"Our study shows that sturgeon are evolving very quickly in some ways. They have evolved a huge range of body sizes. There are dwarf sturgeon the size of a bass and several other species that are nearly as big as a Volkswagen."

The sturgeon finding is just one result in a wide-ranging study of the rates of species formation and anatomical change in fish. The work involved assembling one of the largest evolutionary trees ever created for any group of animals. The evolutionary relationships between nearly 8,000 species of fish are delineated in the branches of the tree, allowing the researchers to make inferences about all 30,000 or so species of ray-finned fish.