About the Authors
Department of Invertebrate Zoology and Geology, California Academy of Sciences, San Francisco, California, United States of America,
The authors have declared that no competing interests exist.
Conceived and designed the experiments: RFJ TMG. Performed the experiments: RFJ. Analyzed the data: RFJ. Contributed reagents/materials/analysis tools: TMG. Wrote the paper: RFJ. Conceptualized and wrote the new classification: TMG RFJ.