Fossil mosses: What do they tell us about moss evolution?

The moss fossil records from the Paleozoic age to the Eocene epoch are reviewed and their putative relationships to extant moss groups discussed. The incomplete preservation and lack of key characters that could define the position of an ancient moss in modern classification remain the problem. Carboniferous records are still impossible to refer to any of the modern moss taxa. Numerous Permian protosphagnalean mosses possess traits that are absent in any extant group and they are therefore treated here as an extinct lineage, whose descendants, if any remain, cannot be recognized among contemporary taxa. Non-protosphagnalean Permian mosses were also fairly diverse, representing morphotypes comparable with Dicranidae and acrocarpous Bryidae, although unequivocal representatives of these subclasses are known only since Cretaceous and Jurassic. Even though Sphagnales is one of two oldest lineages separated from the main trunk of moss phylogenetic tree, it appears in fossil state regularly only since Late Cretaceous, ca. 70 million years ago (Ma), while earlier they were found twice as small leaf fragments from Lower Jurassic (ca. 200 Ma) and Late Ordovician (ca. 455 Ma). Pleurocarpous mosses appear in fossil state near the border between Jurassic and Cretaceous, although most Cretaceous mosses belong to acrocarps. Only in Eocene amber pleurocarps become more numerous than acrocarps. Some Eocene mosses can be assigned to extant families and sometimes genera, although the majority of Eocene pleurocarps are difficult to identify up to the family, as their morphology often allows placement of a particular specimen into several different families.

Ambient and experimental warming effects on an alpine bryophyte community

Alpine and arctic bryophytes have been found to respond negatively to climate change, but since they are often analysed as one functional group, there is limited knowledge on species-specific responses. In this study, we examine how nearly two decades of experimental warming by open top chambers (OTC) and ambient warming have affected the bryophyte community structure in an alpine Dryas octopetala heath in Finse, southwest Norway. In contrast to what we expected, we found that bryophyte abundance, species richness and evenness increased over time in the control plots, indicating a positive response to ambient warming. However, the increase in bryophyte abundance and cover was suppressed in experimentally warmed plots compared to control plots. Bryophyte community composition changed in a similar direction in response to both ambient and experimental warming. Acrocarpous mosses were not affected stronger by warming than pleurocarpous mosses, but individual species and taxa showed contrasting responses. Our study highlights the importance of studying bryophyte responses to environmental change, as well as combining long-term observations with experimental warming.

Pleurocarpous and cladocarpous mosses (Bryophyta) of Parque Nacional da Chapada das Mesas, with newly recorded species from Maranhão and the northeast region of Brazil

Located in southwestern Maranhão, the Parque Nacional da Chapada das Mesas (PNCM), with an extent of about 160,046 ha, is completely inserted in the Cerrado phytogeographic domain. The topography is characterized by a plateau formation consisting of steep hills and medium-altitude mountains with flat tops, which give the PNCM its name. We present an annotated checklist of the mosses that occur in the PNCM. Our checklist includes 26 species of pleurocarpous mosses distributed in 10 families and 22 genera and two species of cladocarpous mosses of the family Orthotrichaceae. The most species-rich families of pleurocarpous mosses were Sematophyllaceae (7 spp.), Pylaisiadelphaceae (6 spp.), and Stereophyllaceae (4 spp.). Eleven species are recorded for the first time from Maranhão and three species are recorded for the first time in the northeast region of Brazil. Taxithelium pluripunctatum (Renauld & Cardot) W.R. Buck and Trichosteleum glaziovii (Hampe) W.R. Buck, are recorded for the first time from Maranhão and the Cerrado phytogeographic domain. Our results expand the knowledge of the Brazilian bryoflora and add distribution data for a number of species in Maranhão and the northeast region.

Morphological characters and SNP markers suggest hybridization and introgression in sympatric populations of the pleurocarpous mosses Homalothecium lutescens and H. sericeum

Hybridization in bryophytes involves a fusion of gametes produced by haploid parental gametophytes of different species. The primary hybrid is thus the short-lived diploid sporophyte, which soon undergoes meiosis prior to the formation of large amounts of haploid spores. We compared morphology of gametophytes (branch leaves) and sporophytes (capsule inclination) from sympatric populations and allopatric populations of H. lutescens and H. sericeum. In addition, we used transcriptome data to select 85 nuclear SNP markers that were fixed for alternative alleles in the two species. The SNPs were used to estimate the degree of hybridization in diploid sporophytes. Our study shows that gametophytes from sympatric populations display intermediate morphology in a number of leaf characters, with exception for leaf sizes, which are markedly smaller than those in allopatric populations. None of the 100 sporophytes appeared to be primary hybrids, but 33 displayed admixing—heterozygotic expression of SNP markers or mismatch of occasional markers in homozygous condition—suggesting that extensive introgression takes place in the sympatric populations. Most sporophytes with intermediate capsule inclination, initially classed as putative hybrids, did not display admixture of nuclear SNP markers. Sixty-seven percent of admixed sporophytes have predominantly nuclear SNPs typical for H. lutescens. Our results suggest that interspecific hybridization and bidirectional introgression are relatively common in the studied sympatric populations, giving rise to viable recombinants, but not complete mixing of the parental genomes. Our study is one of the first detailed accounts of hybridization among pleurocarpous mosses, opening for future studies of gene transfer and introgression between bryophyte lineages and its role in local adaptation and long-term evolutionary diversification.

Сarbon fluxes intensity from substrates and phototrophic consortiums of the photic zones in Montenegro caves

Сarbon dioxide fluxes from substrates and consortiums were estimated for the first time in the photic zones of seven caves of Montenegro. The dependence of consortiums productivity with their species composition and structure, as well as determination of the priority source of carbon dioxide for the primary producers of trophic chains of the photic zones were revealed.Five consortiums were distinguished in the fouling communities of the photic zones of seven karst caves of Montenegro: with the dominance of acrocarpous mosses, pleurocarpous mosses, green algae, cyanobacteria biofilms and sheath-forming cyanobacteria on various substrates. The closed chamber technique was used to calculate carbon fluxes. The net carbon flux, gross respiration of substrates and consortiums, and gross primary production of consortiums in the summer and winter were determined. The biomass of the phototrophic and heterotrophic components of the consortiums was estimated. Isotopic analysis of clay deposits and phytomass of bryophytes in the consotriums as well as on the surface was carried out. All of the investigated consortiums function as a carbon sink in both seasons, providing a negative balance to the atmosphere. Consortiums with the dominance of bryophytes possessed the greatest biomass, spores of micromycetes dominated in the heterotrophic component. The respiration of substrates was maximized on clay deposits, the respiration rate increased in winter. Phototrophic respiration and gross primary production were maximal in the consortiums of acrocarpous mosses and case-forming cyanobacteria in terms of dry phytomass. Increased content of the light carbon isotope 12C in the bryophytes phytomass in the photic zones compared to the bryophytes phytomass on the surface was established.

Octospora conidiophora (Pyronemataceae) – a new species from South Africa and the first report of anamorph in bryophilous Pezizales

Octosporaconidiophorais described as a new species, based on collections from South Africa. It is characterised by apothecia with a distinct margin, smooth or finely warted ellipsoid ascospores, stiff, thick-walled hyaline hairs, warted mycelial hyphae and growth on pleurocarpous mossesTrichosteleumperchlorosumandSematophyllumbrachycarpum(Hypnales) on decaying wood in afromontane forests. It is the first species of bryophilous Pezizales in which an anamorph has been observed; it produces long, claviform, curved, hyaline and transversely septate conidia. Three other cryptic species ofOctosporawere detected using three molecular markers (LSU and SSU nrDNA and EF1α), but these could not be distinguished phenotypically. These are not described formally here and an informal species aggregateO.conidiophoraagg. is established for them. The new species and finds ofLamprosporacampylopodisgrowing onCampylopuspyriformisandNeottiellaalbocinctaonAtrichumandrogynumrepresent the first records of bryophilous Pezizales in South Africa.

Addition of two pleurocarpous mosses to the Bryoflora of South India

A recent exploration and study on bryophytes of Eastern Ghats’ area of Andhra Pradesh has revealed the occurrence of two pleurocarpous mosses viz., Thuidium assimile (Mitt.) A. Jaeger and Anomodon minor subsp. integerrimus (Mitt.) Iwatsuki as new addition to the moss flora of South India. A detailed morpho-taxonomical account and illustration of these taxa are provided.

Cleaning a taxonomic dustbin: placing the European Hypnum species in a phylogenetic context!

The pleurocarpous moss genus Hypnum s.l. is a species-rich (> 40 species) cosmopolitan genus, of which 21 taxa occur in Europe. Although several of these species show high morphological resemblance there are strong indications that the genus is highly paraphyletic, which may be masked by convergent morphological evolution. Using molecular information, we analyse whether the morphological similarity of gametophytes of the European Hypnum taxa is explained by common ancestry or convergence. We provide a phylogenetic reconstruction of the relationships of the currently recognized European Hypnum taxa in a broad pleurocarpous moss context (192 taxa) using the nuclear ITS1-5.8S-ITS2, the plastid rps4 gene and trnL-F, and the mitochondrial nad5 intron. Bayesian tree topologies show that the genus is polyphyletic, and we retain only the Hypnum cupressiforme complex within Hypnum. The genus originally represented half of the moss species diversity, as it accommodated basically all pleurocarpous mosses; here we retain only seven species and one variety. The remainder of the species where resolved either within the three families Amblystegiaceae, Entodontaceae, and Pylaisiaceae, or in an independent clade that we describe as the new family Stereodontaceae. The Stereodontaceae includes five European species, all in the genus Stereodon, where they were already placed in the 18th century. In addition, we describe the four new genera Aquilonium, Insomniella, Jochenia, and Lignocariosa, and make new combinations for several Hypnum species.