Taxonomy and biology of the argonauts (Cephalopoda: Argonautidae) with particular reference to Australian material

Argonauts (Argonautidae: Cephalopoda) are a family of pelagic octopuses that inhabit tropical and temperate oceans of the world. Argonauts are most commonly recognised by the beautiful white shells of females (known as "paper nautiluses") that wash up on beaches throughout the world. Historically, taxonomic delineation of the group has relied on features of these shells—structures not homologous to true molluscan shells and prone to extreme variability. As a consequence, more than 50 species names have been coined worldwide to date. This study constitutes the first thorough examination of argonauts from Australian waters. All argonaut material housed in Australian museums was examined using modern octopus taxonomic methodology and compared to material from key museums throughout the world. Three argonaut species are identified from Australian waters: Argonauta nodosus, Argonauta hians and Argonauta argo. All species can be separated based on morphological characters of males and females, and features of the shells of females. Detailed diagnoses, synonymies, maximum size records, distributional records, nomenclature corrections and biological information are included for each species. Details of the east Pacific Argonauta nouryi, the only other species recognised worldwide, are included for comparative purposes.