Abstract

The larvae of marsh beetles, Scirtidae, are common in freshwater habitats in Australia but are usually ignored in faunal surveys. Most of the commoner genera found in open fresh water have been described, however, numerous larvae have been collected from the specious genera Austrocyphon and Nothocyphon that do not yet have a description. This paper describes those taxa which were known but not described at the time. In addition, it includes generic descriptions of the larvae of an Australian species of Contacyphon, and the larva of a species of Leptocyphon with a further report on its unusual colonial lifestyle and the great reduction of the breathing apparatus of larvae in this genus. Larvae were identified by rearing and/or by genetic matching using mitochondrial cytochrome c oxidase (COI) sequencing. In addition, using the available COI sequences, a phylogenetic analysis was undertaken which supported the monophyly of species in each of the genera Austrocyphon and Nothocyphon. Also evident was the phylogenetic distinction between these two genera and a group of taxa related to N. frater (Blackburn). We have placed these species in a new genus, Fratercyphon. This genus now includes the following three species previously in Nothocyphon; F. frater (Blackburn), F. amita (Zwick) and F. patruelis (Zwick). The monospecific genus Tasmanocyphon Zwick is supported as a distinct evolutionary lineage, as is the unique larva of "Strathgordon" described by Watts in 2014.