Name(s) in cluster
| Ptychodus Agassiz 1836 | urn:lsid:organismnames.com:name:4898904 |
| Ptychodus Agassiz 1835 | urn:lsid:organismnames.com:name:1996034 |
| Ptychodus | urn:lsid:organismnames.com:name:158900 |
| Ptychodus Agassiz 1839 | urn:lsid:organismnames.com:name:5125554 |
| Ptychodus Ag. | urn:lsid:organismnames.com:name:3760527 |
...