The probable association of feather mites of the genus Ingrassia (Analgoidea: Xolalgidae) with the blue penguin Eudyptula minor (Aves: Sphenisciformes) in Australia.

A new feather mite species, Ingrassia eudyptula n. sp. (Xolalgidae: Ingrassiinae), is described from the blue penguin Eudyptula minor (J.B. Forster, 1781) in Australia. This is the first description of a feather mite species from representatives of the avian order Sphenisciformes, which had previously been considered free from feather mites due to their strongly modified plumage and highly aquatic lifestyle. We suggest that most probably this mite species or its ancestor moved onto penguins from a shearwater species (Procellariiformes: Procellariidae) via shared nesting burrows in seabird colonies. In support of this argument, we illustrate similarities between I. eudyptula n. sp. and the closely related I. dubinini Cerny, 1967 from shearwaters (Puffinus spp.).