TABLE 1. Measurements from the two fossil specimens from the Sandringham Sandstone, Black Rock, Victoria, Australia.
| Measurement | Metric (mm) |
| NMV P254995 | |
| Total length of mandible | 103.97 |
| Thickness of mandibular body at m1 | 12.74 |
| Length of preserved toothrow | 29.95 |
| Depth under m1 | 22.87 |
| Depth of mandibular body | 23.32 |
| Height of preserved coronoid fossa | 36.84 |
| NMV P254178 | |
| Total width | 17.14 |
| Total length | 72.01 |
| Width of mid-shaft | 11.56 |
| Width of base dorsal-ventral | 13.17 |
TABLE 2. List of comparative specimens referred to in study.
| Taxon | Specimen Number | Institution | Sex |
| Acrophoca longirostris | MNHN-F-SAS-563 | MNHN | ? |
| Cystophora cristata | NHMUK 1907.9.4.4 | NHML | ? |
| Erignathus barbatus | NHMUK 1908.11.26.1 | NHML | ? |
| Hadrokirus martini | MNHN-F-SAS-16276 | MNHN | ? |
| Halichoerus grypus | NHMUK 1961-5-18-11 | NHML | Male |
| Hydrurga leptonyx | NMV C7375 | NMV | Female |
| Leptonychotes weddellii | NMV C25094 | NMV | Male |
| Lobodon carcinophaga | NMV C7385 | NMV | Male |
| Mirounga leonina | NMV C7407 | NMV | Male |
| Monachus monachus | USNM 219059 | USNM | ? |
| Neomonachus schauinslandi | USNM 243839 | USNM | Female |
| Neomonachus tropicalis | USNM 100354 | USNM | Male |
| Ommatophoca rossii | NMV C7354 | NMV | ? |
| Pagophilus groenlandica | NHMUK 1939.12.10.2 | NHML | ? |
| Phoca vitulina | NHMUK 1919.7.7.3260 | NHML | ? |
| Piscophoca pacifica | MNHN-F-SAS-564 | MNHN | ? |
| Pusa hispida | NHMUK 1938.11.26.6 | NHML | Male |
