The gnathosoma is considered by most authors as the main constitutive character of a monophylum Acari. However, this has been questioned due to fundamental differences regarding its morphology in Anactinotrichida (=Parasitiformes s.l.) and Actinotrichida (=Acariformes). A key character which might indicate homology is represented by stout cuticular structures called corniculi, rutella, and/or pseudorutella present in most of the main groups of mites. However, the homology of these structures has also been doubted. In the present paper a first comparative ultrastructural study on these elements is presented taking representatives of all main groups of Acari in consideration (except of ticks lacking these structures). It was shown that the structures under concern are quite different even in closely related taxa. Hence the question on homology could not be solved definitely. Evidently more studies are needed to elucidate this problem.

Blaszakiella americana gen. et sp. nov., a new genus and species of zerconid mite (Acari: Mesostigmata: Zerconidae) is described and figured. This new genus differs from the closely related Microzercon Blaszak, 1976 by the presence both of small adgenital shields with openings of adgenital glands gv2. A key for females of Zerconidae genera in the Nearctic Region is provided.

In this study, a new species of zerconid mites, Zercon anatolicus, is described and illustrated on the basis of material collected from Turkey. Diagnostic characters of Zercon anatolicus: Anterior margin of ventro-anal shield with two pairs of setae. Dorsal cavities of general size and appearence, star-like with undulated and weakly sclerotised on their anterior margin. Pores Po3 situated beetwen setal rows J and Z, on the line connecting setae Z₄–J₃ located closer to the setae Z₄. Pores Po₄ lie on the line connecting the base of setae S₄–Z₅. Setae J₁–J₅, Z₁, Z₂, Z₅, S₁–S₃ and R₁–R₇ short and smooth. Setae J₆, Z₃–Z₄ and S₄ long and barbed with hyaline ending. Setae J₆ the longest opisthonotal setae (63–76 µm). Opisthonotal shield with distinct reticulate pattern in the anterior region and punctuate pattern in the posterior region. A key to the adults of Zercon species known from Turkey is also given.

A new mite species of the genus Epicrosejus has been described and illustrated based on 4 females collected from decaying material from the inside of an oak hollow (Quercus acutissima Carruth) in South Korea. Key to identify adult forms of the species listed in the genus Epicrosejus included.

Secondary succession of mesostigmatid soil mites was studied in two types of reclaimed electric power plant waste dumps in Łaziska Górne (Upper Silesia, Poland) in 1997–1998. The dumps on which the studies were carried out differed in their construction and structure. We sampled 6 sites from 2 localities (Sites I–III and IV–VI), representing 3 stages of ecological succession. The sites differed floristically and in substrate physiochemistry i.e. organic carbon content (C_org) and total nitrogen (N_t). Site I representing pioneer stage was characterized by a poorly developed herb layer, a lack of trees and shrubs, and low C_org, N_t and humus content. Sites III, V and VI represented a pre-forest stage and were characterized by a larger number of plant species, higher percent cover of trees and shrubs, and high C_org, N_t and humus content. Sites II and IV represented an intermediate stages of succession. In 18 months, we took 540 samples of soil and litter, and we collected 4811 mites, assigned to 86 species of mesostigmatid mites. The mite communities differed between successional stages, mostly with respect to the relative dominance among species. At the pioneer stage of succession, the mite community was characterized by a “degraded” model of species abundance distribution, with a high dominance of Asca bicornis. At more advanced ecological stages (Sites III, V and VI), mite communities had similarities with communities of forest. Some of the most abundant species in Sites III, V and VI were typical forest inhabitants. Sites I–III represent a real succession of plant communities, soil development and mite communities, showing an increase in species richness of mites, diversity indices and of the number of dominant species (creative type of succession). The succession within Sites IV–VI reveals a different course (rise-and-fall).

The modern classification of trombiculid mites from the family Trombiculidae (Acariformes: Parasitengona) is briefly reviewed on the subfamily and tribe level based on the larval characters. Some taxonomical and evolutionary aspects are briefly discussed. The family Trombiculidae is divided into four subfamilies: Leeuwenhoekiinae — Apoloniinae — Trombiculinae — Gahrliepiinae, from which Leeuwenhoekiinae should be placed at the base and Gahrliepiinae at the top of phylogenetic tree. Host-parasite relationships of trombiculid larvae are examined from the point of view that host-parasite specificity is low in trombiculids. Some physiological questions with respect to the realization of the life strategy of trombiculids are considered.

Echinothrombium spinosum (Canestrini, 1885) is redescribed based on female. Characteristics of larvae, described for the first time, deutonymphs and adults as well as data on biology are provided. Data on habitat specificity and phenology of the species as well as on developmental times of larvae are given. A female of E. spinosum, from which larvae were obtained by experimental rearing, has been designated as neotype. Key characters that allow to differentiate E. spinosum from E. rhodinum (C. L. Koch, 1837) pertain mainly to postlarval forms.

The fauna of terrestrial Parasitengona was studied in a human-transformed habitat, located on the Odra River shore in Wrocław agglomeration, and compared with that observed in natural habitats. The anthropogenic influence did not markedly affect the species diversity due to the presence of microhabitats which created favourable conditions for the mites. Altogether 13 species, representing four families and constituting almost nine percent of the Polish fauna of Parasitengona terrestria, were found within the studied area of ca. 200 m². Species composition, compared with that observed in undisturbed habitat, differed with respect to nine taxa. Data on biology and ecology of the examined taxa are provided. The results of laboratory experiments allow for synonymization of Hauptmannia brevicollis Oudemans, 1910 with Abrolophus norvegicus (Thor, 1900) and Hauptmannia pseudolongicollis Haitlinger, 1987 with Abrolophus quisquiliarus (Hermann, 1804).

The external morphology of rare soil inhabiting mites belonging to the monobasic family Stigmocheylidae (Acari: Prostigmata) is examined, based on the material from North America. Homologies of all studied morphological structures with those of other prostigmatic mites are established. An expanded taxonomic diagnosis of the family is provided for the first time. Two new species from North America are described, Stigmocheylus americanus sp. nov. and S. oberon sp. nov. These species differ from S. brevisetus Berlese, 1910, the type species of the genus, by the longer body 510 and 630 µm, respectively (vs. 380 in S. brevisetus) and by the absence of setae c3. Stigmocheylus oberon sp. nov. differs from S. americanus sp. nov. by the absence of g2 (vs. its presence in S. americanus), and by leg setation: setae ve'and ve” on tarsi II–III; v' on tibia IV, l1, l”1, v'1 on genu I, l” on telofemur III, l'on telofemur IV, l” on basifemur I, d on basifemur II, and 4c on coxa IV are present (vs. absence of these setae in S. americanus sp. nov.). All three species differ from S. pilosus (Soliman et Zaher, 1975), the second formerly known species of this family, by having the non segmented peritremes.

A new genus and two new species of quill mites (Acari: Syringophilidae) are described and figured from birds of the order Musophagiformes. Blaszakia gen. nov. differs from the closely related Charadriphilus Bochkov et Chistyakov, 2001 by the rounded posterior margin of the stylophore and small number of chambers in the peritremal branches. The first new species — B. tauracos sp. nov. was recorded from Tauraco livingstoni (Gray) from Tanzania and from T. schalowi (Reichenov) (Musophagidae) from Guinea, the second — B. rossae sp. nov. was recorded from Musophaga rossae Gould (Musophagidae) from the Democratic Rep. of Congo. Syringophilid mites are recorded from birds of this order for the first time.

The first European record of the scutacarid genus Thaumatopelvis Mahunka, 1973 is presented. The mites were extracted from decayed pine litter collected from the Island of Elba (Italy). The finding represents a new species that is described in this paper as Thaumatopelvis blaszaki sp. nov.

Hawaiieupodes termophilus from the superfamily Eupodoidea is redescribed from the Hawaiian holotype and paratypes housed in the Bishop Museum, Honolulu, Hawaii. This is the first redescription since H. termophilus was originally described. Details of body morphology, i.e. idiosoma, gnathosoma, legs with setae, and solenidia are described and a morphological comparison with the genus Penthalodes of the family Penthalodidae is presented as a basis for the discussion of the systematic status of the mite Hawaiieupodes termophilus.

Three new species of mites of the subfamily Tydeinae: Brachytydeus stebayevi, Brachytydeus comaliatus and Brachytydeus karoli from Siberia are described.

Two new species of the subfamily Tydeinae: Brachytydeus fernando and Brachytydeus matador from Spain are described and figured, as well as some comments are added. Eleven species are cited in text as a new combinations.

Two new species of grass-feeding eriophyid mites collected in northern Europe are described. Aceria arenariae sp. nov., inhabiting European beachgrass, Ammophila arenaria (L.) Link, was found in Denmark. Aculochetus blaszaki sp. nov. inhabiting purple moorgrass, Molinia coerulea (L.) Moench was found in Finland. New locality and host records for Abacarus hystrix (Nalepa, 1896) and Aculodes mckenziei (Keifer, 1944) are also given.

Aceria absinthii (Liro, 1943) and Paraphytoptus paradoxus Nalepa, 1896, are new species for the fauna of Serbia. The descriptions of both species are supplemented, with males described for the first time. A. absinthii causes galls on the lower surface of leaves, whereas P. paradoxus is vagrant on leaves of wormwood.

A new phytophagous mite species belonging to the genus Disella Newkirk et Keifer (Eriophyidae: Nothopodinae: Nothopodini), namely D. ovatum sp. nov., infesting Rhododendron ovatum (Lindl.) Planch, et Maxim. (Ericaceae), is described and illustrated.

Two new ectoparasitic mite species of the families Myobiidae (Prostigmata) and Myocoptidae (Astigmata) are described from Poland: Acanthophthirius (Acanthophthirius) longisetosus sp. nov. from Vespertilio murinus Linnaeus, 1758 (Chiroptera: Vespertilionidae) and Trichoecius blaszaki sp. nov. from Apodemus flavicollis (Melchior, 1834) (Rodentia: Muridae).

Xoloptes blaszaki, a new species of the feather mite family Pterolichidae (Pterolichoidea), is described from wing feathers of the Red-legged Partridge Alectoris rufa (L., 1758) (Phasianidae). Fusion of epimerites I and presence of a retrograde ventrobasal apophysis on tibia II in males of the new species differentiate it from the only other described species of Xoloptes (X. claudicans (Robin, 1877)), in which males have free epimerites I and thickened apico-ventral parts of tibiae II. The standard morphological description is supplemented by cytochrome oxidase I sequence data (DNA barcode).

A new feather mites species, Proctophyllodes cetti sp. nov., is described from Cetti's warbler, Cettia cetti (Temminck, 1820) (Sylviidae) from Kazakhstan. The standard morphological description is supplemented by cytochrome subunit oxidase I sequence data (DNA barcode).

Three new species of the feather mite (Analgoidea: Proctophyllodidae: subfamily Pterodectinae) are described from passerines from Central Africa: Montesauria faini sp. nov. from the African Golden-breasted Bunting, Emberiza flaviventris Stephens, 1815 (Emberizidae), M. pallida sp. nov. from the Red-headed Weaver, Anaplectes rubriceps (Sundevall, 1850) (Ploceidae), and Pedanodectes blaszaki sp. nov. from the Copper Sunbird, Cinnyris cupreus (Shaw, 1812), (Nectariniidae).

The adults of Fortuynia atlantica sp. nov. are described in detail, including intraspecific variation of several morphological characters. Sensillus short, smooth, clavate; one pair of lamellar furrows; 14 pairs of notogastral setae vestigial c3; five pairs of genital setae, variations 6 5, 5 6, 5 4, 4 5; two pairs of anal setae, variations 3 2, 2 3. Leg setation (chaetome, solenidia): Leg I 1-4-2-3-18, 1-2-2; leg II 1-4-2-3-15, 1-1-1; leg III 2-3-1-3-15,1-1-0; leg IV1-2-2-3-13,0-1-0. The new species shows a remarkable secondary sexual dimorphism; males are characterized by a pair of rounded lateral notogastral protuberances, four large porose areas on notogaster, and very long, distally lanceolate notogastral setae la and lm, as well as by a less broad genital opening. The species colonizes the intertidal zone of rocky shores of the Bermuda Islands, where it lives mainly in crevices but also under covering mats of algae; it is absent from sandy beaches and mangrove trees. The species is well adapted to overflow with sea water. Feeding biology and other details in behaviour are discussed. It is the first described member of the family Fortuyniidae known from the Atlantic Ocean. This paper is listed as “Contribution #146, Bermuda Biodiversity Project, Bermuda Aquarium Museum & Zoo”.

The morphology of juvenile and adult stages of two oribatid mites, Scutovertex rugosus Mihelčič, 1957 and S. perforatus Sitnikova, 1975 (Oribatida: Scutoverticidae) is described and illustrated. The comparative analysis of morphological features during ontogeny is presented. Moreover, the development duration in various laboratory conditions was studied. The development of S. rugosus lasted from 72 to 135 days, that of S. perforatus from 66 to 85 days.

Cuticular hydrocarbon profiles of representatives of different groups of oribatid mites (Mixonomata: Steganacarus carinatus, Collohmannia gigantea; Desmonomata: Hermannia gibba; Brachypylida: Zetorchestes falzonii) were investigated by gas chromatography — mass spectrometry. In general, cuticular extracts showed a series of straight chain alkanes being arranged in two (or three, respectively) distinctly different patterns: 1) a pattern with a gaussian quantitative distribution of alkanes from C₂₃ to C₃₆ was noticed in extracts of C. gigantea and H. gibba, with C₂₉ – C₃₂ being most abundant. 2) A pattern exhibiting a saw-tooth-like quantitative distribution of alkanes — with only odd-numberd alkanes being abundant — appeared to be characteristic for S. carinatus. 3) Extracts of Z. falzonii showed no hydrocarbons. The hydrocarbons are considered to origin in a lipid layer which is covering the cuticle: this layer is regarded to represent the inner — and in some cases the only — layer of the oribatid cerotegument. The differences in cuticular hydrocarbon profiles among oribatid species may represent a promising point of attachment for further chemosystematic studies.

Oribatid mites are a characteristic element of soil fauna, but they are also found in decomposing wood. However, they are often absent from publications dealing with dead wood. A core question of our study was how much the mite fauna differs between dead wood and the forest floor and at different locations on dead wood. Three dead, fallen beech logs (in the third stage of decay) in the “Góra Chełm” Reserve (Jura Krakowsko-Czçstochowska, Silesian province, south Poland) were examined for log-inhabiting species of mites. Samples were collected at seven microhabitats from the logs and the ground surface adjacent to each log was also sampled. Forty-nine oribatid species (44%) were obligate members of the intra-log community. Our study revealed strong differentiation between oribatid fauna in different microhabitats of decaying logs. No statistically significant differences in oribatid communities in beech logs of the same stage of decay were observed. It may be concluded that oribatid mites are using logs as a separate habitat rather than as an extension of the forest floor.

A new species of the crab spider, Diaea kangarooblaszaki sp. nov. is described and figured from Kangaroo Island located south of the southern coast of South Australia. The species is endemic and commonly occurring within the Island.