Nineteen endemic Australian species of the Gondwanan genus Ceratomerus Philippi are revised, including four described and 15 new species: C. albistylus Hardy, C. athertonius n.sp., C. attenuatus n.sp., C. barringtonensis n.sp., C. bickeli n.sp., C. bulbosus n.sp., C. campbelli (Paramonov), C. falcatus n.sp., C. globosus n.sp., C. hibernatus n.sp., C. inflexus Hardy, C. lobatus n.sp., C. maculatus n.sp., C. malleolus n.sp., C. macalpinei n.sp., C. ordinatus Hardy, C. oreas n.sp., C. orientalis n.sp., and C. victoriae n.sp. This is primarily an aquatic genus, restricted to cascading rocky rainforest streams of eastern Australia from the Tablelands near Cairns to Tasmania. Adults prey on flying aquatic insects and are collected on emergent rocks and riparian vegetation.
The Australian ceratomerine fauna comprises three species groups, with the C. campbelli group apparently most closely related to the C. paradoxus group of Chile. The C. ordinatus group appears closely related to species from New Zealand and Ecuador (high elevations). A key to all Australian species is included and zoogeography discussed.