Via Vittorio Locchi 42, 34143, Trieste, Italy.
Research Department, Meise Botanic Garden, Nieuwelaan 38, 1860, Meise, Belgium.
J Eukaryot Microbiol. 2020 May;67(3):327-336. doi: 10.1111/jeu.12783. Epub 2020 Jan 21.
Myxomycetes (also called Myxogastria or colloquially, slime molds) are worldwide occurring soil amoeboflagellates. Among Amoebozoa, they have the notable characteristic to form, during their life cycle, macroscopic fruiting bodies, that will ultimately release spores. Some 1,000 species have been described, based on the macroscopic and microscopic characteristics of their fruiting bodies. We were interested in Physarum pusillum (Berk. & M.A. Curtis) G. Lister, a very common species described with two variants, each bearing such morphological differences that they could represent two distinct species. In order to test this, we observed key characters in a large selection of specimens attributed to P. pusillum, to its synonyms (in particular Physarum gravidum), and to related species. In addition, the small-subunit ribosomal RNA gene was obtained from seven of these specimens. Based on these data, we provide a comprehensive phylogeny of the order Physarida (Eukaryota: Amoebozoa: Conosa: Macromycetozoa: Fuscisporidia). Morphology and phylogeny together support the reinstatement of P. gravidum Morgan 1896 with a neotype here designated, distinct from P. pusillum, here redefined.
粘菌（也称为粘菌或通俗地称为粘菌）是广泛存在于土壤中的阿米巴鞭毛虫。在变形虫动物界中，它们具有一个显著的特征，即在其生命周期中形成宏观的子实体，最终释放孢子。目前已经描述了大约 1000 种物种，这些物种是基于其子实体的宏观和微观特征来区分的。我们对小光盖伞菌（Physarum pusillum (Berk. & M.A. Curtis) G. Lister）感兴趣，这是一种非常常见的物种，有两个变体，每个变体都有如此明显的形态差异，以至于它们可能代表两个不同的物种。为了验证这一点，我们观察了大量属于小光盖伞菌及其同义词（特别是 P. gravidum）以及相关物种的标本的关键特征。此外，我们还从其中的七个标本中获得了小亚基核糖体 RNA 基因。基于这些数据，我们提供了一个包含 Physarida 目（真核生物：变形虫动物界：Conosa：Macromycetozoa：Fuscisporidia）的综合系统发育。形态学和系统发育共同支持重新确立 P. gravidum Morgan 1896 的地位，并在此指定一个新的模式种，与 P. pusillum 不同，我们在这里重新定义了它。
