Copterus tyloloricatus (Ciliophora, Suctorea), a new suctorian genus and species.

We present the description of the new suctorian genus Copterus gen. n. with type species Copterus tyloloricatus sp. n. from the family Acinetidae, inhabiting the prosomes and urosomes of calanoid copepods from the northern North Pacific Ocean. The new taxon is characterized by (i) an ellipsoidal to triangular, asymmetric, dorsoventrally flattened cell body, which lies horizontally on the lorica surface; (ii) an unflattened lorica; and (iii) the presence of three to five radially arranged bundles of tentacles positioned at the edge of the body or on actinophores.

Epibionts provide their basibionts with associational resistance to predation but at a cost.

Epibiosis is increasingly considered a survival strategy in space-limited environments. However, epibionts can create a new interface between its host, environment and potential predators which may alter predator-prey relationships and biological functioning. Ex-situ experiments investigated the potential costs and benefits of epibiont barnacles on mortality and feeding rate of the mussel, Mytilus edulis, and its predator, the whelk Nucella lapillus. Mussels with living epibiont barnacles suffered no mortality from whelk predation, but when barnacles were absent, mortality was ∼21% over 48 days. Further comparisons revealed the structural complexity of barnacles provided mussels with protection from whelk predation, while the presence of living barnacles increased predator-prey encounters but led to predators targeting barnacles over mussels. Feeding trials revealed feeding rate increased by ∼24% in mussels with living epibionts over mussels with dead or without epibionts, indicating potential costs of hosting epibionts. Our results show that epibionts provide important associational resistance for mussels against whelk predation but a potential cost to the mussel of hosting epibionts requiring increased energy acquisition. These findings advance our understanding of associational resistance derived from epibionts and serve to highlight the potential trade-offs affecting basibiont functioning while showing the importance of positive ecological interactions in ecosystem structure and functioning.

Delayed response of hermit crabs carrying anemones to a benthic impact experiment at the deep-sea nodule fields of the Peru Basin?

The deep Peru Basin is characterised by a unique abyssal scavenging community featuring large numbers of hermit crabs (Probeebei mirabilis, Decapoda, Crustacea). These are atypical hermit crabs, not carrying a shell, but on some occasions carrying an anemone (Actiniaria). The reason why some hermit crabs carry or not carry anemones is thought to be indicative of a changed environment, outweighing the cost/benefit of their relationship. Here we present the temporal variation of abundances of P. mirabilis with and without anemones, spanning more than two decades, following a benthic impact experiment. An overall decrease in hermit crab densities was observed, most noticeable and significant after 26 years and characterised by a loss of Actiniaria on the Probeebei mirabilis' pleon. Whether this is a delayed response to the benthic impact experiment carried out 26 years' prior or a natural variation in the population remains to be corroborated by an extension of the time-series. Attention is drawn to the limitations of our knowledge over time and space of the abyssal community dynamics and the urgent necessity to fill in these gaps prior to any type of deep-sea exploitation.

Coevolutionary Implications of Obligate Commensalism in Sea Turtles: the Case of the Genus Hyachelia Barnard, 1967 (Crustacea, Amphipoda).

Obligate commensalism in the marine environment and its evolutionary role are still poorly understood. Although sea turtles may serve as ideal substrates for epibionts, within amphipods, only the genus Hyachelia evolved in obligate commensalism with turtles. Here, we report a new host record for Hyachelia lowryi on the hawksbill turtle and describe a larger distribution of the genus in the Atlantic Ocean on green and loggerhead turtles. Hyachelia spp. were sampled from nesting sites of Caretta caretta and feeding grounds of Eretmochelys imbricata and Chelonia mydas along the Brazilian coast. Insights regarding the coevolution of this remarkable genus with its hosts based on molecular analyses are inferred based on mitochondrial (COI) and nuclear (18SrRNA) genes using new and previously available sequences from the infraorder Talitrida. Divergence times for Hyachelia are around the Cretaceous (~127.66 Mya), corresponding to an ancient origin and in agreement with modern green turtle (Chelonioidea) radiation. Later, diversification of Hyachelia species is dated at about 26 Mya, suggesting a coevolutionary association between amphipods and Carettini/Chelonini sea turtles.

Truly a hyperparasite, or simply an epibiont on a parasite? The case of Cyclocotyla bellones (Monogenea, Diclidophoridae).

Cyclocotyla bellones Otto, 1823 (Monogenea, Diclidophoridae) is one of the few monogenean species reported as hyperparasitic: the worms dwell on cymothoid isopods, themselves parasites of the buccal cavity of fishes. We present here observations based on newly collected monogenean specimens from Ceratothoa parallela (Otto, 1828), an isopod parasite of Boops boops off Algeria and also investigated its diet to address whether Cy. bellones is indeed a hyperparasite, i.e., whether it feeds on the isopod. We also compared the body shape of various monogeneans belonging to the same family as Cy. bellones, the Diclidophoridae, including Choricotyle cf. chrysophryi Van Beneden & Hesse, 1863, collected from Pagellus acarne off Algeria. No morphological character of the anterior organs suggested any special adaptation in Cy. bellones to the perforation of the crustacean cuticle. The wall of the oesophagus and of the intestine of Cy. bellones was lined with a dark pigment similar to what is usually observed in haematophagous polyopisthocotyleans, and which is derived from ingested fish blood. We noticed that an anterior elongate stem exists only in diclidophorids dwelling on parasitic isopods and never in those attached to the gills. We hypothesize that the anterior stem of the body of Cy. bellones is an anatomical adaptation for the monogenean to feed on the fish while dwelling on the isopod. We thus consider that Cy. bellones is an epibiont of the parasitic crustacean, as it uses it merely as an attachment substrate, and is not a true hyperparasite.

Title: Vraiment un hyperparasite, ou simplement un épibionte sur un parasite ? Le cas de Cyclocotyla bellones (Monogenea, Diclidophoridae). Abstract: Cyclocotyla bellones Otto, 1823 (Monogenea, Diclidophoridae) est l'une des rares espèces de monogènes signalées comme hyperparasites : les vers vivent sur des isopodes cymothoïdes, eux-mêmes parasites de la cavité buccale des poissons. Nous présentons ici des observations basées sur des spécimens de monogènes nouvellement collectés de Ceratothoa parallela (Otto, 1828), un isopode parasite de Boops boops au large de l'Algérie et avons également étudié son régime alimentaire pour déterminer si Cy. bellones est bien un hyperparasite (c'est-à-dire, se nourrit-il de l'isopode ?). Nous avons également comparé la morphologie de divers monogènes appartenant à la même famille que Cy. bellones, les Diclidophoridae, dont Choricotyle cf. chrysophryi Van Beneden & Hesse, 1863, collecté sur Pagellus acarne au large de l'Algérie. Aucun caractère morphologique des organes antérieurs ne suggérait d'adaptation particulière à la perforation de la cuticule des crustacés chez Cy. bellones. La paroi de l'œsophage et de l'intestin de Cy. bellones était tapissée d'un pigment foncé semblable à ce que l'on observe habituellement chez les Polyopisthocotylea hématophages, et qui est issu du sang de poisson ingéré. Nous avons remarqué qu'une partie allongée antérieure n'existe que chez les Diclidophoridae vivant sur des isopodes parasites et jamais chez ceux attachés aux branchies. Nous émettons l'hypothèse que la partie antérieure du corps de Cy. bellones est une adaptation anatomique permettant au monogène de se nourrir du poisson tout en vivant sur l'isopode. Nous considérons donc que Cy. bellones est un épibionte du crustacé parasite, puisqu'il ne l'utilise que comme substrat pour son attachement, et n'est pas un véritable hyperparasite.

Symbiont Community Composition in Rimicaris kairei Shrimps from Indian Ocean Vents with Notes on Mineralogy.

Hydrothermal vent ecosystems are home to a wide array of symbioses between animals and chemosynthetic microbes, among which shrimps in the genus Rimicaris is one of the most iconic. So far, studies of Rimicaris symbioses have been restricted to Atlantic species, including Rimicaris exoculata, which is totally reliant on the symbionts for nutrition, and the mixotrophic species Rimicaris chacei. Here, we expand this by investigating and characterizing the symbiosis of the Indian Ocean species Rimicaris kairei using specimens from two vent fields, Kairei and Edmond. We also aimed to evaluate the differences in mineralogy and microbial communities between two cephalothorax color morphs, black and brown, through a combination of 16S metabarcoding, scanning electron microscopy, fluorescent in situ hybridization, energy-dispersive X-ray spectroscopy, and synchrotron near-edge X-ray absorption structure analyses. Overall, our results highlight that R. kairei exhibits similar symbiont lineages to those of its Atlantic congeners, although with a few differences, such as the lack of Zetaproteobacteria. We found distinct mineralization processes behind the two color morphs that were linked to differences in the vent fluid composition, but the symbiotic community composition was surprisingly similar. In R. exoculata, such mineralogical differences have been shown to stem from disparity in the microbial communities, but our results indicate that in R. kairei this is instead due to the shift of dominant metabolisms by the same symbiotic partners. We suggest that a combination of local environmental factors and biogeographic barriers likely contribute to the differences between Atlantic and Indian Ocean Rimicaris symbioses. IMPORTANCE Hydrothermal vent shrimps in the genus Rimicaris are among the most charismatic deep-sea animals of Atlantic and Indian Oceans, often occurring on towering black smokers in dense aggregates of thousands of individuals. Although this dominance is only possible because of symbiosis, no study on the symbiosis of Indian Ocean Rimicaris species has been conducted. Here, we characterize the Rimicaris kairei symbiosis by combining molecular, microscopic, and elemental analyses, making comparisons with those of the Atlantic species possible for the first time. Although most symbiotic partners remained consistent across the two oceans, some differences were recognized in symbiont lineages, as well as in the mechanisms behind the formation of two color morphs with distinct mineralogies. Our results shed new light on relationships among mineralogy, environmental factors, and microbial communities that are useful for understanding other deep-sea symbioses in the future.

Investigating the epibiotic peritrich Zoothamnium intermedium Precht, 1935: Seasonality and distribution of its relationships with copepods in Chesapeake Bay (USA).

Zoothamnium intermedium is an obligate epibiont ciliate and has been found in a diverse array of hosts and environments. Different studies have reported conflicting distribution patterns and host preferences, even though studies in Chesapeake Bay have suggested that the ciliate has a strong host specificity for two calanoid copepod species. We examined the life cycle, host preferences, and ecological conditions conducive to Z. intermedium presence on copepods in Chesapeake Bay, the largest estuary in North America. The York River tributary was sampled biweekly from fall 2014 through summer 2015 for plankton, peritrichs and bacteria in the water column. Bacterial abundance in the water column peaked in fall and late spring, coinciding with increased abundance and species richness of non-epibiont peritrichs. Among the plankton, only the calanoid copepods Acartia tonsa and Centropages hamatus were colonized by Z. intermedium. The peritrich epibiont displayed higher colonization rates on C. hamatus even when A. tonsa was far more abundant. Multivariate correlation analysis of infestation prevalence on A. tonsa showed a strong correlation with dissolved oxygen, salinity and water temperature. Such correlations, along with differences in host species biology, might be driving the seasonality of this epibiotic relationship.

Epibiont assemblages on limpet shells: Biodiversity drivers in intertidal rocky shores.

Limpet shells can harbour a high diversity of species. Individuals of four limpet species (Patella depressa, Patella ulyssiponensis, Patella vulgata and Siphonaria pectinata) were collected monthly during one year in southern Portugal. Epibiont organisms were identified, counted and the percentage cover of facilitator taxa was also recorded. A total of 86 taxa were identified with abundance reaching 674 epibionts on a single basibiont shell. P. ulyssiponensis showed the highest epibiont species diversity and richness while P. depressa and P. vulgata showed similar diversity and richness. P. depressa had a more even epibiotic community mainly due to higher densities of Chthamalus sp. Overall, basibiont species was the key factor determining the epibiotic community, followed by month/season and erect algae. The presence of erect algae potentiated the epibionts diversity on limpet shells, whereas the occurrence of barnacles tended to decrease it and the presence of crustose algae had no significant effect on epibionts diversity. These findings shed further light on the biological and ecological complex relationships among keystone species inhabiting intertidal rocky shores.

The alien octocoral Carijoa riisei is a biogenic substrate multiplier in artificial Brazilian shipwrecks.

Despite the obvious negative effects caused by invasive species, some recent studies have shown that the impacts at local scale are diverse and not necessarily negative. Arborescent benthic organisms such as octocorals form three-dimensional structures capable of increasing the amount of substrate available and providing shelter for epibiont species. We investigated the role of the alien octocoral Carijoa riisei on the diversity of benthic communities in three shipwrecks on the north-eastern coast of Brazil. We expected that (a) the fauna associated with the octocoral are richer and more diverse compared to the adjacent; (b) some species are exclusively associated with C. riisei; (c) the species that are present both in the areas with and without C. riisei have a greater abundance when associated with the octocoral. For this, we compared the macrobenthic communities associated with C. riisei to those found in adjacent areas where the octocoral was absent. Our study showed that the communities associated with the octocoral were 1.5 times richer and 10 times more abundant than adjacent communities, with 29 exclusive taxa. The dominant taxa were the amphipods Ericthonius brasiliensis and Podocerus brasiliensis and polychaetes of the family Syllidae. These taxa were present in areas with presence and absence of C. riisei, but their abundance was significantly greater where the octocoral was present. Our results reinforce the idea that Carijoa riisei acts as an ecosystem engineer in coastal reefs, creating new habitats and increasing diversity at a local scale, even though it is an alien species.

A new chelonibiid from the Miocene of Zanzibar (Eastern Africa) sheds light on the evolution of shell architecture in turtle and whale barnacles (Cirripedia: Coronuloidea).

The fossil history of turtle and whale barnacles (Coronuloidea: Chelonibiidae, Platylepadidae, Coronulidae and †Emersoniidae) is fragmentary and has only been investigated in part. Morphological inferences and molecular phylogenetic analyses on extant specimens suggest that the roots of whale barnacles (Coronulidae) are to be found among the chelonibiid turtle barnacles, but the hard-part modifications that enabled early coronuloids to attach to the cetacean skin are still largely to be perceived. Here, we reappraise a fossil chelonibiid specimen from the Miocene of insular Tanzania that was previously referred to the living species Chelonibia caretta. This largely forgotten specimen is here described as the holotype of the new species †Chelonibia zanzibarensis. While similar to C. caretta, †C. zanzibarensis exhibits obvious external longitudinal parietal canals occurring in-between external longitudinal parietal septa that abut outwards to form T-shaped flanges, a character so far regarded as proper of the seemingly more derived Coronulidae and Platylepadidae. Along with these features, the presence of a substrate imprint on the shell exterior indicates that †C. zanzibarensis grasped its host's integument in much the same way as coronulids and platylepadids, albeit without the development of macroscopic parietal buttresses and bolsters. Thin section analyses of the inner parietal architecture of some extant and extinct coronuloids conclusively demonstrate that vestiges of comparable external parietal microstructures are present in some living members of Chelonibiidae. This observation strengthens the unity of Coronuloidea while significantly contributing to our understanding of the evolution of the coronuloid shell structure in adapting to a diverse spectrum of hosts.

A checklist of species of the family Zoothamniidae (Ciliophora: Peritrichia), symbionts of crustaceans.

Eight genera are included in the family Zoothamniidae, and at the present the data of the epibiotic species on crustaceans is not updated. Thus, the main goal of the present work is to provide the checklist of zoothamniids worldwide reported as associated to several groups of crustaceans, including some data of their geographic distribution, and also to provide the complete list of species of this peritrich group. We obtained all available data of family Zoothamniidae and checked their taxonomic status. Then we provided the complete list of species including those reported as epibionts on crustacean hosts. We obtained 156 species included in eight genera of Zoothamniidae, being 85 species recorded as symbionts on 86 species of hosts. Genus Zoothamnium contained the higher number (56) of epibiotic species on crustaceans, and genus Pseudohaplocaulus has not been reported for any crustacean. The reviewed data highlights the concentration of records in Europe, and stands out the need to amplify sampling and studies in the Southern Hemisphere. The main groups of crustaceans infested by zoothamniids are the amphipods, isopods and decapods.

New Echinoderm-Crab Epibiotic Associations from the Coastal Barents Sea.

During diving surveys for a Russian research project that monitored introduced species, red king crabs (Paralithodes camtschaticus) were collected at a coastal site of the Barents Sea to study the structure and dynamics of this species. Sampling of the organisms colonizing the crabs was part of this research project. For the first time, the presence of relatively large specimens of the common starfish Asterias rubens as epibionts of P. camtschaticus was observed in July 2010, 2018, and 2019. In 2010 and 2019, we also found three other echinoderm species (the Atlantic sea cucumber Cucumaria frondosa, the green sea urchin Strongylocentrotus droebachiensis, and the brittle star Ophiura sarsii). These findings add to the current list of associated species on king crabs not only in the Barents Sea but also in native areas of this host. Red king crabs have been documented as predators for these echinoderm species, and our records show additional possible interactions between king crabs and echinoderms in this region. More likely, the epibiotic lifestyle allows these echinoderms to avoid predation from red king crabs. There are no potential disadvantages derived by red king crabs through their relationships with the echinoderm epibionts due to low occurrences of these associations. We suggest no negative effects for the local red king crab population and populations of other commercial species in the Barents Sea.

Fish-farming bolsters algal fouling and negatively affects condition and reproduction in European pond turtles (Emys orbicularis).

Fish-farming can lead to eutrophication of freshwater environments through the increase in organic matter resulting from food supplementation and fish wastes. Eutrophication can induce an excessive development of plants and algae on various substrates, including living organisms (algal epibiosis). Although algal epibiosis has been shown to reduce mobility by increasing drag in marine species, its consequences on host species in freshwater ecosystems remain poorly known. In this study, we investigated the individual (age and sex) and environmental (extensive versus intensive fish-farming) determinants of epizoic algae presence and abundance on European pond turtles (Emys orbicularis). We also explored the potential consequences of algal epibiosis on fitness-related traits of E. orbicularis. Based on a large sample size (1112 turtles from 23 ponds), we found that the abundance of algae growing on turtles increased during spring and summer. However, such increase was different across ages and sex; presumably reflecting the influence of thermoregulation (required to increase metabolic rates to sustain growth and reproduction) and thus, periodical drying of the shell, in reducing algal cover. We also found that intensive fish-farming increased algal epibiosis, especially when fish-farming involved food supplementation. Finally, we found that adult female body condition and reproduction of turtles were negatively linked to algal cover, thereby suggesting a potential negative impact of algal fouling on some fitness-related traits of adult female turtles. Future studies should usefully assess the demographic consequences of algal epibiosis induced by fish farming in this long-lived vertebrate.

Ecological and Industrial Implications of Dynamic Seaweed-Associated Microbiota Interactions.

Seaweeds are broadly distributed and represent an important source of secondary metabolites (e.g., halogenated compounds, polyphenols) eliciting various pharmacological activities and playing a relevant ecological role in the anti-epibiosis. Importantly, host (as known as basibiont such as algae)-microbe (as known as epibiont such as bacteria) interaction (as known as halobiont) is a driving force for coevolution in the marine environment. Nevertheless, halobionts may be fundamental (harmless) or detrimental (harmful) to the functioning of the host. In addition to biotic factors, abiotic factors (e.g., pH, salinity, temperature, nutrients) regulate halobionts. Spatiotemporal and functional exploration of such dynamic interactions appear crucial. Indeed, environmental stress in a constantly changing ocean may disturb complex mutualistic relations, through mechanisms involving host chemical defense strategies (e.g., secretion of secondary metabolites and antifouling chemicals by quorum sensing). It is worth mentioning that many of bioactive compounds, such as terpenoids, previously attributed to macroalgae are in fact produced or metabolized by their associated microorganisms (e.g., bacteria, fungi, viruses, parasites). Eventually, recent metagenomics analyses suggest that microbes may have acquired seaweed associated genes because of increased seaweed in diets. This article retrospectively reviews pertinent studies on the spatiotemporal and functional seaweed-associated microbiota interactions which can lead to the production of bioactive compounds with high antifouling, theranostic, and biotechnological potential.

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

Epibiosis is common among ciliates and crustaceans because the calcified surface of the crustacean body offers a suitable site for colonization by the epibiont. Suctoria are among the most common epibiont ciliate groups of freshwater decapod crustaceans. The aim of this study is to increase knowledge of suctorians as epibionts of freshwater decapod crustaceans of the families Cambaridae and Pseudothelphusidae. Crustaceans were collected from three rivers and one pond in Chiapas, Mexico. Six species of suctorian epibionts were recorded: Acineta tuberosa, Podophrya maupasi, P. sandi, Tokophrya cyclopum, T. quadripartita and Trichophrya epistylidis. This is the first record of ciliate epibionts on members of family Pseudothelphusidae (represented by Phrygiopilus montebelloensis and Raddaus bocourti), and the first record of suctorians epibionts on Procambarus (Austrocambarus) sp. (Cambaridae).

In a squeeze: Epibiosis may affect the distribution of kelp forests.

The processes limiting the population recovery of the kelp Saccharina latissima after recent large-scale loss from the south coast of Norway are poorly understood. Previous investigations do, however, suggest that the impacts of biotic interactions (epibiosis and competition) and increased water turbidity are important. We investigated the depth-related patterns of growth, epibiosis, and mortality in two sample populations of kelp, from the south and the southwest coast of Norway. The investigations were performed over a period of seven months, in a crossed translocational study, where kelps were mounted on rigs at six depths (1, 3, 6, 9, 15, and 24 m). In a second experiment, the amounts of light blocked by different epibiont layers growing on the kelp frond were investigated. While growth decreased with depth in spring and summer, the kelp grew faster at 15 m than at shallower depths in fall. Survival was low both in shallow water and below 15 m depth. Epibionts covered the kelp growing at depths from 1 to 9 m, and the laboratory study showed that the coverage may have deprived the individuals of as much as 90% of the available light. Although the depth-related results we present apply-in the strictest sense-only to kelp translocated on rigs, we argue that the relative patterns are relevant for natural populations. Growth and survival of S. latissima is likely to be reduced by heavy loads of epibionts, while depths where epibionts are sparse may be close to the lower limit of the kelps depth distribution along the south coast of Norway. This suggests that a vertical squeeze, or narrowing of the distribution range of kelp forests may be occurring in Norway.

Rhabdostylid Ciliates (Ciliophora, Peritrichia, Epistylididae) as Epibionts on Chironomid Larvae: Evidence of High Specificity and Association with Organic Pollution.

Although epibiont ciliates make up a significant part of the biomass in aquatic ecosystems and may cause perceptible alterations in the population dynamics of their hosts, studies on the extrinsic and intrinsic factors that control the abundance of these microorganisms are scarce in literature. In the present study, we investigated the colonization site and intensity of rhabdostylid epibiont upon chironomid larvae and assessed the influence of organic pollution and chironomid communities on the prevalence and abundance of epibiont ciliates at five sampling stations (two in rural areas and three in urban areas) along a neotropical urban stream over a period of 12 months. Among the 24 genera of chironomids found and the 31,976 larvae analyzed, 96.12% belonged to the Chironomus genus, of which 16.95% (5212) were colonized by Rhabdostyla aff. chironomi. The infestation intensity varied from one to 67 individuals per host with an average intensity of 4.86 (± 33.45). Ciliates were only found colonizing the chironomids' ventral tubules. The high number of chironomid larvae, high host- and site-specificity, low infestation intensity, and absence of apparent structural damage to hosts evidence an intimate relationship between epibiont and basibiont as well as a possibly long coevolutionary history. Both prevalence and abundance of epibiont ciliates were correlated to the pollution rate of the studied stream. There was an alteration in the composition and structure of the chironomid community along the sampling stations. Numeric dominance of Chironomus-tolerant chironomids and its direct correlation to infestation prevalence and to ciliates abundance highlights the predilection of both peritrich ciliates and Chironomus larvae for organically-enriched environments.

Description of Two New Species of the Genus Vorticella (Ciliophora: Peritrichia) Epibionts on Pomacea canaliculata (Mollusca: Ampullariidae: Gastropoda) in Southern Brazil.

The peritrich ciliates Vorticella veloxiiforme n.sp. and Vorticella ampullaria n.sp. were found as epibionts on the ampullarid mollusk Pomacea canaliculata collected from Patos Lagoon, Rio Grande do Sul state, Brazil. The detailed morphology of both species was investigated using live and stained specimens, as well as scanning electron microscopy. Zooids of Vorticella veloxiiforme are cup shaped measuring 57 X 41 µm on average. A J-shaped macronucleus lies in the upper half of the cell. One contractile vacuole was observed in the upper part of the cell. V. ampullaria presents an elongate zooid measuring 70 X 25 µm on average. A C-shaped macronucleus lies in the middle of the cell. Two contractile vacuoles are present: one close to the peristome and the other in the lower half of the cell. The pattern of oral polykinetids was typical of the genus, with all infundibular polykinetids composed by three rows of kinetosomes each. SEM revealed a regular pattern of pores present on the zooid membrane of both species. Analyses of the 18s rDNA placed the two new species in the order Vorticellida close to described species of Vorticella.

A checklist of species of Vorticellidae (Ciliophora: Peritrichia) epibionts of crustaceans.

The family Vorticellidae includes 21 genera, mainly with species worldwide distributed, as free-living, and attached to diverse organisms as epibionts. The goal of this paper is to provide an updated checklist of the worldwide vorticellids reported attached to the crustaceans. We revised and checked all available records of species of vorticellids including their crustacean hosts. We found 96 vorticellid species belonging to 14 genera with at least a report on the body of 81 species of crustaceans. Four genera of ciliates (Vorticella, Pseudovorticella, Carchesium and Intranstylum) had the major number of species living as epibionts. We provide also the complete list of the species of vorticellids, and conclude the need of a taxonomic revision of the family.

A checklist of epibiont suctorian and peritrich ciliates (Ciliophora) on halacarid and hydrachnid mites (Acari: Halacaridae Hydrachnidia).

Based on published records and original data, a list of the epibiont suctorian and peritrich ciliates (Ciliophora) on halacarid and hydrachnid mites is presented. Altogether 13 suctorian and 10 peritrich species from hydrachnid and halacarid mites were listed. From this list, six suctorian and one peritrich species have been reported from halacarid mites, while four suctorian and four peritrich species were found on hydrachnid mites determined up to species level. The remaining specimens were determined upto the generic level. The halacarid and hydrachnid species do not share any suctorian and peritrich species and some of the ciliate species are specific to certain taxonomic groups of the hosts.The host specificity of both suctorian and peritrich ciliates, localization on the host body and environment are discussed. Some ciliate species specific to hydrachnid mites prefer lotic or lentic habitats. In most cases, both suctorian and peritrich ciliates prefer only marine or only fresh water bodies. It was also mentioned that both suctorian and peritrich ciliates have not distinct preferences in localization on their host body.