Pawson has spent the last 60 years carefully studying and classifying thousands of echinoderms, a diverse and ancient group of marine invertebrates. Adrian James Testa, Smithsonian Institution ...

Researchers examine a 500-million-year-old fossil from Morocco and find out that echinoderms went from bilateral to pentaradial symmetry.

Learn how starfish got their shape after a complicated evolutionary process, starting with an ancestor that lived 500 million ...

Starfish are echinoderms, a form of invertebrate marine animals known for radial symmetry and having spiny skin. Researchers said most animal species have similar genetic structures, prompting ...

Image: McLaughlin, Wilson, Rouse/Invertebrate Systematics. These animals are broadly related to starfish, sea cucumbers, and other echinoderms, but not too much is known about them.

Invertebrates, which constitute over 95% of all animal species, are the unheralded engine underpinning Earth’s biodiversity and ecosystem functioning. Their astonishing diversity – ranging ...

The heads of most animals are easily identifiable, but scientists haven’t been able to say the same for sea stars — until now.