Aquatic Mites Research Articles

NEW RECORDS OF WATERMITES (HYDRACHNIDIA) COLLECTED FROM MACROPHYTE AND <i>Cladophora</i> sp. IN SOUTH AMERICA

Aquatic mites show a great morphological variability and inhabit a great diversity of freshwater habitats, especially taking advantage of the complexity of resources provided by South American aquatic plants. The relevance of aquatic mites in a microhabitat not studied so far about Amazonian macrophyte plants and Andean filamentous algae is analyzed. A new species of aquatic mite is described, and with it, the genus Piona and Arrenurus amazonicus are recorded for the first time in Colombian rivers; new records of Sperchon neotropicus associated with Cladophora sp. in the Andean subtropical zone of Argentina and Bolivia are reported. The functional classification proposed by Fernández and Fossati-Gaschignard for aquatic mites with their lifestyle and habitat preferences is contrasted and geographically expanded. Contributions such as this one to the knowledge of new species, biological data, and new localities of aquatic organisms are the basis of the urgent agenda of world biodiversity.

Density and Diversity analysis of Aquatic Mites in Snow-Fed River Ganga near Byasi, Tehri Garhwal, Uttarakhand

Density and Diversity analysis of Aquatic Mites in Snow-Fed River Ganga near Byasi, Tehri Garhwal, Uttarakhand

Insights into the fauna associated with Egeria densa at the upper section of the international Minho River estuary (NW Iberian Peninsula) 3 decades after its establishment

The macrophyte Egeria densa Planchon, 1849 is a freshwater plant native to the subtropical regions of South America. Fast vegetative reproduction and efficient dispersal allow this species to form extensive beds that produce high levels of oxygen in freshwater ecosystems, generating microhabitats that act as refuge and nursery for an array of organisms, increasing sedimentation and light availability. Despite its undisputable ecological role, it is considered invasive and is present on all continents except Antarctica with the first records in Europe occurring at the 20th century. At the international Minho River (NW Iberian Peninsula), the observation of its presence was noted in the 1990s and is now an established population in this ecosystem. This study is the first descriptive-taxonomical assessment of the associated fauna with the exotic macrophyte E. densa, using both morphological and molecular approaches, three decades after its establishment in the international Minho River. Results indicate the presence of a faunal assemblage, composed a total of 20 identified species, including platyhelminths, hydrozoans, bryozoans, molluscs (Gastropoda), annelids (Oligochaeta and Hirudinea), crustaceans (Ostracoda, Copepoda, Branchiopoda and Amphipoda), aquatic mites and insects. Paludicella aff. articulata (Ehrenberg, 1831), Girardia sinensis Chen & Wang, 2015, Lebertia insignis Neuman, 1880 and Ceriodaphnia rigaudi Richard 1894 are recorded for the first time in Portugal.

"Drifting-Density and Diversity of Aquatic Mites in the Spring- Fed Stream Heval from Garhwal Himalaya"

"Drifting-Density and Diversity of Aquatic Mites in the Spring- Fed Stream Heval from Garhwal Himalaya"

Checklist of water mites from mainland Portugal and its archipelagos

This study focuses on aquatic mites from the Portuguese Exclusive Economic Zone, including the mainland area, and Madeira and Azores archipelagos, aiming at compiling all existing information and generating a list of species and all their data on collecting sites. For the present work, we consider aquatic species, those that inhabit the marine, deep sea, intertidal, freshwater, transition water or brackish environments, with life-cycle occurring entirely at water habitats or their vicinity. Furthermore, breeding should take place in water aquatic lifestyles. The dataset search for this checklist started with the first descriptions of water acarids from the Azores Archipelago performed by Théodore Barrois. Primary sources for occurrence confirmation were Süßwasserfauna von Mitteleuropa book collection, The Global Biodiversity Information Facility (GBIF), complemented with an extensive Portuguese literature review and data biodiversity websites, e.g., European Water Mite Research (Watermite.org). In total, 102 valid species were found belonging to 41 genera, and 19 families, nested in the orders Mesostigmata, Sarcoptiformes and Trombidiformes. This is the first work compiling all the species of aquatic mites found in Portuguese territory, as well as data of collection, serving as the basis for future studies.

Occurrence of aquatic mites in terms of their density and diversity from snow-fed river Ganga near Deoprayag, Uttarakhand, India

Occurrence of aquatic mites in terms of their density and diversity from snow-fed river Ganga near Deoprayag, Uttarakhand, India

Diversity of Spring Invertebrates and Their Habitats: A Story of Preferences

Springs, as unique ecotonal habitats between surface and hypogean areas, are considered endangered aquatic ecosystems due to direct and indirect human impacts and climate change issues. They are distinctive water habitats that are often inhabited by a diverse but mostly stenotypic group of organisms. The present study considered 31 springs from the Apuseni Mountains (the Romanian Carpathians) that were classified as rheocrene, helocrene, and limnocrene based on their geomorphology and hydrology. Samples from three substrate types (rocks, sand, and bryophytes) were collected using standard methods for crenic invertebrates. A total of 64,462 individuals belonging to 17 invertebrate taxa were identified: aquatic worms, mollusks, crustaceans, water mites, and insects. Amphipoda and Diptera–Chironomidae were the dominant taxa in most springs. At a community level, patterns of habitat preference were demonstrated for 12 invertebrate groups using the standardized selection index (B) and expressed as the number of springs where a certain group selected rocks, sand, and/or bryophytes: Four groups exhibited preferences for bryophytes (Coleoptera, Diptera, Plecoptera, and Trichoptera), Ephemeroptera exhibited preferences for rocks, and Copepoda exhibited preferences for sand. Amphipoda, Platyhelminthes, and Ostracoda displayed preferences for all three substratum types, while Gastropoda, Hydrachnidia, and Oligochaeta recorded lower percentages in springs where habitat preferences were significant. In addition, crenic invertebrates were divided into three guilds, depending on their dispersion abilities in any stage of their life cycle: sedentary (not-winged groups), mobile (winged groups), and ectoparasites (water mites that were able to leave the springs on their winged hosts). Sedentary taxa recorded higher percentages of abundances and habitat preferences towards rocks and sand, while ectoparasites (Hydrachnidia) and the mobile guilds tended to prefer bryophytes. This segregation might be explained by individual adaptations to the particularities of each type of substratum, such as the bodily form of the copepods, which are well suited for sand interstices, a habitat that our data showed that they preferred. Our results represent novel contributions to the knowledge of habitat preferences of spring invertebrates from the Apuseni Mountains, adding value to similar data from the Western Carpathians, the Alps, and the Dinaric region.

New Findings of Freshwater Halacarid mites (Acari: Halacaridae) in Mexico

Freshwater Halacaridae are poorly known in Mexico. The only species reported so far is Limnohalacarus cultellatus Viets, 1940 from Quintana Roo, but the country is still a white spot for this group of mites. Recently, some halacarid specimens were collected in samples from two locations in Mexico City. Herein we present the records of two species: Porolohmanella violacea (Kramer, 1879), and Porohalacarus alpinus (Thor, 1910), which increase the number of epicontinental halacarids to three. These records are the first for the country and extend the known worldwide distribution range for each of these species. Future studies will certainly increase the number of halacarid species, and probably the percentage of species of these aquatic mites in Mexico.

DNA barcoding and metabarcoding of highly diverse aquatic mites (Acarina) can improve their use in routine biological monitoring

Context Acarina are commonly collected in macroinvertebrate surveys used to monitor freshwater ecosystems. However, they can be difficult to identify morphologically requiring considerable taxonomic skill for identification to finer taxonomic levels. Therefore, in biomonitoring they are identified to subclass despite high species diversity and varied environmental responses. DNA barcoding individuals and DNA metabarcoding of bulk samples enables species to be accurately and routinely identified. However, poor DNA barcode coverage of Australian aquatic mites has hampered their use in DNA studies. Aims Here, we aim to generate DNA barcodes for mites from Greater Melbourne, Australia. Key results For many specimens, we link DNA barcodes to genus-level morphological identifications using genetic analysis of DNA barcodes to understand biodiversity. We then test if new DNA barcodes can improve identification of mites in samples processed with DNA metabarcoding. We found Australian aquatic mites showed high diversity with many DNA barcodes represented by single specimens. Conclusions Increased mite DNA barcode library coverage improved their detection using DNA metabarcoding. Implications Given high species diversity, much effort will be required to improve DNA barcode coverage for aquatic mites in Australia and integrate barcodes with species level taxonomy, allowing Acarina to be better incorporated into DNA-based biological monitoring.

Study of Drifting behaviour of aquatic mites in the snow fed river Alaknanda from Garhwal Himalaya: Density, Diversity and Diel Pattern

Hydrachnida or water mites are most diverse group amongst Acari and they play an important role as bioindicator for their adjoining habitat. In the present study data for drift density, diversity and diel drift pattern was recorded from January 2018 to December 2018. Total 743 individuals belonging to 25 species were noted. Species Atractides panesari, Feltria gereckei, Feltria rubra and Lebertia glabra displayed nocturnal drift and species Torrenticola turkestanica, Monatractides garhwalensis, Sperchon indicus and Sperchon garhwalensis displayed both diurnal and nocturnal drift. Maximum 17 species exhibited diurnal drift throughout the course of the study. Presence of Hygrobates fluviatilis, a pollution tolerant species reflected the polluted condition of water.

CATALOGUE OF AQUATIC MITES FROM THE MINHO RIVER (NW IBERIAN PENINSULA)

Acari are a subclass of chelicerate arthropods that includes mites and ticks. The present study focuses on the taxonomic diversity of aquatic mites in the Portuguese territory of the Minho Region. Our aim was to compile all available information and thus generate a list of species linking them to the site where they were recorded. Aquatic species were all those that live exclusively in the marine environment, deep sea, intertidal, freshwater, brackish water or in transitional environments with the terrestrial environment if their lifestyle is associated with the aquatic environment. Since the first records of Portuguese endemic mites by Lunblad in the 1950s several authors have contributed to accurately catalogue, record, and redescribe this vast group in Portugal and Minho consecutively. In our review in this work, we used the Global Biodiversity Information Facility (GBIF) to obtain previous occurrences supplemented by an extensive literature review and the book collection Süßwasserfauna von Mitteleuropa, among others. Additionally, we resorted to active sampling and by-catch sampling in the Portuguese section of the Rio Minho catchment area. The collected organisms represent 12 new records for the Minho River and among them 10 are new records for Portugal, which were deposited in the Natural History Museum of the Iberian Peninsula - NatMIP (“Museu de História Natural da Península Ibérica”), Vila Nova de Cerveira, Portugal.

Two new species of Rhyncholimnochares (Acari, Hydrachnidia) from Ecuador

South America is one of the least known areas in terms of its fauna of aquatic mites. In this work we report the presence of two new species of the water mite genus Rhyncholimnochares in the Amazonian region of Ecuador, giving the morphological description and the DNA barcode when possible.

Biodiversity and monthly density fluctuations of water mites in Khankra gad, a spring-fed tributary of river Alaknanda, Pauri Garhwal in Uttarakhand, India

Hydrachnidia is an important group of aquatic invertebrates. They play an important role in regulating other invertebrate populations, thus influencing the composition and functionality of river ecosystems. The present study aims to assess the habitat ecology, density and diversity of aquatic mites in the Khankra gad, Rudraprayag district for a period of two year on a monthly basis, from July 2018 to June 2020. The Khankra gad is a perennial spring-fed stream originating from the Bansoun peak in district-Rudraprayag of Garhwal Himalaya (800 m asl). A total of 2537 Hydrachnidia samples were collected, belonging to 6 families viz, Torrenticolidae, Sperchontidae, Feltriidae, Hygrobatidae, Lebertiidae and Aturidae. Sperchontidae, Torrenticolidae and Hygrobatidae were the common families recorded in both spots, whereas Feltriidae was recorded in Spot-1, Lebertiidae and Aturidae were recorded in Spot-2. The highest numbers (1842) of Hydrachnidia were collected from Spot-2. A total of 19 aquatic mite species were recorded in Spot-1 and 25 species in Spot-2 throughout the study period. Aquatic mites showed maximum density (177 units.m-2 in Spot-1 and 274units.m-2 in Spot-2) in December and minimum (11 units.m-2 in Spot-1 and 17 units.m-2 in Spot-2) in July. Various ecological parameters of our study indicated that Khankra gad is a good habitat for aquatic mites.

Taxonomic richness and host range of tropical Asian mussel‐associated mite assemblages (Acari: Unionicolidae) with a description of a new subgenus and species of parasitic mite from freshwater pearl mussels (Unionida: Margaritiferidae)

Freshwater pearl mussels (Bivalvia: Margaritiferidae) are among the most imperiled groups of animals globally. While the parasites and symbionts of the Margaritiferidae are rather poorly known, these mussels were thought to be free of parasitic mites (Acari: Unionicolidae: Unionicola). Here, we report on the discovery of a mite species being associated with the endangered freshwater pearl mussel Gibbosula laosensis (Lea, 1863) from Myanmar. This species, Unionicola (Gibbosulicola) sella subgen. & sp. nov., morphologically resembles mites belonging to the subgenera Coelaturicola and Fulleratax (African and Southeast Asian groups, respectively). Our novel discovery expands the host range of Unionicola mites and reveals that all freshwater mussel families of the order Unionida host these aquatic mites. Our phylogenetic research and available published data reveal that the mussel-associated mite assemblage in Southeast and South Asia contains not less than 17 species and 8 subgenera. Currently, the regional taxonomic richness of this group seems to be largely underestimated. We found that mussel mites from Southeast Asia are narrow host specialists, which are known to occur in a single or a few closely related species belonging to one or two sister genera of freshwater mussels. Finally, our results indicate that mussel mites share generally restricted ranges and that their distribution patterns in Southeast Asia are largely congruent with the boundaries of biogeographic subregions delineated on the basis of phylogenetic studies of freshwater mussels.

Integrative description of Mesobiotus anastasiae sp. nov. (Eutardigrada, Macrobiotoidea) and first record of Lobohalacarus (Chelicerata, Trombidiformes) from the Republic of South Africa

A new species of the genus Mesobiotus is described from the Republic of South Africa using a traditional morphological approach (light and scanning electron microscopy) combined with molecular analysis (18S rRNA, 28S rRNA, ITS-2 and COI markers). Mesobiotus anastasiae sp. nov. differs from all known Mesobiotus species by having a unique combination of characters of the adult animals and the eggs. Adults of the new species have an oral cavity armature without elongate teeth in the second band, while the processes of the egg chorion have a basal collar and distinct rows of large pores. An updated key to the species of the genus Mesobiotus, including 66 of 70 currently described species, is given. An aquatic mite species from the Lobohalacarus weberi complex (freshwater Halacaridae) co-occurs with M. anastasiae sp. nov., suggesting that the newly described tardigrade inhabits constantly wet moss cushion habitats.

POPULATION STRUCTURE AND DRIFTING PATTERN OF AQUATIC MITES IN RANDI GAD, A TRIBUTARY OF RIVER ALAKNANDA IN GARHWAL HIMALAYA, UTTARAKHAND, INDIA

The present paper deals with the population structure and temporal drift pattern study of aquatic mites in Randi gad, which is a third order spring fed tributary of river Alaknanda in Garhwal, Uttarakhand, India. The mites contribute significantly to the structure and function of a stream ecosystem as it is a preferred food of fish and insects. To significantly analyze the drift strength of mites in a stream, a new index, Dobriyal Bahuguna Drifting Index (DBDI) has been developed which is based on the density of mite population in nature and number of drifting individuals in unit time. The maximum mite population in the stream was observed in January (51 units.m-2 ) and minimum in October (35 units.m-2 ) with 7 species. It was found that the mites perform specific monthly and diel drift pattern. Various factors like current velocity, breeding, colonization, habitat disturbance and protection from predators are responsible for it. The DBDI value for different mite species was observed highest in February (0.264) and minimum in November (0.227). It was also observed that maximum drift was preferred during late morning hours (8-12 hrs).

A Critical Appraisal of the Placement of Xiphosura (Chelicerata) with Account of Known Sources of Phylogenetic Error.

Horseshoe crabs (Xiphosura) are traditionally regarded as sister group to the clade of terrestrial chelicerates (Arachnida). This hypothesis has been challenged by recent phylogenomic analyses, but the non-monophyly of Arachnida has consistently been disregarded as artifactual. We re-evaluated the placement of Xiphosura among chelicerates using the most complete phylogenetic data set to date, expanding outgroup sampling, and including data from whole genome sequencing projects. In spite of uncertainty in the placement of some arachnid clades, all analyses show Xiphosura consistently nested within Arachnida as the sister group to Ricinulei (hooded tick spiders). It is apparent that the radiation of arachnids is an old one and occurred over a brief period of time, resulting in several consecutive short internodes, and thus is a potential case for the confounding effects of incomplete lineage sorting (ILS). We simulated coalescent gene trees to explore the effects of increasing levels of ILS on the placement of horseshoe crabs. In addition, common sources of systematic error were evaluated, as well as the effects of fast-evolving partitions and the dynamics of problematic long branch orders. Our results indicated that the placement of horseshoe crabs cannot be explained by missing data, compositional biases, saturation, or ILS. Interrogation of the phylogenetic signal showed that the majority of loci favor the derived placement of Xiphosura over a monophyletic Arachnida. Our analyses support the inference that horseshoe crabs represent a group of aquatic arachnids, comparable to aquatic mites, breaking a long-standing paradigm in chelicerate evolution and altering previous interpretations of the ancestral transition to the terrestrial habitat. Future studies testing chelicerate relationships should approach the task with a sampling strategy where the monophyly of Arachnida is not held as the premise.

Molecular phylogenetic relationships of halacarid mites suggest the reevaluation of traditional subfamily classification

Molecular phylogenetic relationships were examined for marine mites in the subfamilies Halacarinae, Copidognathinae, Rhombognathinae and Halixodinae from the aquatic mite family Halacaridae by using nuclear 18S and 28S ribosomal RNA gene sequences. The analysis revealed incongruences between the clustering obtained in the phylogenetic trees and the current morphological classification in the subfamilies Halacarinae and Rhombognathinae (based on 18S sequences) and in the Rhombognathinae (based on both 28S and combined 18S and 28S sequences). By contrast, the tree clustering was consistent with the morphological taxonomic positions in the Copidognathinae and Halixodinae subfamilies. It can be concluded that molecular phylogenetic analysis challenges the current classifications of Halacarinae and Rhombognathinae subfamilies. Accordingly diagnostic characters for their classification should be reevaluated.

Host insects infested with aquatic mites (Acari: Hydrachnidiae and Stygothrombiae) in Kanagawa and Shizuoka prefectures in Japan

Host insects infested with aquatic mites (Acari: Hydrachnidiae and Stygothrombiae) in Kanagawa and Shizuoka prefectures in Japan

Macroinvertebrate indicators of ecological status in Mediterranean temporary stream types of the Balearic Islands

In the last years the Water Framework Directive (WFD) has encouraged the development of classification systems to assess the ecological status in permanent rivers and streams, but in temporary streams development has been scarce. Here, we constructed an Invertebrate Multimetric index (INVMIB) to assess the ecological status of temporary streams in Mediterranean Islands based on benthic invertebrates following the WFD guidance. We studied 60 temporary streams in different seasons (n=270 samples), corresponding to three different stream types that were a priori established using topographical and valley information: lowland, canyon and mountain streams. We collected invertebrates with a multihabitat-based macroinvertebrate sampling standardised for a sampling area of 2.5m2, and stream water to analyse most relevant water chemistry variables. The analyses of benthic macroinvertebrate assemblages confirmed our stream typology (ANOSIM, R=0.363, p<0.001). The reference community of lowland streams was defined by taxa belonging to the order Diptera, the gastropod Ancylus fluviatilis, and several beetles and EPT taxa. Canyons showed a high diversity strongly dominated by dipterans and aquatic mites together with mayflies. Finally, the amphipod Echinogammarus sicilianus-monomerus, many dipterans of the Chironomidae family, together with beetles, mayflies, stoneflies and caddisflies were highly represented in the reference communities from mountain streams. The developed INVMIBs consisted of a combination of individual metrics that included diversity, tolerance/sensitivity and composition measures. The metrics and developed type-specific multimetric indices responded significantly to the gradients of pressures obtained from PCAs (i.e., general and organic degradation), as an integrated response to the physico-chemical variables, hydromorphological parameters and land uses. Indeed, the classification system obtained with the INVMIBs reflected the ecological quality of temporary streams of the Balearic Islands. The multimetric indices are considered a valid and accurate tool for the assessment of temporary Mediterranean streams, being currently used by the water authorities of the Balearic Islands.