The dawn crested penguin lived around 3 million years ago. The most recent common ancestor shared by the dawn crested penguin and all living crested penguins perhaps lived around five million years ago. The dawn crested penguin is important for showing that crested penguins have likely been part of the seabird fauna of Aotearoa for several millions of years.

The dawn crested penguin was closest in size to the modern erect-crested penguin E. sclateri, which is around 65 cm long and weighs 4 kg. The dawn crested penguin differs from all living crested penguins by having a relatively slender lower jaw when viewed side-on. The slender lower jaw of E. atatu is more similar in shape to that of the yellow-eyed penguin Megadyptes antipodes and may suggest that the diet of crested penguins has changed through time.

The holotype for the dawn crested penguin (NMNZ S.046318) is held in the collections of the Museum of New Zealand Te Papa Tongarewa. It is a partially complete skeleton that was extracted from a calcite-cemented mudstone concretion that was collected from the 3.36–3.06 Ma Tangahoe Formation along the southern Taranaki coast. The holotype includes a cranium, mandible, seven vertebrae, sternum, left coracoid, right coracoid, right humerus, right scapula, right ulna and right radius.

The dawn crested penguin is one of the best known seabirds from the Tangahoe Formation, with a further thirteen specimens comprised of one or more bones referred to the species. Eudyptes penguins are often collectively termed ‘crested penguins’ for their elaborate yellow crest feathers. However, these penguins are also identifiable from a suite of skeletal features (especially in the skull) that enable crested penguins to be identified even when feathers aren’t preserved, as was the case for Eudyptes atatu. The specific epithet atatu is derived from the Te reo Māori term ‘ata tū’ referencing the dawn. The dawn crested penguin was so named because of its importance in understanding the origins of crested penguins, from both the stem position that E. atatu has with respect to other Eudyptes, in addition to being the earliest recorded appearance of crested penguins in Aotearoa.

Naming confusion

Ron Scarlett described Moisley's penguin (Tereingaornis moisleyi) in 1983 based on Pliocene fossil bones from Hawke’s Bay. Four years later Joseph McKee assigned two similar-aged fossil bones from near Hawera, Taranaki, to the same taxon. These fossils are now considered unidentifiable to genus or species, as they could be examples of either or both genus Eudyptes (crested penguins) or genus Megadyptes (yellow-eyed penguins). The names Tereingaornis and T. moisleyi were therefore determined to be nomina dubia by the Birds New Zealand Checklist Committee in 2022, and have been removed from the New Zealand list. It is likely that some or maybe all of these specimens were of the bird now known as Eudyptes atatu, but the fossils available from the 1980s do not display characters that allow them to be assigned to this genus and species with certainty.

References

Checklist Committee (OSNZ). 2022. Checklist of the Birds of New Zealand (Fifth edition). Ornithological Society of New Zealand Occasional Publication No. 1. Wellington, Ornithological Society of New Zealand.

McKee, J.W.A. 1987. The occurrence of the Pliocene penguin Tereingaornis moisleyi (Sphenisciformes: Spheniscidae) at Hawera, Taranaki, New Zealand. New Zealand Journal of Zoology 14: 557-561.

Scarlett, R.J. 1983. Tereingaornis moisleyi – a new Pliocene penguin. New Zealand Journal of Geology and Geophysics 26: 419-428.

Thomas, D.B.; Ksepka, D.T.; Holvast, E.J.; Tennyson, A.J.D. & Scofield, P.R. 2020. Re-evaluating New Zealand’s endemic Pliocene penguin genus. New Zealand Journal of Geology and Geophysics 63: 324–330.

Thomas, D.B.; Tennyson, A.J.D.; Scofield, P.R.; Heath, T.A.; Pett, W. & Ksepka, D.T. 2020. Ancient crested penguin constrains timing of recruitment into seabird hotspot. Proceedings of the Royal Society B 287(1932).

Recommended citation

Thomas, D.B. 2022. Dawn crested penguin. In Miskelly, C.M. (ed.) New Zealand Birds Online. www.nzbirdsonline.org.nz