NEMATODES

taxonomy, morphology and phylogeny

An improved molecular phylogeny of the Nematoda with special emphasis on marine taxa

Publication Type:Journal Article
Year of Publication:2007
Authors:B. H. M. Meldal, Debenham, N. J., De Ley, P., De Ley, I. T., Vanfleteren, J. R., Vierstraete, A. R., Bert, W., Borgonie, G., Moens, T., Tyler, P. A., Austen, M. C., Blaxter, M. L., Rogers, A. D., Lambshead, P. J. D.
Journal:Molecular Phylogenetics and EvolutionMolecular Phylogenetics and Evolution
Volume:42
Pagination:622-636
ISBN Number:1055-7903
Keywords:Adenophorea, analysis, Bayesian inference, BAYESIAN-INFERENCE, Chromadorea, CLASSIFICATION, DNA, DORYLAIMIDA, Enoplea, Evolution, FOSSIL EVIDENCE, Globodera, Hoplolaimidae, LogDet transformation, marine nematodes, MITOCHONDRIAL-DNA, N-SP, Nematoda, NEMATODE, nematodes, parsimony, phylogenetic reconstruction, PHYLOGENIES, phylogeny, PHYLUM NEMATODA, RHABDITIDA, RIBOSOMAL-RNA GENE, Secernentea, SEQUENCES, SSU rDNA, systematics, taxonomy
Abstract:

Phylogenetic reconstructions of relations within the phylum Nematoda are inherently difficult but have been advanced with the introduction of large-scale molecular-based techniques. However, the most recent revisions were heavily biased towards terrestrial and parasitic species and greater representation of clades containing marine species (e.g. Araeolaimida, Chromadorida, Desmodorida, Desmoscolecida, Enoplida, and Monhysterida) is needed for accurate coverage of known taxonomic diversity. We now add small subunit ribosomal DNA (SSU rDNA) sequences for 100 previously un-sequenced species of nematodes, including 46 marine taxa. SSU rDNA sequences for > 200 taxa have been analysed based on Bayesian inference and LogDet-transformed distances. The resulting phylogenies provide support for (i) the re-classification of the Secernentea as the order Rhabditida that derived from a common ancestor of chromadorean orders Araeolaimida, Chromadorida, Desmodorida, Desmoscolecida, and Monhysterida and (ii) the position of Bunonema close to the Diplogasteroidea in the Rhabditina. Other, previously controversial relationships can now be resolved more clearly: (a) Alaimus, Campydora, and Trischistoma belong in the Enoplida, (b) Isolaimium is placed basally to a big clade containing the Axonolaimidae, Plectidae, and Rhabditida, (c) Xyzzors belongs in the Desmodoridae, (d) Comesomatidae and Cyartonema belongs in the Monhysterida, (e) Globodera belongs in the Hoplolaimidae and (0 Paratylenchus dianeae belongs in the Criconematoidea. However, the SSU gene did not provide significant support for the class Chromadoria or clear evidence for the relationship between the three classes, Enoplia, Dorylaimia, and Chromadoria. Furthermore, across the whole phylum, the phylogenetically informative characters of the SSU gene are not informative in a parsimony analysis, highlighting the short-comings of the parsimony method for large-scale phylogenetic modelling. (c) 2006 Elsevier Inc. All rights reserved

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Scratchpads developed and conceived by (alphabetical): Ed Baker, Katherine Bouton Alice Heaton Dimitris Koureas, Laurence Livermore, Dave Roberts, Simon Rycroft, Ben Scott, Vince Smith