The extent to which free-living microorganisms show cosmopolitan distributions has been a contentious aspect of microbial ecology over the last few decades. Testate amoebae are a group of free living protists that can provide important evidence for the nature of the biogeography of microorganisms because there are relatively good data on the distribution of their morpho-species (compared to many other microbial groups). Many testate amoebae appear to exhibit ubiquitous distributions, while some taxa have proven to be endemic to limited regions. The genusHoogenraadia (Gauthier-Lièvre and Thomas 1958) is of particular interest in this context as it appears to be restricted to relatively low latitudes. There are six described species of the genus: H. africana Gauthier-Lièvre and Thomas 1958, H. asiatica Wang and Min 1987, H. cryptostoma Gauthier-Lièvre and Thomas 1958, H. humicola Bonnet 1976, H. ovata Bonnet 1976, and H. sylvatica Vucetich 1974. However, information on these taxa is scattered through a number of different papers – here we provide a summary of what is known about the taxonomy and ecology of this genus. We also reinterpret recent new records of putative H. africana from China (suggesting this identification is not reliable). As an example of a protist taxon largely restricted to the tropics this genus is of particular interest in microbial biogeography and this paper discusses its morphology, ecology and distribution in this context.

Pleurostomatids are raptorial ciliates that form a very distinct group within the Haptoria. Traditionally, the order Pleurostomatida was divided into two families: the Amphileptidae with two perioral kineties and a suture formed by the right side ciliary rows, and the Litonotidae with three perioral kineties and without suture. However, molecular phylogenies depicted the “traditional” Amphileptidae as a paraphyletic assemblage nesting also the Litonotidae. To overcome this problem we have analyzed genealogy of pleurostomatids using morphological data and 18S rRNA gene sequences, including newly sequenced genera Acineria and Kentrophyllum. Specifically, we have combined a morphological and molecular approach and have used also some other phylogenetic tools such as phylogenetic networks, split spectrum analysis, quartet mapping as well as the likelihood method of tracing history of morphological characters. These analyses show that: (1) there are not two but three distinct pleurostomatid lineages – Epiphyllidae fam. nov., Amphileptidae and Litonotidae; (2) epiphyllids (Epiphyllum + Kentrophyllum) represent a basal pleurostomatid group which is defined by two perioral kineties, by the presence of a suture on both the right and the left side of the body, by the loss of the oral bulge extrusomes, and by the extrusome fringe extending all around the body except for the oral region; (3) the families Amphileptidae and Litonotidae are monophyletic each, and represent sister groups; (4) Acineria belongs to the Litonotidae, as already indicated by morphological data; (5) Loxophyllum is a monophyletic and crown genus of the Litonotidae; and (6) Litonotus is paraphyletic, which could be very likely caused by a rapid radiation event that did not allow primary nucleotide homologies to be fixed.

The morphology and infraciliature of four marine scuticociliates, Pleuronema elegans spec. nov., P. setigerum Calkins, 1902, P. grolierei Wang et al., 2008 and Uronema orientalis spec. nov., collected from China seas, were investigated through live observation and protargol staining methods. Pleuronema elegans spec. nov. can be recognized by the combination of the following characters: size in vivo 90–115 × 45–60 µm, slender oval in outline with a distinctly pointed posterior end; about 10 prolonged caudal cilia; consistently two preoral kineties and 18 or 19 somatic kineties; membranelle 2a double-rowed with its posterior end straight; membranelle 3 three-rowed; one macronucleus; marine habitat.Uronema orientalis spec. nov. is distinguished by the following features: in vivo about 40–55 × 20–30 μm with a truncated apical plate; consistently twenty somatic kineties; membranelle 1 single-rowed and divided into two parts which comprise four and three basal bodies respectively; contractile vacuole pore positioned at the end of the second somatic kinety; marine habitat. We also provide improved diagnoses for P. grolierei Wang et al., 2008 and P. setigerum Calkins, 1902 based on current and previous reports. The small subunit rRNA gene of U. orientalis, P. elegans, P. grolierei and P. puytoraci were sequenced. Phylogenetic analyses indicate that Uronema and Pleuronema are not monophyletic.

The genus Sappinia belongs to the family Thecamoebidae within the Discosea (Amoebozoa). For long time the genus comprised only two species, S. pedata and S. diploidea, based on morphological investigations. However, recent molecular studies on gene sequences of the small subunit ribosomal RNA (SSU rRNA) gene revealed a high genetic diversity within the genus Sappinia. This indicated a larger species richness than previously assumed and the establishment of new species was predicted. Here, Sappinia platani sp. nov. (strain PL-247) is described and ultrastructurally investigated. This strain was isolated from the bark of a sycamore tree (Koblenz, Germany) like the re-described neotype of S. diploidea. The new species shows the typical characteristics of the genus such as flattened and binucleate trophozoites with a differentiation of anterior hyaloplasm and without discrete pseudopodia as well as bicellular cysts. Additionally, the new species possesses numerous endocytobionts and dictyosomes. The latter could not be found in previous EM studies of the genus Sappinia. Standing forms, a character of the species S. pedata, could be formed on older cultures of the new species but appeared extremely seldom. A loose layer of irregular, bent hair-like structures cover the plasma membrane dissimilar to the glycocalyx types as formerly detected in other Sappinia strains. 

A total of 85 morpho-species of heterotrophic flagellates are reported from sediments at depths from 25–3000 m in the Gippsland Basin (Australia). They are drawn from the apusomonads, cercomonads, cryptomonads, euglenids, heteroloboseids, stramenopiles, thaumatomonads, and groups of uncertain taxonomic affinities (Protista incertae sedis). Three new species, Ancyromonas impluvium nov. spec.,Kurnaimonas celeris nov. spec., Sinistermonas sinistrorsus nov. spec., one combination, Psammosa unguis nov. comb., and one unidentified species are described. The biogeography of the species seen in Gippsland Basin is discussed with reference to studies in other localities. It appears that many heterotrophic flagellates are cosmopolitan.

Free living amoebae (FLA) are amphizoic protozoa that are widely found in various environmental sources. They are known to cause serious human infections, including a fatal encephalitis, a blinding keratitis, and pneumonia. The main aim of the study was detection and molecular identification of Acanthamoeba spp., Naegleria fowleri, Balamuthia mandrillaris, Sappinia pedata, and Vermoamoeba vermiformis (formerly Hartmannella vermiformis) in artificial water bodies in North-Western Poland. We examined 86 water samples collected during 2-year period from 43 water bodies, including outdoor and indoor swimming pools, firefighting reservoirs, fountains, as well as water network. The samples were filtrated using Filta-Max® membrane filters (IDEXX Laboratories, USA) and, in order to select potentially pathogenic, thermophilic strains and to limit the number of PCR examined samples, the thermal tolerance test was carried out. Obtained filtrates were transferred to non-nutrient agar plates with E. coli. The agar plates were incubated at 37°C and then proliferated amoebae were passaged at 42°C. DNA was extracted from the thermophilic trophozoites and then polymerase chain reactions and sequence analysis were performed for molecular identification of FLA. From the 86 collected water samples 57 strains of FLA were able to proliferate at 37°C and 7 of them showed ability to proliferate at 42°C. For molecular identification ofAcanthamoeba spp. and V. vermiformis, regions of 18S rDNA were amplified. In order to detect B. mandrillaris DNA, we used mitochondrial 16S rDNA as a marker, and for detection of N. fowleri andS. pedata – ITS regions. Based on molecular analysis, isolates were classified to the genusAcanthamoeba (T4 and T11 genotypes, as well as the new genotypes detected earlier in clinical samples and named T16) and V. vermiformis species. Detected strains were highly similar or identical to pathogenic strains detected earlier in patients. Our results show a wide distribution of potential pathogenic FLA, as Acanthamoeba T4, T11, T16 genotypes, and V. vermiformis species in various artificial water bodies located in North-Western Poland and suggest a potential threat to health of humans in this part of the country.