Limnadiid clam shrimp distribution in Australia (Crustacea: Branchiopoda: Spinicaudata)

Clam shrimp (Crustacea: Branchiopoda: Spinicaudata) are ancient freshwater crustaceans inhabiting all continents of our planet. Few detailed distributional studies have been done on clam shrimp in Australia, and the few studies that have been done are quite old. Herein we report data from a series of collections across western, southern and central Australia aimed at delineating the species distributions of clam shrimp in the family Limnadiidae. We found six limnadiid species as well as several unidentified limnadiids distributed throughout Australia. The most successful sampling locations were rock pools located on granite outcrops. Three genera were collected (Eulimnadia, Limnadia, and Limnadopsis), with the former being highly female-biased and the latter two having nearly equal male/female ratios. Males were larger than females in Limnadia and Limnadopsis, and overall size differed among the three genera, with Limnadopsis being the largest and Eulimnadia being the smallest. Pool-to-pool variation was significant for both sex ratios and size, even though in many locations the pools were separated by no more than 20m. Overall, clam shrimp were found to be locally abundant, and we encourage taxonomic research to help studies such as these to correctly identify the range of species that inhabit Australia.