Description of Oromurcia magadanensis sp. nov. (Acari, Oribatida, Ceratozetidae) from Russia, with remarks on biogeography of the genus Oromurcia Thor, 1930.

Species of the genus Oromurcia Thor, 1930 (Oribatida, Ceratozetidae) mainly have an arctic or alpine distribution in the Western Palaearctic region and Greenland. We describe a new species of Oromurcia from Northeast Asia (Magadan Region, Russia) based on adult and juvenile instars. Numerous populations of Oromurcia magadanensis sp. nov. were found under arctic-alpine plants in a narrow stream gully with large snow accumulation on the Ola Plateau (1023 m a.s.l.). Adults of Oromurcia magadanensis sp. nov. differ from those of Oromurcia bicuspidata and O. sudetica by their smaller size, the presence of clavate, distally broadly rounded bothridial seta, tutorium with several teeth distally, and the absence of striations on the lamella. Juvenile instars of the new species differ from those of O. bicuspidata and O. sudetica by the presence of medium-sized gastronotic setae in the larva, and long lateral and posterior gastronotic setae in nymphs. We compare adult and juveniles of Oromurcia magadanensis sp. nov. with those of other members of the ceratozetid subfamily Trichoribatinae Shaldybina, 1966 from arctic or alpine regions, for which ontogeny is known, and provide revised diagnoses for adult and juvenile members of Trichoribatinae. All Oromurcia species are associated with cold wet places (periglacial habitats, bogs and fens, alpine meadows, snowbeds, and, less frequently, montane coniferous forests) in Eastern and Western Palaearctic, but they are absent from High Arctic and Siberian regions that are ultra-cold in winter. This spatial disjunction argues for a former Trans-Palaearctic range that was possibly subdivided by reсurrent cryo-arid Pleistocene episodes.

Hogsbackia africaensis/ gen. nov., sp. nov. (Acari, Oribatida, Ceratozetoidea, Punctoribatidae), from Afromontane forest of South Africa.

A new oribatid mite genus, Hogsbackia gen. nov. (Oribatida, Punctoribatidae), with type species Hogsbackia africaensis sp. nov., is proposed and described from the indigenous Afromontane forest of South Africa. The new genus is closely related to Scotiazetes, from which it is most easily distinguished by body size ratio, number of notogastral and genital setae, type of humeral porose area Ah, position of dorsophragmata, and leg setation. The redescription of Scotiazetes bidens Wallwork, 1966 is presented, based on material from South Georgia (Antarctic region). The generic diagnosis of Scotiazetes is revised, and the genus is transferred from Ceratozetidae to Punctoribatidae. Relationships between the genera Hogsbackia gen. nov., Scotiazetes and other punctoribatid genera are discussed.

Sculpteremaeus olszanowskii gen. nov., sp. nov. (Acari, Oribatida, Cymbaeremaeidae) from chaparral in California, USA, with a reassessment of Cymbaeremaeidae.

A new oribatid mite genus, Sculpteremaeus gen. nov. (Oribatida, Cymbaeremaeidae), with Sculpteremaeus olszanowskii sp. nov. as type species, is proposed and described based on adults. It is from sandy soil-litter in chaparral of California, USA, an environment from which no oribatid mites have been recorded previously. Based on an analysis of adults of all genera of Cymbaeremaeidae, the new genus is closely related to Ametroproctus, from which it is most easily distinguished by the morphology of lamellae, size of lamellar cusps, and shape of the tutorium. We expand the Cymbaeremaeidae family diagnosis, and question the inclusion of Scapheremaeus based on extensive molecular evidence showing its closer relationship with Ameronothroidea and Licneremaeoidea.

Checklist of oribatid mites (Acari: Oribatida) of Canada and Alaska.

This checklist of the oribatid fauna of Canada and Alaska (excluding Astigmata) includes 580 identified species in 249 genera and 96 families. The known fauna of Canada includes 556 identified species in 247 genera, and that of Alaska includes 182 species in 95 genera; 39 of the 42 oribatid superfamilies are represented. We further list ~ 300 species that are currently unidentified, and possibly undescribed. In addition, we list 42 genera that are represented only by unidentified and probably undescribed species. For each species we give combinations and synonymies, specific locations in Alaska and the Provinces and Territories of Canada, habitats, and biogeography.                There are 182 identified species known for Alaska, 152 for Yukon, 122 for Northwest Territories, 58 for Nunavut; 210 for British Columbia, 213 for Alberta, 15 for Saskatchewan, 84 for Manitoba, 167 for Ontario, 210 for Québec, 110 for Nova Scotia, 77 for New Brunswick, 84 for Newfoundland and 6 for Prince Edward Island. The known fauna of Canada is smaller than that of Austria, and is approximately equivalent to that of the Czech Republic. As these countries are much smaller in size than Canada and less ecologically diverse, we consider the Canadian and Alaskan fauna are at most 25% known. The paucity of these data reflects the absence of taxonomic and faunistic studies on Oribatida in State, Provinces or Territories, and especially in the Canadian and Alaskan National Park systems and the hundreds of Provincial Parks.                Despite the almost 90% increase in described species since the catalogue of Marshall et al. (1987), there is a need for focussed, coordinated research on Oribatida in the natural regions throughout Canada and Alaska, and for monographs on families and genera with large numbers of undescribed species, such as Brachychthoniidae, Damaeidae, Cepheidae, Liacaridae, Oppiidae, Suctobelbidae, Hydrozetidae, Phenopelopidae, Scheloribatidae, Haplozetidae and Galumnidae.

Trichoribates sidorchukae sp. nov. (Acari, Oribatida, Ceratozetidae) from tropical montane Ecuador, with revised generic diagnosis.

Species of the oribatid mite genus Trichoribates (Oribatida, Ceratozetidae) are primarily north temperate in distribution, with only two species known from the Neotropics. We describe Trichoribates sidorchukae sp. nov. from the tropical montane of Ecuador, based on adult morphology, the first species in the genus from Ecuador. We provide a revised generic diagnosis to include character states overlooked in previous diagnoses. An identification key to known species of Trichoribates in the Neotropical region is provided.

Acari of Canada.

Summaries of taxonomic knowledge are provided for all acarine groups in Canada, accompanied by references to relevant publications, changes in classification at the family level since 1979, and notes on biology relevant to estimating their diversity. Nearly 3000 described species from 269 families are recorded in the country, representing a 56% increase from the 1917 species reported by Lindquist et al. (1979). An additional 42 families are known from Canada only from material identified to family- or genus-level. Of the total 311 families known in Canada, 69 are newly recorded since 1979, excluding apparent new records due solely to classification changes. This substantial progress is most evident in Oribatida and Hydrachnidia, for which many regional checklists and family-level revisions have been published. Except for recent taxonomic leaps in a few other groups, particularly of symbiotic mites (Astigmata: feather mites; Mesostigmata: Rhinonyssidae), knowledge remains limited for most other taxa, for which most species records are unpublished and may require verification. Taxonomic revisions are greatly needed for a large majority of families in Canada. Based in part on species recorded in adjacent areas of the USA and on hosts known to be present here, we conservatively estimate that nearly 10,000 species of mites occur in Canada, but the actual number could be 15,000 or more. This means that at least 70% of Canada's mite fauna is yet unrecorded. Much work also remains to match existing molecular data with species names, as less than 10% of the ~7500 Barcode Index Numbers for Canadian mites in the Barcode of Life Database are associated with named species. Understudied hosts and terrestrial and aquatic habitats require investigation across Canada to uncover new species and to clarify geographic and ecological distributions of known species.

Tegoribatidae of North America, with proposal of Protectoribates gen. nov., and new species (Acari, Oribatida, Tegoribatidae).

The oribatid mite family Tegoribatidae has been represented in continental North America by the genera Tegoribates and Tectoribates. Herein, I describe a new genus of Tegoribatidae from North America, Protectoribates, and two new species: Protectoribates occidentalis sp. nov., from forest habitats in western North American, and Tegoribates walteri sp. nov., from forest habitats in California, based on adults and immatures. The descriptions of adults of the type species of Tegoribates, T. subniger Ewing, and other North American species, T. americanus Hammer and T. bryophilus Woolley, are expanded and immatures of T. americanus are described for the first time. Immatures of Protectoribates are apheredermous whereas those of Tegoribates are eupheredermous, though retaining centrodorsal setae. Scutozetes Hammer 1952 is transferred from Tegoribatidae to Ceratozetidae after re-examination of type material. I provide a revised diagnosis for Tegoribates and a key to tegoribatid genera and species for North America. Finally, I provide a revised diagnosis for Tegoribatidae based on world genera.

Contribution to the knowledge of the oribatid mite family Nesozetidae (Acari, Oribatida).

A new oribatid mite species of the genus Nesozetes (Oribatida, Nesozetidae) is described from moss (Sphagnum sp.) on the seepage area below a permanent spring in South Africa. Nesozetes membranus sp. nov. differs from its only congener, Nesozetes rostropterus, described from Fiji, by the presence of a second pair of membranes located in the podosomal region, setiform bothridial setae and striate subcapitular mentum. A revised diagnosis of Nesozetidae, discussion on its taxonomic status, and information on distribution and ecology of Nesozetes species are given.

Zealandozetes southensis gen. nov., sp. nov. (Acari, Oribatida, Maudheimiidae) from alpine cushions plant in New Zealand.

A new oribatid mite genus, Zealandozetes gen. nov. (Oribatida, Maudheimiidae), with type species Zealandozetes southensis sp. nov., is proposed and described based on adult and juvenile instars. It inhabits the soil under and around cushion-forming plants in the high-altitude alpine zone of two mountain ranges (the Pisa Range and The Remarkables) in the South Island of New Zealand. It is distinguished from species of Maudheimia by having pteromorphs reduced to pleural carinae, notogastral saccules, small pedotecta I, and both postanal porose area and Ah expressed as complex saccules. Juveniles are similar to those of Maudheimia, except the humeral organ of Z. southensis is cupule-like and gastronotic microsclerites are lacking. We give a revised diagnosis for Maudheimiidae and discuss both supportive and contradictory evidence for inclusion of Zealandozetes. Finally, we discuss endemism of Zealandozetes with reference to the knowledge of New Zealand biogeography and its oribatid fauna.

Sexual dimorphism in Autogneta, with description of three new species from North America and new diagnosis of the genus (Acari, Oribatida, Autognetidae).

Species in the oribatid mite genus Autogneta are primarily Palaearctic, with a few, mainly unidentified records from North America. Strong sexual dimorphism is reported in the genus for the first time; it is expressed by a posterior porose region on the male notogaster that in some species is associated with modifications of notogastral setae h1 and p1. Herein, I describe 3 new dimorphic Autogneta species from North America, based on adult specimens: A. aokii sp. nov. and A. schusteri sp. nov., from California, USA, and A. flaheyi sp. nov., from British Columbia and Alberta, Canada. New diagnoses for 2 other dimorphic species, the type species Autogneta longilamellata (Michael) and A. amnica Jacot, are presented that accommodate their previously unreported dimorphic males. Autogneta flumengalei Jacot is recombined as Conchogneta flumengalei (Jacot) comb. nov. Finally, I give a key to adults of Autogneta species known from North America.

Revision of Fenestrobates (Acari, Oribatellidae) with description of F. marauni sp. nov., from South America, and new diagnosis for Oribatellidae.

We propose a new species of the oribatid mite genus Fenestrobates (Oribatellidae), F. marauni sp. nov., based on adult specimens from Ecuador. The type species, F. capucinus Balogh and Mahunka, 1969 from Bolivia, is redescribed. We confirm the recombination of two species from the Russian Far East, F. rossicus Krivolutsky, 1974 from the Primorsky Region, and F. vicinus Ryabinin, 1975 from the Khabarovsk Region, as Oribatella rossicus (Krivolutsky) and O. vicinus (Ryabinin), and we give revised diagnoses for each. We present a new diagnosis for Fenestrobates and argue for its recognition as a genus distinct from Oribatella on the basis of the apomorphic development of a large, pouch-like depression positioned ventrally between pedotectum I and the lateral body wall, and absence of small ridges anteriorly on the notogaster. Based on these changes and new information, we give a revised diagnosis for Oribatellidae and provide a key to included genera.

Phylogenetic relationships of Tectoribates: nymphal characters of new North American species place the genus in Tegoribatidae (Acari, Oribatida).

Species in the oribatid mite genus Tectoribates are primarily Palaearctic and Neotropical, with scattered, unidentified records from North America. Herein, we describe 3 new Tectoribates species from dry forest and prairie habitats in North America: T. alcecampestris sp. nov., from Alberta, T. borealis sp. nov., from southern Alberta and Ontario, both on the basis of adults and nymphs, and T. campestris sp. nov., from dry grassland habitats in Ontario and Kansas, on the basis of adults. We provide a revised and expanded diagnosis for adults of Tectoribates. We assess relationships of Tectoribates, using characters of adults and newly discovered apheredermous, plicate immatures. We include observations on Pseudotectoribates which is closely related to Tectoribates. The closest relatives of these genera are hypothesised to be among the Tegoribatidae (Achipterioidea) rather than among the Achipteriidae (Achipterioidea), Oribatellidae (Oribatelloidea), or Ceratozetoidea, as suggested in previous classifications. Finally, we give a key to adults of the world fauna of Tectoribates.

Adoribatella, Ferolocella, Joelia and Ophidiotrichus (Acari, Oribatida, Oribatellidae) of North America.

In North America, species diversity in the oribatid family Oribatellidae is primarily in the genus Oribatella Banks, but the genera Adoribatella Woolley, Ferolocella Grabowski, Joelia Oudemans and Ophidiotrichus Grandjean are also represented. I provide detailed diagnoses for these genera and the previously described species, Adoribatella punctata Woolley, known from Colorado and Oregon, USA, and Alberta, Canada, Ferolocella tessalata Berlese known from Missouri, Virginia, West Virginia, Georgia, Wisconsin, Ohio, Alabama, Arkansas and Texas, USA, and Ophidiotrichus exastus Woolley, known from North Carolina, Alabama, Missouri, Tennessee and Georgia, USA. I describe Joelia appalachia sp. nov., based on adult specimens, from West Virginia. A key is given to distinguish adults of these genera from those of Oribatella. Character states shared by adults of Oribatellidae are discussed, the synonymy of Gendzella Kuliev with Ferolocella is rejected, and arguments are presented for movement of Adoribatella from Oribatellidae to the Ceratozetoidea.

Revealing the hyperdiverse mite fauna of subarctic Canada through DNA barcoding.

Although mites are one of the most abundant and diverse groups of arthropods, they are rarely targeted for detailed biodiversity surveys due to taxonomic constraints. We address this gap through DNA barcoding, evaluating acarine diversity at Churchill, Manitoba, a site on the tundra-taiga transition. Barcode analysis of 6279 specimens revealed nearly 900 presumptive species of mites with high species turnover between substrates and between forested and non-forested sites. Accumulation curves have not reached an asymptote for any of the three mite orders investigated, and estimates suggest that more than 1200 species of Acari occur at this locality. The coupling of DNA barcode results with taxonomic assignments revealed that Trombidiformes compose 49% of the fauna, a larger fraction than expected based on prior studies. This investigation demonstrates the efficacy of DNA barcoding in facilitating biodiversity assessments of hyperdiverse taxa.

Oribatid mites in soil toxicity testing-the use of Oppia nitens (C.L. Koch) as a new test species.

Few soil invertebrate species are available for the toxic assessment of soils from boreal or other northern ecozones, yet these soils cover the majority of Canada's landmass as well as significant portions of Eurasia. Oppia nitens (C.L. Koch) is an herbivorous and fungivorous oribatid mite found in soil throughout Holarctic regions, including Canada. Soil tests using O. nitens were performed using 15 different forest soil types and horizons to investigate test variability in adult survival and reproduction. Adult survival (86.1 +/- 1.1%) was consistent across soil types, with a coefficient of variation (CV) of 15%. However, reproduction varied significantly, ranging from 2.9 (+/-1.1) to 86.2 (+/-11.7) individuals, with a corresponding CV of 118 and 30%, respectively. Of the soil factors assessed (NH(3), NO(3), pH, phosphorus [P], organic matter content (OM), carbon:nitrogen (C:N), sand, silt, clay, and sodium adsorption ratio), soil organic matter (OM) explained 68% of the variation observed for reproduction. Increasing the OM using Sphagnum sp. peat moss resulted in optimal reproduction at 7% OM (8% peat content) with the lowest variability (CV of 20%). When assessing the toxicity of a reference chemical, boric acid, the effect of peat amendment reduced lethality to adults with no observable difference on reproduction. The use an age-synchronized culture reduced the test variability for reproduction relative to the use of unsynchronized cultures. Oppia nitens is a good candidate species for a standardized test design, with adult survival easily assessed in a relatively simple design. A long-term reproduction test with O. nitens will require the use of a synchronized population and, on occasion, OM amendment when testing soils with low organic matter content.

Does plant species co-occurrence influence soil mite diversity?

Few studies have considered whether plant taxa can be used as predictors of belowground faunal diversity in natural ecosystems. We examined soil mite (Acari) diversity beneath six grass species at the Konza Prairie Biological Station, Kansas, USA. We tested the hypotheses that soil mite species richness, abundance, and taxonomic diversity are greater (1) beneath grasses in dicultures (different species) compared to monocultures (same species), (2) beneath grasses of higher resource quality (lower C:N) compared to lower resource quality, and (3) beneath heterogeneous mixes of grasses (C3 and C4 grasses growing together) compared to homogeneous mixes (C3 or C4 grasses) using natural occurrences of plant species as treatments. This study is the first to examine the interaction between above- and belowground diversity in a natural setting with species-level resolution of a hyper-diverse taxon. Our results indicate that grasses in diculture supported a more species and phylogenetically rich soil mite fauna than was observed for monocultures and that this relationship was significant at depth but not in the upper soil horizon. We noted that mite species richness was not linearly related to grass species richness, which suggests that simple extrapolations of soil faunal diversity based on plant species inventories may underestimate the richness of associated soil mite communities. The distribution of mite size classes in dicultures was considerably different than those for monocultures. There was no difference in soil mite richness between grass combinations of differing resource quality, or resource heterogeneity.