About the Authors

Rebecca Fay Johnson
Department of Invertebrate Zoology and Geology, California Academy of Sciences, San Francisco, California, United States of America,

Corresponding Author

rjohnson@calacademy.org

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

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.