70 research outputs found

    A new species of Pachycara Zugmayer, 1911 (Teleostei: Zoarcidae) from deep-sea chemosynthetic environments in the Caribbean Sea.

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    The 28th species of the eelpout genus Pachycara Zugmayer, 1911, is described from specimens collected from an active hydrothermal vent field at a depth of about 2300 m at the Mid-Cayman Spreading Centre of the Caribbean Sea. A tentatively identified early juvenile is recorded at a methane seep at a depth of 1049 m near Tobago. The new species is distinguished from its congeners mainly by its few pectoral fin rays, low vertebral counts, single, mediolateral branch of the lateral line system and presence of scales on the nape and cheeks

    How the mollusc got its scales: convergent evolution of the molluscan scleritome

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    Radiation of dramatically disparate forms among the phylum Mollusca remains a key question in metazoan evolution, and requires careful evaluation of homology of hard parts throughout the deep fossil record. Enigmatic early Cambrian taxa such as Halkieria and Wiwaxia (in the clade Halwaxiida) have been proposed to represent stem-group aculiferan molluscs (Caudofoveata + Solenogastres + Polyplacophora), as complex scleritomes were considered to be unique to aculiferans among extant molluscs. The ‘scaly-foot gastropod’ (Neomphalina: Peltospiridae) from hydrothermal vents of the Indian Ocean, however, also carries dermal sclerites and thus challenges this inferred homology. Despite superficial similarities to various mollusc sclerites, the scaly-foot gastropod sclerites are secreted in layers covering outpockets of epithelium and are largely proteinaceous, while chiton (Polyplacophora: Chitonida) sclerites are secreted to fill an invaginated cuticular chamber and are largely calcareous. Marked differences in the underlying epithelium of the scaly-foot gastropod sclerites and operculum suggest that the sclerites do not originate from multiplication of the operculum. This convergence in different classes highlights the ability of molluscs to adapt mineralized dermal structures, as supported by the extensive early fossil record of molluscs with scleritomes. Sclerites of halwaxiids are morphologically variable, undermining the assumed affinity of specific taxa with chitons, or the larger putative clade Aculifera. Comparisons with independently derived similar structures in living molluscs are essential for determining homology among fossils and their position with respect to the enigmatic evolution of molluscan shell forms in deep time

    The heart of a dragon: 3D anatomical reconstruction of the ‘scaly-foot gastropod’ (Mollusca: Gastropoda: Neomphalina) reveals its extraordinary circulatory system

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    Introduction The ‘scaly-foot gastropod’ (Chrysomallon squamiferum Chen et al., 2015) from deep-sea hydrothermal vent ecosystems of the Indian Ocean is an active mobile gastropod occurring in locally high densities, and it is distinctive for the dermal scales covering the exterior surface of its foot. These iron-sulfide coated sclerites, and its nutritional dependence on endosymbiotic bacteria, are both noted as adaptations to the extreme environment in the flow of hydrogen sulfide. We present evidence for other adaptations of the ‘scaly-foot gastropod’ to life in an extreme environment, investigated through dissection and 3D tomographic reconstruction of the internal anatomy. Results Our anatomical investigations of juvenile and adult specimens reveal a large unganglionated nervous system, a simple and reduced digestive system, and that the animal is a simultaneous hermaphrodite. We show that Chrysomallon squamiferum relies on endosymbiotic bacteria throughout post-larval life. Of particular interest is the circulatory system: Chrysomallon has a very large ctenidium supported by extensive blood sinuses filled with haemocoel. The ctenidium provides oxygen for the host but the circulatory system is enlarged beyond the scope of other similar vent gastropods. At the posterior of the ctenidium is a remarkably large and well-developed heart. Based on the volume of the auricle and ventricle, the heart complex represents approximately 4 % of the body volume. This proportionally giant heart primarily sucks blood through the ctenidium and supplies the highly vascularised oesophageal gland. Thus we infer the elaborate cardiovascular system most likely evolved to oxygenate the endosymbionts in an oxygen poor environment and/or to supply hydrogen sulfide to the endosymbionts. Conclusions This study exemplifies how understanding the autecology of an organism can be enhanced by detailed investigation of internal anatomy. This gastropod is a large and active species that is abundant in its hydrothermal vent field ecosystem. Yet all of its remarkable features—protective dermal sclerites, circulatory system, high fecundity—can be viewed as adaptations beneficial to its endosymbiont microbes. We interpret these results to show that, as a result of specialisation to resolve energetic needs in an extreme chemosynthetic environment, this dramatic dragon-like species has become a carrying vessel for its bacteria

    Moving conferences online: lessons learned from an international virtual meeting

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    We consider the opportunities and challenges associated with organizing a conference online, using a case study of a medium-sized (approx. 400 participants) international conference held virtually in August 2020. In addition, we present quantifiable evidence of the participants’ experience using the results from an online post-conference questionnaire. Although the virtual meeting was not able to replicate the in-person experience in some aspects (e.g. less engagement between participants) the overwhelming majority of respondents found the meeting an enjoyable experience and would join similar events again. Notably, there was a strong desire for future inperson meetings to have at least some online component. Online attendance by lower-income researchers was higher compared with a past, similarthemed in-person meeting held in a high-income nation, but comparable to one held in an upper-middle-income nation. This indicates that online conferences are not a panacea for diversity and inclusivity, and that holding in-person meetings in developing economies can be at least as effective. Given that it is now relatively easy to stream contents of meetings online using low-cost methods, there are clear benefits in making all presented content accessible online, as well as organizing online networking events for those unable to attend in person

    sFDvent: A global trait database for deep‐sea hydrothermal‐vent fauna

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    Motivation: Traits are increasingly being used to quantify global biodiversity patterns, with trait databases growing in size and number, across diverse taxa. Despite grow‐ ing interest in a trait‐based approach to the biodiversity of the deep sea, where the impacts of human activities (including seabed mining) accelerate, there is no single re‐ pository for species traits for deep‐sea chemosynthesis‐based ecosystems, including hydrothermal vents. Using an international, collaborative approach, we have compiled the first global‐scale trait database for deep‐sea hydrothermal‐vent fauna – sFD‐ vent (sDiv‐funded trait database for the Functional Diversity of vents). We formed a funded working group to select traits appropriate to: (a) capture the performance of vent species and their influence on ecosystem processes, and (b) compare trait‐based diversity in different ecosystems. Forty contributors, representing expertise across most known hydrothermal‐vent systems and taxa, scored species traits using online collaborative tools and shared workspaces. Here, we characterise the sFDvent da‐ tabase, describe our approach, and evaluate its scope. Finally, we compare the sFD‐ vent database to similar databases from shallow‐marine and terrestrial ecosystems to highlight how the sFDvent database can inform cross‐ecosystem comparisons. We also make the sFDvent database publicly available online by assigning a persistent, unique DOI. Main types of variable contained: Six hundred and forty‐six vent species names, associated location information (33 regions), and scores for 13 traits (in categories: community structure, generalist/specialist, geographic distribution, habitat use, life history, mobility, species associations, symbiont, and trophic structure). Contributor IDs, certainty scores, and references are also provided. Spatial location and grain: Global coverage (grain size: ocean basin), spanning eight ocean basins, including vents on 12 mid‐ocean ridges and 6 back‐arc spreading centres. Time period and grain: sFDvent includes information on deep‐sea vent species, and associated taxonomic updates, since they were first discovered in 1977. Time is not recorded. The database will be updated every 5 years. Major taxa and level of measurement: Deep‐sea hydrothermal‐vent fauna with spe‐ cies‐level identification present or in progress. Software format: .csv and MS Excel (.xlsx).This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited

    The Professionalisation of Non-Denominational Religious Education in England: politics, organisation and knowledge

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    ArticleIn response to contemporary concerns, and using neglected primary sources, this article explores the professionalisation of teachers of Religious Education (RI/RE) in non-denominational, state-maintained schools in England. It does so from the launch of Religion in Education (1934) and the Institute for Christian Education at Home and Abroad (1935) to the founding of the Religious Education Council of England and Wales (1973) and the British Journal of Religious Education (1978). Professionalisation is defined as a collective historical process in terms of three inter-related concepts: (1) professional self-organisation and professional politics, (2) professional knowledge, and (3) initial and continuing professional development. The article sketches the history of non-denominational religious education prior to the focus period, to contextualise the emergence of the professionalising processes under scrutiny. Professional self-organisation and professional politics are explored by reconstructing the origins and history of the Institute of Christian Education at Home and Abroad, which became the principal body offering professional development provision for RI/RE teachers for some fifty years. Professional knowledge is discussed in relation to the content of Religion in Education which was oriented around Christian Idealism and interdenominational networking. Changes in journal name in the 1960s and 1970s reflected uncertainties about the orientation of the subject and shifts in understanding over the nature and character of professional knowledge. The article also explores a particular case of resistance, in the late 1960s, to the prevailing consensus surrounding the nature and purpose of RI/RE, and the representativeness and authority of the pre-eminent professional body of the time. In conclusion, the article examines some implications which may be drawn from this history for the prospects and problems of the professionalisation of RE today

    The C-Band All-Sky Survey (C-BASS):Design and capabilities

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    The C-Band All-Sky Survey (C-BASS) is an all-sky full-polarisation survey at a frequency of 5 GHz, designed to provide complementary data to the all-sky surveys of WMAP and Planck, and future CMB B-mode polarization imaging surveys. The observing frequency has been chosen to provide a signal that is dominated by Galactic synchrotron emission, but suffers little from Faraday rotation, so that the measured polarization directions provide a good template for higher frequency observations, and carry direct information about the Galactic magnetic field. Telescopes in both northern and southern hemispheres with matched optical performance are used to provide all-sky coverage from a ground-based experiment. A continuous-comparison radiometer and a correlation polarimeter on each telescope provide stable imaging properties such that all angular scales from the instrument resolution of 45 arcmin up to full sky are accurately measured. The northern instrument has completed its survey and the southern instrument has started observing. We expect that C-BASS data will significantly improve the component separation analysis of Planck and other CMB data, and will provide important constraints on the properties of anomalous Galactic dust and the Galactic magnetic field.Comment: 21 pages, 9 figure
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