Expanding geographic distribution knowledge of Galerinamarginata (Batsch) Kühner (Agaricales, Hymenogastraceae) with a novel Antarctic record.

Background: The investigation of Agaricales diversity in the Antarctica is limited, with only seven genera reported for the region. Galerina stands out as the genus with the highest species diversity, including 12 species in Antarctica. This research reports the presence of G.marginata in the region, providing the first complete morphological description for the specimen developing in Antarctica. Sampling was conducted during the Austral summer of 2022/2023 as part of the XLI Brazilian Antarctic Operation in Point Smellie, Byers Peninsula, Livingston Island, South Shetland Archipelago, Antarctica. Phylogenetic relationships reconstructed by Maximum Likelihood demonstrate that G.marginata forms a monophyletic clade with over 60% bootstrap support in most branches. The isolate in this study was found to be internal to the main cluster. Evolutionary reconstructions using the Maximum Likelihood method indicate that the branches correspond to the Antarctic isolate being an internal clade within the marginata group. Recording fungal populations in polar regions offers information about their adaptation and survival in inhospitable environments. Understanding the species' distribution in Antarctica encourages future investigations into its ecology and interactions with other organisms. Here, data are presented to establish an initial foundation for monitoring the G.marginata population in Antarctica and assessing the potential impacts of climate change on its development and survival in the forthcoming years. New information: We report the third occurrence of Galerinamarginata (Batsch) Kühner in Antarctica and provide, for the first time, a comprehensive morphological description of an individual of the species for the Antarctic continent, accompanied by phylogenetic analyses and comprehensive discussions regarding its diversity and global distribution.

Chromosomal distribution of major rDNA and genome size variation in Belostoma angustum Lauck, B. nessimiani Ribeiro & Alecrim, and B. sanctulum Montandon (Insecta, Heteroptera, Belostomatidae).

Known as "electric-light bugs", belostomatids potentially act as agents of biological control. The Belostoma genus has holokinetic chromosomes, interspecific variation in diploid number, sex chromosome system and DNA content. Thus, the chromosomal complement, the accumulation of constitutive heterochromatin and the distribution of rDNA clusters by fluorescence in situ hybridization (FISH) in Belostoma angustum (BAN), Belostoma sanctulum (BSA), and Belostoma nessimiani (BNE) were evaluated. In addition, a comparative analysis of the DNA content of these species and B. estevezae (BES) was performed. BES has the highest Belostoma DNA content, while BSA has the lowest. BAN showed 2n = 29 + X1X2Y, while BSA and BNE had 2n = 14 + XY. BSA showed 18S rDNA markings on sex chromosomes, while BNE and BAN did on autosomes. The difference between BSA and BNE occurs because of the possible movement of the rDNA cluster in BNE. We suggest the occurrence of fusion in the autosomes of BSA and BNE, and fragmentation in the sex chromosomes in BAN. Also, the genome size of 1-2 pg represents a haploid DNA content of a common ancestor, from which the genomes of BES and BAN had evolved by gene duplication and heterochromatinization events.