ABSTRACT Nivicolous myxomycetes are a group of amoebozoan protists dependent on long-lasting snow cover worldwide. Recent fine-scale analysis of species diversity from the austral Andes revealed high intraspecific variability of most taxa, suggesting independent evolutionary processes and significant differences in species compositions between the Northern (NH) and Southern (SH) Hemispheres. The present study is the second part of this analysis based on representatives of Trichiales. A total of 173 South American collections were studied based on morphological and molecular data, and 15 taxa have been identified. Two of them, Hemitrichia crassifila and Perichaena patagonica, are proposed as new species confirmed by a phylogeny of Trichiales. However, their affinity to the genera in which they are proposed are not confirmed due to polyphyletic character of all genera of Trichiales. Four species, Dianema subretisporum, Trichia contorta var. karstenii, T. nivicola, and T. sordida, are reported for the first time from the Southern Hemisphere. One species, T. alpina, is new for Argentina. Additionally, we provide the first record of Perichaena megaspora from Chile. Specimen frequency and species diversity of Trichiales found at nivicolous localities in the austral Andes are unexpectedly high, exceeding those of Stemonitidales, the most numerous group in the Northern Hemisphere, where Trichiales play a marginal role. By contrast, Trichiales appear the main component of nivicolous assemblages in the Andes. Results of the present work, together with the earlier analysis of Stemonitidales, indicate that the Andes constitute an exceptionally important evolutionary hot spot for nivicolous myxomycetes characterized by an outstanding species diversity.

中文翻译：

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来自安第斯山脉南部的 Nivicolous Trichiales：意想不到的多样性，包括两个新物种

摘要 Nivicolous 粘菌是一群依赖于全球持久积雪的变形虫原生生物。最近对南安第斯山脉物种多样性的精细分析揭示了大多数分类群的高种内变异性，表明北半球 (NH) 和南半球 (SH) 之间存在独立的进化过程和物种组成的显着差异。本研究是基于 Trichiales 代表的分析的第二部分。根据形态学和分子数据研究了总共 173 个南美收藏，并确定了 15 个分类群。其中两个，Hemitrichia crassifila 和 Perichaena patagonica，被提议作为由 Trichiales 系统发育确认的新物种。然而，由于所有 Trichiales 属的多系特征，它们与提出它们的属的亲和力未得到证实。四种，Dianema subretisporum，Trichia contorta var。karstenii、T. nivicola 和 T. sordida 是首次从南半球报道。T. alpina 是阿根廷的新物种。此外，我们提供了智利 Perichaena megaspora 的第一个记录。在南安第斯山脉的 nivicolous 地区发现的 Trichiales 的样本频率和物种多样性出乎意料地高，超过了 Stemonitidales，这是北半球数量最多的群体，其中 Trichiales 发挥了边缘作用。相比之下，Trichiales 出现在安第斯山脉的 nivicolous 组合的主要组成部分。当前工作的结果，连同早先对 Stemonitidales 的分析，