First data on Myxomycetes of the State Nature Preserve “Sut-Khol”, Republic of Tuva (Tyva), Russia

First records of Myxomycetes from the Republic of Tuva, Russia, are presented. We identified 24 speci es of myxomycetes from 12 genera, 7 families and 4 orders in the State Natural Customer “Sut-Khol”. For the Republic of Tu va, 14 species of myxomycetes have been identified for the first time. Arcyria globosa, first identified on the bark of a live Сaragana in the Asian part of Russia using the “moist chamber”. We have also identified a rare species of Echinostelium fragile on the bark of a live Pinus sylvestris.


Introduction
Myxomycetes are fungus like protists with a unique life cycle that includes vegetative (trophic) and generative stages. The vegetative phase of the life cycle is represented by multinucleated plasmodium, mononuclear amebes or zoospores. Zoospores and amebes are two forms of the same stage, and the transition process occurs when the humidity of the environment changes. The fruit bodies of myxomycetes (sporangia, plasmodiocarps, etalia, pseudoethalia) look very similar to the miniature fruit bodies of fungi.
Myxomycetes are found in all terrestrial biomes where there are living plants or dead plant debris. In forests, myxomycetes inhabit large woody substrates -fallen tree trunks, stumps, fallen branches, coniferous and deciduous litter, bark of living woody plants, old fallen cones of coniferous trees, stems and leaves of herbaceous plants. In the steppes and deserts, the growth of myxomycetes is confined to periods of intense rains. Myxomycetes of arid biotopes are identified in laboratory conditions by the method of wet chambers, growing them on natural substrates containing cysts and sclerotia. The lower parts of perennial dwarf shrubs, grass litter, and herbivorous animal dung are used as substrates.
A little more than 1000 species of myxomycetes have now been identified in the world. About 455 species of myxomycetes are currently known in Russia [1].
The flora of higher plants and vegetation of the Republic of Tyva has been studied quite well [2][3][4], in contrast to myxomycetes. The study of myxomycetes of the Republic of Tuva was first started by us in 2020.

Materials and methods
In 2021, a study of myxomycetes was carried out in the State Natural Customer "Sut-Khol". The Natural Customer is located in the spurs of the Western Sayan, in the central part of the Sut-Khol kozhuun. On the studied territory the sporophores of myxomycetes were collected and substrates were selected for growing of myxomycetes in "moist chambers".
Species identification was carried out using a Stemi DV4 stereo microscope, Axiolab Ere and Zeiss Axio Imager A1 light microscopes (Carl Zeiss Microscopy, Germany) in CSBG SB RAS. For microscopy, sporocarps were preserved as permanent slides in polyvinyl lactophenol.

Results and Discussion
We identified 24 species of myxomycetes from 12 genera, 7 families, and 4 orders. Below is an annotated list of species, indicating the species of myxomycetes, habitats, substrates and herbarium numbers. The species of myxomycetes, first identified in the Republic of Tyva, are marked «*», new for Asian part of Russia -«**», records of other species have been published by us previously [6].

Conclusions
As a result of the studies carried out for the Republic of Tuva, 14 new species of myxomycetes were identified, one of which -Arcyria globosa (Fig. 1. A.), first identified in the Asian part of Russia. Previously, A. globosa was identified in eight regions in the European part of Russia [7].
A rare species of myxomycetes, Echinostelium fragile, was identified on the bark of a living pine by the method of "moist chambers » (Fig. 1. B). Previously, this species was identified in five regions of Russia, including the European part [8], in Eastern Siberia [9], we also identified it earlier in Western Siberia in the Altai Territory, the Republic of Altai, and the Novosibirsk Region [10][11][12]. We will continue the study of myxomycetes in the Republic of Tuva, as it makes a significant contribution to understanding the distribution patterns and ecology of myxomycetes in Inner Asia.