Systematic revision of the feather mite genera Apexolichus Gaud et Atyeo and Titanolichus Gaud et Atyeo (Astigmata,Pterolichidae), parasites of parrots of the Old World (Psittaciformes,Psittacidae)

We present a systematic revision and phylogenetic analysis of feather mites of the closely related genera Apexolichus Gaud et Atyeo, 1996 and Titanolichus Gaud et Atyeo, 1996 (Pterolichidae, Pterolichinae). New diagnoses for Apexolichus and Titanolichus and keys to all known species are provided. We redescribe all species of the genus Protolichus Mégnin et Trouessart, 1884, described by E. Trouessart over a century ago, and which have been transferred to these genera. Two new species are described: Apexolichus psephoti sp. nov. from Psephotus varius Clark A.H., 1910 (type host) and P. haematonotus (Gould, 1838); and Titanolichus triangulifer sp. nov. from Barnardius zonaris (Shaw, 1805) (type host) and Northiella haematogaster (Gould, 1838). New synonymies are proposed: Apexolichus splendens (Favette et Trouessart, 1904) syn. nov. is a junior synonym of A. velifer (Trouessart, 1899); A. distensis (Favette et Trouessart, 1904) syn. nov. is a junior synonym of A. affinis (Mégnin et Trouessart, 1884). Apexolichus platycerci (Mironov, Dabert et Proctor, 2003) comb. nov. is a new combination for this species, which was formerly placed in the genus Titanolichus. Phylogenetic analysis (MP) confirms the monophyly of the genera Apexolichus and Titanolichus. Both of these genera, together with the monotypic genus Sideroferus Gaud et Atyeo, 1996 (being a sister group of Titanolichus), form a clade within the Protolichus generic group and are restricted in their host associations to parrots of the tribe Platycercini (Psittacidae, Psittacinae), members of which occur in the Australia and Indo-Malayan region. Representatives of each genus are restricted to a particular genus or a few genera of Platycercini. Host associations of these genera are briefly discussed.