A. T. Kearsley

University of Kent, Cantorbery, England, United Kingdom

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Publications (305)669.9 Total impact

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    ABSTRACT: Calcium–aluminum-rich inclusions (CAIs) from the metal-rich (CH/CB-like) carbonaceous chondrite Isheyevo are mineralogically pristine and show no evidence for postcrystallization alteration. Many of them are composed of very refractory minerals, such as hibonite (CaAl 12 O 19), grossite (CaAl 4 O 7), aluminum-rich pyroxene, and perovskite (CaTiO 3). Twenty-eight out of 35 studied CAIs from Isheyevo have oxygen isotopic compositions similar to those of CAIs from the CM and CR carbonaceous chondrites (Δ 17 O ∼ −20‰). Five igneous CAIs are 16 O-depleted to a level observed in Isheyevo chondrules (Δ 17 O −10‰), suggesting remelting and isotope exchange in an 16 O-poor gaseous reservoir. Two CAIs, WA9 and B1, show the highest enrichment in 16 O (δ 17 O ∼ −68‰, δ 18 O ∼ −66‰, Δ 17 O ∼ −34‰) ever observed among refractory inclusions. In the context of the self-shielding model for the evolution of oxygen isotopes in the solar accretion disk, these CAIs may have recorded the initial oxygen isotopic composition of the solar system, and hence of the Sun.
    The Astrophysical Journal 12/2015; 698(1):18-22. DOI:10.1088/0004-637X/698/1/L18 · 5.99 Impact Factor
  • T. K. Croat · C. Floss · B. A. Haas · M. J. Burchell · A. T. Kearsley
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    ABSTRACT: We present results of FIB–TEM studies of 12 Stardust analog Al foil craters which were created by firing refractory Si and Ti carbide and nitride grains into Al foils at 6.05 km s−1 with a light-gas gun to simulate capture of cometary grains by the Stardust mission. These foils were prepared primarily to understand the low presolar grain abundances (both SiC and silicates) measured by SIMS in Stardust Al foil samples. Our results demonstrate the intact survival of submicron SiC, TiC, TiN, and less-refractory Si3N4 grains. In small (<2 μm) craters that are formed by single grain impacts, the entire impacting crystalline grain is often preserved intact with minimal modification. While they also survive in crystalline form, grains at the bottom of larger craters (>5 μm) are typically fragmented and are somewhat flattened in the direction of impact due to partial melting and/or plastic deformation. The low presolar grain abundance estimates derived from SIMS measurements of large craters (mostly >50 μm) likely result from greater modification of these impactors (i.e., melting and isotopic dilution), due to higher peak temperatures/pressures in these crater impacts. The better survivability of grains in smaller craters suggests that more accurate presolar grain estimates may be achievable through measurement of such craters. It also suggests small craters can provide a complementary method of study of the Wild 2 fine fraction, especially for refractory CAI-like minerals.
    07/2015; 50(8). DOI:10.1111/maps.12474
  • The Microscience Microscopy Congress 2015, Manchester Central, UK; 06/2015
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    ABSTRACT: Energy-dispersive X-ray spectrometry (EDS) of fine-scale structures in pristine solid samples requires low electron beam accelerating voltage. Consequently, only low to intermediate energy X-ray lines having many peak overlaps can be evaluated, requiring spectral deconvolution. The necessity of low probe current would give low X-ray count rates with traditional EDS detectors. The additional time required to acquire sufficient data for deconvolution risks, altering the specimen as a result of beam-sample interaction or sample contamination. Furthermore, the sample drift which may be significant usually at high magnifications is a limiting factor. Our work uses an XFlash FlatQUAD silicon drift detector (SDD), allowing us to overcome these limitations, and offering additional benefits as demonstrated here. Five studies are presented here: (1) The examination of impact craters in aluminium foils produced in the laboratory under the collection conditions of NASA’s Stardust mission (6 kV). Residues of projectile can be clearly distinguished from the target with no detector shadowing effects across the field of view. (2) The analysis of an uncoated, broken surface from the Martian meteorite Tissint using low beam current at high vacuum (4 kV, < 10 pA). The mapped area revealed a thin coating of carbon with nitrogen, and an enrichment of these elements with topographic features. (3) The analysis of Beggiatoa alba which is an indicator species for pollution at marine or freshwater environments (5 kV). EDS maps of cells show the accumulation of nitrate with sulphur in massive vacuoles and local enrichment of phosphorous. (4) Mineralisation in the ovipositor of a parasitoid wasp examined in VP (5 kV, 20 Pa). Sufficient data quality allowed deconvolution of overlapping element lines for Zn (L) and Na (K). (5) Nanoparticle identification and structural discrimination. The analysis of nanoparticles on thin film supports is now possible using an FE-SEM in transmission mode (STEM). It can be concluded that element analysis at low voltage, in combination with an annular SDD, provides both high spatial resolution and high detection sensitivity without the necessity of applying a conductive coating or working in low vacuum. Further results on palaeontology andcultural heritage will be presented.
    EMAS 2015 - 14th European Workshop on MODERN DEVELOPMENTS AND APPLICATIONS IN MICROBEAM ANALYSIS, Portorož, Slovenia; 05/2015
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    ABSTRACT: The lunar magma ocean model is a well-established theory of the early evolution of the Moon. By this model, the Moon was initially largely molten and the anorthositic crust that now covers much of the lunar surface directly crystallized from this enormous magma source. We are undertaking a study of the geochemical characteristics of anorthosites from lunar meteorites to test this model. Rare earth and other element abundances have been measured in situ in relict anorthosite clasts from two feldspathic lunar meteorites: Dhofar 908 and Dhofar 081. The rare earth elements were present in abundances of approximately 0.1 to approximately 10× chondritic (CI) abundance. Every plagioclase exhibited a positive Eu-anomaly, with Eu abundances of up to approximately 20×CI. Calculations of the melt in equilibrium with anorthite show that it apparently crystallized from a magma that was unfractionated with respect to rare earth elements and ranged in abundance from 8 to 80×CI. Comparisons of our data with other lunar meteorites and Apollo samples suggest that there is notable heterogeneity in the trace element abundances of lunar anorthosites, suggesting these samples did not all crystallize from a common magma source. Compositional and isotopic data from other authors also suggest that lunar anorthosites are chemically heterogeneous and have a wide range of ages. These observations may support other models of crust formation on the Moon or suggest that there are complexities in the lunar magma ocean scenario to allow for multiple generations of anorthosite formation.
    Philosophical Transactions of The Royal Society A Mathematical Physical and Engineering Sciences 09/2014; 372(2024). DOI:10.1098/rsta.2013.0241 · 2.15 Impact Factor
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    ABSTRACT: We report the quantitative characterization by synchrotron soft X-ray spectroscopy of 31 potential impact features in the aerogel capture medium of the Stardust Interstellar Dust Collector. Samples were analyzed in aerogel by acquiring high spatial resolution maps and high energy-resolution spectra of major rock-forming elements Mg, Al, Si, Fe, and others. We developed diagnostic screening tests to reject spacecraft secondary ejecta and terrestrial contaminants from further consideration as interstellar dust candidates. The results support an extraterrestrial origin for three interstellar candidates: I1043,1,30 (Orion) is a 3 pg particle with Mg-spinel, forsterite, and an iron-bearing phase. I1047,1,34 (Hylabrook) is a 4 pg particle comprising an olivine core surrounded by low-density, amorphous Mg-silicate and amorphous Fe, Cr, and Mn phases. I1003,1,40 (Sorok) has the track morphology of a high-speed impact, but contains no detectable residue that is convincingly distinguishable from the background aerogel. Twenty-two samples with an anthropogenic origin were rejected, including four secondary ejecta from impacts on the Stardust spacecraft aft solar panels, nine ejecta from secondary impacts on the Stardust Sample Return Capsule, and nine contaminants lacking evidence of an impact. Other samples in the collection included I1029,1,6, which contained surviving solar system impactor material. Four samples remained ambiguous: I1006,2,18, I1044,2,32, and I1092,2,38 were too dense for analysis, and we did not detect an intact projectile in I1044,3,33. We detected no radiation effects from the synchrotron soft X-ray analyses; however, we recorded the effects of synchrotron hard X-ray radiation on I1043,1,30 and I1047,1,34.
    Meteoritics & planetary science 09/2014; 49(9):1562-1593. DOI:10.1111/maps.12220 · 3.10 Impact Factor
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    ABSTRACT: Under the auspices of the Stardust Interstellar Preliminary Examination, picokeystones extracted from the Stardust Interstellar Dust Collector were examined with synchrotron Fourier transform infrared (FTIR) microscopy to establish whether they contained extraterrestrial organic material. The picokeystones were found to be contaminated with varying concentrations and speciation of organics in the native aerogel, which hindered the search for organics in the interstellar dust candidates. Furthermore, examination of the picokeystones prior to and post X-ray microprobe analyses yielded evidence of beam damage in the form of organic deposition or modification, particularly with hard X-ray synchrotron X-ray fluorescence. From these results, it is clear that considerable care must be taken to interpret any organics that might be in interstellar dust particles. For the interstellar candidates examined thus far, however, there is no clear evidence of extraterrestrial organics associated with the track and/or terminal particles. However, we detected organic matter associated with the terminal particle in Track 37, likely a secondary impact from the Al-deck of the sample return capsule, demonstrating the ability of synchrotron FTIR to detect organic matter in small particles within picokeystones from the Stardust interstellar dust collector.
    Meteoritics & planetary science 09/2014; 49(9):1548-1561. DOI:10.1111/maps.12125 · 3.10 Impact Factor
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    ABSTRACT: On the basis of an interstellar dust model compatible with Ulysses and Galileo observations, we calculate and predict the trajectories of interstellar dust (ISD) in the solar system and the distribution of the impact speeds, directions, and flux of ISD particles on the Stardust Interstellar Dust Collector during the two collection periods of the mission. We find that the expected impact velocities are generally low (<10 km s−1) for particles with the ratio of the solar radiation pressure force to the solar gravitational force β > 1, and that some of the particles will impact on the cometary side of the collector. If we assume astronomical silicates for particle material and a density of 2 g cm−3, and use the Ulysses measurements and the ISD trajectory simulations, we conclude that the total number of (detectable) captured ISD particles may be on the order of 50. In companion papers in this volume, we report the discovery of three interstellar dust candidates in the Stardust aerogel tiles. The impact directions and speeds of these candidates are consistent with those calculated from our ISD propagation model, within the uncertainties of the model and of the observations.
    Meteoritics & planetary science 09/2014; 49(9):1680-1697. DOI:10.1111/maps.12219 · 3.10 Impact Factor
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    77th Annual Meeting of the Meteoritical-Society; 09/2014
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    ABSTRACT: Here, we report analyses by synchrotron X-ray fluorescence microscopy of the elemental composition of eight candidate impact features extracted from the Stardust Interstellar Dust Collector (SIDC). Six of the features were unambiguous tracks, and two were crater-like features. Five of the tracks are so-called "midnight" tracks-that is, they had trajectories consistent with an origin either in the interstellar dust stream or as secondaries from impacts on the Sample Return Capsule (SRC). In a companion paper reporting synchrotron X-ray diffraction analyses of ISPE candidates, we show that two of these particles contain natural crystalline materials: the terminal particle of track 30 contains olivine and spinel, and the terminal particle of track 34 contains olivine. Here, we show that the terminal particle of track 30, Orion, shows elemental abundances, normalized to Fe, that are close to CI values, and a complex, fine-grained structure. The terminal particle of track 34, Hylabrook, shows abundances that deviate strongly from CI, but shows little fine structure and is nearly homogenous. The terminal particles of other midnight tracks, 29 and 37, had heavy element abundances below detection threshold. A third, track 28, showed a composition inconsistent with an extraterrestrial origin, but also inconsistent with known spacecraft materials. A sixth track, with a trajectory consistent with secondary ejecta from an impact on one of the spacecraft solar panels, contains abundant Ce and Zn. This is consistent with the known composition of the glass covering the solar panel. Neither crater-like feature is likely to be associated with extraterrestrial materials. We also analyzed blank aerogel samples to characterize background and variability between aerogel tiles. We found significant differences in contamination levels and compositions, emphasizing the need for local background subtraction for accurate quantification.
    Meteoritics & planetary science 09/2014; 49(9):1594-1611. DOI:10.1111/maps.12206 · 3.10 Impact Factor
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    ABSTRACT: The NASA Stardust spacecraft exposed an aerogel collector to the interstellar dust passing through the solar system. We performed X-ray fluorescence element mapping and abundance measurements, for elements 19 <= Z <= 30, on six "interstellar candidates," potential interstellar impacts identified by Stardust@Home and extracted for analyses in picokeystones. One, I1044,3,33, showed no element hot-spots within the designated search area. However, we identified a nearby surface feature, consistent with the impact of a weak, high-speed particle having an approximately chondritic (CI) element abundance pattern, except for factor-of-ten enrichments in K and Zn and an S depletion. This hot-spot, containing approximately 10 fg of Fe, corresponds to an approximately 350 nm chondritic particle, small enough to be missed by Stardust@Home, indicating that other techniques may be necessary to identify all interstellar candidates. Only one interstellar candidate, I1004,1,2, showed a track. The terminal particle has large enrichments in S, Ti, Cr, Mn, Ni, Cu, and Zn relative to Fe-normalized CI values. It has high Al/Fe, but does not match the Ni/Fe range measured for samples of Al-deck material from the Stardust sample return capsule, which was within the field-of-view of the interstellar collector. A third interstellar candidate, I1075,1,25, showed an Al-rich surface feature that has a composition generally consistent with the Al-deck material, suggesting that it is a secondary particle. The other three interstellar candidates, I1001,1,16, I1001,2,17, and I1044,2,32, showed no impact features or tracks, but allowed assessment of submicron contamination in this aerogel, including Fe hot-spots having CI-like Ni/Fe ratios, complicating the search for CI-like interstellar/interplanetary dust.
    Meteoritics & planetary science 09/2014; 49(9):1626-1644. DOI:10.1111/maps.12144 · 3.10 Impact Factor
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    ABSTRACT: Abstract–Hard X-ray, quantitative, fluorescence elemental imaging was performed on the ID22NI nanoprobe and ID22 microprobe beam lines of the European Synchrotron Research facility (ESRF) in Grenoble, France, on eight interstellar candidate impact features in the framework of the NASA Stardust Interstellar Preliminary Examination (ISPE). Three features were unambiguous tracks, and the other five were identified as possible, but not definite, impact features. Overall, we produced an absolute quantification of elemental abundances in the 15 ≤ Z ≤ 30 range by means of corrections of the beam parameters, reference materials, and fundamental atomic parameters. Seven features were ruled out as interstellar dust candidates (ISDC) based on compositional arguments. One of the three tracks, I1043,1,30,0,0, contained, at the time of our analysis, two physically separated, micrometer-sized terminal particles, the most promising ISDCs, Orion and Sirius. We found that the Sirius particle was a fairly homogenous Ni-bearing particle and contained about 33 fg of distributed high-Z elements (Z > 12). Orion was a highly heterogeneous Fe-bearing particle and contained about 59 fg of heavy elements located in hundred nanometer phases, forming an irregular mantle that surrounded a low-Z core. X-ray diffraction (XRD) measurements revealed Sirius to be amorphous, whereas Orion contained partially crystalline material (Gainsforth et al. 2014). Within the mantle, one grain was relatively Fe-Ni-Mn-rich; other zones were relatively Mn-Cr-Ti-rich and may correspond to different spinel populations. For absolute quantification purposes, Orion was assigned to a mineralogical assemblage of forsterite, spinel, and an unknown Fe-bearing phase, while Sirius was most likely composed of an amorphous Mg-bearing material with minor Ni and Fe. Owing to its nearly chondritic abundances of the nonvolatile elements Ca, Ti, Co, and Ni with respect to Fe, in combination with the presence of olivine and spinel as inferred from XRD measurements, Orion had a high probability of being extraterrestrial in origin.
    Meteoritics & planetary science 09/2014; 49(9):1612. DOI:10.1111/maps.12208 · 3.10 Impact Factor
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    ABSTRACT: Here, we report the identification of 69 tracks in approximately 250 cm2 of aerogel collectors of the Stardust Interstellar Dust Collector. We identified these tracks through Stardust@home, a distributed internet-based virtual microscope and search engine, in which > 30,000 amateur scientists collectively performed >9 9 107 searches on approximately 106 fields of view. Using calibration images, we measured individual detection efficiency, and found that the individual detection efficiency for tracks > 2.5 lm in diameter was >0.6, and was >0.75 for tracks >3 lm in diameter. Because most fields of view were searched >30 times, these results could be combined to yield a theoretical detection efficiency near unity. The initial expectation was that interstellar dust would be captured at very high speed. The actual tracks discovered in the Stardust collector, however, were due to low-speed impacts, and were morphologically strongly distinct from the calibration images. As a result, the detection efficiency of these tracks was lower than detection efficiency of calibrations presented in training, testing, and ongoing calibration. Nevertheless, as calibration images based on low-speed impacts were added later in the project, detection efficiencies for lowspeed tracks rose dramatically. We conclude that a massively distributed, calibrated search, with amateur collaborators, is an effective approach to the challenging problem of identification of tracks of hypervelocity projectiles captured in aerogel.
    Meteoritics & planetary science 09/2014; 49(9):1509. DOI:10.1111/maps.12168 · 3.10 Impact Factor
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    ABSTRACT: The NASA Stardust mission used silica aerogel slabs to slowly decelerate and capture impinging cosmic dust particles for return to Earth. During this process, impact tracks are generated along the trajectory of the particle into the aerogel. It is believed that the morphology and dimensions of these tracks, together with the state of captured grains at track termini, may be linked to the size, velocity, and density of the impacting cosmic dust grain. Here, we present the results of laboratory hypervelocity impact experiments, during which cosmic dust analog particles (diameters of between 0.2 and 0.4 μm), composed of olivine, orthopyroxene, or an organic polymer, were accelerated onto Stardust flight-spare low-density (approximately 0.01 g cm−3) silica aerogel. The impact velocities (3–21 km s−1) were chosen to simulate the range of velocities expected during Stardust's interstellar dust (ISD) collection phases. Track lengths and widths, together with the success of particle capture, are analyzed as functions of impact velocity and particle composition, density, and size. Captured terminal particles from low-density organic projectiles become undetectable at lower velocities than those from similarly sized, denser mineral particles, which are still detectable (although substantially altered by the impact process) at 15 km s−1. The survival of these terminal particles, together with the track dimensions obtained during low impact speed capture of small grains in the laboratory, indicates that two of the three best Stardust candidate extraterrestrial grains were actually captured at speeds much lower than predicted. Track length and diameters are, in general, more sensitive to impact velocities than previously expected, which makes tracks of particles with diameters of 0.4 μm and below hard to identify at low capture speeds (<10 km s−1). Therefore, although captured intact, the majority of the interstellar dust grains returned to Earth by Stardust remain to be found.
    Meteoritics & planetary science 09/2014; 49(9):1666-1679. DOI:10.1111/maps.12173 · 3.10 Impact Factor
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    21st General Meeting of the International Mineralogical Association, Gauteng, South Africa.; 09/2014
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    ABSTRACT: We discuss the inherent difficulties that arise during "ground truth" characterization of the Stardust interstellar dust collector. The challenge of identifying contemporary interstellar dust impact tracks in aerogel is described within the context of background spacecraft secondaries and possible interplanetary dust particles and beta-meteoroids. In addition, the extraction of microscopic dust embedded in aerogel is technically challenging. Specifically, we provide a detailed description of the sample preparation techniques developed to address the unique goals and restrictions of the Interstellar Preliminary Exam. These sample preparation requirements and the scarcity of candidate interstellar impact tracks exacerbate the difficulties. We also illustrate the role of initial optical imaging with critically important examples, and summarize the overall processing of the collection to date.
    Meteoritics & planetary science 09/2014; 49(9):1522-1547. DOI:10.1111/maps.12147 · 3.10 Impact Factor
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    ABSTRACT: The Stardust Interstellar Preliminary Examination team analyzed thirteen Al foils from the NASA Stardust interstellar collector tray in order to locate candidate interstellar dust (ISD) grain impacts. Scanning electron microscope (SEM) images reveal that the foils possess abundant impact crater and crater-like features. Elemental analyses of the crater features, with Auger electron spectroscopy, SEM-based energy dispersive X-ray (EDX) spectroscopy, and scanning transmission electron microscope-based EDX spectroscopy, demonstrate that the majority are either the result of impacting debris fragments from the spacecraft solar panels, or intrinsic defects in the foil. The elemental analyses also reveal that four craters contain residues of a definite extraterrestrial origin, either as interplanetary dust particles or ISD particles. These four craters are designated level 2 interstellar candidates, based on the crater shapes indicative of hypervelocity impacts and the residue compositions inconsistent with spacecraft debris.
    Meteoritics & planetary science 09/2014; 49(9):1698-1719. DOI:10.1111/maps.12136 · 3.10 Impact Factor
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    ABSTRACT: With the discovery of bona fide extraterrestrial materials in the Stardust Interstellar Dust Collector, NASA now has a fundamentally new returned sample collection, after the Apollo, Antarctic meteorite, Cosmic Dust, Genesis, Stardust Cometary, Hayabusa, and Exposed Space Hardware samples. Here, and in companion papers in this volume, we present the results from the Preliminary Examination of this collection, the Stardust Interstellar Preliminary Examination (ISPE). We found extraterrestrial materials in two tracks in aerogel whose trajectories and morphology are consistent with an origin in the interstellar dust stream, and in residues in four impacts in the aluminum foil collectors. While the preponderance of evidence, described in detail in companion papers in this volume, points toward an interstellar origin for some of these particles, alternative origins have not yet been eliminated, and definitive tests through isotopic analyses were not allowed under the terms of the ISPE. In this summary, we answer the central questions of the ISPE: How many tracks in the collector are consistent in their morphology and trajectory with interstellar particles? How many of these potential tracks are consistent with real interstellar particles, based on chemical analysis? Conversely, what fraction of candidates are consistent with either a secondary or interplanetary origin? What is the mass distribution of these particles, and what is their state? Are they particulate or diffuse? Is there any crystalline material? How many detectable impact craters (>100 nm) are there in the foils, and what is their size distribution? How many of these craters have analyzable residue that is consistent with extraterrestrial material? And finally, can craters from secondaries be recognized through crater morphology (e.g., ellipticity)?
    Meteoritics & planetary science 09/2014; 49(9):1720. DOI:10.1111/maps.12221 · 3.10 Impact Factor
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    ABSTRACT: Seven particles captured by the Stardust Interstellar Dust Collector and returned to Earth for laboratory analysis have features consistent with an origin in the contemporary interstellar dust stream. More than 50 spacecraft debris particles were also identified. The interstellar dust candidates are readily distinguished from debris impacts on the basis of elemental composition and/or impact trajectory. The seven candidate interstellar particles are diverse in elemental composition, crystal structure, and size. The presence of crystalline grains and multiple iron-bearing phases, including sulfide, in some particles indicates that individual interstellar particles diverge from any one representative model of interstellar dust inferred from astronomical observations and theory.
    Science 08/2014; 345(6198):786. DOI:10.1126/science.1252496 · 33.61 Impact Factor
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    Emma Jude · Zerina Johanson · Anton Kearsley · Matt Friedman
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    ABSTRACT: As the closest living relatives of tetrapods, lungfishes are frequently used as extant models for exploring the fin-to-limb transition. These studies have generally given little consideration to fossil taxa. This is because even though lungfish fins are relatively common in the fossil record, the internal structure of these fins is virtually unknown. Information on pectoral-fin endoskeletons in fossil representatives of Dipnomorpha (the lungfish total group) is limited to effectively poorly preserved remains in the lungfishes Dipterus and Conchopoma and more complete material in the porolepiform Glyptolepis. Here we describe a well-preserved pectoral-fin endoskeleton in the Middle Devonian (Givetian) lungfish Pentlandia macroptera from the John o'Groats fish bed, Caithness, northeastern Scotland. The skeleton is in association with a cleithrum and clavicle, and consists of a series of at least eight mesomeres. Extensive series of preaxial and postaxial radials are present. Some of the radials are jointed, but none branch. No mesomere articulates with multiple radials on either its pre- or post-axial face. The first two mesomeres, corresponding to the humerus and ulna, bear well-developed axial processes. Uniquely among dipnomorphs, a distinct ossification center corresponding to the radius is present in Pentlandia. A review of anatomy and development of the pectoral-fin endoskeleton in the living Neoceratodus is presented based on cleared and stained material representing different size stages. These developmental data, in conjunction with new details of primitive lungfish conditions based on Pentlandia, highlight many of the derived features of the pectoral-fin skeleton of Neoceratodus, and clarify patterns of appendage evolution within dipnomorphs more generally.
    08/2014; 2. DOI:10.3389/feart.2014.00018

Publication Stats

3k Citations
669.90 Total Impact Points


  • 2015
    • University of Kent
      • Center for Astrophysics and Planetary Science
      Cantorbery, England, United Kingdom
  • 2004–2015
    • Natural History Museum, London
      • Department of Earth Sciences
      Londinium, England, United Kingdom
  • 2012
    • Universität Stuttgart
      Stuttgart, Baden-Württemberg, Germany
  • 2010
    • The University of Sheffield
      • Department of Chemistry
      Sheffield, England, United Kingdom
  • 1999–2004
    • Oxford Brookes University
      Oxford, England, United Kingdom