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Mitchell, Edward
Résultat de la recherche
Ribosomal RNA genes challenge the monophyly of the hyalospheniidae (Amoebozoa : Arcellinida)
2008, Lara, Enrique, Heger, Thierry J, Ekelund, Flemming, Lamentowicz, Mariusz, Mitchell, Edward
To date only five partial and two complete SSU rRNA gene sequences are available for the lobose testate amoebae (Arcellinida). Consequently, the phylogenetic relationships among taxa and the definition of species are still largely dependant on morphological characters of uncertain value, which causes confusion in the phylogeny, taxonomy and the debate on cosmopolitanism of free-living protists. Here we present a SSU rRNA-based phylogeny of the Hyalospheniidae including the most common species. Similar to the filose testate amoebae of the order Euglyphida the most basal clades have a terminal aperture; the ventral position of the pseudostome appears to be a derived character. Family Hyalospheniidae appears paraphyletic and is separated into three clades: (1) Heleopera sphagni, (2) Heleopera rosea and Argynnia dentistoma and (3) the rest of the species from genera Apodera, Hyalosphenia, Porosia and Nebela. Our data support the validity of morphological characters used to define species among the Hyalospheniidae and even suggest that taxa described as varieties may deserve the rank of species (e.g. N. penardiana var. minor). Finally our results suggest that the genera Hyalosphenia and Nebela are paraphyletic, and that Porosia bigibbosa branches inside the main Nebela clade. (c) 2007 Elsevier GmbH. All rights reserved.
The Revised Classification of Eukaryotes
, Adl, Sina M., Simpson, Alastair G. B., Lane, Christopher E., Lukeš, Julius, Bass, David, Bowser, Samuel S., Brown, Matthew W., Burki, Fabien, Dunthorn, Micah, Hampl, Vladimir, Heiss, Aaron, Hoppenrath, Mona, Lara, Enrique, le Gall, Line, Lynn, Denis H., McManus, Hilary, Mitchell, Edward, Mozley-Stanridge, Sharon E., Parfrey, Laura W., Pawlowski, Jan, Rueckert, Sonja, Shadwick, Laura, Schoch, Conrad L., Smirnov, Alexey, Spiegel, Frederick W.
This revision of the classification of eukaryotes, which updates that of Adl et al. [J. Eukaryot. Microbiol. 52 (2005) 399], retains an emphasis on the protists and incorporates changes since 2005 that have resolved nodes and branches in phylogenetic trees. Whereas the previous revision was successful in re-introducing name stability to the classification, this revision provides a classification for lineages that were then still unresolved. The supergroups have withstood phylogenetic hypothesis testing with some modifications, but despite some progress, problematic nodes at the base of the eukaryotic tree still remain to be statistically resolved. Looking forward, subsequent transformations to our understanding of the diversity of life will be from the discovery of novel lineages in previously under-sampled areas and from environmental genomic information.