Unexpected discovery of <i>Typhlodromus</i> (<i>Typhlodromus</i>) <i>athiasae</i> in the United States and complementary descriptions of 3 additional Phytoseiidae (Parasitiformes: Mesostigmata) species from vineyards and walnut orchards in California

Abstract Phytoseiid mites (Mesostigmata: Phytoseiidae) are an extensively studied group of predatory mites due to their promising role as biological control agents of several species. Accurate identification of these mites is essential for the success of biological control efforts targeting pest species. In this study, we reported, for the first time, the presence of Typhlodromus (Typhlodromus) athiasae Porath &amp; Swirski in California, where it was found on winegrapes and walnuts. This finding was unexpected since previously, the distribution of this species was restricted to the western Palearctic region, particularly in Mediterranean and Middle Eastern countries. We also provided the complementary descriptions of 3 additional species; Galendromus (Galendromus) occidentalis (Nesbitt), Metaseiulus (Metaseiulus) citri (Garman &amp; McGregor), and Amblyseius similoides Buchelos. Several important morphological features, including a complete set of dorsal solenostomes and leg chaetotaxy currently used to discriminate phytoseiid species, were missing in the original descriptions and re-descriptions of these species. In addition, the important diagnostic characters of these species are reviewed to facilitate species delimitation. We report the absence of a posterodorsal seta (pd), a seta usually present in other members of the subfamily Typhlodrominae, on trochanter I in G. (G.) occidentalis and M. (M.) citri. Therefore, we believe that the placement of the tribe Metaseiulini within the subfamily Typhlodrominae warrants reconsideration and highlights the need for integrative studies to reassess the current placement of this tribe within the family Phytoseiidae.