02459nas a2200181   4500008004100000245017300041210006900214260008800283300001300371490000700384520166800391100001602059700001902075700002002094700001302114700001302127856013702140       2007                        eng d00aColonization patterns of Nematoda on decomposing algae in the estuarine environment: Community assembly and genetic structure of the dominant species Pellioditis marina0 aColonization patterns of Nematoda on decomposing algae in the es  a5400 BOSQUE BLVD, STE 680, WACO, TX 76710-4446 USAbAMER SOC LIMNOLOGY OCEANOGRAPHY  a992-10010 v523 aWe performed a field experiment in the Westerschelde Estuary (The Netherlands) to characterize the colonization dynamics of nematodes in relation to the proximity of a source population and to local environmental conditions. The effects of colonization on the population genetic structure of the dominant species, Pellioditis marina, were simultaneously investigated. Two contrasting sites, each containing four patches with defaunated algae, were sampled seven times during 1 month. Site A was situated amidst Fucus stands, which permanently harbor P. marina, while site B was approximately 100 m from any source population and experienced more stressful environmental conditions. We hypothesized that (1) colonization in site A would proceed faster than in site B and that (2) founder events and genetic bottlenecks would affect population genetic structure and differentiation at site B more than at site A. We screened 992 individuals for variation in 426 base pairs of the cytochrome oxidase c subunit 1 gene with the single-strand conformation polymorphism method. The algal deposits at site A were indeed more rapidly colonized and reached fivefold higher densities of nematodes than those in site B. Haplotype composition in site A was very similar to that of the source population, while rare haplotypes were abundant and genetic diversity was lower in site B. We conclude that founder effects and genetic bottlenecks structured the populations in site B. The genetic differences between patches in each site further indicate that effective migration in P. marina is low and that priority effects influence the genetic structure of P. marina populations.1 aDerycke, S.1 aVan Vynckt, R.1 aVanoverbeke, J.1 aVincx, M1 aMoens, T  uhttps://nematoda.myspecies.info/content/colonization-patterns-nematoda-decomposing-algae-estuarine-environment-community-assembly-an02492nas a2200289   4500008004100000245014900041210006900190260007600259300000900335490000800344520150100352653000801853653000901861653001701870653001801887653001301905653000801918653002301926653001901949100001601968700001601984700001902000700002002019700001302039700001302052856013702065       2008                        eng d00aDisentangling taxonomy within the Rhabditis (Pellioditis) marina (Nematoda, Rhabditidae) species complex using molecular and morphological tools0 aDisentangling taxonomy within the Rhabditis Pellioditis marina N  a9600 GARSINGTON RD, OXFORD OX4 2ZG, OXON, ENGLANDbBLACKWELL PUBLISHING  a1-150 v1523 aCorrect taxonomy is a prerequisite for biological research, but currently it is undergoing a serious crisis, resulting in the neglect of many highly diverse groups of organisms. In nematodes, species delimitation remains problematic due to their high morphological plasticity. Evolutionary approaches using DNA sequences can potentially overcome the problems caused by morphology, but they are also affected by theoretical flaws. A holistic approach with a combination of morphological and molecular methods can therefore produce a straightforward delimitation of species. The present study investigates the taxonomic status of some highly divergent mitochondrial haplotypes in the Rhabditis (Pellioditis) marina species complex by using a combination of molecular and morphological tools. We used three molecular markers (COI, ITS, D2D3) and performed phylogenetic analyses. Subsequently, morphometric data from nearly all lineages were analysed with multivariate techniques. We included R. (P.) mediterranea and R. (R.) nidrosiensis to infer species status of the observed lineages. The results showed that highly divergent genotypic clusters were accompanied by morphological differences, and we created a graphical polytomous key for identifications. This study indisputably demonstrates that R. (P.) marina and R. (P.) mediterranea belong to a huge species complex and that biodiversity in free-living marine nematodes may be seriously underestimated. (C) 2008 The Linnean Society of London.10aCOI10aD2D310adelimitation10aDNA-barcoding10aholistic10aITS10aPellioditis marina10apolytomous key1 aDerycke, S.1 aFonseca, G.1 aVierstraete, A1 aVanfleteren, J.1 aVincx, M1 aMoens, T  uhttps://nematoda.myspecies.info/content/disentangling-taxonomy-within-rhabditis-pellioditis-marina-nematoda-rhabditidae-species-comp