Institute of Botany and Landscape Ecology, University of Greifswald, Greifswald, Germany.
PLoS One. 2012;7(4):e35359. doi: 10.1371/journal.pone.0035359. Epub 2012 Apr 18.
The phylogenetic position of the slime-mould genus Lamproderma (Myxomycetes, Amoebozoa) challenges traditional taxonomy: although it displays the typical characters of the order Stemonitales, it appears to be sister to Physarales. This study provides a small subunit (18S or SSU) ribosomal RNA gene-based phylogeny of Lamproderma and its allies, with new sequences from 49 specimens in 12 genera. We found that the order Stemonitales and Lamproderma were both ancestral to Physarales and that Lamproderma constitutes several clades intermingled with species of Diacheopsis, Colloderma and Elaeomyxa. We suggest that these genera may have evolved from Lamproderma by multiple losses of fruiting body stalks and that many taxonomic revisions are needed. We found such high genetic diversity within three Lamproderma species that they probably consist of clusters of sibling species. We discuss the contrasts between genetic and morphological divergence and implications for the morphospecies concept, highlighting the phylogenetically most reliable morphological characters and pointing to others that have been overestimated. In addition, we showed that the first part (~600 bases) of the SSU rDNA gene is a valuable tool for phylogeny in Myxomycetes, since it displayed sufficient variability to distinguish closely related taxa and never failed to cluster together specimens considered of the same species.
黏菌门（变形菌门，变形虫）的分类地位挑战了传统的分类学：尽管它显示出典型的 Stemonitales 目特征，但它似乎与 Physarales 目有关。本研究提供了基于小亚基（18S 或 SSU）核糖体 RNA 基因的 Lamproderma 及其近缘种的系统发育，包括来自 12 属 49 个标本的新序列。我们发现，Stemonitales 目和 Lamproderma 目都是 Physarales 的祖先，而 Lamproderma 目由几个分支组成，与 Diacheopsis、Colloderma 和 Elaeomyxa 的物种交织在一起。我们推测，这些属可能是通过多次失去子实体柄而从 Lamproderma 进化而来的，因此需要进行许多分类修订。我们发现三个 Lamproderma 种内存在如此高的遗传多样性，它们可能由姐妹种组成。我们讨论了遗传和形态分化之间的对比，以及对形态种概念的影响，强调了系统发育上最可靠的形态特征，并指出了其他被高估的特征。此外，我们表明，SSU rDNA 基因的第一部分（约 600 个碱基）是黏菌系统发育的有用工具，因为它具有足够的可变性，可以区分密切相关的分类群，而且从未未能将被认为是同一物种的标本聚在一起。
