Although the size range can only be loosely estimated, the birds seem to have stood between 43 and 55 inches (1.1 and 1.4 m) high in life (i.e. somewhat larger than an emperor penguin), placing this species and its congener Palaeeudyptes marplesi among the largest penguin species known.

It was described from a single, slightly damaged, tarsometatarsus (BM A.1084) found in the Late Oligocene Otekaike Limestone (23-28, possibly up to 34 MYA) at Kakanui, New Zealand.

An older date seems quite possible in fact as other bones have now been recovered from the Late Eocene (34-37 MYA) of the La Meseta Formation on Seymour Island, Antarctica (Tambussi et al., 2006), but given the considerable distances in age and range involved, it is not completely certain that the bones belong to a single species.

This remains the only fossil unequivocally assigned to this species, but numerous other bones have been found that may belong to it too.

These fossils were once uncritically considered as being from P. antarcticus, merely because other large penguins were not known at that time, but have not been subject to scientific review according to modern standards.