ABOVE: Dorsal (left) and ventral (right) views of a modern-day Astrophiura permira skeleton
THUY ET AL.
Most brittle stars have round bodies with long, flexible arms. But the brittle star genus Astrophiura has arms that are fused together, similar to the appearance of certain sea stars. Astrophiura is thought to have evolved around 175–200 million years ago, but scientists based this estimate on data from modern-day animals because not a single fossil of it had ever been found—until now. According to a study published November 13 in PeerJ, researchers have discovered the first fossil from this genus, along with another brittle star fossil, that suggest this pentagon appearance evolved in separate lineages of these animals more than once.
A team led by Ben Thuy, a paleontologist at the Luxembourg National Museum of Natural History, excavated brittle star fossils in Germany and the United Kingdom. They found lateral arm plates, spiny bones ...
