Search Results for: Volume Exact Match 9

Fossil Focus: Diploporitans

Fossil Focus: Diploporitans

Fossil Focus
by Sarah L. Sheffield*1 Introduction: Echinoderms, a group of marine animals that includes familiar organisms such as sea stars and sea urchins, were much more diverse in the past than they are today. There are five living classes of echinoderms (sea stars, sea urchins, brittle stars, sea cucumbers and crinoids), but more than 20 extinct classes are known only from the fossil record. During the Palaeozoic Era (542 million to 251 million years ago), especially, echinoderms were incredibly diverse and thrived all over the globe (Fig. 1). This was a time of significant environmental change, with the climate ranging from very warm oceans with high sea levels and high atmospheric carbon dioxide concentrations to much colder oceans, with extensive glacial ice. By studying how fossil ...