Periacineta mexicana n. sp. (Ciliophora, Suctoria, Discophryida), Epizoic on Mexican Backswimmers of the Genus Buenoa (Insecta, Hemiptera, Notonectidae)

A new species of suctorian in the genus Periacineta, epibiotic on aquatic bugs (Hemiptera, Heteroptera, Nepomorpha), is described on the basis of morphological characteristics of the cell body, lorica, tentacular placement, and stalk, and its 18S rRNA partial sequence gene. Periacineta mexicana n. sp. is a loricate suctorian with elongate body and rounded apical region; tentacles are distributed randomly over apical region and not grouped into fascicles. Macronucleus in adult is elongate and located centrally. The suctorian usually forms closely aggregated pseudocolonies. We provide morphological data based on optical and scanning electron microscopy. A comparison with similar congeners, and emended diagnosis of the genus Periacineta also are provided. The ciliates were found attached to the first two pairs of legs of Mexican notonectids Buenoa pallens and Buenoa spp. (backswimmers)

New records of suctorians (Ciliophora: Suctoria) as epibionts of aquatic true bugs (Hemiptera: Prosorrhyncha: Nepomorpha) from two regions: Mexico and Eastern Europe

Here, we provide new records of suctorians (Ciliophora: Suctoria), epibionts of aquatic true bugs (Hemiptera: Prosorrhyncha: Nepomorpha) collected in Ukraine, Belarus and Mexico. The worldwide distribution of the 16 species we found is updated, from which, 15 species are new records as epibionts of 15 species of aquatic true bugs. Only for the suctorian Discophrya gessneri Matthes, we confirm the previous record (epibiont of Aphelocheirus aestivalis Fabricius). We conclude that the relationship between the suctorians and aquatic true bugs is poorly studied and some suctorian genera (Discophrya Lachmann and Periacineta Collin) inhabit as nepomorphans as other aquatic insects (Coleoptera). However the high degree of specificity at the species level of these genera is evident, for which we provide some possible explanations according to the group of basibiont

Ciliates as Symbionts

Although many ciliates are free-living, more than 140 families of ciliates (Alveolata, Ciliophora) include symbiotic species of animals. Symbiosis, defined as an interaction between two species, is analyzed in this chapter to show a wide diversity of symbiotic systems in ciliates (epibiosis, commensalism, mutualism, and parasitism), providing some data about ciliate strategies showing their success as symbionts. Some species are free-living as well symbionts, facultative symbionts, and obligate symbionts. Analysis of reconstructions of ancestral state evidence that the parasitism arose numerous times and independently among the lineages of ciliates. At least three evolutionary routes can be traced: (1) transition from free-living to mutualism and parasitism, (2) transition from free-living to parasitism, and (3) regression from parasitism to free-living. The evolution of the symbiosis in ciliates demonstrates a higher diversification rate concerning free-living ciliates. The analysis of the evolution of the life cycles complexity, exploring molecular data of the phases of the ciliate cycle in their hosts is also essential. We propose new approaches for an integrative study of symbiotic ciliates

A taxonomic revision of order Pilisuctorida (Ciliophora, Apostomatia) with keys to the subordinate taxa

Dovgal, Igor, Mayén-Estrada, Rosaura (2015): A taxonomic revision of order Pilisuctorida (Ciliophora, Apostomatia) with keys to the subordinate taxa. Zootaxa 4040 (5): 543-558, DOI: http://dx.doi.org/10.11646/zootaxa.4040.5.

Suctorians (Ciliophora: Suctoria) as epibionts of decapods of families Cambaridae and Pseudothelphusidae

Ramírez-Ballesteros, Mireya, Mayén-Estrada, Rosaura (2019): Suctorians (Ciliophora: Suctoria) as epibionts of decapods of families Cambaridae and Pseudothelphusidae. Zootaxa 4648 (2): 384-392, DOI: https://doi.org/10.11646/zootaxa.4648.2.1

Ecological Study of the Active Ciliate Community from Bromeliads during the Humid Season in Different Types of Forests of the Mexican Neotropics

Bromeliads are a Neotropical family of monocots, colonized by several families of ciliates, with some species that inhabit only this type of microecosystems. Ecological factors such as the presence of water, plant volume, seasonality and predators, have been recognized as important factors, which play a role in the ciliate community structure in tank bromeliads. The objective of this study is to describe different communities of active ciliates from epiphytic and terrestrial bromeliads that inhabit the dry tropical forest, montane cloud forest, oak forest and semideciduous tropical forest in the Mexican Neotropics during the humid season of the year 2016. We found 22 species of active ciliates. A higher richness of ciliate species was found in the bromeliads of the montane cloud forest. Based on statistical tests, we determine that the pH and water temperature, plant diameter, its distance above the ground and altitude above sea level in relation to ciliate abundance explain <50% of the variation; however, the combination of plant diameter and its distance above the ground shows a positive effect in relation to ciliate abundance. We provide new evidence that bromeliads that inhabit mountains and lowland forests in a larger geographic area host ciliate communities with different species composition

Distribution and prevalence of 15 species of epibiont peritrich ciliates on the crayfish Cambarellus patzcuarensis Villalobos, 1943 in Lake Patzcuaro, Michoacan, Mexico

The goal of the present study was to know the distribution and prevalence of ciliated Protozoa attached to the exoskeleton and gills of the crayfish, Cambarellus patzcuarensis. Samples of crayfish were taken at two sites in Patzcuaro Lake, Michoacan, Mexico. Fifteen species of ciliated Protozoa (peritrichs) were found attached as epibionts on the crayfish. Their distribution and prevalence on 14 body parts of the basibiont is presented. Community structures were analysed using Jaccard's index and principal component analysis. The results showed that the gills had no similarity with respect to the other body parts as regards peritrich attachment. The pereiopods and the uropods were the body parts with the highest species richness, the gills had the lowest. Cothurnia variabilis is the only species with a high degree of specificity to the body region to which it is attached (gills). Of the 15 species found, only one has been reported exclusively as an epibiont on crustaceans

First record of Lagenophrys dennisi (Ciliophora : Peritrichia) on the exoskeleton of crayfish Cambarellus patzcuarensis

Lagenophrys dennisi, a peritrich ciliate, was observed attached to the exoskeleton of the crayfish Cambarellus patzcuarensis in lake Patzcuaro, Michoacan, Mexico. Lagenophrys dennisi presents a hemispheroidal, suboval or oval lorica in dorsal view, the distinctive lorica aperture consists of a pair of lips highly arched unthickened, and smooth. Comparison of morphometric characters of the ciliate with previous records is made. Structures such as a "V"-shaped lorica suture, collar ridges, and myoneme are proposed for species identification. An anterior crescentic thickening on the dorsal surface of the lorica was observed under the scanning electron microscope. lagenophryids were associated with 11 of 13 body parts with antennules and rostrum showing the highest prevalence. lagenophrys dennisi was also found attached to submerged glass slides. This study represents the first record of L. dennisi on C. patzcuarensis and the first record of its presence in Mexico

Ciliate species from tank-less bromeliads in a dry tropical forest and their geographical distribution in the Neotropics

Durán-Ramírez, Carlos Alberto, Mayén-Estrada, Rosaura (2018): Ciliate species from tank-less bromeliads in a dry tropical forest and their geographical distribution in the Neotropics. Zootaxa 4497 (2): 241-257, DOI: https://doi.org/10.11646/zootaxa.4497.2.