Clam shrimps galore!

The diverse and ever-expanding number of Australian Clam Shrimp species makes for a promising future in their taxonomy and biodiversity.

In temporary pools, clam shrimps are important converters of algal biomass to animal flash which is then passed on to predatory beetles and water birds. Until recently we knew very little about their diversity.

I have been studying these small invertebrates for years, with 2016 being a highlight for me with the publication of 20 new species, based on my own collections, those caught by others over the years and those that are housed in the Australian Museum. There was one I knew of as a boy wandering the coastal dunes of the Clarence coast; mineral sand mining of the 60s-70s destroyed its habitat, but I finally found them in a pond last year. I named them Paralimnadia ammolophos, meaning it is found in sand dunes.

Two species occur sporadically in the rock pools on top of Uluru, one endemic (restricted to one place) and the other also found in pools on top of Mt Kaputar. I named the first Eulimnadia uluruensis and the second Paralimnadia saxitalis (meaning frequenting rocks). Actually, six other species live in similar pools across Australia, more than in any other country.

The Paroo in northwest NSW has the greatest diversity per unit area, some 18 species overall and 5 new ones described this year. Each has its own physicochemical requirements so that almost all pools of various characteristics have at least one species, sometimes up to 5. Years ago I found and described the most salt tolerant clam shrimp in the world, Eocyzicus parooensis, in the Paroo.

Visiting German scientists to the Museum have also contributed and presently one is helping me, by DNA analysis, to investigate a new suspected species from mountain pools in northeast NSW. Other problems yet to be resolved concern rock pool species from the Kimberley and the genus Australimnadia, a large (18 mm) endemic genus with 2-3 species.

Just 10 years ago only 26 species were known from Australia. Now we have the most diverse clam shrimp fauna in the world — 72 species at last count. Evolutionary adaptations to the abundant and varied temporary pools in our arid landscape are to blame, and inquisitive scientists like myself.

Professor Brian Timms, Honorary Research Associate.