New York • Sponges are getting squeezed out of a distinctive role in evolution. A new study says they don't represent the oldest branch of the animal family tree after all.
The DNA research gives the spot instead to comb jellies, a group of gelatinous marine animals with names like the sea walnut and the sea gooseberry.
All animals evolved from a single ancestor and scientists want to know more about how that happened. More than half a billion years ago, long before humans appeared, the first split in the tree separated one lineage from all other animals. Traditionally, scientists have thought it was sponges.