Oribatid mites (Acariformes, Sarcoptiformes: Oribatida) in the gills of Salmo spp. (Actinopterygii: Salmonidae) parr - Short communication.

Live oribatid mites of the family Malaconothridae were found on Salmo spp. parr caught in the rivers of Northwest Russia. The mites were localised in the gill filaments and enclosed in connective tissue capsules. The encapsulation was accompanied by hyperplasia and displacement of the respiratory epithelium. One mite specimen was an adult female, while all the other specimens were protonymphs. The adult female and one protonymph specimen were identified as Tyrphonothrus sp. Other protonymphs could be identified only at the family level. The obtained partial 18S rDNA sequence of one protonymph was 100% identical to that of Tyrphonothrus maior (NCBI accession No. KY922215). This is the first report of living malaconothrid mites encapsulated in fish gills, and the phenomenon may assume parasitic behaviour. However, the nature of the relationship between the mites and the fish requires further investigations.

Micronectagriseola Horvath, 1899 - a new species of the family Corixidae (Heteroptera) for the fauna of the Middle Urals.

BACKGROUND: Micronecta (Micronecta) griseola Horvath, 1899 is a representative of water bugs of the family Corixidae. It is expanding its range eastwards according to our observations in Russia. In the last decade, the species has become more common in Western Siberia. NEW INFORMATION: The article presents the first records of M.griseola from the territory of the Middle Urals (Russia). The distribution of the species and the features of its biology are considered.

A new water mite genus from Kazakhstan (Acari, Hydrachnidia, Hydryphantidae).

This paper describes a new genus of the water mite family Hydryphantidae. The material was collected by V. Stolbov in 2019 in running waters in Kazakhstan. The material was sampled with a common hand net with 250 µm mesh size. The water mites were fixed in 75% ethanol.

Description of a new hygrobatid genus from Chile (Acari, Hydrachnidia: Hygrobatidae).

This paper describes a new genus of the water mite family Hygrobatidae. The material was collected by V. Stolbov in 2014 and A. Prokin in 2015 in running waters in Chile. The material was sampled with a common hand net with 250 µm mesh size. The water mites were fixed in 75% ethanol.