Funding for this research was provided by:
Austrian Science Fund (M2368-B25)
Università degli Studi di Torino (ex-60% 2017 and 2018)
Received: 12 December 2018
Accepted: 9 April 2019
First Online: 25 April 2019
Ethics approval and consent to participate
: Not applicable.
: The authors thank Dirk Hovestadt (The Netherlands) for the permission to include his photos of the dental plates of <i>Myliobatis aquila</i> used for comparison [see Additional fileInternalRef removed].
: The authors declare that they have no competing interests.
: Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.