An unusual find in a dry clime

on 21 Mar 2017 

While taking a walk around a clay pan on Bon Bon during the Christmas break, we were very surprised to see a small snail in a tiny puddle of water leftover from the last rain.

You may be wondering why we were surprised to find a snail? Well, here at Bon Bon Station Reserve our species list for aquatic (or water-loving) species is very short, as this is one of the driest habitable landscapes in Australia.  There are no permanent water holes to provide refuges for aquatic animals in any of the creeks on Bon Bon or in any of the catchment systems leading into the reserve from further afield.

The only other aquatic species recorded are the desert trilling frog (also known as Sudell’s frog) Neobatrachus sudelli (this frog survives the dry times by burrowing underground) and the shield or tadpole shrimp Triops australiensis.  This unusual animal survives in very harsh environments because it’s eggs can weather the long dry periods between rain events.

In 2016 we recorded 220mm of rain at Bon Bon homestead, (about 70mm above average) and as a result we did hear some frogs and found lots of tadpoles and shield shrimps in the puddles and swamps that filled for a short time.  Our younger volunteers who were helping us during winter were very pleased to have a chance to see (and photograph) these unusual critters.

Recently we sent the photo of our unexpected Bon Bon snail to Rob Wager (Bush Heritage’s freshwater ecologist), and he thinks it belongs to a group of molluscs called Camaeid snails (commonly called land snails).  He says, they are air breathing and have a mechanism by which they can seal the shell to preserve moisture in dry times. 

“I think the one you have found is of the genus Sinumelon. I cannot tell which species. They display high levels of local endemism and indeed yours may be new, as the arid area specimens are rather poorly studied.”

Rob Wager also said he would not be surprised if there were other species of land snails at Bon Bon.

So Bon Bon may yet reveal another snail surprise after the next big shower of rain!