ABSTRACT
A new family, Costacaridae, is proposed for Costacarus reyesi n.g., n. sp., a celaenopsoid mite collected from a millipede in Mexico. The female of this family is distinct from other Celaenopsoidea by having a single dorsal shield, a separate anal shield, latigynial shields free from all adjacent shields, and ventromarginal shields absent. The male is unknown. A key to the families of the superfamily Celaenopsoidea based on females is given.