A novel association between oribatid mites and leafy liverworts (Marchantiophyta: Jungermanniidae), with a description of a new species of Birobates Balogh, 1970 (Acari: Oribatida: Oripodidae)

This paper contains a description of a new species of oribatid mite, Birobates hepaticolus sp. nov., from eucalypt woodland and rainforest in North Queensland, Australia. Adults and immatures of B. hepaticolus live completely enclosed within the ventral lobules of the corticolous liverwort Frullania ferdinandi-muelleri Steph. The ventral lobes provide a protected, moisture-buffered microhabitat on tree bark that would otherwise be subject to extremes of wetting and drying. Analysis of gut contents indicates that B. hepaticolus appears to feed on liverwort tissue. To our knowledge this is the first documented example of an association between an oribatid mite and a leafy liverwort based on the provision of food and habitat. The genus Birobates is redefined and diagnosed.