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Abstract Purpose The ecological interdependence between macroorganisms and their microbial communities promotes stable associations over time, potentially leading to their evolutionary co-diversification. The detection of intricate eco-evolutionary interactions between animals and their microbiota is challenging, primarily due to complex bacterial communities related to poorly resolved host population structure. Strikingly, co-diversification in invertebrates, characterized by generally less complex microbiota, remains largely unexplored. Here, we compared the bacterial communities associated with two distinct lineages of Nacella limpets, a dominant shallow water patellogastropod of the Southern Ocean shores with a well-described population structure. Our goals were to elucidate the uniqueness of Nacella microbiota, resulting from an ecological filter that selectively favors certain bacterial taxa. Additionally, we aimed to depict the genetic structure of bacterial symbiont seeking evidence of co-diversification with Nacella. Methods We sequence the V4-V5 regions of the bacterial 16S rRNA gene in three distinct microenvironments associated with Nacella: rock substrate, radula, and whole intestine. These samples were collected from two populations of Nacella deaurata and Nacella concinna, located in the West Antarctic Peninsula and Falkland/Malvinas Islands, respectively. Results We assessed ecological filtering patterns in the limpet microbiota, uncovering unique bacterial communities in both radulas and intestines, with specifically enriched bacterial taxa compared to the surrounding environment. By examining microdiversity patterns of core bacterial taxa, we revealed a deep phylogeographic structure of Psychrilyobacter in Nacella intestines. Conclusion We highlight the Southern Ocean limpets of the Nacella genus as a novel and promising model for studying co-diversification between marine mollusks and their resident microbiota.

Purpose: The ecological interdependence between macroorganisms and their microbial communities promotes stable associations over time, potentially leading to their evolutionary co-diversification. The detection of intricate eco-evolutionary interactions between animals and their microbiota is challenging, primarily due to complex bacterial communities related to poorly resolved host population structure. Strikingly, co-diversification in invertebrates, characterized by generally less complex microbiota, remains largely unexplored. Here, we compared the bacterial communities associated with two distinct lineages of Nacella limpets, a dominant shallow water patellogastropod of the Southern Ocean shores with a well-described population structure. Our goals were to elucidate the uniqueness of Nacella microbiota, resulting from an ecological filter that selectively favors certain bacterial taxa. Additionally, we aimed to depict the genetic structure of bacterial symbiont seeking evidence of co-diversification with Nacella. Methods: We sequence the V4-V5 regions of the bacterial 16S rRNA gene in three distinct microenvironments associated with Nacella: rock substrate, radula, and whole intestine. These samples were collected from two populations of Nacella deaurata and Nacella concinna, located in the West Antarctic Peninsula and Falkland/Malvinas Islands, respectively. Results: We assessed ecological filtering patterns in the limpet microbiota, uncovering unique bacterial communities in both radulas and intestines, with specifically enriched bacterial taxa compared to the surrounding environment. By examining microdiversity patterns of core bacterial taxa, we revealed a deep phylogeographic structure of Psychrilyobacter in Nacella intestines. Conclusion: We highlight the Southern Ocean limpets of the Nacella genus as a novel and promising model for studying co-diversification between marine mollusks and their resident microbiota. [ABSTRACT FROM AUTHOR]

Background and Aims Worldwide, invasive species are spreading through marine systems at an unprecedented rate with both positive and negative consequences for ecosystems and the biological functioning of organisms. Human activities from shipping to habitat damage and modification are known vectors of spread, although biological interactions including epibiosis are increasingly recognized as potentially important to introduction into susceptible habitats. Methods We assessed a novel mechanism of spread – limpets as transporters of an invasive alga, Sargassum muticum , into beds of the seagrass Zostera marina – and the physiological impact of its invasion. The association of S. muticum with three limpet species and other habitats was assessed using intertidal surveys on rocky shores and snorkelling at two seagrass sites in the UK. A 4-year field study tested the effect of S. muticum on Z. marina shoot density, dry weight and phenolic compounds (caffeic and tannic acid) content, and a laboratory experiment tested the impact of S. muticum on nutrient partitioning (C/H/N/P/Si), photosynthetic efficiency (F v/ F m) and growth of Z. marina. Results On rocky shores 15 % of S. muticum occurrences were attached to the shells of live limpets. In seagrass beds 5 % of S. muticum occurrences were attached to the shells of dead limpets. The remainder were attached to rock, to cobblestones, to the seagrass matrix or embedded within the sand. Z. marina density and phenolics content was lower when S. muticum co-occurred with it. Over 3 years, photosynthetic responses of Z. marina to S. muticum were idiosyncratic, and S. muticum had no effect on nutrient partitioning in Z. marina. Conclusions Our results show limpets support S. muticum as an epibiont and may act as a previously unreported transport mechanism introducing invaders into sensitive habitats. S. muticum reduced production of phenolics in Z. marina , which may weaken its defensive capabilities and facilitate proliferation of S. muticum. The effect of S. muticum on Z. marina photosynthesis requires further work but having no effect on the capacity of Z. marina to sequester nutrients suggests a degree of resilience to this invader. [ABSTRACT FROM AUTHOR]

The limpet Patella aspera is an endemic species to the Macaronesian Islands. Its high economic value and vulnerability to exploitation has triggered the interest in the development of its aquaculture. Significant progress has been made in recent years, with the establishment of artificial fertilization and larval production protocols. However, there are at least two major challenges that need to be addressed before a commercial production can be achieved: larval settlement and juvenile grow-out. The aim of this research was to study the effect of different algae substrates (Ulvella lens, Amphora sp., Entomoneis sp., Navicula salinicola and Nitzschia sp.) on P. aspera settlement and to test the effect of two diets on juvenile growth: a mono diet based on U. lens versus a mixed diet composed by U. lens and the diatoms Nitzschia sp. and Navicula salinicola. Results showed that U. lens was the most efficient settlement cue, given that 84.6% of the post-larvae obtained were found on this algae substrate. In the following trial, U. lens was selected as the base diet for the grow-out phase. The rearing system used ensured juvenile survival percentages above 80%. The regular supply of the diatom mixture, as a dietary supplement, significantly enhanced juvenile growth performance. After 220 days post fertilization, limpets that grew on the mixed diet (U. lens plus diatoms) presented an average shell length of 19.280 ± 5.296 mm. Additionally, developed gonads were observed in females with less than 8 months. This study presents the first record of P. aspera juvenile grow-out, born from artificial fertilization, which represents a major step toward the development of limpet aquaculture.

Seagrass habitats are declining worldwide, placing several seagrass‐associated animals at risk of extinction. The Critically Endangered limpet Siphonaria compressa is one of the rarest molluscs in Africa, and has been reported from only two disjunctive lagoons in South Africa. Being a highly specialized grazer that lives exclusively on the narrow blades of Cape eelgrass, Zostera capensis, which is itself listed as Endangered in the South African Red List and has decreased in abundance, conservation initiatives are urgently needed to ensure the long‐term survival of S. compressa.Molecular data (sequence data from the mitochondrial genome and single nucleotide polymorphism data of the nuclear genome) and morphological data were analysed to determine whether the two populations are conspecific, with implications for whether translocation between localities could be a viable management strategy to restore either population in the event of a collapse, or to maintain the genetic diversity of each population.Strong evidence emerged for the distinctness of the two populations, including a lack of shared mtDNA haplotypes that indicate an absence of contemporary gene flow, a divergence time that dates to the late Pleistocene, and a number of morphological characters that distinguish their shells. These findings indicate that the two populations are distinct cryptic subspecies.As the two populations occur in different temperature‐defined marine biogeographical regions, they are probably adapted to different thermal environments. Translocations are not recommended, as this management strategy has considerable potential to result in outbreeding depression and exacerbate the extinction risk. Instead, each population should be managed separately, and several alternative conservation measures are discussed, including the protection and restoration of seagrass beds. [ABSTRACT FROM AUTHOR]

Patella ferruginea (Gastropoda, Patellidae) is an endemic and endangered marine invertebrate species from the Western Mediterranean that presents two ecomorphotypes. Currently, there is no objective and nonmanipulative method to determine these ecomorphotypes in the field. The present study uses the geometric morphometrics approach to investigate variation in the shell‐shape allometric trajectories of both ecomorphotypes. In addition, we propose a new manipulation‐free tool to assign ecomorphotype in the field. A total of 190 shells, 123 from the lamarcki (20.0 to 86.7 mm) and 67 from the rouxi (25.3 to 95.9 mm) ecomorphotypes, were analyzed using three different 2D landmark and semilandmark configurations capturing the lateral, internal, and dorsal shell views. We provide compelling graphical and analytical evidence that these ecomorphotypes differ in allometric growth patterns. However, the findings of the current study do not support that lamarcki and rouxi correspond to different ontogenetic states of P. ferruginea. We hypothesize that the difference in the allometric trajectories between the rouxi and the lamarcki ecomorphotypes could be due to environmental constraints, but it might also be due to currently undetected genetic factors. Since the allometry‐free shape lateral view presented the most significant reliability in assigning ecomorphotypes, we evaluate an easy and inexpensive tool to assign individuals in the field to each ecomorphotype using a contour gauge and a simple landmark configuration (only three landmarks). Cross‐validated classification indicated that ecomorphotype assignations for lateral contour present total reliability calculated at 93.15%. Therefore, we encourage it to be implemented in future research to avoid sacrificing or manipulating specimens of this endangered species. [ABSTRACT FROM AUTHOR]

Octopus vulgaris type III preys upon molluscs by drilling a hole in the shell, through which it injects venom, weakening the muscles and allowing the octopus to remove and eat the mollusc flesh. In False Bay, South Africa, the abalone Haliotis midae, the kelp limpet Cymbula compressa and the helmet snail Semicassis zeylanica, are all common octopus prey, but each has a very different shell morphology and underlying anatomy. It is hypothesized that O. vulgaris type III targets the muscle attachment site of all three species and that the precision of drilling should correlate with the relative size of these muscle attachment sites. Measurements of the locations of drill holes from collected shells of each species showed that drilling locations were significantly non-random. In the abalone and limpet, the muscle attachment site was targeted two and 4.5 times more frequently than expected, respectively. Octopus vulgaris type III drilled helmet snails with extreme precision, with over half the holes drilled on the spire at an angle of 45° and 90° from the lip. Kernel density heat maps demonstrated that octopus drilled abalone with low precision, limpets with medium precision and helmet snails with high precision. The reason for the high precision in the helmet snail remains speculative, as the main drilling location did not align with the columellar muscle attachment and no target could be defined. This study is the first to assess octopus drilling in temperate southern Africa and to compare drilling precision across different prey species. [ABSTRACT FROM AUTHOR]

Gonadal development in limpets is well-known. However, the integration of fecundity data on coastal management actions remains overlooked. Here, we use fecundity of two exploited limpets (Patella ordinaria and P. aspera) to demonstrate its potential as a conservation tool to preserve the harvested populations of both species. From October 2021 to June 2022, 158 females of P. ordinaria and 70 of P. aspera were collected from the coastal rocky shores of the archipelago of Madeira (NE Atlantic Ocean). The fecundity in both species appears to be determinate, and estimated batch fecundity 365,638 ± 204,462 oocytes for P. ordinaria and 73,029 ± 43,496 oocytes for P. aspera. The presence of spawning individuals of both species until May is of significant relevance to their management and conservation. A harvest-ban (November-March) is currently implemented in the coastal governance actions of P. ordinaria and P. aspera. Based on the fecundity results, small adjustments can be made to further improve the conservation of adult individuals, which are important for the continuity of future generations. So far, fecundity data constitute an overlooked life trait of key importance to preserve populations of exploited species, primarily those with limited mobility such as semi-sessile littoral limpets.

The influx of volcanic ash into seawater alters particle composition with implications for the cellular, physiological and anatomical response of suspension-feeding organisms. Adult females of Crepipatella peruviana were exposed to three diets consisting of a fixed concentration of 50,000 cells ml−1 of the microalga Isochrysis galbana plus different concentrations of ash particles (30, 90 and 150 mg L−1). The objective was to determine the cellular, physiological and anatomical responses. Mortality increased with ash concentrations, while feeding and respiration rates, tissue weight, and condition index decreased. The gills showed severe degradation of cilia and the presence of large mucous aggregates of cilia and ash. An increase in ash resulted in decreased lipid peroxidation and protein carbonyls, but increased total antioxidant capacity and phenols. Thus, volcanic ash particles may exert a high impact at both cellular and physiological levels for C. peruviana , where inhibition of gill function reduces the ability to acquire food. [Display omitted] • Volcanic ash entering water changes seston composition affecting suspension-feeders. • Ash in the sea water impact the physiological and cellular response. • Mortality increased with increasing ash concentrations in diet. • Volcanic activity can eliminate communities of water suspension-feeders. [ABSTRACT FROM AUTHOR]

In this study, monthly heavy metal concentrations in the whole-body tissue of Patella caerulea (Mediterranean limpets), a bioindicator species living in the coastal zone of the Gulf of Izmit (Marmara Sea), were examined for the first time. The mean metal concentrations in Patella caerulea (mg kg−1 dw) were 2.01–5.74 Cd, 2.45–12.90 Cu, 0.74–1.95 Pb, 21.12–109.57 Zn, 16.31–154.67 Ni, and 1120.67–3086.00 Fe. Cd levels in all months and Pb levels in October and November were found to be above the safe limits set by international organizations. The estimated daily intakes and estimated weekly intakes determined for each heavy metal were below the acceptable daily intakes and provisional tolerable weekly intakes. However, the target hazard quotient and total target hazard quotient values calculated for Cd, Ni, and Fe were found to be higher than 1. The carcinogenic risk value was also found to be high. [ABSTRACT FROM AUTHOR]

Structural and physiochemical properties contribute to the biological adaptation of deep-sea animals to their harsh living environment but have hardly been investigated systematically. In the present study, we for the first time applied various material characterization techniques including transmission electron microscopy (TEM), scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), and Fourier-transform infrared (FT-IR) spectroscopy to investigate the shell microstructures and chemical composition of a deep-sea limpet Eulepetopsis crystallina collected from the Tiancheng hydrothermal vent field at a depth of around 2,700 m in the Southwest Indian Ocean. Analyses of shell microstructural morphology and diffraction patterns of E. crystallina explicitly revealed the layered structures, exfoliation characteristics, and crystallographic orientation of each layer’s unit cell which was tilted at a small angle sequentially. In comparison with ordinary shallow-water limpet Cellana toreuma shells, E. crystallina shells showed a unique chemical composition and contained pure calcite of calcium carbonate polymorph and the trace of phosphate originated from regional phosphatic sediments of the Southwest Indian Ocean. The further microscopic analyses indicated that the shell of the deep-sea limpet E. crystallina features integrated and untruncated layer structures with a compressed width, possibly owning to the ultra-high hydrostatic pressure, which confirmed the effects of the living environment on the shell microstructure of deep-sea animals.

The purpose of this paper is to provide for the first time data on a hard substratum macroinvertebrate species inhabiting El Mellah, the unique coastal lagoon in Algeria, and to increase knowledge on limpet species in South Mediterranean protected areas. Between the summer 2019 and the spring 2020, several biological and population dynamics aspects of the high-shore limpet Patella rustica were investigated. Based on length-frequency distribution analysis using the FiSAT II software, the age of sampled limpets ranged from one to five years old, and the estimated growth parameters were identified as L∞= 40.55 mm, K= 0.39 year-1, with a growth performance index (Φ') of 2.81. Morphometric analysis revealed significant positive allometric relationships indicating variations in body proportions during ontogenesis. Condition index exhibited strong seasonality, with the highest value (41.27±3.27) recorded during winter. Overall, this study revealed that P. rustica from El Mellah lagoon follows similar morphological and physiological patterns to other populations in the range of the species across oceanic and marine coastal waters. [ABSTRACT FROM AUTHOR]

The Antarctic limpet, Nacella concinna, is one of the most abundant benthic marine invertebrates found in the intertidal zone of King George Island, Antarctica. The shell of N. concinna is often encrusted with the coralline algae Clathromorphum obtectulum. In this study, to reveal the relationship between the limpet and coralline algae, we examined how the coralline algae affect the physical condition (survival and health) and morphology of the limpet. We cultured the limpets for 22 days and compared mortality, weight, condition factor (CF), fatty acid content, and the structure of the shell surface between limpets both with and without coralline algae in the laboratory. We also measured the environmental factors (i.e., temperature, pH, and salinity) of the seawater at each sampling site and the CF of the limpets and correlated them with coverage of coralline algae. The presence of coralline algae significantly increased the mortality of the limpets by 40% and the shell weight by 1.4-fold but did not affect the CF. Additionally, coralline algae altered the fatty acid profiles related to the limpet's lipid metabolism (saturated fatty acids (SFA) and some polyunsaturated fatty acids (PUFA)). Specifically, C16:0, C17:0, C18:0, and total SFA increased, whereas C18:2 and C18:3 decreased. However, observations with a scanning electron microscope showed that shell damage in limpets with coralline algae was much less than in limpets without coralline algae, suggesting that coralline algae may provide protection against endolithic algae. The area of coralline algae on the limpet shell was positively correlated with the pH and temperature of the seawater. The results suggest that although coralline algae are generally assumed to be parasitical, the relationship between N. concinna and coralline algae may change to mutualism under certain conditions. [ABSTRACT FROM AUTHOR]

Limpets are common inhabitants of the midlittoral and upper infralittoral zones and play an important ecological role in the coastal ecosystem. The study aimed to assess growth, meat yield, morphological aspects, condition and reproduction features of Patella caerulea. About 58% of collected Mediterranean limpets were concentrated in the 25.0-34.9 mm shell length group. The average meat yield ratio was calculated as 39.34%. Mean growth increments for shell length (SL) and total weight (TW) were 23.99% and 97.99%, respectively. Results exhibited relatively high correlation coefficients among variables. Mean condition factor value was calculated as 14.2. Spawning occurs over a short period with ovigerous females observed on two month periods. Mean fecundity was calculated as 90,983±28,675 eggs/g whereas mean egg diameter was estimated as 160.6 µm. This study presents first baseline information about biological and morphological of Mediterranean Limpets population in Black Sea. [ABSTRACT FROM AUTHOR]

Siphonariidae is a panpulmonate family that occurs in intertidal rocky shores worldwide within temperate to tropical areas. Although the egg masses of Siphonaria sirius are commonly found in lower intertidal rocky shores in summer, there is a lack of information on their embryonic development. We examined the embryonic development and duration of S. sirius both in the laboratory and in the field. The study was conducted in Shirahama, Wakayama, Japan, during the summer of 2014 and 2015. The embryonic developmental process of S. sirius was similar to that of other planktotrophic siphonariids. However, S. sirius hatched within four days after oviposition at 27.35°C in the laboratory, which is the shortest in the Siphonariidae. In the field, hatching occurred notably faster at 1.6 days after oviposition, although the average temperature (27.42°C) was similar to that in the laboratory. The presence of egg predators, as well as other environmental factors, may be responsible for the short embryonic period of this species, especially in the field. [ABSTRACT FROM AUTHOR]

Limpets are one of the most abundant and familiar rocky shore organisms globally. They are perhaps most famous for their ability to cling onto rocks, but they are also well known for their grazing activity, which has an important structuring function. In contrast to other molluscs, such as oysters and mussels, which are celebrated for their gastronomic and cultural importance, little is known about the provisioning and cultural services of the humble limpet, and they are often referred to as 'famine food'. Using an interdisciplinary approach, this paper describes the importance of limpets in the diets and cultures of humans globally. Not only were limpets often the dominant shellfish eaten by early modern humans, but also they sustained the poor during times of famine and destitution. Today, they are considered a delicacy in many cultures. They are popular as bait and their shells have been used for a wide variety of uses, including tools, currency, offerings, traditional medicine, jewellery and artworks. They have important spiritual and religious relevance, featuring in myriad traditions, superstitions and folklore. Whilst limpets are not exploited on a global scale, there are many regions where populations are vulnerable to over-exploitation and possible extinction. Appropriate management is required if we are to protect these underappreciated animals. This comprehensive review rectifies the limpet's reputation as 'famine food' and attests to the important role that limpets played in past and present coastal cultural heritage and food culture. [ABSTRACT FROM AUTHOR]

Microplastics (MPs) accumulation in rocky shore organisms has limited knowledge. This study investigated MPs accumulation in filter-feeding oysters, herbivorous limpets and carnivorous snails to assess their performance as sentinel species in the MPs trophic transfer. The samples were obtained along a contamination gradient in the Santos Estuarine System, Brazil. All three studied species showed MPs concentrations related to the contamination gradient, being the oysters the species that showed the highest levels, followed by limpets and snails (average of less and most contaminated sites of 1.06–8.90, 2.28–5.69 and 0.44–2.10 MP g−1, respectively), suggesting that MPs ingestion rates are linked to feeding habits. MPs were mainly polystyrene and polyacetal. The polymer types did not vary among sites nor species. Despite minor differences in percentages and diversity of size, shape, and color classes, the analyzed species were equally able to demonstrate dominance of small, fiber, transparent, black and blue MPs. Thus, oysters, limpets, and snails are proposed as sentinels of MPs in monitoring assessments. [Display omitted] • Oysters accumulated more microplastics (MPs) than limpets and snails. • Filter-feeders accumulated more MPs than herbivores and carnivorous. • All species similarly reflected the known contamination gradient. • Minor differences in MP types were seen spatially and among species. • Oysters, limpets and snails can be used as sentinels of MPs contamination. [ABSTRACT FROM AUTHOR]

Considerable research has examined the influence of herbivores on the maintenance of plant diversity, but fewer studies have examined the reciprocal effect of plant diversity on the animals that use the plant community for food and shelter, particularly in marine systems. Several mechanisms could underlie such effects. Animal diversity and abundance could be increased by complementary use of different plants by different animals, or by an indirect effect of plant diversity on plant production that results in more total plant biomass in high plant-diversity communities. Alternatively, plant species identity could play a dominant role leading to sampling effects or no effect of diversity at all. We conducted a six-year field manipulation of the richness of rocky shore seaweeds in northern California and measured the effects of algal richness and identity on the invertebrate community, from meiofauna to macrofauna. We found that diverse algal communities hosted more species of both large and small invertebrates than the average algal monoculture but that the mechanisms underlying this pattern differed substantially for organisms of different size. More species of macrofauna occurred in the polycultures than in any of the monocultures, likely due to the greater total cover of algae produced in polycultures. Rare and common macrofaunal taxa responded to host plant species richness in opposite ways, with more occurrences of rare taxa and lower abundance of very common taxa in the polycultures. In contrast, meiofaunal richness in polycultures was no different than that of monocultures of finely branched species, leading to strong effects of algal identity. Our findings are similar to those from terrestrial systems in that the effects of plant diversity we observed were most related to the greater amount of habitat in polycultures as a result of overyielding in algal biomass. However, our findings differ from those in terrestrial systems in that the primary mechanisms for both richness and identity effects appear related to the value of plants as shelter from harsh abiotic conditions or predation rather than food, and in that animal body size altered the mechanisms underlying diversity effects.

Abstract Background The Notch signaling pathway governs the specification of different cell types in flies, nematodes and vertebrates alike. Principal components of the pathway that activate Notch target genes are highly conserved throughout the animal kingdom. Despite the impact on development and disease, repression mechanisms are less well studied. Repressors are known from arthropods and vertebrates that differ strikingly by mode of action: whereas Drosophila Hairless assembles repressor complexes with CSL transcription factors, competition between activator and repressors occurs in vertebrates (for example SHARP/MINT and KyoT2). This divergence raises questions on the evolution: Are there common ancestors throughout the animal kingdom? Results Available genome databases representing all animal clades were searched for homologues of Hairless, SHARP and KyoT2. The most distant species with convincing Hairless orthologs belong to Myriapoda, indicating its emergence after the Mandibulata-Chelicarata radiation about 500 million years ago. SHARP shares motifs with SPEN and SPENITO proteins, present throughout the animal kingdom. The CSL interacting domain of SHARP, however, is specific to vertebrates separated by roughly 600 million years of evolution. KyoT2 bears a C-terminal CSL interaction domain (CID), present only in placental mammals but highly diverged already in marsupials, suggesting introduction roughly 100 million years ago. Based on the LIM-domains that characterize KyoT2, homologues can be found in Drosophila melanogaster (Limpet) and Hydra vulgaris (Prickle 3 like). These lack the CID of KyoT2, however, contain a PET and additional LIM domains. Conservation of intron/exon boundaries underscores the phylogenetic relationship between KyoT2, Limpet and Prickle. Most strikingly, Limpet and Prickle proteins carry a tetra-peptide motif resembling that of several CSL interactors. Overall, KyoT2 may have evolved from prickle and Limpet to a Notch repressor in mammals. Conclusions Notch repressors appear to be specific to either chordates or arthropods. Orthologues of experimentally validated repressors were not found outside the phylogenetic group they have been originally identified. However, the data provide a hypothesis on the evolution of mammalian KyoT2 from Prickle like ancestors. The finding of a potential CSL interacting domain in Prickle homologues points to a novel, very ancestral CSL interactor present in the entire animal kingdom.

The Antarctic limpet, Nacella concinna, is one of the most abundant benthic marine invertebrates found in the intertidal zone of King George Island, Antarctica. The shell of N. concinna is often encrusted with the coralline algae Clathromorphum obtectulum. In this study, to reveal the relationship between the limpet and coralline algae, we examined how the coralline algae affect the physical condition (survival and health) and morphology of the limpet. We cultured the limpets for 22 days and compared mortality, weight, condition factor (CF), fatty acid content, and the structure of the shell surface between limpets both with and without coralline algae in the laboratory. We also measured the environmental factors (i.e., temperature, pH, and salinity) of the seawater at each sampling site and the CF of the limpets and correlated them with coverage of coralline algae. The presence of coralline algae significantly increased the mortality of the limpets by 40% and the shell weight by 1.4-fold but did not affect the CF. Additionally, coralline algae altered the fatty acid profiles related to the limpet’s lipid metabolism (saturated fatty acids (SFA) and some polyunsaturated fatty acids (PUFA)). Specifically, C16:0, C17:0, C18:0, and total SFA increased, whereas C18:2 and C18:3 decreased. However, observations with a scanning electron microscope showed that shell damage in limpets with coralline algae was much less than in limpets without coralline algae, suggesting that coralline algae may provide protection against endolithic algae. The area of coralline algae on the limpet shell was positively correlated with the pH and temperature of the seawater. The results suggest that although coralline algae are generally assumed to be parasitical, the relationship between N. concinna and coralline algae may change to mutualism under certain conditions.

A native strain of the entomopathogenic fungus Beauveria bassiana (Bb-C001) was isolated from a naturally infected Triatoma infestans, Klug (Hemiptera: Reduviidae) adult cadaver in the Gran Chaco region, Salta province, Argentina. The isolate was both phenotypic and molecularly characterized in a context of fungus-insect interaction, by measuring the expression pattern of toxin genes during infection and immune response of T. infestans. The commercial strain GHA of B. bassiana, which was previously used in field interventions to control these vectors, was used as reference in this study. The phylogenetic trees based on both ribosomal internal transcribed spacer (ITS) and elongation factor 1-alpha (EF1-α) indicated that Bb-C001 fits into a B. bassiana cluster, and the sequence-characterized amplified regions (SCAR) showed that Bb-C001 is different from the GHA strain. There were no differences between both strains regarding viability, radial growth, and conidia production, either in the median survival time or insect mortality. However, Bb-C001 showed a higher expression than GHA of the bassianolide synthetase gene (BbbslS) during infection, and similar levels of the beauvericin synthetase gene (BbbeaS). Immune-related genes of T. infestans nymphs (limpet-2 and defensin-1, -2, and -6) were later expressed and thus insects failed to stop the infection process. These results showed that B. bassiana Bb-C001 is a promised fungal strain to be incorporated in the current biological control programs of T. infestans in Salta province, Argentina. [ABSTRACT FROM AUTHOR]

Populations of the European flat oyster Ostrea edulis have experienced catastrophic declines across Europe and subsequent spread of the non‐native species Crepidula fornicata has led to its occurrence in exceptionally high densities in some areas previously dominated by O. edulis.Spatial and temporal concurrence of C. fornicata larvae within the zooplankton community occurs throughout the O. edulis spawning season. A C. fornicata larval peak density of 374.7 ± 96.5 larvae/ml (mean ± SD) was observed in Langston Harbour sympatrically with O. edulis density of 45.7 ± 20.1 larvae/ml in early August. Overall oyster larvae contribution to the zooplankton community was higher in Portsmouth Harbour (12%) than C. fornicata contribution (9.6%), whilst the opposite occurred in Langstone (oysters, 11.7%; C. fornicata, 12%).Larval abundance is not reflected in recruitment on the seabed, owing to the conspecific substrate preference of O. edulis. Settlement of O. edulis spat was significantly greater on settlement discs covered with recently deceased oyster shells; 6.7 ± 1.2 (mean ± SE) spat/disc vs old smooth oyster shells, 2.7 ± 1.3, C. fornicata shell 1.7 ± 0.3, cemented discs 2 ± 1 or the plastic control disc 0.7 ± 0.7.Settlement substrate type matters in the presence of high benthic and larval densities of C. fornicata. The Solent has become a substrate‐limited system for O. edulis; substrate management or reef deployment is required to restore a self‐recruiting population.Finally, although C. fornicata may provide functional equivalence in terms of filtering services, it supports a significantly different and less biodiverse faunal community from that of O. edulis. Therefore C. fornicata does not provide equivalence as an ecosystem engineer and mechanisms of ecological phase shift are occurring within areas dominated by this invasive species. [ABSTRACT FROM AUTHOR]

Cold seeps, characterized by the methane, hydrogen sulfide, and other hydrocarbon chemicals, foster one of the most widespread chemosynthetic ecosystems in deep sea that are densely populated by specialized benthos. However, scarce genomic resources severely limit our knowledge about the origin and adaptation of life in this unique ecosystem. Here, we present a genome of a deep-sea limpet Bathyacmaea lactea , a common species associated with the dominant mussel beds in cold seeps. We yielded 54.6 gigabases (Gb) of Nanopore reads and 77.9-Gb BGI-seq raw reads, respectively. Assembly harvested a 754.3-Mb genome for B. lactea , with 3,720 contigs and a contig N50 of 1.57 Mb, covering 94.3% of metazoan Benchmarking Universal Single-Copy Orthologs. In total, 23,574 protein-coding genes and 463.4 Mb of repetitive elements were identified. We analyzed the phylogenetic position, substitution rate, demographic history, and TE activity of B. lactea. We also identified 80 expanded gene families and 87 rapidly evolving Gene Ontology categories in the B. lactea genome. Many of these genes were associated with heterocyclic compound metabolism, membrane-bounded organelle, metal ion binding, and nitrogen and phosphorus metabolism. The high-quality assembly and in-depth characterization suggest the B. lactea genome will serve as an essential resource for understanding the origin and adaptation of life in the cold seeps. [ABSTRACT FROM AUTHOR]

In this study, to obtain further information on the structural diversity of non‐methylene‐interrupted (NMI) fatty acids (FA) in the gonads of the limpet Cellana toreuma, previously unreported minor NMI FA, fractionated by argentation thin‐layer chromatography (TLC), in the ovaries were characterized by gas chromatography–mass spectrometry (GC–MS) analysis of their 3‐pyridylcarbinol derivatives. As a result, five novel NMI FA were identified as 5,14‐pentadecadienoic acid (15: 2Δ5,14), 5,9,18‐nonadecatrienoic acid (19:3Δ5,9,18), 5,9,20‐heneicosatrienoic acid (21:3Δ5,9,20), 7,13,20‐heneicosatrienoic acid (21:3Δ7,13,20), and 5,9,22‐tricosatrienoic acid (23:3Δ5,9,22). Possible biosynthetic pathways for these FA are also discussed in relation to structural variations of NMI FA regioisomers. This study clearly reinforces the findings of our previous works with structurally diverse NMI FA with a terminal double bond. [ABSTRACT FROM AUTHOR]

Scutellastra mexicana is the largest known patellid limpet species and probably is one of the most endangered marine invertebrates.The species was once distributed along the American Pacific coast from Mexico to Peru, but their large size (up to 35 cm long) and easy accessibility (shallow sublittoral), made it very vulnerable to human collection and now is extinct on most of the mainland Mexican coast.In August 2017, a large population of this species was found on María Cleofas island, off the coast of west‐central Mexico (Marías Archipelago, Pacific Ocean). This constitutes the only report of a population of this species since 1988.A total of 808 adult individuals of up to 26 cm in length and 20 cm in width were estimated, together with the presence of juveniles, suggesting that it is a self‐sustaining population. The population was monitored in August 2017 and August 2018.Although the species is under the category 'Special Protection' in the General Mexican Wild Law, and that María Cleofas island is a Biosphere Reserve, fishermen that operate with impunity in the area decimated the limpet population within a year of its discovery. Abundance in the shallowest area decreased significantly from 120 individuals per transect (65 m long and 2.75 m wide) in August 2017 to 48 individuals in August 2018, and the estimated adult population decreased from 808 to 304 limpets.Neither passive national conservation policies nor local practices have reduced current threats to biodiversity and resource depletion in Marías Archipelago. Protected areas like this are 'paper parks'—parks in name only—because there is no active conservation strategy or protection of marine species. [ABSTRACT FROM AUTHOR]

Our ability to reliably use radiocarbon (14C) dates of mollusk shells to estimate calendar ages may depend on the feeding preference and habitat of a particular species and the geology of the region. Gastropods that feed by scraping are prone to incorporation of carbon from the substrate into their shells as evidenced by studies comparing the radiocarbon dates of shells and flesh from different species on different substrates (Dye 1994; Hogg et al. 1998). Limpet shells (Patella sp.) are commonly found in prehistoric midden deposits in the British Isles and elsewhere, however these shells have largely been avoided for radiocarbon dating in regions of limestone outcrops. Results from limpets (Patella vulgata) collected alive on limestone and volcanic substrates on the coasts of Ireland indicate that the shells were formed in equilibrium with the seawater, with no significant 14C offsets. Limpets collected from the east coast of Northern Ireland have elevated 14C due to the output of Sellafield nuclear fuel reprocessing plant. In all locations, the flesh was depleted in 14C compared to the shells. The results will have an important consequence for radiocarbon dating of midden deposits as well as the bone of humans and animals who fed on the limpets. [ABSTRACT FROM AUTHOR]

The story of the discovery and study of the Monoplacophora (or Tryblidia) and how they have contributed to our understanding of the evolution of the Mollusca highlights the importance of integrating data from the fossil record with the study of living forms. Monoplacophora were common in the early Paleozoic and were thought to have become extinct during the Devonian Period, approximately 375 Mya. In the mid 1950s, they were recovered from abyssal depths off of Costa Rica and were immediately heralded as a “living fossil.” The living specimens confirmed that some of the organs (kidneys, heart, and gills) were repeated serially, just like the shell muscles that had been observed in fossil specimens. This supported the hypothesis that they were closely related to other segmented organisms such as annelids and arthropods. Today, there are 29 described living species and a growing body of work examining their anatomy, phylogeny, and ecology. Additional fossil specimens have also been discovered, and what was once thought to be a possible missing link between annelid worms and mollusks now appears to be a highly specialized branch of the molluscan tree that tells us little about the ancestral mollusk condition. However, some assumptions and generalizations from those early days still remain—such as the abyssal nature of the living species. A large part of the evolutionary history of the lineage remains to be discovered and will likely prove more complicated and interesting than afforded by the living fossil designation.

Though difficult to quantify, chemicals in agricultural and urban runoff are contributing to population declines of commercially valuable marine species. Although these pollutants may not be immediately lethal to marine organisms, they can impair key biological processes, hindering reproduction and causing early death.

Many marine invertebrates use adhesive secretions to attach to underwater surfaces and functional groups borne by their adhesive proteins and carbohydrates, such as catechols and phosphates, play a key role in adhesion. The occurrence of sulfates as recurrent moieties in marine bioadhesives suggests that they could also be involved. However, in most cases, their presence in the adhesive material remains speculative. We investigated the presence of sulfated biopolymers in five marine invertebrates representative of the four types of adhesion encountered in the sea: mussels and tubeworms for permanent adhesion, limpets for transitory adhesion, sea stars for temporary adhesion and sea cucumbers for instantaneous adhesion. The dry adhesive material of mussels, sea stars and sea cucumbers contained about 1% of sulfate. Using anti-sulfotyrosine antibodies and Alcian Blue staining, sulfated proteins and sulfated proteoglycans and/or polysaccharides were identified in the secretory cells and adhesive secretions of all species except the tubeworm. Sulfated proteoglycans appear to play a role only in the non-permanent adhesion of sea stars and limpets in which they could mediate cohesion within the adhesive material. In mussels and sea cucumbers, sulfated biopolymers would rather have an anti-adhesive function, precluding self-adhesion.

The red-blooded limpet ' Shinkailepas ' briandi (Neritimorpha: Phenacolepadidae) is one of the commonest gastropod species at deep-sea hydrothermal vents on the Mid-Atlantic Ridge (MAR). We investigated its population connectivity along MAR as the first such study for gastropods and explored the importance of larval migration for the distribution of vent-endemic animals. Our analyses, based on 1.3-kbp DNA sequences from the mitochondrial COI gene, showed a panmictic population throughout its geographic and bathymetric ranges that span from the northernmost and shallowest Menez Gwen vent field (38°N; 814–831 m depth) to the southernmost and deepest Ashadze field (13°N; 4090 m). Early development of this species is presumed to have a long pelagic duration as a planktotrophic larva; the hatchling with a shell diameter of 170–180 μm attains a constant settlement size of 706 ± 8 μm (mean ± SD). Retention of eye pigmentation in newly settled juveniles, along with the genetic panmixia, suggests that the hatched larva of ' S. ' briandi migrates vertically to the surface water, presumably to take advantage of richer food supplies and stronger currents for dispersal, as has been shown for confamilial species at hydrothermal vents and cold methane seeps. [ABSTRACT FROM AUTHOR]

A native strain of the entomopathogenic fungus Beauveria bassiana (Bb-C001) was isolated from a naturally infected Triatoma infestans, Klug (Hemiptera: Reduviidae) adult cadaver in the Gran Chaco region, Salta province, Argentina. The isolate was both phenotypic and molecularly characterized in a context of fungus-insect interaction, by measuring the expression pattern of toxin genes during infection and immune response of T. infestans. The commercial strain GHA of B. bassiana, which was previously used in field interventions to control these vectors, was used as reference in this study. The phylogenetic trees based on both ribosomal internal transcribed spacer (ITS) and elongation factor 1-alpha (EF1-α) indicated that Bb-C001 fits into a B. bassiana cluster, and the sequence-characterized amplified regions (SCAR) showed that Bb-C001 is different from the GHA strain. There were no differences between both strains regarding viability, radial growth, and conidia production, either in the median survival time or insect mortality. However, Bb-C001 showed a higher expression than GHA of the bassianolide synthetase gene (BbbslS) during infection, and similar levels of the beauvericin synthetase gene (BbbeaS). Immune-related genes of T. infestans nymphs (limpet-2 and defensin-1, -2, and -6) were later expressed and thus insects failed to stop the infection process. These results showed that B. bassiana Bb-C001 is a promised fungal strain to be incorporated in the current biological control programs of T. infestans in Salta province, Argentina.

Limpet (Scutellastra cochlear) serves as seafood recipe and an important member of the aquatic food chain. It is an abundant mollusc in some aquatic environment in South Africa. In this study, we investigated the potential of the molluscs harvested from the Buffalo, Swartkops, and Kowie estuaries in the Eastern Cape Province, South Africa to serve as transient or maintenance reservoir of Vibrio species. The mollusc and source water samples were collected monthly from the rivers between December 2016 and November 2017. The reservoir category of the limpet samples recovered was determined by employing the combination of MPN-PCR method and statistical analysis (comparison of mean and proportion tests). The densities of Vibrio spp. in limpet and their source water samples were determined using MPN-PCR methods. Presumptive isolates were recovered by processing the samples with thiosulfate-citrate-bile salts-sucrose agar and where necessary, samples were enriched with alkaline peptone water. The presumptive isolates were identified using PCR methods with emphasis on six Vibrio species of public health importance. Vibrio spp. were detected in all the limpet samples but not in all the water samples. The densities of Vibrio spp. in the limpet samples were more than the densities of Vibrio species in their source water and these were significant at P < 0.05. In like manner, five out of the six key Vibrio pathogens targeted in this study were more prevalent in limpet samples than in source water samples. Based on our findings, we concluded that our method though could be improved on, is efficient for the determination of reservoir types of bacterial-carrying organisms. We also concluded that the limpet found in the estuaries are not just a transient but a maintenance reservoir of Vibrio spp. which could cause vibrio-related infections.

Background & objectives: Vector ecology and taxonomy of snails is a prerequisite for controlling schistosomiasis in the tropics. The ecology of the freshwater limpet genus Ferrissia was investigated for detection of cercariae larvae in them, and taxonomic description of a new species of the genus Ferrissia. Methods: This study was conducted in 15 perennial streams from five different hills of south India. To study the seasonal patterns, a stream from each hill was selected and sampled in three seasons. In each study site, triplicate sampling was done and specimens were collected from stream substrates as well as waste material submerged in stream. Microscopic examination was carried out for detecting cercariae larvae in limpets. Results: Three freshwater limpets (F. tenuis, F. verruca and F. fivefallsiensis) were observed. Seasonality influenced the abundance of limpets. The highest abundance was observed during post-monsoon (December and January). The distribution of Ferrissia was observed at riffle in pebbles, leaf litter and wastes (polyethylene bags and snacks cover) submerged in water. No cercariae larvae were found from the body of limpets. In this study, we described a new species of Ferrissia fivefallsiensis. Interpretation & conclusion: Our results showed the distribution, habitat preference and seasonality of limpets, and recommend the detection of Schistosoma from limpets as well as human samples by use of molecular tools.

Abstract: Aim: To examine the role of ocean temperature and chemistry as drivers of interpopulation differences in multiple phenotypic traits between rear and leading edge populations of two species of limpet. Location: The coast of north‐central Chile, western South America. Taxon: Mollusca, Gastropoda (Lottidae). Methods: We used field and laboratory experiments to study the ecology and physiology of individuals from populations located at the overlap of the rear and leading edges of their respective geographical distributions. At the same time, we characterized local environmental regimes, measuring seawater physical and chemical properties. Results: Towards the edge of their range, individuals from the leading edge species gradually reduced their shell length, metabolic rate and thermal response capacity, and increased carbonate content in their shells. Individuals of the rear edge species showed dissimilar responses between sites. Contrasting behavioural responses to experimental heating reconciled observations of an unintuitive higher maximal critical temperature and a smaller thermal safety margin for individuals of the rear edge populations. Physical–chemical characterization of seawater properties at the site located on the core of the upwelling centre showed extreme environmental conditions, with low oxygen concentration, high pCO2 and the episodic presence of corrosive seawater. These challenging environmental conditions were reflected in reduced growth for both species. Main conclusions: We found different spatial patterns of phenotypic plasticity in two sister species around the leading and trailing edges of their distributions. Our results provide evidence that environmental conditions around large upwelling centres can maintain biogeographical breaks through metabolic constraints on the performance of calcifying organisms. Thus, local changes in seawater chemistry associated with coastal upwelling circulation emerge as a previously overlooked driver of marine range edges. [ABSTRACT FROM AUTHOR]

Fracture toughness is an important property for many biological materials, but it can be difficult to obtain accurate and relevant values of toughness in such materials owing to complexities of geometry, material anisotropy, etc. Here we present the results of the first ever attempt to describe and measure cracking and fracture toughness in the shells of limpets. Three different experiments were devised. Firstly, small single-edge-notched bend specimens were machined, enabling us to measure K IC for through-thickness cracks growing in the circumferential direction in the shell walls, giving a value of 0.98 MPa√m. Secondly, radial notches were cut into intact shells which were loaded in compression through the apex. Failure occurred by crack propagation from the notch roots, and finite element analysis (FEA) was used to obtain critical K values. However the analysis gave a surprisingly high toughness value and the results were very sensitive to test variables, especially friction. The experiment demonstrated the remarkable resistance of shells to this kind of damage, but could not be used to measure K IC. Thirdly, impact tests were carried out to create internal damage in the form of delamination cracks. This allowed us to estimate toughness in terms of a crack propagation energy G IC for these cracks of 146 J/m 2 , equivalent to a K IC of 2.59 MPa√m. Scanning electron microscopy showed that the delamination cracks had much smoother fracture surfaces than those from the through-thickness cracks, however they displayed a regular structure of folds or pleats at the 100 nm scale which may act to hinder crack face movements during shear/compression loading as occurs under impact, which is a common cause of damage for these shells in their natural surroundings. [ABSTRACT FROM AUTHOR]

Abstract: Molluscan aquaculture produces the most food fish by volume in the global mariculture market. The historical, cultural and ecological value of molluscs makes them a highly sought‐after delicacy in many regions of the world. Specifically, the aquaculture of abalone and that of limpets are two key industries with striking similarities and importance within the context of food production and food security. In this review, the current knowledge of these two commercially important seafood species is explored for a comprehensive understanding of its aquaculture status. The various culture methods and systems, animal nutrition and necessary improvements are discussed for abalone and limpets, respectively. For abalone, the knowledge base is extensive and some reviews have been written to compile essential information regarding different aspects of this healthy industry. For limpets, there is a small collection of aquaculture literature, and this is, to the authors’ knowledge, the first comprehensive review of the research. Our goal was to reveal, within the area of aquaculture research, the current status of both abalone and limpet industries while exposing their respective knowledge gaps for appropriate development of new technologies. With a firm understanding of these molluscs, the production of abalone and limpet will be sustainable for the long term. [ABSTRACT FROM AUTHOR]

Highly diverse dienoic fatty acids (FA), especially non‐methylene‐interrupted (NMI) FA, have been recognized in triacylglycerols (TAG) and polar lipids of ovaries of the limpet Cellana toreuma. To gain additional insights into the structural diversity of FA in ovaries, this study aimed to clarify previously undescribed minor monoenoic FA isomers and unidentified minor NMI FA by combined argentation thin‐layer chromatography (TLC) and gas chromatography–mass spectrometry (GC‐MS) of their 3‐pyridylcarbinol derivatives. A total 66 monoenoic FA from C14 to C22, including 12 branched‐chain FA, were identified. A surprising finding was a series of 13 heptadecenoic acids with double bonds at either Δ5, Δ6, Δ7, Δ8, Δ9, Δ10, Δ11, Δ12, Δ13, Δ15, or Δ16 positions. Besides previously identified NMI FA, 7,18‐nonadecadienoic (19:2Δ7,18), 9,18‐nonadecadienoic (19:2Δ9,18), 11,18‐nonadecadienoic (19:2Δ11,18), 7,20‐heneicosadienoic (21:2Δ7,20), and 11,20‐heneicosadienoic (21:2Δ11,20) acids, two novel related NMI FA, 5,16‐heptadecadienoic (17:2Δ5,16) and 7,16‐heptadecadienoic (17:2Δ7,16) acids, were found in TAG. These findings could provide new insights into clarifying the biological characteristics of marine NMI FA. [ABSTRACT FROM AUTHOR]

The oxygen isotope composition (δ 18 O) recorded in shells of the gastropods Patella candei crenata and Phorcus atratus from the Canary Islands (27–29°N) potentially provide invaluable high-resolution paleoclimatic data. However, because these two species have never been studied isotopically, it is necessary to calibrate and validate this approach by using live-collected specimens that can be compared to present-day climate data. For P. candei crenata , live organisms were collected at 15-day intervals for nearly one year (between 2011 and 2012) from the rocky-intertidal coast of SE Tenerife along with sea surface temperatures (SST) and seawater δ 18 O values. The δ 18 O values of the last growth episode along the shell growth margin, representing the conditions when organisms were collected, illustrate that P. candei crenata δ 18 O values were 1.3 ± 0.2‰ higher than expected values from isotopic equilibrium. This finding resulted in estimated SST 5.7 ± 0.6 °C lower than observed values. This offset or “vital effect” is uniform and predictable, and therefore can be corrected by subtracting 1.3‰ from the measured shell δ 18 O value. Adjusted temperatures from the shell coincided with observed SST in the study area. Therefore, Patella candei crenata shells are reliable repositories of SST data, in agreement with other species of Patella from higher latitudes. For Phorcus atratus , a live specimen was analyzed isotopically along shell-growth direction. The intrashell δ 18 O values showed the entire range of measured SST in the region without an apparent “vital effect”, in correspondence with other Phorcus species from the Mediterranean. Both Patella candei crenata and Phorcus atratus are common components of archaeological and Pleistocene-Holocene paleontological sites across the Canary Archipelago. This study suggests that well-preserved shells of these two taxa retrieved from ancient settings have the capacity to serve as excellent high-resolution paleotemperature archives for the tropical/subtropical eastern Atlantic region. [ABSTRACT FROM AUTHOR]

In our previous study, unusual odd-numbered dienoic acids with a terminal olefin were found as minor components in ovaries of the Japanese limpet Cellana toreuma, and the synthetic interests have been focused onto their structural confirmation and the inspection into their potential biological activity. Here, we describe an efficient and stereoselective total synthesis of two new unusual dienoic acids, 19:2∆7,18 and 21:2∆7,20, through a common pathway involving the strategic combination of alkyne-zipper reaction and Lindlar hydrogenation for the construction of their unique carbon chains. In our synthetic study, 2-propyn-1-ol was at first subjected to alkylation and alkyne-zipper reaction to form the two fragments, and the subsequent carbon chain elongation was achieved by the usual coupling reaction to obtain the C-19 and C-21 products bearing an internal acetylenic group. Then, the internal acetylenic group of these products was subjected to Lindlar hydrogenation to form a Z-alkenyl moiety, and the subsequent deprotection of the products was carried out under an acidic condition without isomerization of the internal Z-alkenyl group. Total synthesis of target fatty acids, 19:2∆7,18 and 21:2∆7,20, was finally accomplished by two-step oxidation of the resulting alcohols into carboxylic acids in a highly chemoselective manner, and the structures of these unusual natural fatty acids were finally elucidated by identifying the GC-MS spectra of the methyl esters of authentic and synthetic fatty acids. [ABSTRACT FROM AUTHOR]

The strength and direction of interspecific interactions governing communities is expected to change with increasing global temperatures. However, in many ecosystems it remains unclear which species interactions are most likely to be altered under increasing thermal stress and what impacts, if any, such altered interactions will have on community structure. We investigated the interactive effects of increased temperature and altered species interactions on the structure of a rocky intertidal community by deploying black and white plates in areas with or without the dominant grazer, the limpet Cellana tramoserica . Plates effectively manipulated substratum temperature, whilst anti-fouling paint effectively manipulated the strength of algal-herbivore interactions. Plates without C. tramoserica quickly developed and maintained abundant macroalgal assemblages irrespective of thermal stress. By contrast, the abundance of barnacles remained relatively low and did not differ across thermal treatments, although they were slightly more abundant in plots where C. tramoserica had been excluded. These results support recent findings that altered species interactions are anticipated to have greater effects on community structure than the direct impacts of warming, challenging the view community structure under warming climatic conditions can be predicted from individual responses of populations to increasing thermal stress. Based on these and other recent findings we therefore advocate for greater inclusion of biotic interactions into climate change models that aim to predict the state of future ecological communities. [ABSTRACT FROM AUTHOR]