Evolutionary biologists have re-written the animal tree of life. A new study uses new genomics tools to answer old questions about animal evolution -- and offers up a few surprises among the branches.

The study involved 40 million base pairs of new DNA data taken from 29 animal species. It settles some long-standing debates about the relationships between major groups of animals and offers up a few surprises.

The big shocker: Comb jellyfish -- common and extremely fragile jellies with...