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• We investigated the diversity and biogeography of Chilean ciliates, a neglected taxon. • The checklist of Chilean ciliates consists of 207 species including 15 endemic taxa. • Oligohymenophoreans and spirotricheans are the best represented taxa in Chile. • Analyses suggest that ∼58–74% of ciliate diversity remains undescribed in Chile. • Chilean ciliates have a biogeographic pattern akin to that of Chilean plants/animals. There is a significant gap in research and knowledge on the diversity and distribution of Chilean ciliates. To tackle these issues, we used cultures and protargol preparations to describe the ciliates present in poorly explored areas. At these sites, we identified 45 ciliate morphospecies, 35 of which represent unprecedent records to Chile. Then, we brought together our records with literature data to construct a species checklist. This checklist summarises 132 years of data and describes the identity, habitat and distribution of 207 species, including 15 species potentially endemic to Chile. This checklist is far from complete: a diversity estimate suggests that at least two-thirds of the ciliate species occurring in Chile have yet to be described. The checklist is dominated by freshwater taxa because ciliates from marine, brackish and terrestrial environments have rarely been investigated in Chile. Finally, after controlling for sampling artefacts, we found that ciliates exhibit a bell-shaped latitudinal diversity gradient in Chile. This peculiar biogeographical pattern is common in Chile. Plants, animals and testate amoebae also exhibit a bell-shaped latitudinal diversity gradient in Chile. This finding suggests that the historical contingencies that drove the biogeography of the Chilean biota also shaped ciliate biogeography. [ABSTRACT FROM AUTHOR]

Copemetopus Villeneuve-Brachon, 1940 is a rare, poorly known sapropelic ciliate genus composed of only two valid nominal species. Over time, Copemetopus was taxonomically assigned to Heterotrichea and Armophorea classes, but its phylogenetic affinities remained unknown. Until the present study, there were no molecular data available for Copemetopus representatives. Here, we present the 18S and 28S-rDNA sequences and the phylogenetic position of Copemetopus verae sp. nov., as well as its detailed morphological description based on live observations, protargol impregnation, and scanning electron microscopy. Transmission electron micrographs of the type species C. subsalsus Villeneuve-Brachon, 1940 reveal new morphological traits and a unique somatic ciliature pattern of Copemetopus , composed by short segments of dikinetids with one or two supplementary kinetosomes. The phylogenetic trees recovered Copemetopus as the sister group of the genus Protocruzia , both constituting early-divergent lineages that split first from a common ancestor of Intramacronucleta. Morphological and molecular evidence suggest that Copemetopus is neither a heterotrichean nor an armophorean ciliate, but a distinct clade related to Protocruzia. [ABSTRACT FROM AUTHOR]

• Atypical S. yagiui and S. minus morphotypes with two macronuclei were reported and investigated. • We present the first record of S. yagiui in South America. • 18S rRNA-based phylogenetic analysis confirms the identity of the atypical forms. Spirostomum is a widely distributed heterotrichean genus composed of well-known species with described ecology and phylogenetic affinities. The morphological classification of Spirostomum species is mostly based on the body size/shape, number of cortical granule rows and macronuclear characteristics. These features along with molecular phylogenies based on ribosomal genes divide the genus into two phylogroups, one including species with a compact macronucleus, and another including species with a moniliform macronucleus. Here, we present our observations on atypical Spirostomum specimens with unusually two distinct macronuclei and shortened adoral zone of membranelles. These atypical forms appeared in the cultures of S. minus and S. yagiui , sampled at different sites in South America (Chile and Brazil) and associated with unrelated substrate types. Morphological observations of living and stained cells, 18S rRNA gene analyses, and a thorough investigation of the literature suggest that the atypical phenotype may be a result of uncommon pathways during the conjugative process. Thus, we demonstrate that studies of ciliate natural populations and their morphological variations, especially from undersampled biogeographical regions, can reveal the boundaries of widely used morphological characters for Spirostomum taxonomy and species identification. [ABSTRACT FROM AUTHOR]

The genus Parablepharisma Jankowski, 2007 at present includes five species, most of which have not been studied in detail, therefore phylogenetic affinities remained uninvestigated up to now. Parablepharisma is traditionally placed within Heterotrichea based on insufficient existing morphological data, and there are no available Parablepharisma gene sequences in molecular databases to support this placement. This work presents an 18S rDNA-based phylogeny of P. bacteriophora (Kahl, 1932) Jankowski, 2007 and P. brasiliensis sp. nov. We also provide a redescription of P. bacteriophora and P. chlamydophorum (Kahl, 1932) Jankowski, 2007 based on live morphological observations combined with silver impregnation and scanning and transmission electron microscopy. According to characters such as macro- and micronucleus number, the position of the ectosymbiotic bacteria, and the presence/absence of caudal cilia, two new species are described, i.e. P. granulata sp. nov. and P. brasiliensis sp. nov. In addition, we establish Kahlium gen. nov. to include P. chlamydophorum , which has a segmented anterior paroral portion and a twisted posterior paroral section as diagnostic features. To include Parablepharisma and Kahlium gen. nov., we propose Parablepharismidae fam. nov. According to our phylogenetic analyses, Parablepharisma belongs to SAL (Spirotrichea, Armophorea, Litostomatea), being a sister group of Cariacotrichea. [ABSTRACT FROM AUTHOR]

Pregnancy during radiotherapy is not a common clinical situation. We describe a fetal dose estimation necessary before starting a course of radiotherapy for a brain tumor in a patient unexpectedly pregnant at the time scheduled for the beginning of treatment. To estimated the dose to the fetus during the programmed course of radiotherapy before deciding if the patient should advance with the treatment or not. The initial plan was optimized to avoid fetus exposure to radiation without compromising dose to the target volume. We considered the real patient distances between plan isocenter and 3 critical points: uterus fundus, umbilical and pubis. Using an anthropomorphic phantom and solid water slabs we positioned an ionizing chamber at different depths, corresponding to these points, and determined the estimated doses for the complete course of radiotherapy. The maximum dose value measured was 2,5 cGy, well below the 10 cGy reported tolerance value. After explaining the situation to the patient and the risks involved, a decision was taken to go on with the treatment as planned. A set of 3 pairs of TLD dosimeters was used over the patient belly, in these same positions during every treatment fraction. The TLDs readings at the end confirmed the estimated values measured in the phantom. The previous evaluation of the estimated dose to the fetus allowed the patient to successfully complete the radiotherapy course. The pregnancy went on normally and the patient delivered a healthy child. The authors have nothing to disclose. [ABSTRACT FROM AUTHOR]

Competing Interests: Conflict of interest The authors declare that they have no conflict of interest.