Halacarid Mites Research Articles

Psammobiont halacarid mites (Acari: Halacaridae) from Türkiye: description of two new species of the genus Atelopsalis Trouessart, 1896 and Scaptognathus Trouessart, 1889 and two new records

In this paper, two new species from the genera Atelopsalis Trouessart, 1896 and Scaptognathus Trouessart, 1889 are described from the eastern Mediterranean Sea, off the coast of Antalya, Türkiye. Atelopsalis mediterranea sp. nov. is described based on female, male, and deutonymph specimens collected from soft sand sediment in Kaş, Antalya. Scaptognathus antalyaensis sp. nov. is described based on female and male specimens from soft sediment in Kundu, Antalya. In addition to these new species, two arenicolous halacarid mites, Acarochelopodia delamarei Angelier, 1954 and Anomalohalacarus anomalus (Trouessart, 1894), are reported from the Turkish coasts for the first time. Both psammic halacarid mites were found in medium coarse sand sediment habitats at Örnekköy Beach.

The genus Maracarus (Acari: Halacaridae), description of three new species and one new record from Türkiye

Three new and one previously known species belonging to the halacarid mite genus Maracarus Bartsch, 2016 are described on the basis of the specimens collected from fine and medium coarse sand sediment from Muğla and Antalya, Türkiye. The new species, Maracarus almiri n. sp., Maracarus pedroi n. sp., and Maracarus terueae n. sp., are found to belong to the gracilipes group. Additionally, previously known species Maracarus gracilipes (Trouessart 1888) is reported for the first time from Turkish coast.

A new species of Agauopsis (Acari, Halacaridae) from South Korea belonging to A. brevipalpus group

A new marine halacarid mite of the genus Agauopsis Viets, 1927 is recorded from mussels in the intertidal bedrock of the southern coast of South Korea. Agauopsis bisetosa n. sp. belonging to the A. brevipalpus group, is characterized by an ‘H’-shaped areola on the anterior dorsal plate, two pairs of costae on the posterior dorsal plate, a tectum with a truncate anterior margin, posterior epimeral plate with two ventral setae, telofemur I with one ventral and two ventromedial dentate spines, and tibia II with one ventral and one ventromedial dentate spines. Notably, the presence of two ventral setae on the posterior epimeral plate is a unique characteristic of the new species. This study deals with a description of A. bisetosa n. sp., accompanied by detailed illustrations drawn under a differential interference contrast microscope and scanning electron microscope photomicrographs. Additionally, it includes a character comparison table of the A. brevipalpus group and a key for known Agauopsis species in the northwest Pacific, both including the new species.

Taxonomic diversity and biomass of the invertebrate fauna of nine drinking water treatment plants and their non-chlorinated distribution systems

Invertebrates such as Asellus aquaticus, halacarid mites, copepods and cladocerans are known to regularly occur in drinking water distribution systems (DWDS). An eight-year study investigated the biomass and taxonomic composition of invertebrates in the finished water of nine Dutch drinking water treatment plants (using surface water, ground water or dune-infiltrated water) and their non-chlorinated distribution systems. The main aims of the study were to examine the source waters’ influence on invertebrate biomass and composition in the distribution networks and to describe invertebrate ecology in relation to the habitat of filters and the DWDS.Invertebrate biomass of the finished drinking waters of the surface water treatment plants was significantly higher than in the finished waters of the other treatment plants. This difference was due to the higher nutrient levels of the source water. The main part of the biomass in the finished water of the treatment plants consisted of rotifers, harpacticoid copepods, copepod larvae, cladocerans and oligochaetes, which are small-sized, euryoecious and tolerate broad environmental conditions. Most of them reproduce asexually.Most species found in the DWDS are known to be detritivores, but all are benthic and euryoecious organisms, many of which have a cosmopolitan distribution. The euryoeciousness of these freshwater species was also shown by their occurrence in brackish waters and ground or hyporheic waters and the ability of many eurythermic species to overwinter in the DWDS habitat. These species are preadapted to the oligotrophic environment of the DWDS and can develop stable populations there. Most species can reproduce asexually and the sexually reproducing invertebrates (Asellus aquaticus, cyclopoids and probably also halacarids) have obviously overcome the potential problem of finding a mating partner. This study also showed a significant correlation of DOC in the drinking water with the invertebrate biomass. A. aquaticus was the dominant biomass component in six out of nine locations and was highly correlated with the Aeromonas counts in the DWDS. Thus, invertebrate monitoring in DWDS is an important additional parameter in understanding biological stability conditions in non-chlorinated DWDS.

Biases and distribution patterns in hard‐bodied microscopic animals (Acari: Halacaridae): Size does not matter, but generalism and sampling effort do

AbstractAimThe interplay between distribution ranges, species traits and sampling and taxonomic biases remains elusive amongst microscopic animals. This ignorance obscures our understanding of the diversity patterns of a major component of biodiversity. Here, we used marine Halacaridae to explore whether differences between marine provinces can explain their distribution patterns or if differential sampling efforts across regions prevent any macroecological inference. Furthermore, we test if certain functional traits influence their distribution patterns.LocationEurope.ResultsWhereas geographical variables provided a better explanation for differences in species composition, sampling effort and distance from marine biological stations accounted for the majority of differences in European Halacaridae richness. Species occurring in more habitats showed broader geographical ranges and accumulated more records. Species traits like generalism affected the distribution of halacarid species.Main ConclusionsWe propose that the sampling effort of halacarid mites in Europe might be explained by two different cognitive biases: the convenience of selecting certain sampling localities compared to others and the tendency of zoologists to scrutinise habitats where their target organisms are more common.

Changes in Water Source Cause Shifts in Invertebrate Biomass, Composition, and Regrowth in a Non-Chlorinated Drinking Water Distribution System

Invertebrates such as Asellus aquaticus, halacarid mites, copepods and cladocerans are common in drinking water distribution systems. The Zeeuws-Vlaanderen drinking water distribution system (DWDS) of Evides water company is divided into western and eastern sections, initially supplied with drinking water derived from a eutrophic reservoir (water) and groundwater, respectively. The drinking water derived from eutrophic reservoir water was characterised as less biologically stable than the drinking water from groundwater. Due to groundwater level protection measures, since 2015 the groundwater supply to the eastern section has been gradually replaced with supply from the drinking water treatment plant, which uses eutrophic reservoir water as source water. This change caused increased regrowth conditions, as observed by regulated microbial regrowth indicators (HPC22 and Aeromonas), increased invertebrate biomass, and the dominant occurrence of Asellus aquaticus, confirming observations in other Evides DWDSs. The results from the western section supplied with the same less biological stable drinking water, however, showed that the occurrence of microbial regrowth, invertebrate biomass and A. aquaticus is not only related to the biological stability of the supplied drinking water, but also to the influence of DWDS-specific conditions. The DWDS configuration as well as higher water demands in summer (western section) and/or higher sediment and Fe accumulation in the DWDS (eastern section) are suggested factors affecting regrowth and therefore subjects for further research.

An annotated checklist of halacarid mites (Acari, Halacaridae) from India.

A compilation of halacarid mite species (Halacaridae) from India has been carried out based on published records. Indian halacarid records were mostly found among algal habitats, some are also reported associated with pneumatophores and halophytes. Copidognathus is the most dominant genus with 19 species reported from the Indian coast. Reports of halacarid mites from Indian interstitial habitats are mostly doubtful and needs verification. Acarochelopodia delamarei, Copidognathus fabricii, Scaptognathus hallezi, Simognathus minutus should be excluded from Indian record. The real diversity and distribution of Indian halacarid fauna is far from being complete and future investigations may reveal further new taxa.

A checklist of halacarid and hydrachnid mites (Acari, Halacaridae amp; Hydrachnidia) associated with sponges (Porifera).

A compilation of halacarid and hydrachnid mite species found associated with sponges has been carried out based on published records. Altogether 78 halacarid mites species belonging to 15 genera viz. Agaue (9 species), Agauopsis (7 species), Arhodeoporus (1 species), Atelopsalis (1 species), Bradyagaue (1 species), Copidognathus (27 species), Halacarellus (7 species), Halacaropsis (2 species), Halacarus (5 species), Lohmannella (3 species), Maracarus (3 species), Rhombognathides (3 species), Rhombognathus (4 species), Spongihalacarus (1 species), and Thalassarachna (4 species) are reported. Twenty-four hydrachnid mite species belonging to three families viz. Hygrobatidae (2 species), Unionicolidae (20 species) and Pontarachnidae (2 species) are included. Some species of Unionicolidae are mentioned as possible sponge-mite species. Further studies, emphasizing developmental studies of unionicolid mites to get better ideas about associations with freshwater sponges are needed. Molecular sequencing will reveal more cryptic species and improve the quality of re-descriptions of currently recognized species in these sponge associated mites.

A checklist of halacarid mites (Acari, Halacaridae) associated with echinoderms (Echinodermata)

A compilation of halacarid mite species (Halacaridae) found associated with echinoderms (Echinodermata) has been carried out based on published records. In this paper, we listed 20 halacarid mite species associated with echinoderms altogether. These 20 species belong to 10 genera, viz. Agaue (2 species), Agauopsis (1 species), Copidognathus (5 species), Enterohalacarus (1 species), Halacarellus (4 species), Halacaropsis (1 species), Halacarus (2 species), Rhombognathides (2 species), Rhombognathus (1 species) and Thalassarachna (1 species).

A checklist of deep-sea halacarid mites (Acari, Halacaridae) found from more than 1000 m depth

A compilation of deep-sea halacarid mite species found from more than 1000 m depth has been carried out based on published records. Altogether 57 species belong to genera Agaue (6 species), Agauides (1 species), Atelopsalis (1 species), Bathyhalacarus (11 species), Bradyagaue (3 species), Colobocerasides (1 species), Copidognathus (16 species), Halacarellus (2 species), Halacarus (3 species), Lohmannella (5 species), Pelacarus (1 species), Thalassarachna (2 species), Werthella (4 species) and Werthelloides (1 species) are enlisted from deep-sea more than 1000 m depth. Forty-eight species are determined up to species level while 9 species determined up to generic level only. The richness of halacarid mites from more than 1000 m depth in different marine provinces is most likely related to the intensity of faunistic surveys.

Sympagic fauna in the northern part of the Barents Sea and adjacent Nansen Basin

Sympagic fauna in the northern Barents Sea and southern Nansen Basin were studied between 1 April 2019 and 5 May 2019 during the expedition Transarctica-2019. Ice cover was represented primarily by thin and medium first-year ice and less by second-year ice. The total abundance of sympagic fauna varied from 0 to 5906.2 ind/m2, with averages of 2244 ± 485 ind/m2 and 3437 ± 1713 ind/m2 recorded for the northern Barents Sea shelf and Nansen Basin, respectively. Sea-ice fauna was dominated by copepod nauplii (66.7%) and Harpacticoida (28.3%), while such taxa as Calanoida (1.8%), Amphipoda (1.5%), Nematoda (1.2%) and Acari (0.5%) were comparatively rare in the lowermost 10 cm of ice cores; Crustaceans were the most diverse group, whereas copepod nauplii was most abundant, especially in April and early May 2019. When compared with published data, diversity of sea-ice fauna in this study was lower for both the Barents Sea and Nansen Basin, and there were no statistically significant differences detected between the community compositions of the different geographic regions. The sea-ice motion reconstruction combined with the composition of sea-ice fauna, particularly the presence of ice nematodes, amphipods, and halacarid mites, suggest that the origin of the sympagic fauna is closely associated with the ice formation area near Franz Josef Land.

A checklist of halacarid mites (Acari: Halacaridae) associated with decapod crustaceans (Arthropoda, Crustacea, Decapoda)

A compilation of halacarid mite species (Halacaridae) found associated with decapod crustaceans (Arthropoda, Crustacea, Decapoda) has been carried out based on published records. In this paper, we listed 24 species associated with crustaceans altogether. These 24 species belong to 10 genera, viz. Arhodeoporus (1 species), Astacopsiphagus (1 species), Copidognathus (11 species), Halacarellus (2 species), Limnohalacarus (1 species), Lohmannella (1 species), Porohalacarus (1 species), Porolohmannella (1 species), Soldanellonyx (2 species), Thalassarachna (3 species). Majority of the association types are probably commensals or occasional invaders in nature and only a few species are assumed to be parasitic.

Deciphering the synergistic impact of elevated temperature and oil pollution on meiobenthic community structure: A benthocosm study

Meiobenthos has been considered as an excellent tool for biomonitoring assessment. Elevated temperature and oil pollution are considered as the most pervasive aspects of global environmental changes and matter of concern for contemporary society. Presently, very limited information is available about the synergistic effect of these stressors on meiobenthic community structure and tolerance potential from tropical intertidal environment. Here, we assessed their impacts on meiobenthic community by conducting a 60 days long benthocosm experiment selecting three sets of temperature (25°, 30° and 35 °C) and two sets of diesel oil (low and high) combinations. Gradual changes in their community composition were revealed discernibly with exposures to both the disturbances after 30 and 60 days of experimental period. Diversity profiles for the nematodes were less affected, but copepods showed a graded response of decreasing density with increasing dose of both the stressors. Other meiobenthic taxa such as halacarid mite, turbellaria and polycheate juveniles were adversely affected and eliminated from the treatments, howbeit abundance of ostracods, foraminiferans and bivalve settlers varied significantly. A 3-factor PERMANOVA indicated a significant effect of temperature, diesel, between their interaction and interaction among stressors and time on meiofaunal abundances. In case of free-living nematodes, temperature rise and diesel contamination synchronously led to an elimination of k-selected species like Halalaimus gracilis, H. longicaudatus, Oxystomina aesetosa and Pomponema sp. with a significant decrease in abundance of H. capitulatus and Oncholaimus sp. The r-selected species Daptonema invagiferoum, Sabatieria praedatrix, Theristus acer, Monhystera sp. and Thalassomonhystera sp. had endured even at high doses of diesel treatment in three different temperatures set up. The effects were evident in term of changes in life strategies with an increment of opportunistic species and increased trophic diversity of deposit feeders in treated sediments. Overall, elevated temperature together with diesel oil contamination were found to alter species dynamics within shallow intertidal meiobenthic communities, which might have significant Armageddon on benthic ecosystem functioning.

Parasitic halacarid mites (Acari, Halacaridae): survey on literature

The article deals with a survey on literature of parasitic halacarid mites. Exact nature of rela- tionship between mites and their invertebrate hosts is unknown for most of these associations, as live observations not found. Some species are assumed to be parasitic.

Evaluating the boundaries of marine biogeographic regions of the Southwestern Atlantic using halacarid mites (Halacaridae), meiobenthic organisms with a low dispersal potential.

AimWe evaluated traditional biogeographic boundaries of coastal marine regions in Southwestern Atlantic using DNA sequence data from common, rocky‐shore inhabiting, marine mites of the genera Agauopsis and Rhombognathus, family Halacaridae.MethodsWe investigated geographic population genetic structure using CO1 gene sequences, estimated divergence times using a multigene dataset and absolute time‐calibrated molecular clock analyses, and performed environmental niche modeling (ENM) of common marine mite species.Results Agauopsis legionium has a shallow history (2.01 Ma) with four geographically differentiated groups. Two of them corresponded to the traditional Amazonian and Northeastern ecoregions, but the boundary between the two other groups was inferred at the Abrolhos Plateau, not Cabo Frio. Rhombognathus levigatoides s. lat. was represented by two cryptic species that diverged 7.22 (multilocus data) or 10.01 Ma (CO1‐only analyses), with their boundary, again at the Abrolhos Plateau. ENM showed that A. legionium has suitable habitats scattered along the coast, while the two R. levigatoides cryptic species differ considerably in their niches, especially in parameters related to upwelling. This indicates that genetic isolation associated with the Abrolhos Plateau occurred in both lineages, but for the R. levigatoides species complex, ecological niche specialization was also an important factor.Main conclusionsOur study suggests that the major biogeographic boundary in the Southwestern Atlantic lies not at Cabo Frio but at the Abrolhos Plateau. There two biogeographically relevant factors meet (a) changes in current directions (which limit dispersal) and (b) abrupt changes in environmental parameters associated with the South Atlantic Central Waters (SACW) upwelling (offering distinct ecological niches). We suggest that our result represents a general biogeographic pattern because a barrier at the Abrolhos Plateau was found previously for the fish genus Macrodon (phylogeographic data), prosobranch mollusks, ascidians, and reef fishes (community‐level data).

Contributions to the knowledge of freshwater halacarid mites (Acari: Halacaridae) of Turkey

Based on the freshwater halacarid mite specimens collected from four different provinces (Antalya, Denizli, Isparta and Muğla) of Turkey, two species of the genus Halacarellus and Porohalacarus are reported and illustrated in the present study. Halacarellus hyrcanus (Viets, 1928) is only recored from Muğla, while Porohalacarus alpinus (Thor, 1910) is recorded from Isparta, Denizli and Antalya. The deutonymph of P. alpinus is given first time in this study with original illustrations. Additionally, comparisons of the worldwide idiosoma lengths and localities of the two species are presented here.

Does vertical distribution of meiobenthic community structure differ among various mangrove habitats of Sundarban Estuarine System?

Mangroves are the most productive environments that play significant ecological and socioeconomic roles. For the first time we investigated vertical stratification of meiofaunal community and nematode species composition from the sediments of five mangroves (Aegiceras corniculatum, Bruguiera gymnorrhiza, Avicennia alba, Rhizophora mangle and Sonneratia caseolaris) at Bali Island in the worlds’ largest mangrove ecosystem of Sundarbans, India. Among different mangrove species, S.caseolaris had the highest density of meiofauna with the lowest in B. gymnorrhiza. A total of eight taxa were recorded from the sediment of different mangrove habitats. In terms of percentage composition, free-living nematodes dominated followed by harpacticoid copepods, kinorhynch, ostracods, foraminifera, polychaete, halacarid mite and bivalve juvenile. The vertical profile of meiofaunal composition suggested upper 3–4 cm harboured 90% of total meiofauna, although they were present up to 15 cm depth. Environmental variables explained meiofaunal community structure. Availability of food sources such as phaeopigments, Chlorophyll a, organic carbon and sediment texture controlled meiofaunal distribution. The nematode fauna consisted of 52 species belonging to 39 genera and 20 families. The trophic structure of nematode taxa revealed a community dominated by epistrate feeders (2A) followed by selective deposit feeders (1A). Moreover, marine nematode genera were used to test Maturity Index (MI), life strategy or biological traits (i.e. c–p classes) and Index of Trophic Diversity (ITD) for assessing ecological health. Higher MI among different mangrove vegetation indicated a stable environment; moreover, biological trait analysis showed that mangrove sediments were dominated by r-strategists. Lower values of ITD index revealed a proportionate occurrence of trophic diversity in nematode communities among different vegetation. In the current context of habitat destruction and anthropogenic perturbations, investigation of ecological interactions between mangroves and meiofauna would be imperative for ecosystem monitoring and sustainable development in future.

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.

New record of the genus Scaptognathus (Acari: Halacaridae) from Antalya with a checklist of marine halacarid mites of Turkey

This paper presents the first results of a study on the Scaptognathus (Acari: Halacaridae) mites from the Mediterranean Sea coast of Turkey. Two species, S. hallezi Trouessart, 1894 and S. sabularius Andre, 1961, are newly recorded from Turkey. They are briefly described with drawings, habitats, and worldwide distributions. Additionally, a checklist is provided for the marine halacarid species of Turkey.

WATER MITES (ACARIFORMES: HYDRACHNIDIA, HALACAROIDEA) OF BOGS OF WESTERN SIBERIA (RUSSIA)

Water mites (Acariformes, Hydrachnidia, Halacaroidea) were studied in 8 different bogs and fens of Western Siberia. 28 species of Hydrachnidia and 5 species of Halacaridae were found in them. The species composition in the bogs was very different. In the fens the abundance and species diversity were higher than in sphagnum bogs and the fauna were based on spring species. The representatives of the halacarid mites dominated in sphagnum bogs, which were not found in the fens. The specific similarity of the studied bogs was low. At the same time, the peculiarities of seasonal dynamics in bogs and fens were similar and resembled temporary water bodies: high numbers in the spring and an abruptly decline in the summer, with a slight increase in autumn.