Some decades ago I was travelling around Australia and was lucky enough to climb Uluru. Pools on top of the rock had been produced by recent rain and, curiously, in many of them strange aquatic invertebrates were present (see photo). This specimen is sitting in my camera lens cap, which has a diameter of 62 millimetres. It looks like an ancient trilobite. Why and how was it on top of the famous, massive rock, and what is it? What happens to the creatures when the short-lived puddles dry up?
• The animal pictured is a shield shrimp, Triops australiensis. They are crustaceans in the class Branchiopoda - meaning "gill-legged" - and this term reflects the fact that they use their legs for breathing as well as for motility.
Their external morphology appears to have remained unchanged for 220 million years or more, and one species, Triops cancriformis, has ...
To continue reading this article, subscribe to receive access to all of newscientist.com, including 20 years of archive content.