Hakataramea albatross

Plotornis archaeonautes is the earliest uncontroversial record of an albatross from the Southern Hemisphere and the earliest record of any procellariiform (albatross or petrel) in New Zealand. The species reveals that stem lineage albatrosses were widespread by the onset of the Neogene.

Albatrosses are among the most intensely studied groups of living birds, yet their fossil record remains sparse. Despite modern albatrosses being more abundant and widespread in the Southern Hemisphere, the vast majority of fossil albatrosses known come from Northern Hemisphere localities.

The Hakataramea albatross was found in an early Miocene (22.7–22.0 Ma) layer in a limestone quarry in the Hakataramea Valley, South Canterbury. It is one of the oldest albatrosses known but the oldest widely accepted fossil albatross is Tydea septentrionalis from the early Oligocene of Belgium.

P. archaeonautes is one of three described albatross species in the extinct genus Plotornis. P. delfortrii is known from the Miocene of France and P. graculoides is known from the Miocene of Italy. Some isolated bones of an indeterminate species from the Oligocene of the eastern United States have also been assigned to this genus.

The holotype specimen of P. archaeonautes consists of a partial skeleton, including parts of the skull and wing bones. An isolated partial tarsometatarsus and a partial radius from the same quarry likely also belong to this species. P. archaeonautes was smaller than most extant albatrosses.

P. archaeonautes is the first species of Plotornis for which skull material has been discovered. It had a more slender beak than modern albatrosses (a feature also found in Aldiomedes, a fossil from the Pliocene of New Zealand), which may indicate a diet more focused on fish than the scavenging predominant in living albatross species.

The name archaeonautes means ancient mariner in Greek, referencing both the ancient age and wide oceanic distribution of the genus Plotornis, as well as Samuel Taylor Coleridge’s poem The Rime of the Ancient Mariner.

The holotype specimen is held in the collection of the Geology Department, University of Otago, Dunedin, while the two referred fragments are in the collection of the Museum of New Zealand Te Papa Tongarewa, Wellington.