Date and Time
Bath Royal Literary and Scientific Institution, 16-18 Queen Square, Bath BA1 2HN
Asterozoans including starfish (asteroids) and their close relatives the brittle stars (ophiuroids) are amongst the most instantly recognisable and iconic marine animals. They are a dominant and successful group of living echinoderms based on their diversity, abundance, and biogeographic distribution. Despite their ecological success and a fossil record spanning more than 480 million years, the early evolution of asterozoans and their echinoderm cousins more generally, remains a mystery. In-fact, they seem to appear suddenly in the early Ordovician with no apparent ancestor in the Cambrian. New discoveries from France and Morocco have begun to resolve this mystery.
Exceptionally preserved fossils, combined with an understanding of the developmental biology have allowed us to reconstruct the sequence of evolution of the asterozoans (with a comprehensive phylogenetic framework). We explore the earliest common ancestors the somasteroids and their Cambrian echinoderm relatives, including a fossil, which is the earliest starfish like animal so far recorded in the fossil record. We then follow these exceptional fossils through the Ordovician as true ophiuroids and asteroids appear and show how they rapidly diversified during the biotic revolution we call the Great Ordovician Biodiversification Event. We demonstrate that these animals survived until the Permian, with some of their descendants still found in the oceans today.
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