1,721,012 research outputs found
On the systematics and ecology of two new species of Provanna (Gastropoda: Provannidae) from deep-sea hydrothermal vents in the Caribbean Sea and Southern Ocean
Full text linkThe recent discovery and exploration of deep-sea hydrothermal vent fields in the Mid-Cayman Spreading Centre, Caribbean Sea (Beebe Vent Field, 4956–4972 m depth) and the East Scotia Ridge, Southern Ocean (E2 and E9 vent fields, 2394–2641 m depth) have yielded extensive collections of two new provannid species, Provanna beebei n. sp. and P. cooki n. sp. Morphological and molecular taxonomy (530 bp of the mitochondrial cytochrome c oxidase subunit I gene) confirm P. beebei n. sp. and P. cooki n. sp. as distinct species; these species are formally described, and details are provided of their distribution, habitat and species associations. Bayesian and maximum likelihood analyses support the placement of P. beebei n. sp. and P. cooki n. sp within the genus Provanna and show that these two new deep-sea species form a well-supported clade with the abyssal West Pacific P. cingulata. Provanna beebei n. sp. and P. cooki n. sp. represent the first records of Provanna from hydrothermal vents in the Caribbean Sea and Southern Ocean, respectively, and extend the known geographic range of the genus. For the first time, intraspecific phenotypic variation in size and sculpture has been reported for Provanna. At the East Scotia Ridge, shell-size frequency distributions and median shell size of P. cooki n. sp. varied significantly between the E2 and E9 vent fields, as well as between diffuse flow and high-temperature venting habitats within each field. The variation in shell sculpture in relation to habitat was also observed in P. cooki n. sp
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
Exploring our oceans: Using the global classroom to develop ocean literacy
No full textDeveloping the ocean literacy of individuals of all ages from all countries, cultures, and economic backgrounds is essential to inform choices for sustainable living in the future, but how we reach and represent diverse voices is a challenge. Massive Open Online Courses (MOOCs) offer a possible tool to achieve this goal, as they can potentially reach large numbers of people including those from lower and middle income regions. The number of MOOCs themed around ocean science and/or literacy is growing rapidly, and here we share experience of developing and delivering a MOOC entitled “Exploring Our Oceans,” which has run ten times in the past 4 years with around 40,000 participants worldwide. The “Exploring Our Oceans” MOOC incorporates a blend of online teaching techniques grounded in both instructivist and constructivist theories, thereby emphasizing contributions from a global community of learners and encouraging individual, independent action in relation to ocean citizenship. The impacts of this MOOC include evidence of changed awareness and attitudes to ocean issues; increased applications and participation in undergraduate and postgraduate programs; development of communication and outreach skills in the postgraduate community and partnership building with Nelson Mandela University, South Africa. These impacts, and vignettes of learner experiences in the course, are discussed in the context of the effectiveness of MOOCs in developing global ocean literacy
Distribution, population structure, reproduction and diet of Ophiolimna antarctica (Lyman, 1879) from Kemp Caldera in the Southern Ocean
No full textA new population of Ophiolimna antarctica (Lyman, 1879) was discovered at 1546 m in Kemp Caldera, a topographic feature with active hydrothermal venting at the southern end of the South Sandwich Islands, Southern Ocean. The distribution, population structure, reproduction, and diet of O. antarctica were investigated. O. antarctica were found predominantly on basalt with an over-dispersed distribution. The mean density was 17 individuals m?2 with a range of 9–24 individuals m?2. There was a bimodal population structure, with separate juvenile and adult peaks. Sexes were separate and the sex ratio was not significantly different from equality. The maximum oocyte diameter was 520 ?m, suggesting direct or lecithotrophic development, whilst individual females reproduced asynchronously. Stomach contents included crustacean fragments, flocculate material, diatoms, forams, fish scales, and ophiuroid tissues and spines, which was indicative of omnivory. There was no apparent influence of hydrothermal vents <500 m away on the diet of Ophiolimna antarctica. The ecology of Ophiolimna antarctica is consistent with what is known for other Antarctic and deep-sea ophiuroid species
The ‘scaly-foot gastropod’: a new genus and species of hydrothermal vent-endemic gastropod (Neomphalina: Peltospiridae) from the Indian Ocean
No full textThe ‘scaly-foot gastropod’ is widely recognized as an iconic species of deep-sea hydrothermal vent ecosystems in the Indian Ocean. Uniquely among gastropods, this species carries hundreds of dermal sclerites on its foot and these scales can be covered in iron sulphide that also covers its shell, making it the only extant metazoan known to utilize iron sulphide as part of its skeleton. It has not been formally named, despite attracting great attention from both scientists and the general public alike, although a manuscript name has occasionally been used in various sources. The RRS James Cook JC67 expedition in 2011 sampled the biota of the Longqi vent field (37°47.027?S, 49°38.963?E), Southwest Indian Ridge, for the first time, revealing a previously unknown population of the ‘scaly-foot gastropod’. The present study gives a formal name to the ‘scaly-foot gastropod’, Chrysomallon squamiferum n. gen., n. sp. with Longqi vent field as the type locality. The erection of the new monotypic genus is supported by both morphological and molecular characterization, differentiating it from existing genera of the family Peltospiridae. Analysis of the cytochrome c oxidase subunit I gene reveals a 24–26% pairwise distance between Chrysomallon and five other genera of Peltospiridae, while the range among those five genera is 14–25%. The new genus is placed in the family Peltospiridae based on morphological characteristics, including lack of sexual dimorphism, no copulatory organ, the distal end of marginal teeth being subdivided into many denticles and the ventral margin of the gill leaflets carrying a series of bulges. A five-gene Bayesian phylogenetic reconstruction does not contradict the placement within Peltospiridae
A new species of Pachycara Zugmayer, 1911 (Teleostei: Zoarcidae) from deep-sea chemosynthetic environments in the Caribbean Sea.
No full textThe 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
Low connectivity between ‘scaly-foot gastropod’ (Mollusca: Peltospiridae) populations at hydrothermal vents on the Southwest Indian Ridge and the Central Indian Ridge
No full textHydrothermal vents on mid-oceanic ridges are patchily distributed and host many taxa endemic to deep-sea chemosynthetic environments, whose dispersal may be constrained by geographical barriers. The aim of this study was to investigate the connectivity of three populations of the ‘scaly-foot gastropod’ (Chrysomallon squamiferum Chen et al., 2015), a species endemic to hydrothermal vents in the Indian Ocean, amongst two vent fields on the Central Indian Ridge (CIR) and Longqi field, the first sampled vent field on the Southwest Indian Ridge (SWIR). Connectivity and population structure across the two mid-oceanic ridges were investigated using a 489-bp fragment of the cytochrome oxidase c subunit I (COI) gene. Phylogeographical approaches used include measures of genetic differentiation (F ST), reconstruction of parsimony haplotype network, mismatch analyses and neutrality tests. Relative migrants per generation were estimated between the fields. Significant differentiation (F ST?=?0.28–0.29, P?<?0.001) was revealed between the vent field in SWIR and the two in CIR. Signatures were detected indicating recent bottleneck events followed by demographic expansion in all populations. Estimates of relative number of migrants were relatively low between the SWIR and CIR, compared with values between the CIR vent fields. The present study is the first to investigate connectivity between hydrothermal vents across two mid-ocean ridges in the Indian Ocean. The phylogeography revealed for C. squamiferum indicates low connectivity between SWIR and CIR vent populations, with implications for the future management of environmental impacts for seafloor mining at hydrothermal vents in the region, as proposed for Longqi
Is it sex in chains? Potential mating stacks in deep-sea hydrothermal vent snails
No full text“Mating stacks” have been widely documented in calyptraeid slipper limpets, which are protandric and exhibit sequential hermaphroditism. Gigantopelta is a genus of peltospirid snails endemic to deep-sea hydrothermal vents containing two species, one distributed on the East Scotia Ridge in the Southern Ocean and another on the Southwest Indian Ridge in the Indian Ocean. Here, we report the observation that both species form extensive (often >15 individuals) “snail chains”. These chains are potentially analogous to ‘mating stacks’ of calyptraeids, or alternatively, maybe a behaviour to facilitate spermatophore transfer. Both Gigantopelta species apparently have separate sexes and are sexually mature at a small size. However, it remains unclear whether they undergo sex change during their life.</p
FIGURE 3. A in A new species of Pachycara Zugmayer, 1911 (Teleostei: Zoarcidae) from deep-sea chemosynthetic environments in the Caribbean Sea
No full textFIGURE 3. A) Photographic ventral view of head and pectoral region of Pachycara caribbaeum sp. nov. holotype in fresh condition (scale bar 20 mm; image by Adrian Glover, BMNH); B) microCT ventral view of holotype head and pectoral region (image by Daniel Sykes, BMNH).Published as part of Anderson, M. Eric, Somerville, Russell & Copley, Jonathan T., 2016, A new species of Pachycara Zugmayer, 1911 (Teleostei: Zoarcidae) from deep-sea chemosynthetic environments in the Caribbean Sea, pp. 71-77 in Zootaxa 4066 (1) on page 73, DOI: 10.11646/zootaxa.4066.1.5, http://zenodo.org/record/27053
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
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