The Experts below are selected from a list of 8991 Experts worldwide ranked by ideXlab platform
Philippe Bouchet - One of the best experts on this subject based on the ideXlab platform.
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Global diversity of gastropods (Gastropoda; Mollusca) in freshwater
Freshwater Animal Diversity Assessment, 2008Co-Authors: Ellen E Strong, Winston F. Ponder, Olivier Gargominy, Philippe BouchetAbstract:The world’s gastropod fauna from continental waters comprises ∼4,000 valid described species and a minimum of 33–38 independent lineages of Recent Neritimorpha, CaenoGastropoda and Heterobranchia (including the Pulmonata). The caenogastropod component dominates in terms of species richness and diversity of morphology, physiology, life and reproductive modes and has produced several highly speciose endemic radiations. Ancient oligotrophic lakes (e.g., Baikal, Ohrid, Tanganyika) are key hotspots of gastropod diversity; also noteworthy are a number of lower river basins (e.g., Congo, Mekong, Mobile Bay). But unlike many other invertebrates, small streams, springs and groundwater systems have produced the most speciose associations of freshwater gastropods. Despite their ecological importance in many aquatic ecosystems, understanding of even their systematics is discouragingly incomplete. The world’s freshwater gastropod fauna faces unprecedented threats from habitat loss and degradation and introduced fishes and other pests. Unsustainable use of ground water, landscape modification and stock damage are destroying many streams and springs in rural/pastoral areas, and pose the most significant threats to the large diversity of narrow range endemics in springs and ground water. Despite comprising only ∼5% of the world’s gastropod fauna, freshwater gastropods account for ∼20% of recorded mollusc extinctions. However, the status of the great majority of taxa is unknown, a situation that is exacerbated by a lack of experts and critical baseline data relating to distribution, abundance, basic life history, physiology, morphology and diet. Thus, the already considerable magnitude of extinction and high levels of threat indicated by the IUCN Red List of Threatened Species is certainly a significant underestimate.
Casey W. Dunn - One of the best experts on this subject based on the ideXlab platform.
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Phylogenomic analyses of deep gastropod relationships reject OrthoGastropoda.
Proceedings of The Royal Society B: Biological Sciences, 2014Co-Authors: Felipe Zapata, Nerida G. Wilson, Mark Howison, Katharina M. Jörger, Freya E. Goetz, Michael Schrödl, Sonia C S Andrade, Casey W. DunnAbstract:Gastropods are a highly diverse clade of molluscs that includes many familiar animals, such as limpets, snails, slugs and sea slugs. It is one of the most abundant groups of animals in the sea and the only molluscan lineage that has successfully colonized land. Yet the relationships among and within its constituent clades have remained in flux for over a century of morphological, anatomical and molecular study. Here, we re-evaluate gastropod phylogenetic relationships by collecting new transcriptome data for 40 species and analysing them in combination with publicly available genomes and transcriptomes. Our datasets include all five main gastropod clades: PatelloGastropoda, VetiGastropoda, Neritimorpha, CaenoGastropoda and Heterobranchia. We use two different methods to assign orthology, subsample each of these matrices into three increasingly dense subsets, and analyse all six of these supermatrices with two different models of molecular evolution. All 12 analyses yield the same unrooted network connecting the five major gastropod lineages. This reduces deep gastropod phylogeny to three alternative rooting hypotheses. These results reject the prevalent hypothesis of gastropod phylogeny, OrthoGastropoda. Our dated tree is congruent with a possible end-Permian recovery of some gastropod clades, namely CaenoGastropoda and some Heterobranchia subclades.
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Phylogenomic analyses of deep gastropod relationships reject OrthoGastropoda
bioRxiv, 2014Co-Authors: Felipe Zapata, Nerida G. Wilson, Mark Howison, Katharina M. Jörger, Freya E. Goetz, Michael Schrödl, Sonia C S Andrade, Casey W. DunnAbstract:Gastropods are a highly diverse clade of molluscs that includes many familiar animals, such as limpets, snails, slugs, and sea slugs. It is one of the most abundant groups of animals in the sea and the only molluscan lineage that has successfully colonised land. Yet the relationships among and within its constituent clades have remained in flux for over a century of morphological, anatomical and molecular study. Here we re-evaluate gastropod phylogenetic relationships by collecting new transcriptome data for 40 species and analysing them in combination with publicly available genomes and transcriptomes. Our datasets include all five main gastropod clades: PatelloGastropoda, VetiGastropoda, Neritimorpha, CaenoGastropoda and Heterobranchia. We use two different methods to assign orthology, subsample each of these matrices into three increasingly dense subsets, and analyse all six of these supermatrices with two different models of molecular evolution. All twelve analyses yield the same unrooted network connecting the five major gastropod lineages. This reduces deep gastropod phylogeny to three alternative rooting hypotheses. These results reject the prevalent hypothesis of gastropod phylogeny, OrthoGastropoda. Our dated tree is congruent with a possible end-Permian recovery of some gastropod clades, namely CaenoGastropoda and some Heterobranchia subclades.
Steinar Vatne - One of the best experts on this subject based on the ideXlab platform.
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Contents of carbon based defence compounds in the old forest lichen Lobaria pulmonaria vary along environmental gradients
Fungal Ecology, 2011Co-Authors: Steinar VatneAbstract:Abstract We quantified carbon based secondary compounds (CBSC) in 182 Lobaria pulmonaria thalli sampled in a range of forest types along an elevation gradient in southern Norway to assess the importance of external and internal factors as a source of variation for the CBSC content. The best multiple regression model for CBSC content included altitude, soil pH, dry weight (DW) per area and thallus size. Total CBSC content decreased with altitude and increased with pH. L. pulmonaria maximizes its CBSC content in sites with long gastropod grazing seasons (lowland forests) and high gastropod abundance (calcareous soils). Secondly, we assessed grazing damage in the L. pulmonaria thalli to test the hypothesis that natural populations of gastropods respond to the CBSC level in situ . We found a significantly negative correlation between the stictic acid concentration and grazing damage from gastropods, which is consistent with an evolutionary arms race between lichens and gastropods. This relationship became stronger when using the tree trunk as a factor in the ANCOVA, consistent with spatial variation in gastropod occurrences.
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Grazing damage in the old forest lichen Lobaria pulmonaria increases with gastropod abundance in deciduous forests.
The Lichenologist, 2010Co-Authors: Steinar Vatne, Torstein SolhøyAbstract:Abstract: Gastropod abundance was quantified in forest litter around 33 trees harbouring Lobariapulmonaria in southern Norway. In total, 1709 snails representing 28 species were found, and thenumberofsnailspeciesstronglyincreasedwiththetotalnumberofspecimensfound.Numberofsnailspecies, as well as snail abundance, was highest around trees on high pH soils. There was a positiverelationship between number of snail specimens and cover of grazing traces on L. pulmonaria ,presumablybecausecalcareoussoilsfacilitatebothlitterdwellingandclimbinggastropods.Theresultssuggest that gastropods may limit the distribution of L. pulmonaria in calcareous broad-leaved forests. Key words: epiphytes, herbivory, leaf litter, pH, snails Introduction Some gastropods eat lichens, but the grazingimpact depends, among other factors, on thecontent of lichen compounds that have adeterringeffect(e.g.Zukal1895;Stahl1904;Lawrey 1980). As lichen compounds canbe non-destructively extracted from livinglichens (Solhaug & Gauslaa 2001), their de-terring effect can be quantified in experi-ments (Gauslaa 2005). Gastropod grazingdecreases with increasing concentration ofcertain lichen compounds such as the sticticacid complex in
Ellen E Strong - One of the best experts on this subject based on the ideXlab platform.
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Global diversity of gastropods (Gastropoda; Mollusca) in freshwater
Freshwater Animal Diversity Assessment, 2008Co-Authors: Ellen E Strong, Winston F. Ponder, Olivier Gargominy, Philippe BouchetAbstract:The world’s gastropod fauna from continental waters comprises ∼4,000 valid described species and a minimum of 33–38 independent lineages of Recent Neritimorpha, CaenoGastropoda and Heterobranchia (including the Pulmonata). The caenogastropod component dominates in terms of species richness and diversity of morphology, physiology, life and reproductive modes and has produced several highly speciose endemic radiations. Ancient oligotrophic lakes (e.g., Baikal, Ohrid, Tanganyika) are key hotspots of gastropod diversity; also noteworthy are a number of lower river basins (e.g., Congo, Mekong, Mobile Bay). But unlike many other invertebrates, small streams, springs and groundwater systems have produced the most speciose associations of freshwater gastropods. Despite their ecological importance in many aquatic ecosystems, understanding of even their systematics is discouragingly incomplete. The world’s freshwater gastropod fauna faces unprecedented threats from habitat loss and degradation and introduced fishes and other pests. Unsustainable use of ground water, landscape modification and stock damage are destroying many streams and springs in rural/pastoral areas, and pose the most significant threats to the large diversity of narrow range endemics in springs and ground water. Despite comprising only ∼5% of the world’s gastropod fauna, freshwater gastropods account for ∼20% of recorded mollusc extinctions. However, the status of the great majority of taxa is unknown, a situation that is exacerbated by a lack of experts and critical baseline data relating to distribution, abundance, basic life history, physiology, morphology and diet. Thus, the already considerable magnitude of extinction and high levels of threat indicated by the IUCN Red List of Threatened Species is certainly a significant underestimate.
Felipe Zapata - One of the best experts on this subject based on the ideXlab platform.
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Phylogenomic analyses of deep gastropod relationships reject OrthoGastropoda.
Proceedings of The Royal Society B: Biological Sciences, 2014Co-Authors: Felipe Zapata, Nerida G. Wilson, Mark Howison, Katharina M. Jörger, Freya E. Goetz, Michael Schrödl, Sonia C S Andrade, Casey W. DunnAbstract:Gastropods are a highly diverse clade of molluscs that includes many familiar animals, such as limpets, snails, slugs and sea slugs. It is one of the most abundant groups of animals in the sea and the only molluscan lineage that has successfully colonized land. Yet the relationships among and within its constituent clades have remained in flux for over a century of morphological, anatomical and molecular study. Here, we re-evaluate gastropod phylogenetic relationships by collecting new transcriptome data for 40 species and analysing them in combination with publicly available genomes and transcriptomes. Our datasets include all five main gastropod clades: PatelloGastropoda, VetiGastropoda, Neritimorpha, CaenoGastropoda and Heterobranchia. We use two different methods to assign orthology, subsample each of these matrices into three increasingly dense subsets, and analyse all six of these supermatrices with two different models of molecular evolution. All 12 analyses yield the same unrooted network connecting the five major gastropod lineages. This reduces deep gastropod phylogeny to three alternative rooting hypotheses. These results reject the prevalent hypothesis of gastropod phylogeny, OrthoGastropoda. Our dated tree is congruent with a possible end-Permian recovery of some gastropod clades, namely CaenoGastropoda and some Heterobranchia subclades.
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Phylogenomic analyses of deep gastropod relationships reject OrthoGastropoda
bioRxiv, 2014Co-Authors: Felipe Zapata, Nerida G. Wilson, Mark Howison, Katharina M. Jörger, Freya E. Goetz, Michael Schrödl, Sonia C S Andrade, Casey W. DunnAbstract:Gastropods are a highly diverse clade of molluscs that includes many familiar animals, such as limpets, snails, slugs, and sea slugs. It is one of the most abundant groups of animals in the sea and the only molluscan lineage that has successfully colonised land. Yet the relationships among and within its constituent clades have remained in flux for over a century of morphological, anatomical and molecular study. Here we re-evaluate gastropod phylogenetic relationships by collecting new transcriptome data for 40 species and analysing them in combination with publicly available genomes and transcriptomes. Our datasets include all five main gastropod clades: PatelloGastropoda, VetiGastropoda, Neritimorpha, CaenoGastropoda and Heterobranchia. We use two different methods to assign orthology, subsample each of these matrices into three increasingly dense subsets, and analyse all six of these supermatrices with two different models of molecular evolution. All twelve analyses yield the same unrooted network connecting the five major gastropod lineages. This reduces deep gastropod phylogeny to three alternative rooting hypotheses. These results reject the prevalent hypothesis of gastropod phylogeny, OrthoGastropoda. Our dated tree is congruent with a possible end-Permian recovery of some gastropod clades, namely CaenoGastropoda and some Heterobranchia subclades.
