KPg boundary (e.g. Prodiacodon, Deltatheridium) that have yet to be phylogenetically tested in a character-rich context with molecular data. We present here phylogenetic analyses of >6000 newly scored anatomical observations drawn from six untested fossils and added to the largest existing morphological matrix for mammals. These data are combined with sequence data from 27 nuclear genes. Results show the existence of a new eutherian sister clade to Placentalia, which we name and characterize. The extinct clade Leptictidae is part of this placental sister clade, indicating that the sister clade survived the KPg event to co-exist in ancient ecosystems during the Paleogene radiation of placentals. Analysing the Cretaceous metatherian Deltatheridium in this character-rich context reveals it is a member of Marsupialia, a finding that extends the minimum age of Marsupialia before the KPg boundary. Numerous shared-derived features from multiple anatomical systems support the assignment of Deltatheridium to Marsupialia. Computed tomography scans of exquisite new specimens better document the marsupial-like dental replacement pattern of Deltatheridium. The new placental sister clade has both Asian and North American species, and is ancestrally characterized by shared derived features such as a hind limb modified for saltatorial locomotion

    The seroprevalence of hepatitis C virus infection among children and their mothers attending for dental care in Glasgow, Scotland, United Kingdom

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    This paper describes a voluntary anonymous survey to investigate the seroprevalence of Hepatitis C (HCV) in children in Glasgow, UK attending a Dental Hospital and the proportion of HCV positive mothers who have a child who is HCV seropositive. The study was undertaken among children and accompanying parents and household contacts attending a general anaesthetic assessment clinic at Glasgow Dental Hospital and School. Children were asked to provide an oral fluid specimen for HCV testing. Accompanying adults were asked to provide demographic data on the child and information on familial risk factors for HCV infection using a standardised questionnaire. Birth mothers were also asked to provide an oral fluid specimen. Specimens and questionnaires were linked by a unique anonymous study number. Between June 2009 and December 2011, samples were collected from 2141 children and 1698 mothers. None of the samples from the children were HCV seropositive but 16 (0.9%, 95% CI 0.6% to 1.5%) of the specimens from mothers were HCV antibody positive. In summary, the prevalence of HCV seropositivity in the birth mothers of the children was similar to that estimated in the general population served by the hospital and showed no evidence of mother-to-child transmission of HCV

    Fetal alcohol spectrum disorder: development of concensus referral criteria for specialist diagnostic assessment in Australia

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    Background: Fetal alcohol spectrum disorder (FASD) is known to be under-recognised in Australia. The use of standard methods to identify when to refer individuals who may have FASD for specialist assessment could help improve the identification of this disorder. The purpose of this study was to develop referral criteria for use in Australia. Method: An online survey about FASD screening and diagnosis in Australia, which included 23 statements describing criteria for referral for fetal alcohol syndrome (FAS) and FASD based on published recommendations for referral in North America, was sent to 139 health professionals who had expertise or involvement in FASD screening or diagnosis. Survey findings and published criteria for referral were subsequently reviewed by a panel of 14 investigators at a consensus development workshop where criteria for referral were developed.Results: Among the 139 health professionals who were sent the survey, 103 (74%) responded, and 90 (65%) responded to the statements on criteria for referral. Over 80% of respondents agreed that referral for specialist evaluation should occur when there is evidence of significant prenatal alcohol exposure, defined as 7 or more standard drinks per week and at least 3 standard drinks on any one day, and more than 70% agreed with 13 of the16 statements that described criteria for referral other than prenatal alcohol exposure. Workshop participants recommended five independent criteria for referral: confirmed significant prenatal alcohol exposure; microcephaly and confirmed prenatal alcohol exposure; 2 or more significant central nervous system (CNS) abnormalities and confirmed prenatal alcohol exposure; 3 characteristic FAS facial anomalies; and 1 characteristic FAS facial anomaly, growth deficit and 1 or more CNS abnormalities .Conclusion: Referral criteria recommended for use in Australia are similar to those recommended in North America. There is a need to develop resources to raise awareness of these criteria among health professionals and evaluate their feasibility, acceptability and capacity to improve the identification of FASD in Australia

    A modified Delphi study of screening for fetal alcohol spectrum disorders in Australia

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    Background: There is little reliable information on the prevalence of fetal alcohol spectrum disorders (FASD) in Australia and no coordinated national approach to facilitate case detection. The aim of this study was to identify health professionals’ perceptions about screening for FASD in Australia. Method: A modified Delphi process was used to assess perceptions of the need for, and the process of, screening for FASD in Australia. We recruited a panel of 130 Australian health professionals with experience or expertise in FASD screening or diagnosis. A systematic review of the literature was used to develop Likert statements on screening coverage, components and assessment methods which were administered using an online survey over two survey rounds. Results: Of the panel members surveyed, 95 (73%) responded to the questions on screening in the first survey round and, of these, 81 (85%) responded to the second round. Following two rounds there was consensus agreement on the need for targeted screening at birth (76%) and in childhood (84%). Participants did not reach consensus agreement on the need for universal screening at birth (55%) or in childhood (40%). Support for targeted screening was linked to perceived constraints on service provision and the need to examine the performance, costs and benefits of screening. For targeted screening of high risk groups, we found highest agreement for siblings of known cases of FASD (96%) and children of mothers attending alcohol treatment services (93%). Participants agreed that screening for FASD primarily requires assessment of prenatal alcohol exposure at birth (86%) and in childhood (88%), and that a checklist is needed to identify the components of screening and criteria for referral at birth (84%) and in childhood (90%). Conclusions: There is an agreed need for targeted but not universal screening for FASD in Australia, and sufficient consensus among health professionals to warrant development and evaluation of standardised methods for targeted screening and referral in the Australian context. Participants emphasised the need for locally-appropriate, evidence-based approaches to facilitate case detection, and the importance of ensuring that screening and referral programs are supported by adequate diagnostic and management capacity

    Gills and epipods in Penaeoidea.

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    <p>Among the shallow-water clades, Agripenaeina (and other members of Penaeini) have the highest number of gills and epipods. Deep-water clades have the highest numbers across all of Penaeoidea. Listed are the total numbers of gills and epipods per side, based on the ancestral states for each clade, using parsimony. App = associated appendix, Max = maxilliped, Per = pereiopod.</p

    Members of Agripenaeina and Trachypenaeini from the Late Jurassic.

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    <p><sup>†</sup><i>Antrimpos speciosus</i> (panels <b>a</b> and <b>b</b>, CM-33420) and <sup><b>†</b></sup><i>Drobna deformis</i> (panels <b>e</b> and <b>f</b>, CM-29467), fossils from the Solnhofen limestone, Germany (ca. 145 mya [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0158840#pone.0158840.ref018" target="_blank">18</a>]) preserve key features that link them phylogenetically to shallow-water penaeoideans. <sup>†</sup><i>Antrimpos speciosus</i> belongs to Agripenaeina, the clade accounting for 90% of shrimp farmed for human consumption, and is shown in comparison to <i>Penaeus monodon</i> (<b>c</b>, giant tiger shrimp), a living member of Agripenaeina. <sup><b>†</b></sup><i>Drobna deformis</i> is the sister taxon of <i>Sicyonia</i> (Trachypenaini), and is shown in comparison to the living <i>Sicyonia lancifer</i> (<b>g</b>, rock shrimp). <b>d</b> and <b>h</b> show derived features shared by fossil and living shrimp. Additional synapomorphies for all clades are listed in <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0158840#pone.0158840.s006" target="_blank">S2</a> and <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0158840#pone.0158840.s007" target="_blank">S3</a> Tables. Scale bars = 3 cm.</p

    Minimum age phylogenetic tree of Penaeoidea.

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    <p>Agripenaeina, the clade of farmed shrimp, acquired a large body size despite the physiological constraints of their warm and shallow-water habitats. This clade is at least 145 my old because it includes a Late Jurassic species (<sup><b>†</b></sup><i>Antrimpos speciosus</i>) that inhabited the warm waters preserved in the Late Jurassic Solnhofen limestone [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0158840#pone.0158840.ref014" target="_blank">14</a>,<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0158840#pone.0158840.ref015" target="_blank">15</a>]. Ecological associations between shallow-water penaeoideans and mangrove forests occurred independently more than once, as clades of mangrove-associated shrimp (e.g., Agripenaeina and Trachypenaeini) predate the proposed Late Cretaceous origin of modern mangroves [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0158840#pone.0158840.ref016" target="_blank">16</a>]. Shrimp silhouettes illustrate differences in maximum body size for each clade. Topology shown emerges from parsimony (strict consensus of 24 trees) and Bayesian analyses, with some Bayesian incongruences noted in the Extended Results. Topology mapped to stratigraphic record with range extensions (cones) dictated by fossil placements (black dots indicate first appearance datum in the stratigraphic record) [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0158840#pone.0158840.ref017" target="_blank">17</a>]. Bremer Support (blue) and jackknife values over 50% (green) are indicated. Values in parentheses were calculated without fossil taxa (fossil exclusion produces a congruent tree). Bayesian posterior probabilities in black, with values italicized for clades that are congruent except for the placement of <sup>†</sup><i>Aeger tipularius</i>, which occupies a different position in the Bayesian tree (see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0158840#pone.0158840.s004" target="_blank">S4 Fig</a>). Tree icon and vertical shading indicate earliest evidence of modern mangroves [<a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0158840#pone.0158840.ref016" target="_blank">16</a>].</p

    Ice sheet collapse following a prolonged period of stable sea level during the last interglacial

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    During the last interglacial period, 127-116 kyr ago, global mean sea level reached a peak of 5-9m above present-day sea level. However, the exact timing and magnitude of ice sheet collapse that contributed to the sea-level highstand is unclear. Here we explore this timing using stratigraphic and geomorphic mapping and uranium-series geochronology of fossil coral reefs and geophysical modelling of sea-level records from Western Australia. We show that between 127 and 119 kyr ago, eustatic sea level remained relatively stable at about 3-4 m above present sea level. However, stratigraphically younger fossil corals with U-series ages of 118.1±1.4 kyr are observed at elevations of up to 9.5 m above present mean sea level. Accounting for glacial isostatic adjustment and localized tectonics, we conclude that eustatic sea level rose to about 9 m above present at the end of the last interglacial. We suggest that in the last few thousand years of the interglacial, a critical ice sheet stability threshold was crossed, resulting in the catastrophic collapse of polar ice sheets and substantial sea-level rise
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