The Brazilian Pampa presents a high diversity of fauna and flora within a mosaic of environments. The aim of this study was to evaluate the assemblages of predatory mites (Phytoseiidae and Stigmaeidae) in three different Pampa environments: Grassland shrub vegetation, Grazing Exclusions fenced for six years and Riparian Forest with tree vegetation. Phytoseiidae and Stigmaeidae were evaluated with a total of 324 plant sampled from nine sites in three environments. Twenty-two Phytoseiidae species and six Stigmaeidae species were found. Riparian Forest presented the highest abundance of predatory mites (243) and the greatest species diversity. Mites were more abundant in Grazing Exclusions (64) than in Grassland (25) environments, but species diversity was similar. In Riparian Forest, the most abundant species were Amblyseius tamatavensis Blommers, Amblyseius herbicolus (Chant) and Agistemus floridanus González-Rodríguez. Arrenoseius gaucho Ferla, Silva and Moraes and Zetzellia malvinae Matioli, Ueckermann and Oliveira were the most abundant in Grassland environment. Our results demonstrate that the Brazilian Pampa has a high diversity of predatory mites and mite communities seem to be affected by the type of environment, showing the importance of this ecosystem as a reservoir of natural enemies.

A new species of Stigmaeidae (Acari: Trombidiformes), namely Eustigmaeus crassifolius Bizarro & Johann n. sp., is described and illustrated based on females collected on Byrsonima crassifolia (L.) Kunth (Malpighiaceae) in Belém city (1°26'09.2'' S 48°26'28.6'' W), Pará state, Brazil. A dichotomous key of Brazilian species of Eustigmaeus genus is provided.

A new species of Stigmaeidae (Acari: Trombidiformes), namely Eustigmaeus crassifolius Bizarro & Johann n. sp., is described and illustrated based on females collected on Byrsonima crassifolia (L.) Kunth (Malpighiaceae) in Belém city (1°26'09.2'' S 48°26'28.6'' W), Pará state, Brazil. A dichotomous key of Brazilian species of Eustigmaeus genus is provided.

Two mite species belonging to the genus Agistemus Summers (Acari: Stigmaeidae) were collected from wild plants known as “chile piquín” (Capsicum anuumm L. var. glabriusculum) in two protected naturals areas, state of Tamaulipas, Mexico. Agistemus piquinnus Monjarás-Barrera & Johann n. sp. is described and illustrated. Agistemus brasiliensis Matioli, Ueckermann & Oliveira, 2002 is a new record for Mexico. A key to the Agistemus species of Mexico is provided.

Two new species of Eustigmaeus: E. bochkovi n. sp., collected from rotten log in Khabarovsky Kray, and E. grandis n. sp., collected from soil in Primorsky Kray, are described from Russia. The genus Paravillersia Kuznetsov, 1978 is considered as a junior synonym of Eustigmaeus Berlese, 1910; Paravillersia grata Kuznetsov, 1978 is considered as a junior synonym of Eustigmaeus ottavii (Berlese, 1910), E. ioanninensis Kapaxidi and Papadoulis, 1999 is considered as a junior synonym of E. pinnata Kuznetsov, 1977a, and Paravillersia jamaliensis Khaustov, 2014 moved to the genus Villersia Oudemans, 1927.