The comprehensive checklist of myxomycetes of Ukraine, based on extended occurrence and reference datasets.

Background: A significant body of valuable data about the myxomycetes of Ukraine lies in a "grey zone". This encompasses undigitised historical books and articles published in languages such as Polish, French or German, as well as proceedings from local conferences, articles featured in local scientific journals and annual reports submitted to public authorities by employees of protected areas, published in Ukrainian or Russian. Yet, due to their exclusive existence in print and often the Cyrillic alphabet, these publications remain neither findable nor accessible to a wider audience. New information: The datasets presented here aim to summarise over 150 years of myxomycetes research in Ukraine. The majority of the data has been extracted from published literature sources spanning the years 1842 to 2023, with a minor supplement from unpublished herbarium specimens. The datasets include 5036 georeferenced occurrences, 339 taxa and 91 literature sources. Seventy-one of the used literature sources, mostly published before 2010, were uploaded to Zenodo and are available in open access.

Dataset of barcoded Reticulariaceae: ten years of DNA sequencing.

Background: As a result of the ten years (2012-2022) work under the critical revision of the genera of Reticulariaceae, a set of papers was published. Collection data of hundreds of specimens, used as a material for these studies, were provided as supplements of corresponding papers, but remained unpublished in biodiversity databases. New information: Here, we represent an occurrence dataset "Barcoded Reticulariaceae of the World", published in GBIF. It includes data on 523 myxomycete collections (including 36 types) gathered from five continents and spanning 24 countries. The dataset encompasses 43 distinct species and one subspecies of myxomycetes, including rare, endemic, and recently-described taxa. Species included to the database mainly belong to the genera Alwisia, Lycogala, Reticularia, Siphoptychium, Thecotubifera and Tubifera (Reticulariaceae), but as well Lindbladia and Licaethalium (Cribrariaceae). Nearly all of the research material, with the exception of several old collections, underwent molecular barcoding, primarily involving the 18S rDNA gene, but also the elongation factor 1α gene and mitochondrial cytochrome oxidase subunit I gene. For those sequences that are stored in the NCBI GenBank, accession numbers are provided in the dataset. Newly-described species make up a significant part of the studied herbarium collections; many of them can be characterised as common for their region. A particularly high level of taxonomic novelty is observed in Australia, which may be explained by the endemism of the local myxomycete biota.

Tasmaniomyxa umbilicata, a new genus and new species of myxomycete from Tasmania.

A new genus and species of myxomycete, Tasmaniomyxa umbilicata, is described based on numerous observations in Tasmania and additional records from southeastern Australia and New Zealand. The new taxon is characterized by an unusual combination of characters from two families: Lamprodermataceae and Didymiaceae. With Lamprodermataceae the species shares limeless sporocarps, a shining membranous peridium, an epihypothallic stalk, and a cylindrical columella. Like Didymiaceae, it has a soft, flaccid, sparsely branched capillitium, with rough tubular threads that contain fusiform nodes and are firmly connected to the peridium. Other characters of T. umbilicata that also occur in many Didymiaceae are the peridium dehiscing into petaloid lobes, the yellow, motile plasmodium, and the spores ornamented with larger, grouped and smaller, scattered warts. The transitional position of the new taxon is reflected by a three-gene phylogeny, which places T. umbilicata at the base of the branch of all lime-containing Physarales, thus justifying its description as a monotypic genus.

Fifteen new species from the myxomycete genus Lycogala.

Based on a study of 255 collections from four continents and four floristic kingdoms, we describe 15 new species of the genus Lycogala. The new species, all morphologically close to L. epidendrum, L. exiguum, and L. confusum, differ from each other by the structure of the peridium and, in some cases, also by the color of the fresh spore mass and the ornamentation of the capillitium and spores. Species delimitation is confirmed by two independently inherited molecular markers, as well as previously performed tests of reproductive isolation and genetic distances. We studied authentic material of L. exiguum and L. confusum and found fresh specimens of these species, which allowed us to obtain molecular barcodes and substantiate the separation of new species from these taxa. We propose to retain the name L. epidendrum for the globally most abundant species, for which we provide a more precise description and a neotypification. Two formerly described species, L. leiosporum and L. fuscoviolaceum, we consider to be dubious. We do not recognize the species L. terrestre.

Two independent genetic markers support separation of the myxomycete Lycogala epidendrum into numerous biological species.

Lycogala epidendrum is one of the most widely known myxomycete species and the first-ever discovered representative of this group. Using 687 original DNA sequences from 330 herbarium specimens from Europe, Asia, North and Central America, and Australia, we constructed the first detailed phylogenies of the genus Lycogala, based on two independently inherited genetic markers, the ribosome small subunit 18S rRNA nuclear gene (18S rDNA) and the mitochondrial cytochrome oxidase subunit I gene (COI). In both phylogenies, L. epidendrum appeared to be a polyphyletic group, represented by numerous clades. The four other recognized species of the genus (L. confusum, L. conicum, L. exiguum, and L. flavofuscum) are scattered between branches corresponding to L. epidendrum. A barcode gap analysis revealed 60 18S rDNA phylogroups of L. epidendrum, which are distant from each other not less than from other species of the genus Lycogala. For 18 of these phylogroups with both 18S rDNA and COI sequences available, recombination patterns were analyzed to test for reproductive isolation. In contrast to the results of a simulation assuming panmixis, no crossing between ribosomal and mitochondrial phylogroups was found, thus allowing the conclusion that all tested phylogroups represent biospecies. More than one third (39.6%) of the studied specimens share a single 18S rDNA phylogroup, which we consider to be L. epidendrum s. str. This group displays the broadest geographic distribution and the highest intraspecific genetic variability. Nearly all (93.3%) of the remaining non-singleton 18S rDNA phylogroups are restricted to certain continents or even regions. At the same time, various reproductively isolated phylogroups occur sympatric at a given location.