59 research outputs found

    Development and application of a novel and compact long-wavelength fluorescence spectrometer

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    Long wavelength (>600nm) fluorescence offers many advantages when applied to analysis, including minimal autofluorescence and scattered light from biological samples and the possibility of compact, robust, yet sensitive instruments. Modern clinical analysis has a number of specific requirements, namely specificity, sensitivity and speed, whilst the ability to monitor samples away from the laboratory is increasingly in demand. Immunoassays possess all these attributes and can be used in the following: environmental monitoring; clinical analysis; therapeutic drug monitoring. This research work describes a novel portable fluorescence spectrophotometer using long wavelength detection which can be used in all environments

    A new long-wavelength fluorigenic substrate for alkaline phosphatase: synthesis and characterisation

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    Naphthofluorescein diphosphate has been synthesised from the parent dye, and shown to be an attractive longwavelength alternative to other fluorigenic substrates for the determination of alkaline phosphatase. Its application to the determination of theophylline, an inhibitor of this enzyme, has been demonstrated. The optimum excitation wavelength of the hydrolysis product naphthofluorescein has been found to depend on the presence of additives such as cyclodextrins and (3-[3-cholamidopropyl]-dimethylamino)-1-propane sulfonate (CHAPS): such effects can be used to raise the excitation wavelength to match the output of a 635 nm diode laser in a simple and sensitive fluorescence detector

    A New Genus of Plesiosaur (Reptilia: Sauropterygia) from the Pliensbachian (Early Jurassic) of England, and a Phylogeny of the Plesiosauria

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    Two new species of plesiosaur have been recognised from the Pliensbachian (Early Jurassic) of England. They share derived characters and so are referred to the same new genus, Raptocleidus. Raptocleidus blakei is from Blockley Station Quarry, Gloucestershire (holotype specimen LEICT G1.2002) while Raptocleidus bondi is from the coast of Dorset (holotype specimen NHMUK R16330). The two new species share characters with different family-level groups of plesiosaur; the pliosaurids, leptocleidians and rhomaleosaurids. This makes classification of the new taxa problematic using purely comparative anatomical techniques. To further investigate their systematic position within the Plesiosauria, a phylogenetic analysis was performed. This is the largest analysis of plesiosaurian relationships ever attempted. The new species were found to be basal members of a paraphyletic assemblage which form successive sister groups to the Leptocleidia but which lie outside of this node-based taxon. The new stem-based taxon Leptocleidomorpha has been erected to encompass the new clade. The Leptocleidomorpha formed a novel sister group relationship with the Pliosauridae with the branching point situated at the very base of the Jurassic or earlier. The new clade Eupliosauria has been erected to encompass this new group. Finally two clades (Cryptoclidinae Williston, 1925 and Muraenosaurinae White, 1940) have been newly defined to describe diversity within the plesiosauroid clade Cryptoclididae. Additional specimens have been identified that may prove to be new taxa pending further work

    Lomax et al. Wahlisaurus massarae new specimen (Triassic-Jurassic boundary)

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    Supplemental material for:<div><br></div><div><p>Lomax, D. R., Evans, M. and Carpenter, S. 2018. An ichthyosaur from the UK Triassic–Jurassic boundary: a second specimen of the leptonectid ichthyosaur <i>Wahlisaurus massarae</i> Lomax 2016. Geological Journal.</p></div

    Holotype of <i>Avalonnectes arturi</i> (NHMUK 14550).

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    <p><b>A–B</b>, skull in dorsal view; <b>C–E</b>, postcranial skeleton; in left dorsolateral (<b>C</b>) and left lateral (<b>D–E</b>) views. In line drawings (<b>B</b>, <b>E</b>) dark grey tone indicates damage and light grey tone indicates the palate. Abbreviations: ca, caudal vertebra [number following indicates order in preserved series]; ce, cervical vertebra; d, dorsal vertebra; depr, depression; ecto, ectopterygoid; epip, epipterygoid; exp, expanded neural spine apex; fr, frontal; jug, jugal; l., left [followed by name of element]; mx, maxilla; p, ‘pectoral’ vertebra; par, parietal; pmx, premaxilla; po, postorbital; pofr, postfrontal; prfr, prefrontal; qua, quadrate; r., right [followed by name of element]; s, sacral vertebra; sq, squamosal; unexp, unexpanded neural spine apex. Scale bars equal 50 mm (<b>A–B</b>), 20 mm (<b>C</b>), and 200 mm (<b>D–E</b>).</p

    The anatomy of <i>Stratesaurus</i> (Reptilia, Plesiosauria) from the lowermost Jurassic of Somerset, United Kingdom

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    <div><p>ABSTRACT</p><p>We provide a complete description of one of the oldest plesiosaurians, <i>Stratesaurus taylori</i> from the earliest Hettangian of the United Kingdom. At least 25 apomorphies distinguish <i>S. taylori</i> from the sympatric <i>Thalassiodracon hawkinsii</i>, to which all three specimens of <i>S. taylori</i> were originally referred. Several features of the skull of <i>S. taylori</i> suggest specialization on small prey items, or sieve feeding. In particular, it has anteriorly inclined premaxillary and mesial maxillary teeth and an only weakly heterodont maxillary dentition. This indicates niche partitioning among sympatric small-bodied plesiosaurians: <i>T. hawkinsii</i> has a pronouncedly heterodont dentition. With a body length estimated around 2 m, <i>S. taylori</i> is one of the smallest plesiosaurians, comparable to <i>T. hawkinsii</i>. Our anatomical review of <i>S. taylori</i> suggests difficulty determining its precise phylogenetic affinities. This is consistent with a general lack of phylogenetic resolution among earliest Jurassic plesiosaurians, which may result from missing data on their Triassic ancestry. However, due to its plesiomorphic morphology and well-characterized anatomy, we recommend <i>S. taylori</i> as an ingroup representative of Plesiosauria for future cladistic analyses of Triassic sauropterygians.</p><p>SUPPLEMENTAL DATA—Supplemental materials are available for this article for free at <a href="http://www.tandfonline.com/UJVP" target="_blank">www.tandfonline.com/UJVP</a></p></div

    Phylogeny of Lower Jurassic plesiosaurians.

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    <p>Temporally-calibrated strict consensus of 42 MPTs recovered from our phylogenetic analysis. Triangular symbols represent non-neoplesiosaurian plesiosaurians (mainly rhomaleosaurids), squares represent pliosaurids and circles represent plesiosauroids. Unfilled shapes represent British taxa whereas grey-filled shapes represent German and French taxa. Key localities yielding abundant remains from four narrow horizons are indicated by grey bands, although contemporaneous specimen are known from other localities: <b>A</b>, Street, Somerset, UK (lowermost Hettangian); <b>B</b>, Lyme Regis and Charmouth, Dorset, UK (late Hettangian–Sinemurian); <b>C</b>, Holzmaden and vicinity, Baden-Württemberg, Germany (<i>H. falciferum</i> Chronozone; lower Hettangian); <b>D</b>, Yorkshire, UK (<i>H. bifrons</i> Chronozone; lower Hettangian). Dashed lines indicate polytomy at base of Pistosauria prior to deletion of <i>Pistosaurus</i> from the set of MPTs.</p

    Holotype of <i>Stratesaurus taylori</i> (OUMNH J.10337).

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    <p><b>A–B</b>, skull in dorsal view, <b>C–E</b>, anterior cervical vertebrae in left lateral (<b>C</b>), ventral (<b>D</b>) and anterior (<b>E</b>) views, <b>F</b>, <b>H–I</b>, left ilium in dorsal (<b>F</b>), lateral (<b>H</b>) and posterior (<b>I</b>) views, <b>G</b>, ‘pectoral’ vertebra; in left lateral view. In line drawing (<b>B</b>), grey tone indicates damage. Abbreviations: bs, basisphenoid; exof, exoccipital facet of basioccipital; jug, jugal; fr, frontal; hy, hyoid; lpmx, left premaxilla; mx, maxilla; occ, occipital condyle; pal, palatine; par, parietal; po, postorbital; popr, posterolateral process of prezygapophysis; prz, prezygapophysis; pt, pterygoid; qua, quadrate; rmx, right maxilla; rpmx, right premaxilla; scler, sclerotic ring; sq, squamosal. Scale bars equal 50 mm (<b>A–B</b>, <b>F</b>, <b>H–I</b>) and 20 mm (<b>C–E</b>, <b>G</b>).</p

    Holotype of <i>Eoplesiosaurus antiquior</i> (TTNCM 8348) in right lateral view.

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    <p>Image in <b>A</b> is a composite made from four photographs (divisions are indicated by black and white lines), with enlargement of anterior cervical vertebrae (<b>B</b>; magnified portion is enlarged x2.0 times). Gastralia are not shown in line drawing (<b>C</b>). Abbreviations: ca, caudal vertebra; ce, cervical vertebra [number following indicates order in preserved series]; chv, chevron; l., left [followed by name of element]; pro, lateral projection; prz, prezygapophysis; r., right [followed by name of element]; trp, transverse process. Scale bars equal 200 mm (<b>A</b>, <b>C</b>) and 50 mm (<b>B</b>).</p

    Results of maximum likelhood model fitting of Lower Jurassic plesiosaurian trunk length evolution.

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    <p>Results of maximum likelhood model fitting of Lower Jurassic plesiosaurian trunk length evolution.</p
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