rbins:Elegancy for #FossilFriday! These beautiful crinoidea, or sea lilies, were echinoderms like st
rbins:Elegancy for #FossilFriday! These beautiful crinoidea, or sea lilies, were echinoderms like starfish and sea urchins. They were pseudoplanktonic filter feeders, made up of a calcareous stalk at the end of which were flexible arms, which caught algae, unicellular organisms, small crustaceans and the larvae of invertebrates floating in the water.In abundance, fossilized species, such as the Seirocrinus subangularis, formed “meadows” on the seabeds. Having appeared in the Cambrian period, they were badly affected by the most significant mass extinction that earth has ever seen. Almost 95% of marine species and 70% of terrestrial species disappearedat the end of the Permian period, 250 million years ago.Crinoids similar to these fossils still cover tropical seabeds today. They were believed to be extinct for a long time – in fact, these modern species were only identified after the discovery of their fossilized ancestors!These sea lilies - actual size 3 by 2 metres - are on display in our Gallery of Evolution. -- source link
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