Bryobia arborea n. sp. and Morphological Characters Distinguishing It from B. praetiosa Koch (Acarina: Tetranychidae)

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The clover, or brown, mite, Bryobia praetiosa Koch, was described in 1836 from specimens collected an shrubbery in Germany. The systematics of the species is complex and confusing. By 1838, Koch had described four species in the genus Bryobia but he preserved no type specimens and his descriptions do not agree with his illustrations (7, 12). Subsequent workers either placed Koch's species in synonomy nor described new species. Two species, speciosa Koch and ribis Thomas, have created the most controversv. B. speciosa was accepted as valid by Koch, Berlese, Canestrini and Fanzago, ind Oudemans, but rejected by von Hanstein and Trägårdh (2, 12). The gooseberry mite, B. ribis, was recognized as a valid species by Thomas and von Hanstein but Oudemans and Trägårdh placed it in synonomy with B. praetiosa (12). Further confusion was caused by the descriptions of additional new species of Bryobia and by descriptions of immature stages of B. praetiosa (8). The following taxonomic characters used by early acarologists in describing species of Bryobia have since been considered too variable for distinguishing species: number of femoral and tarsal hairs on the foreleg, body size, concavity of dorsum, and size and shape of cephalothoracic plate (7, 8, 12). Consequently, taxonomists have been at a loss to interpret Koch's original descriptions and subsequent redescriptions became inevitable. Because of the lack of morphological distinctions the modern trend has been to group all previously proposed species into one valid species (7, 8). As a result, 20 synonyms are now recognized for B. praetiosa (8).