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A new peltospirid snail (Gastropoda Neomphalida) adds to the unique biodiversity of Longqi vent field, Southwest Indian Ridge
No full textThe biodiversity of deep-sea hydrothermal vents in the Indian Ocean remains poorly characterised compared with that of their Pacific and Atlantic counterparts. Although the Longqi hydrothermal vent field is the most extensively explored vent site on the ultra-slow-spreading Southwest Indian Ridge, it is still a source of new discoveries. Here, we report and formally describe a new peltospirid snail from Longqi–Lirapex felix sp. nov. Known from only two specimens, it differs from other named Lirapex species by a depressed spire and the lack of coil loosening on the body whorl. Examinations of the external anatomy and radular characteristics agree with its placement in Lirapex, which is also supported by a molecular phylogeny reconstructed using the barcoding fragment of the mitochondrial cytochrome c oxidase I (COI) gene. This is the fifth peltospirid snail known to inhabit the Longqi field, three of which (including Lirapex felix sp. nov.) have been found nowhere else. There is growing evidence that the Longqi field represents a biogeographically unique site among Indian Ocean vents. The discovery of Lirapex felix sp. nov. adds to the unique biodiversity of Longqi field, with implications for conservation in the light of potential deep-sea mining. This work is registered in ZooBank under: urn:lsid:zoobank.org:pub:3B892762-2110-4A1E-A80D-1779CBEC5EB3.</p
Figure 5 in A new peltospirid snail (Gastropoda: Neomphalida) adds to the unique biodiversity of Longqi vent field, Southwest Indian Ridge
No full textFigure 5. Consensus tree from phylogenetic reconstruction using Bayesian inference, based on 570 bp of the barcoding fragment of the mitochondrial COI gene. Node values show Bayesian posterior probabilities; only those above 0.7 are shown. GenBank accession numbers of the sequences used are indicated in parentheses.Published as part of Chen, Chong, Han, Yuru, Copley, Jonathan T. & Zhou, Yadong, 2021, A new peltospirid snail (Gastropoda: Neomphalida) adds to the unique biodiversity of Longqi vent field, Southwest Indian Ridge, pp. 851-866 in Journal of Natural History 55 (13-14) on page 862, DOI: 10.1080/00222933.2021.1923851, http://zenodo.org/record/546419
Figure 2 in A new peltospirid snail (Gastropoda: Neomphalida) adds to the unique biodiversity of Longqi vent field, Southwest Indian Ridge
No full textFigure 2. Lirapex felix sp. nov., type specimens. (a–d) Holotype (RSIO 35733), shell width 2.6 mm, shell height 2.1 mm; (e–h) paratype (NSMT-Mo 79160), shell width 3.7 mm, shell height 3.1 mm; (i) close-up of the holotype near the umbilicus, showing the axial ribbing sculpture. Scale bars: a–h = 1 mm; i = 200 μm.Published as part of Chen, Chong, Han, Yuru, Copley, Jonathan T. & Zhou, Yadong, 2021, A new peltospirid snail (Gastropoda: Neomphalida) adds to the unique biodiversity of Longqi vent field, Southwest Indian Ridge, pp. 851-866 in Journal of Natural History 55 (13-14) on page 857, DOI: 10.1080/00222933.2021.1923851, http://zenodo.org/record/546419
Figure 3 in A new peltospirid snail (Gastropoda: Neomphalida) adds to the unique biodiversity of Longqi vent field, Southwest Indian Ridge
No full textFigure 3. Lirapex felix sp. nov., scanning electron micrographs. (a) Protoconch, holotype (RSIO 35733), arrows indicate the transition between protoconch and teleoconch; (b) shell sculpture, holotype (RSIO 35733); (c) operculum, paratype (NSMT-Mo 79160); (d–e) radula, holotype (RSIO 35733); (f) shell microsculpture, paratype (NSMT-Mo 79160), arrows indicate shell pores. Scale bars: a = 100 μm; b = 200 μm; c = 1 mm; d = 50 μm; e–f = 20 μm.Published as part of Chen, Chong, Han, Yuru, Copley, Jonathan T. & Zhou, Yadong, 2021, A new peltospirid snail (Gastropoda: Neomphalida) adds to the unique biodiversity of Longqi vent field, Southwest Indian Ridge, pp. 851-866 in Journal of Natural History 55 (13-14) on page 858, DOI: 10.1080/00222933.2021.1923851, http://zenodo.org/record/546419
Figure 4 in A new peltospirid snail (Gastropoda: Neomphalida) adds to the unique biodiversity of Longqi vent field, Southwest Indian Ridge
No full textFigure 4. Lirapex felix sp. nov., soft parts, paratype (NSMT-Mo 79,160). (a) Right view; (b) anterior view with part of the mantle roof removed, visceral mass digitally removed at the dashed line; (c) ventral view; (d) left view. Abbreviations: a, anus; c, ctenidium; d, digestive gland; et, epipodial tentacle; f, foot; i, intestine; k, left kidney; lm, left columellar muscle; op, opercular attachment; ov, ovary; p, pericardium; pe, pallial edge; r, rectum; rm, right columellar muscle; s, stomach; sn, snout; t, cephalic tentacle. Scale bars: a, c–d = 1 mm; b = 0.5 mm.Published as part of Chen, Chong, Han, Yuru, Copley, Jonathan T. & Zhou, Yadong, 2021, A new peltospirid snail (Gastropoda: Neomphalida) adds to the unique biodiversity of Longqi vent field, Southwest Indian Ridge, pp. 851-866 in Journal of Natural History 55 (13-14) on page 859, DOI: 10.1080/00222933.2021.1923851, http://zenodo.org/record/546419
Neomphalida McLean 1990
No full textOrder NEOMPHALIDA McLean, 1990 Superfamily NEOMPHALOIDEA McLean, 1981 Family PELTOSPIRIDAE McLean, 1989 Lirapex Warén and Bouchet, 1989 Type species Lirapex humatus Warén and Bouchet, 1989 (by original designation). Diagnosis Small- to medium-sized (<5 mm) coiled peltospirid snails with skeneiform shells. Shell sculpture ranging from smooth to carrying distinct axial sculpture that is strongest at shoulder and umbilicus. Protoconch with distinct spiral ridges on the posterior part that disappear towards the anterior half. Radula with hook-like marginals. Thin and transparent multispiral operculum present. Sexes separate. Cephalic tentacles smooth, not modified into copulatory organ. Snout of even breadth. Epipodial tentacle only present around opercular attachment (Warén and Bouchet 1989, 2001; Chen et al. 2017a).Published as part of Chen, Chong, Han, Yuru, Copley, Jonathan T. & Zhou, Yadong, 2021, A new peltospirid snail (Gastropoda: Neomphalida) adds to the unique biodiversity of Longqi vent field, Southwest Indian Ridge, pp. 851-866 in Journal of Natural History 55 (13 - 14) on pages 855-856, DOI: 10.1080/00222933.2021.1923851, http://zenodo.org/record/546419
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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