A new genus, Pygmaeomyces, and two new species are described based on phylogenetic analyses and phenotypic and ecological characters. The species delimitation was based on concordance of gene genealogies. The Pygmaeomyces cultures were isolated from the roots of mountain laurel (Kalmia latifolia) and pitch pine (Pinus rigida) from the acidic and oligotrophic New Jersey pygmy pine plains; however, they likely have a broader distribution because their internal transcribed spacer (ITS) sequences have high similarity to a number of environmental sequences from multiple independent studies. Based on the phylogeny and phenotypic characters, a new family, Pygmaeomycetaceae, is proposed to accommodate this new lineage in Mucoromycotina. Pygmaeomycetaceae corresponds to Clade GS23, which was identified based on a sequence-only soil fungal survey and was believed to be a distinct new class. Compared with the culture-based methods, we observed that sequence-only analyses tend to overestimate the taxonomic level. Results from this work will facilitate ecological and evolutionary studies on root-associated fungi.

中文翻译：

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Pygmaeomycetaceae，侏儒松平原毛霉菌属中的一个新的根相关科

基于系统发育分析以及表型和生态特征描述了一个新属 Pygmaeomyces 和两个新物种。物种划分是基于基因谱系的一致性。Pygmaeomyces 培养物是从来自酸性和贫营养的新泽西侏儒松平原的山月桂（Kalmia latifolia）和松树（Pinusrigida）的根中分离出来的；然而，它们可能具有更广泛的分布，因为它们的内部转录间隔 (ITS) 序列与来自多个独立研究的许多环境序列具有高度相似性。基于系统发育和表型特征，提出了一个新的家庭，Pygmaeomycetaceae，以适应毛霉菌纲中的这个新谱系。Pygmaeomycetaceae 对应于 Clade GS23，这是基于仅序列土壤真菌调查确定的，并被认为是一个独特的新类别。与基于培养的方法相比，我们观察到仅序列分析倾向于高估分类水平。这项工作的结果将促进对根相关真菌的生态和进化研究。