A brief overview of freshwater species of naked amoebae genus Mayorella Schaeffer, 1926 (Amoebozoa; Discosea)

Aim. Naked amoebae are widespread in water bodies and terrestrial biotopes. These organisms are difficult to reproduce in laboratory conditions and identify by morphological and genetic characteristics. Therefore, the aim of the study was to identify species of naked amoebae of the genus Mayorella from water bodies in Ukraine, establish clonal cultures, identify them based on the 18S rRNA gene, and determine the position of these protists in the Amoebozoa phylogenetic tree. Methods. Reproduction of naked amoebae on non-nutrient agar-agar, establishment of clonal cultures, DNA sequencing, phylogenetic analysis. Results. Five species of naked amoebae of the genus Mayorella have been recorded in freshwater bodies in Ukraine: Mayorella cantabrigiensis, Mayorella vespertilioides, Mayorella penardi, Mayorella viridis, Mayorella sp. Based on the 18s rRNA gene, species identification Mayorella vespertilioides (OP739500) and Mayorella sp. (OP729930). In the constructed phylogenetic tree of Amoebozoa (based on 20 sequences of the 18S rRNA gene of different species of naked amoebae), representatives of the genus Mayorella form a separate cluster within Discosea. In addition, the Discosea group includes species from the orders Vannellida, Dactylopodida and Thecamoebida. The Tubulinea cluster groups together species of amoeba from the genera Amoeba, Chaos and Saccamoeba. Conclusions. Based on modern light microscopy and DNA sequencing, we have identified five species of naked amoebae of the genus Mayorella. Clonal cultures have been established for two species. In the phylogenetic tree, Mayorella-like amoebae are grouped within the Discosea molecular cluster.