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In recent years, negative-sense RNA virus classification and taxon nomenclature have undergone considerable transformation. In 2016, the new order Bunyavirales was established, elevating the previous genus Hantavirus to family rank, thereby creating Hantaviridae. Here we summarize affirmed taxonomic modifications of this family from 2016 to 2019. Changes involve the admission of >30 new hantavirid species and the establishment of subfamilies and novel genera based on DivErsity pArtitioning by hieRarchical Clustering (DEmARC) analysis of genomic sequencing data. We outline an objective framework that can be used in future classification schemes when more hantavirids sequences will be available. Finally, we summarize current taxonomic proposals and problems in hantavirid taxonomy that will have to be addressed shortly.

Hypocreomycetidae is a highly diverse group with species from various habitats. This subclass has been reported as pathogenic, endophytic, parasitic, saprobic, fungicolous, lichenicolous, algicolous, coprophilous and insect fungi from aquatic and terrestrial habitats. In this study, we focused on freshwater fungi of Hypocreomycetidae which resulted 41 fresh collections from China and Thailand. Based on morphological and phylogenetic analyses, we identified 26 species that belong to two orders ( Hypocreales and Microascales ) and six families ( Bionectriaceae , Halosphaeriaceae , Microascaceae , Nectriaceae , Sarocladiaceae and Stachybotryaceae ). Ten new species are introduced and 13 new habitats and geographic records are reported. Mariannaea superimposita, Stachybotrys chartarum and S. chlorohalonatus are recollected from freshwater habitats in China. Based on phylogenetic analysis of combined LSU, ITS, SSU, rpb 2 and tef 1-α sequences data, Emericellopsis is transferred to Hypocreales genera incertae sedis ; Pseudoacremonium is transferred to Bionectriaceae ; Sedecimiella is placed in Nectriaceae ; Nautosphaeria and Tubakiella are excluded from Halosphaeriaceae and placed in Microascales genera incertae sedis ; and Faurelina is excluded from Hypocreomycetidae . Varicosporella is placed under Atractium as a synonym of Atractium . In addition, phylogenetic analysis and divergence time estimates showed that Ascocodina , Campylospora , Cornuvesica and Xenodactylariaceae form distinct lineages in Hypocreomycetidae and they evolved in the family/order time frame. Hence, a new order ( Xenodactylariales ) and three new families ( Ascocodinaceae , Campylosporaceae and Cornuvesicaceae ) are introduced based on phylogenetic analysis, divergence time estimations and morphological characters. Ancestral character state analysis is performed for different habitats of Hypocreomycetidae including freshwater, marine and terrestrial taxa. The result indicates that marine and freshwater fungi evolved independently from terrestrial ancestors. The results further support those early diverging clades of this subclass, mostly comprising terrestrial taxa and freshwater and marine taxa have been secondarily derived, while the crown clade ( Nectriaceae ) is represented in all three habitats. The evolution of various morphological adaptations towards their habitual changes are also discussed.

The genus Mycoplasma, including species earlier classified in the genera Eperythrozoon and Haemobartonella, contains ~ 120 species and constitutes an extensively polyphyletic assemblage of bacteria within the phylum Tenericutes. Due to their small genome sizes and lack of unique characteristics, the relationships among the mycoplasmas/Tenericutes are not reliably discerned. Using genome sequences for 140 Tenericutes, their evolutionary relationships were examined using multiple independent approaches. Phylogenomic trees were constructed for 63 conserved proteins, 45 ribosomal proteins, three main subunits of RNA polymerase and 16S rRNA gene sequences. In all of these trees, Tenericutes species reliably grouped into four main clades designated as the “Acholeplasma”, “Spiroplasma”, “Pneumoniae” and “Hominis” clusters. These clades are also distinguished based on a similarity matrix constructed based on 16S rRNA gene sequences. Mycoplasma species were dispersed across 3 of these 4 clades highlighting their extensive polyphyly. In parallel, our comparative genomic analyses have identified > 100 conserved signature indels (CSIs) and 14 conserved signature proteins (CSPs), which are uniquely shared by the members of four identified clades, strongly supporting their monophyly and identifying them in molecular terms. Mycoplasma mycoides, the type species of the genus Mycoplasma, and a small number of other Mycoplasma species, formed a strongly supported clade within the “Spiroplasma” cluster. Nine CSIs and 14 CSPs reliably distinguish this clade from all other Mycoplasmatales species. The remainder of the Mycoplasmatales species are part of the “Pneumoniae” and “Hominis” clusters, which group together in phylogenetic trees. Here we are proposing that the order Mycoplasmatales should be emended to encompass only the Mycoplasma species within the “Spiroplasma” cluster and that a new order, Mycoplasmoidales ord. nov., should be created to encompass the other Mycoplasma species. The “Pneumoniae” and the “Hominis” clusters are proposed as two new families, Mycoplasmoidaceae fam. nov., which includes the genera Eperythrozoon, Ureaplasma, and the newly proposed genera Malacoplasma and Mycoplasmoides, and Metamycoplasmataceae fam. nov. to contain the newly proposed genera Metamycoplasma, Mycoplasmopsis, and Mesomycoplasma. The results presented here allow reliable discernment, both in phylogenetic and molecular terms, of the members of the two proposed families as well as different described genera within these families including members of the genus Eperythrozoon, which is comprised of uncultivable organisms. The taxonomic reclassifications proposed here, which more accurately portray the genetic diversity among the Tenericutes/Mycoplasma species, provide a new framework for understanding the biological and clinical aspects of these important microbes.

The nucleocytoplasmic large DNA viruses (NCLDVs) comprise a monophyletic group of viruses that infect animals and diverse unicellular eukaryotes. The NCLDV group includes the families Poxviridae, Asfarviridae, Iridoviridae, Ascoviridae, Phycodnaviridae, Mimiviridae and the proposed family “Marseilleviridae”. The family Mimiviridae includes the largest known viruses, with genomes in excess of one megabase, whereas the genome size in the other NCLDV families varies from 100 to 400 kilobase pairs. Most of the NCLDVs replicate in the cytoplasm of infected cells, within so-called virus factories. The NCLDVs share a common ancient origin, as demonstrated by evolutionary reconstructions that trace approximately 50 genes encoding key proteins involved in viral replication and virion formation to the last common ancestor of all these viruses. Taken together, these characteristics lead us to propose assigning an official taxonomic rank to the NCLDVs as the order “Megavirales”, in reference to the large size of the virions and genomes of these viruses.

Species with relatively small, membraneous, black ascomata, with or without long necks, unitunicate, cylindrical asci with apical rings and fusiform, hyaline ascospores with or without mucilaginous sheaths are common in freshwater habitats in tropical and temperate regions. Many of these taxa have originally been recorded as Annulatascaceae -like taxa. Twenty genera have been included in the family Annulatascaceae , mostly based on morphological characters, while molecular work and phylogenetic analyses are lacking for many genera. In this study, nine new Annulatascaceae -like taxa collected from Thailand were morphologically examined. Pure cultures obtained from single ascospores were used in molecular studies. The nine new strains and several other strains of Annulatascaceae-like Sordariomycetes species were used to establish phylogenetic and evolution relationships among the taxa, based on combined LSU, SSU, ITS and RPB2 sequence data. Phylogenetic analyses provide evidence to introduce one new order and six new families, to accommodate taxa excluded from Annulatascaceae sensu stricto. A new order Atractosporales is established based on the molecular study, including three new introduced families Conlariaceae , Pseudoproboscisporaceae and Atractosporaceae . Conlariaceae is introduced for the genus Conlarium which comprises two species, Conlarium duplumascosporun and a new Hyphomycetous asexual morph taxon Conlarium aquaticum which has subglobose or irregular, brown, clathrate, muriform conidia. Pseudoproboscisporaceae includes Pseudoproboscispora and Diluviicola , while Atractosporaceae includes the genera Rubellisphaeria and Atractospora. Barbatosphaeria , Xylomelasma and Ceratostomella form a distinct stable lineage which is introduced as a new family Barbatosphaeriaceae in Diaporthomycetidae families incertae sedis. A new family Lentomitellaceae is introduced in Diaporthomycetidae families incertae sedis , to accommodate the genus Lentomitella. Woswasiaceae is introduced to accommodate Woswasia , Xylochrysis and Cyanoannulus in Diaporthomycetidae families incertae sedis . Three new species of Fluminicola viz. F. saprophytica , F. thailandensis and F. aquatica are introduced. A new sexual morph, Dictyosporella thailandensis, is reported and Dictyosporella is excluded from Annulatascaceae and placed in Diaporthomycetidae genera incertae sedis . The first sexual morph of Sporidesmium , S. thailandense is also described. The new species Atractospora thailandensis , Diluviicola aquatica and Pseudoproboscispora thailandensis are also introduced. Platytrachelon is added to Papulosaceae based on phylogenetic analysis and morphological characters. Aquaticola , Fusoidispora and Pseudoannulatascus are excluded from Annulatascaceae and placed in Diaporthomycetidae genera incertae sedis . Mirannulata is accommodated in Sordariomycetes, genera incertae sedis .

Coccoid Ulvophyceae are often overlooked despite their wide distribution. They occur as epiphytes on marine seaweeds or grow on stones or on shells of mussels and corals. Most of the species are not easy to identify based solely on morphology. However, they form two groups based on the flagellated cells during asexual reproduction. The biflagellated coccoids are monophyletic and represent the genus Sykidion (Sykidiales). In contrast, the quadriflagellated taxa are polyphyletic and belong to different genera and orders. The newly investigated strains NIES-1838 and NIES-1839, originally identified as Halochlorococcum, belong to the genus Chlorocystis (C. john-westii) among the order Chlorocystidales. The unidentified strain CCMP 1293 had almost an identical SSU and ITS-2 sequence to Symbiochlorum hainanense (Ignatiales) but showed morphological differences (single chloroplast, quadriflagellated zoospores) compared with the original description of this species (multiple chloroplasts, aplanospores). Surprisingly, the strain SAG 2662 (= ULVO-129), together with the published sequence of MBIC 10461, formed a new monophyletic lineage among the Ulvophyceae, which is highly supported in all of the bootstrap and Bayesian analyses and approximately unbiased tests of user-defined trees. This strain is characterized by a spherical morphology and also form quadriflagellated zoospores, have a unique ITS-2 barcode, and can tolerate a high variation of salinities. Considering our results, we emend the diagnosis of Symbiochlorum and propose the new genus Solotvynia among the new order Solotvyniales.

A second version of the syntaxonomical classification of calcareous Norway spruce communities is presented for the region of Slovak Western Carpathians. Recent knowledge on delimitation of natural Norway spruce woodlands in Slovakia is summarized as well. As result, four in Slovakia traditionally recognized associations are distinguished: on the ecologically most extreme habitats, followed by (a replacement for pseudonymically used ), tall-forb community of and ca. species-poor low-forb community of (syn. ). Additionally, two new associations are differentiated: ass. prov. standing between and and acidified on deeper soils developed over rocks of the Mráznica formation. For nomenclatural reasons, new order is described for species-rich calcicolous communities of the class as well as subordinated new alliance for the supramontane calcicolous Norway spruce communities.

In contrast to almost all other invertebrate phyla that constructed biomineralized skeletons during the “Cambrian explosion” and maintained them during the entire fossil record, ascidian tunicates evolved this protective and stabilizing advantage only during the Permian, although soft-bodied representatives of this subphylum made their first appearance already in the early Cambrian. It remains enigmatic why these compound calcareous skeletons persisted only until the Late Triassic, subsequently followed by less-rigid internal skeletons from the Lower Jurassic onwards, which consist of scattered isolated spicules only. In addition to recently described aragonitic ascidian exoskeletons from the Permian and Triassic, new discoveries of similar, but colonial ascidian compound endoskeletons in the lower Carnian exhibit a short-living branch of this group, which moreover contain the first indubitable calcareous spicules. The latter are embedded in the solid endoskeleton, which is composed of polygonal aragonitic plates with smooth outer and zigzag lined inner boundaries. They consist of irregular, parallel (orthogonal), or fan-shaped (clinogonal) arrangements of acicular aragonite crystals. The following taxa are described as new: order Cassianomorpha new order with the family Cassianosomidae new family and the genus Toscanisoma new genus with the species T. multipartitum new species and T. triplicatum new species.

Based on a total of 14 inclusions from Burmese amber the new insect order Tarachoptera is established. The family Tarachocelidae previously described from Burmese amber and then placed in Amphiesmenoptera incertae sedis is assigned to this new order. The genus Kinitocelis gen. nov. is established to accommodate three new fossil species: K. hennigi spec. nov., K. divisinotata spec. nov. and K. brevicostata spec. nov. The new genus differs from Tarachocelis gen. nov. by the absence of androconial scales on the wings and the loss of Cu2 in the forewings. The species are described in detail and the critical characters are illustrated by line drawings and photos. Both males and females were described. The species can be distinguished by traits in the wing venation. The new order Tarachoptera is placed in the superorder Amphiesmenoptera based on the presence of seven amphiesmenopteran apomorphies and nine tarachopteran apomorphies. Apomorphic characters of Trichoptera and Lepidoptera could not be disclosed, which suggests an independent origin and evolution from an amphiesmenopteran ancestor which was not the ancestor of the Trichoptera-Lepidoptera clade. The species of Tarachoptera are tiny insects with a wing span of 2.3–4.5 mm but highly specialized according to their aberrant morphology. Aspects of the presumed life history of the adults were deduced from some of the derived morphological traits that could be interpreted as adaptations to a highly structured micro-environment.

Species of the red algal order Acrochaetiales mostly inhabit marine environments, with only two freshwater taxa Audouinella and Ottia. A new genus and species are described for freshwater red alga Pauciramus yunnanensis from Ailao Mountain, Yunnan, China. It is closely related to Ottia and a new order Ottiales was proposed for these genera. Pauciramus has unique combination of morphological characteristics including the following: plants caespitose and densely pulvinate, slender uniseriate filaments with well-developed rhizoids, rarely branched, cylindrical vegetative cell with a single, ribbon-shaped and parietal chloroplast, reproduction by tetrasporangia, and dense sporangial branchlet only at the upper portion of filaments. Phylogenetic analysis of sequence data from the plastid ribulose-1,5-bisphosphate carboxylase-oxygenase large-subunit ( rbc L), small subunit gene of the ribosomal cistron (SSU) and barcode region near the 5′ end of the mitochondrial cytochrome oxidase subunit I (COI-5P) indicated that: the new taxon, P. yunnanensis , was in a well-supported clade with Ottia meiospora , and this clade was sister to order Palmariales and Acrochaetiales. To adhere to the principle of monophyly, a new freshwater order Ottiales including Ottia and Pauciramus is proposed. Despite the high sequence interspecific divergences and obvious morphological differences between genera Ottia and Pauciramus , seems impractical to establish a new family for a monospecific genus. Therefore, we temporarily classified Pauciramus into the family Ottiaceae, and made necessary revisions to the description to accommodate this genus.