Re-evaluating New Zealand's endemic Pliocene penguin genus

Fossil penguins from late Neogene sediments are important for understanding the origins of modern penguins. Recent advances in penguin taxonomy and geometric morphometrics allow us to revisit previously described Pliocene fossils and potentially gain new insight into the evolutionary relationships of early crown penguin species. Here we re-evaluate the holotype of Tereingaornis moisleyi, a Pliocene fossil penguin discovered near Te Reinga Falls in the North Island of New Zealand. The holotype (hereafter referred to as the Te Reinga Falls fossil) does not possess any apomorphies that justify recognition as a distinct genus or species, and cannot be distinguished from the living crested penguins (Eudyptes spp.) or yellow-eyed penguin (Megadyptes antipodes) using discrete osteological characters or morphometric analysis. We propose that Tereingaornis moisleyi be considered a nomen dubium. The Te Reinga Falls fossil indicates that a penguin approximately the size of the extant tawaki (Fiordland crested penguin, Eudyptes pachyrhynchus) was present in New Zealand during the middle of the Pliocene (Waipipian Stage, 3.7-3.0 Ma), but a more complete specimen would be needed to confidently resolve the evolutionary relationships between this fossil and other penguins.