Abstract

Nematodes of the genus Fergusobia Currie (Tylenchida : Neotylenchidae) and flies of the genus Fergusonina Malloch (Diptera : Fergusoninidae) together form the only known mutualistic association between insects and nematodes that induces galls in young meristematic tissues in Myrtaceae. Six new species of Fergusobia are described (F. quinquenerviae, sp. nov., F. cajuputiae, sp. nov., F. dealbatae, sp. nov., F. leucadendrae, sp. nov., F. nervosae, sp. nov., and F. viridiflorae, sp. nov.) and partial descriptions are presented for a further two species. Together, these taxa form a putative monophyletic group, apparently restricted to species of Melaleuca in the broad-leaved M. leucadendra-complex, from coastal Queensland and north-east New South Wales, Australia. Each species of nematode has a mutualistic association with a particular species of Fergusonina fly and (with one exception) each association is apparently restricted to one particular species of Melaleuca.