A new species of oribatid mite of the genus Spatiodamaeus (Oribatida: Damaeidae) is described from the Russian Far East. Spatiodamaeus ziemowitisp. nov. differs from all species of the genus by the presence of bothridial setae with attenuate tips, prodorsobasal tubercles La, narrowly phylliform dorsal notogastral setae, and one pair of median ventral tubercles. The generic placement of the new species is discussed.

A new species of oribatid mites of the genus Plonaphacarus, Plonaphacarus olszanowskisp. nov. family Steganacaridae is described from Kibale NP (Uganda).

A new species Rotundabaloghia (Circobaloghia) olszanowskiisp. nov. is described based on females and males from Ivory Coast. The new species differs from the other Afrotropical rotundabaloghid mites in following character combination: the setae v7 and v8 smooth and wider than other ventral setae, female genital and ventral shields are ornamented by oval pits, setae st1 and st2 longer than st3 and st4 and a small, rounded depression is situated close to posterior end of pedofossae IV. This character combination is unknown within the African rotundabaloghids. On the other hand, the first report of R. (C.) ghanaensis Hirschmann, 1992 is presented from Togo, with the re-description of the male specimens and the first description of the females. This is the first record of this family in Togo.

A new species of ptyctimous mites of the genus Arphthicarus (Oribatida, Steganacaridae) is described from the litter in East Tibet, China. Arphthicarus olszanowskiisp. nov. differs from Arphthicarus indicus (Bayoumi et Mahunka, 1979) by prodorsal lateral carinae absent, lamellar setae longer than half length of interlamellar setae, vestigial notogastral setae present, mentum setae h<h–h, formula of genital setae 7(4+3): 2, and setae ad₃ much shorter than ad₂. A key to all known species of Arphthicarus from the Palaearctic and Oriental Regions is proposed to facilitate further studies of this group.

The prostigmatic mites including Heterostigmata (Acari: Trombidiformes) comprise one of the most myrmecophilous mite lineages. One of the well known heterostigmatic ant-associates genus is Petalomium (Pygmephoroidea: Neopygmephoridae). In an investigation on ant-associate mites in some parts of central and southern Iran, five species of the genus Petalomium Cross were collected from ants of the genera Camponotus, Lasius and Messor (Hymenoptera: Formicidae). One new species, P. olszanowskiisp. nov., is described and illustrated here. The other species include P. aleinikovae (Sevastianov, 1967), P. crinitusKhaustov and Trach, 2013, P. formicarum (Berlese, 1903), and P. gottrauxiMahunka, 1977. Except the latter, all species are new to arthropod fauna of Iran. In addition, P. aleinikovae is redescribed, and world distributions and host records of all the congeners are reviewed.

We found five species of oribatid mites belonging to the families Scheloribatidae and Oripodidae from Babeldaob Island of Palau Republic, which is an island country located in the western Pacific Ocean. Two new species, Euscheloribates olszanowskiisp. nov. and Oripoda minusculasp. nov. are described from litter and soil of the primary and secondary forests in Palau, and supplementary descriptions of three hitherto known species, Perscheloribates benguetensis (Corpuz-Raros, 1980), Protoripoda insularis Balogh, 1970 and Scheloribates praeincisus (Berlese, 1910) are provided. Following the descriptions and comparisons, we discuss aspects of the taxonomy, distribution and habitat ecology of all studied species.

Two new species of oribatid mites of the family Haplozetidae are described on the basis of adult specimens sampled from leaf forest litter in Andasibe-Mantadia National Park of eastern Madagascar. Indoribates olszanowskiisp. nov. differs from all species of the genus by the presence of lineolate notogastral surface. Protoribates ziemowiti sp. nov. differs from Protoribates magnus (Aoki, 1982) by the presence of lanceolate bothridial setae with well-developed, setiform apex, four pairs of notogastral setae, and femora II rounded anteroventrally. The genus Indoribates is recorded in the Ethiopian region for the first time; the genus Protoribates is recorded in Madagascar for the first time.

The present study is based on oribatid mite material collected from secondary forest in southern part of Côte d'Ivoire in 2013. A list of identified taxa, including 51 species from 42 genera and 25 families is provided; of these, 10 species, seven genera and two families are recorded for the first time in the fauna of this country, and one genus (Exoripoda) is recorded for the first time in the Afrotropical region. Two new species are described. Granuloppia olszanowskii Ermilov sp. nov. differ from all species of Granuloppia by the presence of bifurcate bothridial setae. Exoripoda olszanowskii Ermilov sp. nov. differs from Exoripoda suramericana by the larger body size, the presence of dilated distally lamellar setae, and the absence of rough sculpturing on notogaster.

Applying an integrative taxonomy approach, we describe a new tardigrade species from Nepal. Light and scanning electron microscopy are used for morphological as well as morphometric analysis of the new species. Furthermore, multilocus molecular data (nuclear markers, i.e., 18S rRNA, 28S rRNA, ITS-2 and mitochondrial COI barcode sequences) were analysed to confirm the novelty of species. The p–distances enabled an independent verification of Richtersius ziemowitisp. nov. as species new to science and molecular data allowed us to determine the phylogenetic position of the new species. Morphologically, Richtersius ziemowitisp. nov. differs from nominal Ric. coronifer mainly by lower pores density on cuticle, smaller eggs and lower number of processes on the egg circumference. What is more, we identified double (overlapping) peaks in mutated loci in the 28S rRNA chromatograms and obtained heterozygous sequences.

Two new species of Scutacaridae, Scutacarus variabilissp. nov. and S. olszanowskiisp. nov. are described from Faan Meintjes Nature Reserve, central South Africa. Both species were collected from the workers of Anoplolepis sp. ants. An unusual variability in number of setae on tibiotarsus IV in S. variabilis is discussed.

Two new species of the Tarsonemus minimax group are described: T. olszanowskii and T. sabelisi. Their morphological descriptions and depictions are presented, and characteristic of their systematic and geographic distribution in the context of the group are discussed. Revised diagnosis and updated key for identification of T. minimax group member-species are included. The current state of knowledge on the group is also summarized.

Two new species of Eutarsopolipus (Acariformes: Tarsonemoidea: Podapolipidae) are described from Australian species of Clivina (Coleoptera: Carabidae): Eutarsopolipus divisussp. nov. from Clivina procera Putzeys and Eutarsopolipus olszanowskiisp. nov. from Clivina quadratifrons Sloane. Both new species do not fit into any of the current species groups of Eutarsopolipus, although may be members of the ochoai group that have secondarily lost their claws. A further autapomorphy for the male (known for C. divisus only) is its unusual divided plate CD, which is unique in the Tarsonemoidea.

This paper reports on a new species of mite of the genus Gaeolaelaps from South Africa — Gaeolaelaps olszanowskiisp. nov. collected from soil in grassland. The new species is described based on morphological characters of the adult female. The new species is characterised by a number of exceptional characters in the genus: dorsal shield with 36 pairs of setae, genital shield drop-shaped, markedly expanded laterally past level of setae st5, subcapitulum with irregularly denticulate lines projecting outward from hypostomal groove, deutosternal rows with only 2–5 denticles, genua of legs II and III with only ten and eight setae, respectively (usually with 11 and nine setae, respectively). However, the chelicerae, internal malae and labrum of this new species are similar to freeliving forms, suggesting that it may be a predator of small invertebrates living in soil.

A new quill mite species Rafapicobia olszanowskiisp. nov., belonging to the subfamily Picobiinae (Acariformes: Syringophilidae), is described from quills of contour feathers of the Toucan Barbet Semnornis ramphastinus (Jardine) (Piciformes: Semnornithidae) from Ecuador. Our finding is the first record of syringophilid mites on birds of the family Semnornithidae.

The major aim of the paper was to provide a description of a new species Microuroobovella olszanowskii (Acari: Uropodina) from Italy. The species has been found in a large number in rotten wood of the cork oak (Quercus suber L.) in Toscania. The morphology of the species is considerably different from other European species described so far, which proves that the species is new to science, and, what is more important, it is also a new genus in the suborder of Uropodina. Moreover, the species seems to be related to species from the genus of Uroobovella sensu Hirschmann.