Morphological abnormalities in ticks seem to be very rare phenomena. In this paper, we describe interesting anomalies in adult Dermacentor reticulatus collected as questing ticks by flagging as part of a tick-borne encephalitis program in Battaune, Federal State of Saxony, Germany, at the end of September 2016. The observed anomalies in the three D. reticulatus adults were: general anomalies (gynandromorphism) and local anomalies (malformation of capitulum and abnormalities of appendages). One D. reticulatus specimen displayed gynandromorphism, the presence of both male and female features within the same organism. One female showed abnormal morphology of right palp, while also missing the right porose area, and multiple atrophied extremities: i.e. of the right leg IV and of the left legs III and IV. The third specimen, a male, presented an atrophied extremity of the right leg III (meiomely). This is the first report of complete mosaic type gynandromorphism in a flagged D. reticulatus and the first report of morphological abnormalities in D. reticulatus in Germany.

The oribatid mite family Liacaridae (Acari, Oribatida) is recorded in Vietnam for the first time. Two new species of liacarids of the genera Liacarus and Xenillus are described from Tam Dao National Park, northern Vietnam. Liacarus vietnamensis sp. nov. is similar to L. laterostris Mihelčič, 1954 in the morphology of lamellar cusps (inner teeth well-developed; interlamellar tubercle absent) and in having long interlamellar setae and short notogastral setae, but differs by the directions of lamellar cusps and morphology of bothridial setae. Xenillus tamdaoensis sp. nov. is similar to X. longipilus Pérez-Íñigo & Peña, 1995 in having long notogastral setae, insertion of notogastral setae lm posterior to la, and the presence of an interlamellar tubercle, but differs by the morphology and position of lamellar cusps, size of the interlamellar tubercle and length of interlamellar setae.

Study of morphological characters of Tetranychus macfarlanei Baker & Pritchard and Tetranychus malaysiensis Ehara revealed high similarity by comparing all the important characters in addition to the characters pointed out by Ehara to separate those two species. Molecular phylogeny of seven Indian populations of T. macfarlanei and one population of T. malaysiensis from Philippines along with few distantly related species of Tetranychus was attempted. High degree of similarity between these two species at mitochondrial COI gene (96%) as well as ITS2 (rDNA) (96–99%) region was evident. Based on both morphological features and molecular data, T. malaysiensis is proposed as a junior synonym of T. macfarlanei based on ICZN's law of priority. Also more female characters are prompted in this study to distinctly discriminate T. macfarlanei from its most resembling species, Tetranychus ludeni Zacher. Tetranychus macfarlanei has emerged as a pest of several cultivated crop plants in India.

A new species of Molothrognathus Summers and Schlinger (1955) (Caligonellidae), Molothrognathus brasiliensis Silva, Brentano & Ferla sp. nov., is described and illustrated, and Paraneognathus wangae (Fan & Li, 1995) is reported for the first time from south of Brazil.

A new genus of pygmephorid mites, Micropygmephorus gen. nov. (Acari: Pygmephoroidea: Pygmephoridae), and two new species, M. pusillus sp. nov. and M. heterotrichus sp. nov. are described from nests of and phoretic on termites, Trinervitermes trinervoides (Sjöstedt, 1911) (Isoptera: Termitidae), from South Africa. The taxonomic position of the new genus is discussed.

Two new species of oribatid mites of the genus Pergalumna (Oribatida, Galumnidae) are described from the Tam Dao National Park of Northern Vietnam. Pergalumna kunsti sp. nov. differs from P. magnipora xishuangbanna Aoki & Hu, 1993 by the larger body size, barbed bothridial setae, peanut-shell shaped notogastral porose areas Aa, lamellar setae longer than interlamellar setae and smooth genital plates. Pergalumna storkani sp. nov. differs from P. paratsurusakii Ermilov, Shtanchaeva, Kaluz & Subias, 2013 by the larger body size, rounded rostrum, strong and erect adanal setae ad₂, lamellar setae longer than interlamellar setae, and the absence of a median pore.

The feather mite Hieracolichus hirundo (Mégnin & Trouessart, 1884) (Astigmata: Gabuciniidae) is recollected from the type host, the harpy eagle Harpia harpyja (Linnaeus, 1758) (Accipitriformes: Accipitridae), and redescribed based on the type and newly collected materials. Illustrations of this mite are provided for the first time.

The nymphal instars of two species, Pergalumna myrmophila (Berlese, 1914) and P. striatiprodorsum Ermilov, Alvarado-Rodríguez & Retana-Salazar, 2014, based on materials from Russia and the Antilles, respectively, are described and illustrated. The nymphs of these species are generally similar in their habitus. Basic characteristics of nymphs are the well-developed transverse furrow on the gastronotic shield as well as circumgenital and adanal macrosclerites; the gastronotic setae d-, l-, h- and p-series, which are represented by their alveoli, and the position of famulus ε on tarsus I. Additionally, comparative analyses of juvenile instars of species belonging to Galumnidae are given based on our own data and available literature sources.

A new species of the genus Aethiophenax Mahunka, 1981 (Acari: Prostigmata: Acarophenacidae), A. mycetophagi Arjomandi and Hajiqanbar sp. nov., is described and illustrated based on adult females. Mites were collected from the beneath elytra of hairy fungus beetles, Mycetophagus quadripustulatus (Linnaeus, 1761) (Col.: Tenebrionoidea: Mycetophagidae) grazing on oyster mushrooms on a bough of a tree in Mazandaran province, northern Iran. The new species, as fourth representative of the genus, is characterized by all dorsal setae thin and relatively long (26–35) in comparison with those of congeners; all ventral setae thin, setae 2a longest and 1b shortest of venter of idiosoma; tibiotarsus I with solenidion ϕ slightly clavate and as long as ω; tarsi II with seta pl″ modified and spine-like; genu III with two setae (l′ and v′). A key to the world species of the genus is also provided.

A new species of Galumna (Galumna) (Oribatida, Galumnidae) are described from a sample of grass rhizosphere, from a meadow of the Tam Dao National Park, Northern Vietnam. Galumna (Galumna) dkrivolutskyi sp. nov. differs from G. pseudotriquetra Ermilov, 2015(b) by the larger body size, bothridial heads slightly developed unilaterally and by the absence of sejugal suture medially. A supplementary description of G. discifera Balogh, 1960 is present based on Vietnamese specimens. Morphological additions to description of the Vietnamese species, G. acutirostrum Ermilov & Anichkin, 2010, are given. An identification key to known species of Galumna (Galumna) from the Oriental region is provided.

The present investigation was undertaken to obtain information about the structural and morphological properties of the silk of two-spotted spider mite Tetranychus urticae Koch (Acari: Tetranychidae) by means of the atomic force microscope (AFM), scanning electron microscope (SEM), energy dispersive X-ray spectrophotometer (EDX) and attenuated total reflection Fourier transmission infrared spectroscopy (ATRFTIR) techniques. AFM images show that the shapes of silken threads produced by both female and male mites are similar and have non-uniform cylindrical structure. In general, the appearance of silks produced by female mites is smoother than those of the male mites. In addition, it is determined that the silk threads produced by both female and male individuals have single and double stranded structure. There were differences in the thread dimensions of female and male which could depend on the body size of the mites. However, there is no statistically significant correlation between the body size of the mites and their thread dimensions. The silk material was found to consist predominantly of C, N and O elements and minor fractions of Al, P, Cl and K. The ATR-FTIR spectrum of the silk of two-spotted spider mite exhibited characteristic vibrational modes originating from amid groups, which were attributed to random coil and β-sheet molecular conformation in the protein structure of the silk of two-spotted spider mite. Understanding the features of the two-spotted spider mite silks may be of practical importance for the future studies related to biomaterial and material science.

One new species of larval Trombidium Fabricius, 1775, T. montenegrinum sp. nov. collected off-host on grasses, is described and illustrated. Descriptions of T. botovicum and T. daunum are corrected. A key to world species of larval Trombidium is presented. Using published records and original data, a checklist was compiled of the terrestrial parasitengone mites of Montenegro. The total number of species recorded from Montenegro up to date is 51 species, in 25 genera and 7 families. Additionally, first records for Montenegro are given for Charletonia krendowskyi Feider, 1954, Marantelophus multisetosa (Zhang & Goldarazena, 1996), Abrolophus stanislavae (Haitlinger, 1986), Erythraeus (Zaracarus) hamedanicus Saboori et al. 2004, Erythraeus (Z.) preciosus Goldarazena & Zhang, 1998 and Johnstoniana parva Wendt et al., 1994.