Nivicolous Trichiales from the austral Andes: unexpected diversity including two new species

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.

KEYWORDS:

• Amoebozoa
• Argentina
• Chile
• Myxomycetes
• neotropics
• SEM
• species distribution
• 2 new taxa

ACKNOWLEDGMENTS

We thank Marianne Meyer and the curators of the following herbaria: AH, BM, BPI, BR, KR, KRAM, M, MA, and O, for loan of the comparative material, Yolanda Ruiz and Anna Łatkiewicz for their technical assistance with SEM, Carlos de Mier for his help with the photographs, Anna-Maria Fiore-Donno for making available an alignment of the bright-spored phylogeny published by Fiore-Donno et al. (2013), Michał Ronikier for a critical reading of the manuscript, and two anonymous reviewers and especially the editor, P. Brandon Matheny, for valuable comments improving this study.

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Funding

This research was supported by the Spanish government (grants CGL2014-52584P and PGC2018-094660-B-I00), the Polish National Science Centre (grant N N303 799440), the statutory fund of the W. Szafer Institute of Botany of the Polish Academy of Sciences, and the SYNTHESYS Project financed by European Community Research Infrastructure Action under the FP7 “Capacities” Program at Real Jardín Botánico (CSIC), granted to Anna Ronikier (ES-TAF 160).