About the Authors

Andrey Giljov

Affiliation Department of Vertebrate Zoology, Saint-Petersburg State University, St. Petersburg, Russia

Karina Karenina

Affiliation Department of Vertebrate Zoology, Saint-Petersburg State University, St. Petersburg, Russia

Yegor Malashichev

malashichev@gmail.com

Affiliations Department of Vertebrate Zoology, Saint-Petersburg State University, St. Petersburg, Russia, Department of Embryology, Saint-Petersburg State University, St. Petersburg, Russia

Competing Interests

The authors have declared that no competing interests exist.

Author Contributions

Conceived and designed the experiments: AG KK YM. Performed the experiments: AG KK. Analyzed the data: AG KK YM. Contributed reagents/materials/analysis tools: YM. Wrote the paper: AG KK YM.