Systematics of stream-inhabiting species of Limnochares (Acari: Eylaoidea: Limnocharidae) in North America

Abstract Limnochares anomala Habeeb is redescribed from streams in western North America and Limnochares appalachiana n. sp. is described from streams in eastern North America. These are the only two species of Limnochares with well developed sclerotized platelets on the idiosomal dorsum, a widespread adaptation in rheobiontic water mites to provide increased integumental support for muscle attachments related to their crawling mode of locomotion. Marked differences in structure and arrangement of these platelets in the two species are considered as the result of homoplasy. A new key is presented for North American species of Limnochares.