1830
Ungula plana sp. nov. — Pander, pp. 59, fig. 28:3,5
1890
Ungula convexa sp. nov. — Pander, pp. 59, fig. 28:1,2
1989
Ungula convexa Pander, 1830 — Popov & Khazanovitch, pp. 117, fig. Pl. 6:3-13, 15-17; 7:1-11
2002
Obolus apollinis Eichwald, 1829 — Emig, pp. 5
2003
Ungula convexa Pander, 1830 — Popov & Holmer, fig. 3A; 4D-F; 6A-C
2013
Ungula convexa Pander, 1830 — Lang & Puura, pp. 23