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A new genus of large hydrothermal vent-endemic gastropod (Neomphalina: Peltospiridae)
Full text linkRecently discovered hydrothermal vent fields on the East Scotia Ridge (ESR, 56–60°S, 30°W), Southern Ocean, and the South West Indian Ridge (SWIR, 37°S 49°E), Indian Ocean, host two closely related new species of peltospirid gastropods. Morphological and molecular (mitochondrial cytochrome c oxidase subunit I, COI) characterization justify the erection of Gigantopelta gen. nov. within the Peltospiroidae with two new species, Gigantopelta chessoia sp. nov. from ESR and Gigantopelta aegis sp. nov. from SWIR. They attain an extremely large size for the clade Neomphalina, reaching 45.7?mm in shell diameter. The oesophageal gland of both species is markedly enlarged. Gigantopelta aegis has a thick sulphide coating on both the shell and the operculum of unknown function. The analysis of a 579-bp fragment of the COI gene resulted in 19–28% pairwise distance between Gigantopelta and six other genera in Peltospiridae, whereas the range amongst those six genera was 12–28%. The COI divergence between the two newly described species of Gigantopelta was 4.43%. Population genetics analyses using COI (370?bp) of 30 individuals of each species confirmed their genetic isolation and indicate recent rapid demographic expansion in both species. <br/
Figure 9. Consensus tree reconstructed from a 489 in A new genus of large hydrothermal vent-endemic gastropod (Neomphalina: Peltospiridae)
No full textFigure 9. Consensus tree reconstructed from a 489-bp fragment of the cytochrome c oxidase subunit I gene using Bayesian inference. Node values represent Bayesian posterior probabilities.Published as part of Chen, Chong, Linse, Katrin, Roterman, Christopher N., Copley, Jonathan T. & Rogers, Alex D., 2015, A new genus of large hydrothermal vent-endemic gastropod (Neomphalina: Peltospiridae), pp. 319-335 in Zoological Journal of the Linnean Society (Zool. J. Linn. Soc.) 175 (2) on page 330, DOI: 10.1111/zoj.12279, http://zenodo.org/record/533841
Figure 5 in A new genus of large hydrothermal vent-endemic gastropod (Neomphalina: Peltospiridae)
No full textFigure 5. Protoconchs: A, Gigantopelta chessoia sp. nov., scale bar = 100 μm; B, Gigantopelta aegis sp. nov., scale bar = 100 μm. Juvenile operculum: C, G. chessoia sp. nov., scale bar = 500 μm; D, G. aegis sp. nov., scale bar = 500 μm.Published as part of Chen, Chong, Linse, Katrin, Roterman, Christopher N., Copley, Jonathan T. & Rogers, Alex D., 2015, A new genus of large hydrothermal vent-endemic gastropod (Neomphalina: Peltospiridae), pp. 319-335 in Zoological Journal of the Linnean Society (Zool. J. Linn. Soc.) 175 (2) on page 325, DOI: 10.1111/zoj.12279, http://zenodo.org/record/533841
Figure 6 in A new genus of large hydrothermal vent-endemic gastropod (Neomphalina: Peltospiridae)
No full textFigure 6. Radula. Overview: A, Gigantopelta chessoia sp. nov.; B. Gigantopelta aegis sp. nov.; scale bars = 100 μm. Central and lateral teeth close-up: C, G. chessoia sp. nov.; D, G. aegis sp. nov.; scale bars = 20 μm. Marginal teeth close-up: E, G. chessoia sp. nov.; F. G. aegis sp. nov.; scale bars = 10 μm.Published as part of Chen, Chong, Linse, Katrin, Roterman, Christopher N., Copley, Jonathan T. & Rogers, Alex D., 2015, A new genus of large hydrothermal vent-endemic gastropod (Neomphalina: Peltospiridae), pp. 319-335 in Zoological Journal of the Linnean Society (Zool. J. Linn. Soc.) 175 (2) on page 326, DOI: 10.1111/zoj.12279, http://zenodo.org/record/533841
Data from: Connectivity in the cold: the comparative population genetics of vent-endemic fauna in the Scotia Sea, Southern Ocean.
No full textWe report the first comparative population genetics study for vent fauna in the Southern Ocean using cytochrome C oxidase I and microsatellite markers. Three species are examined: the kiwaid squat lobster, Kiwa tyleri, the peltospirid gastropod Gigantopelta chessoia and a lepetodrilid limpet, Lepetodrilus sp. collected from vent fields 440 km apart on the East Scotia Ridge (ESR) and from the Kemp Caldera on the South Sandwich Island Arc, ~95 km eastwards. We report no differentiation for all species across the ESR, consistent with panmixia or recent range expansions. A lack of differentiation is notable for Kiwa tyleri, which exhibits extremely abbreviated lecithotrophic larval development, suggestive of a very limited dispersal range. Larval lifespans may, however, be extended by low temperature-induced metabolic rate reduction in the Southern Ocean, muting the impact of dispersal strategy on patterns of population structure. COI diversity patterns suggest all species experienced demographic bottlenecks or selective sweeps in the past million years and possibly at different times. ESR and Kemp limpets are divergent, although with evidence of very recent ESR-Kemp immigration. Their divergence, possibility indicative of incipient speciation, along with the absence of the other two species at Kemp, may be the consequence of differing dispersal capabilities across a ~1000 m depth range and/or different selective regimes between the two areas. Estimates of historic and recent limpet gene flow between the ESR and Kemp are consistent with predominantly easterly currents in the region and potentially therefore, cross-axis currents on the ESR, with biogeographic implications for the region.,Zip file of input filesIncludes fasta sequence files, microsatellite genotype files, as well as other input filesData_accessibility.zip</span
Figure 10. Haplotype parsimonious networks constructed from cytochrome c oxidase subunit I in A new genus of large hydrothermal vent-endemic gastropod (Neomphalina: Peltospiridae)
No full textFigure 10. Haplotype parsimonious networks constructed from cytochrome c oxidase subunit I sequences of 30 specimens of: A, Gigantopelta chessoia sp. nov.; B, Gigantopelta aegis sp. nov. Open circles are represented haplotypes, number inside the circles and sizes of the circles correspond to number of individuals sharing the haplotype. Filled circles are hypothesized intermediate haplotypes that are not represented by sequences.Published as part of Chen, Chong, Linse, Katrin, Roterman, Christopher N., Copley, Jonathan T. & Rogers, Alex D., 2015, A new genus of large hydrothermal vent-endemic gastropod (Neomphalina: Peltospiridae), pp. 319-335 in Zoological Journal of the Linnean Society (Zool. J. Linn. Soc.) 175 (2) on page 331, DOI: 10.1111/zoj.12279, http://zenodo.org/record/533841
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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