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Exploring the use of Cytochrome Oxidase c Subunit 1 (COI) for DNA barcoding of free-living marine nematodes
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Background: The identification of free-living marine nematodes is difficult because of the paucity of easily scorable diagnostic morphological characters. Consequently, molecular identification tools could solve this problem. Unfortunately, hitherto most of these tools relied on 18S rDNA and 28S rDNA sequences, which often lack sufficient resolution at the species level. In contrast, only a few mitochondrial COI data are available for free-living marine nematodes. Therefore, we investigate the amplification and sequencing success of two partitions of the COI gene, the M1-M6 barcoding region and the I3-M11 partition. Methodology: Both partitions were analysed in 41 nematode species from a wide phylogenetic range. The taxon specific primers for the I3-M11 partition outperformed the universal M1-M6 primers in terms of amplification success (87.8\% vs. 65.8\%, respectively) and produced a higher number of bidirectional COI sequences (65.8\% vs 39.0\%, respectively). A threshold value of 5\% K2P genetic divergence marked a clear DNA barcoding gap separating intra-and interspecific distances: 99.3\% of all interspecific comparisons were 〉0.05, while 99.5\% of all intraspecific comparisons were 〈0.05 K2P distance. Conclusion: The I3-M11 partition reliably identifies a wide range of marine nematodes, and our data show the need for a strict scrutiny of the obtained sequences, since contamination, nuclear pseudogenes and endosymbionts may confuse nematode species identification by COI sequences.
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Exploring the use of micro-computed tomography (micro-CT) in the taxonomy of sea cucumbers: a case-study on the gravel sea cucumber Neopentadactyla mixta (Östergren, 1898) (Echinodermata, Holothuroidea, Phyllophoridae)
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RBINS Staff Publications 2021
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Extension of the phasmid genus Presbistus to Cambodia with a new species and notes on genitalia and captive breeding (Phasmida, Aschiphasmatidae, Aschiphasmatinae)
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RBINS Staff Publications 2022 OA
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Extraordinary morphological changes in valve morphology during the ontogeny of several species of the Australian ostracod genus Bennelongia (Crustacea, Ostracoda)
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RBINS Staff Publications
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Extreme convergence in egg-laying strategy across insect orders
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RBINS Staff Publications
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Extreme drought periods can change spatial effects on periphytic ostracod metacommunities in river-floodplain ecosystems
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Hydrological regimes are seasonally variable in river-floodplain ecosystems. Thus, since in these environments the local and regional factors change at different temporal scales, factors structuring metacommunities might also differ over time. However, temporal dynamics of metacommunities have rarely been assessed. Here, we investigated the influence of environmental and spatial factors over time on the metacommunity structuring of periphytic ostracods in the river-floodplain system of the Upper Paraná River (Brazil). The spatial factors turned out to be more important than environmental factors, and differences in the percentage of explanation of the factors structuring ostracod metacommunities over time were significant, mainly during extreme drought period. Our results showed that the high spatial influence might be related to the low connectivity amongst environments during such extreme drought period, which can increase dispersal limitation, and consequently can increase the turnover of ostracod species throughout the region, leading to a higher beta-diversity of ostracod metacommunities.
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RBINS Staff Publications 2019
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Extreme tolerance of sexual and parthenogenetic resting eggs of Eucypris virens (Crustacea, Ostracoda).
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RBINS Staff Publications
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Extreme tolerance ot environmental stress of sexual and parthenogenetic resting eggs of Eucypris virens (Crustacea, Ostracoda)
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RBINS Staff Publications
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Factors affecting the divergence of mate recognition systems in the Limnocytherinae (Crustacea, Ostracoda). In: HORNE, D.J. & MARTENS K. (eds.) Proceedings of the XIII International Symposium on Ostracoda
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RBINS Staff Publications
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Factors affecting the metacommunity structure of periphytic ostracods (Crustacea, Ostracoda): a deconstruction approach based on biological traits
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Metacommunity studies using the deconstruction approach based on biological traits have received a great deal of attention in recent years as they often better describe characteristics of the species that reflect adaptations to a specific environment. This approach has not yet been used for ostracods, which are nevertheless highly diverse crustaceans and abundant in continental aquatic environments. Here, we investigate the influence of environmental and spatial factors on the metacommunity structure of periphytic ostracods in 27 tropical floodplain lakes in the Upper Paraná River floodplain (Brazil). An analysis of variance partitioning was used to estimate the relative importance of these factors (environmental and spatial) on both the entire community as well as after its deconstruction according to the biological traits (size and locomotion mode). Ostracods, regardless of body size, are good dispersers at regional scales. In addition, as expected, swimming ostracods were better dispersers at local scales than non-swimmers, which were influenced mainly by the diversity of aquatic macrophytes. Environmental factors (species sorting mechanism) seem important in structuring the entire ostracods metacommunity, as well as for most categories of biological traits. The unexplained variability remained high showing that other variables, not measured here, must be important. The analysis based on deconstruction, when compared to the analysis based on the metacommunity as a whole, contributed to a better assessment of ostracod metacommunity structuring.
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RBINS Staff Publications 2018
