The remains of a 380-million-year-old giant fish have been found in Australia. Its 'living fossil' descendant, the coelacanth, is still alive today.

The coelacanth Ngamugawi virngarri in its Devonian reef habitat. (Image credit: Katrina Kenny) What are the common features of ginkgo (tree), nautilus (mollusk), and coelacanth (fish)? Although they bear no superficial resemblance and are not closely related, their evolutionary histories…