New insights into the phylogeny of the dark-spored Myxomycetes (Amoebozoa: Conosa: Myxogastria: Fuscisporidia) and polyphyly of the genus Stemonitis.

About a thousand described species of Myxomycetes, colloquially named slime molds, are present in most terrestrial habitats. Molecular environmental sampling has revealed that a significant proportion of sequences could not be assigned to known species, with some specific groups showing a high hidden diversity. One of such group included Stemonitis and allied genera, with only a few closely related reference sequences from known species and many distantly related sequences from environmental sampling. To improve the phylogeny and help defining genera in this lineage, we provided nine new small-subunit ribosomal RNA gene sequences of Stemonitis and allied genera, along with microscopical observations. We showed that the genus Stemonitis is polyphyletic, clearly separated into two groups, with the main distinguishing feature being spore ornamentation. The first group included the type species Stemonitis fusca, and was characterized by reticulate spores, while the second contained species with warted spores (e.g. S. flavogenita and S. axifera) and many undetermined environmental sequences. In addition, we show that the related genera Stemonitopsis, Stemonaria and Symphytocarpus were polyphyletic and that their circumscription was based on inconsistent characters. Instead, representatives of these genera clustered into the two clades according to their spore ornamentation. Our study provides a first insight in the genetic diversity of Stemonitis and allied genera and proposes spore ornamentation as an evolutionary informative character to distinguish genera in this group.

Jaar van publicatie:2020

Toegankelijkheid:Closed