Study: Sturgeon not 'living fossils' but show rapid evolution

ANN ARBOR, Mich., June 6 (UPI) -- Sturgeon in the U.S. Great Lakes, once thought "living fossils" virtually unchanged for millions of years, are in fact evolutionary speedsters, scientists say.

University of Michigan researchers and colleagues say in at least one measure of evolutionary change -- changes in body size over time -- sturgeon have been one of the fastest-evolving fish on Earth.

"Sturgeon are thought of as a living fossil group that has undergone relatively slow rates of anatomical change over time," Michigan evolutionary biology Professor Daniel Rabosky said. "But that's simply not true."

Sturgeon have been around more than 100 million years and today consist of 29 species worldwide, including the lake sturgeon found in the Great Lakes.

While there are fewer sturgeon species as compared to other fish they show a great variety in body size, suggesting rapid evolution in at least that one characteristic, the researchers said

"Our study shows that sturgeon are evolving very quickly in some ways," Rabosky said. "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."