New DNA research by Science Researcher Lara Shepherd and Vertebrate Curators Colin Miskelly and Alan Tennyson has revealed parallel evolution in the small seabirds called prions. This unexpected result requires recognition of an eighth species of prion. Their research also revealed that all the birds formerly known as ‘fulmar prions’ are endemic to Aotearoa New Zealand. This means that we have gained two additional endemic bird species, and Australia has lost a breeding species.
Aotearoa New Zealand is the centre of diversity for prions, a group of small seabirds. In a recent DNA study, we focused on examining the relationships of fairy and fulmar prions.
Fairy prions or tītī wainui are abundant around Aotearoa New Zealand with as many as 4 million pairs breeding here. Dead fairy prions are commonly seen washed up on our beaches. They also have breeding colonies in Australia as well as on a number of subantarctic islands.
Fulmar prions are far less common, only breeding on remote islands of the southern hemisphere, such as the Tini Heke Snares, Moutere Hauriri Bounty, and Rēkohu Chatham island archipelagos. The main morphological difference between fairy and fulmar prions is in the robustness of their bills, but there are also differences in their plumage, diet, calls, and behaviour.
Same same, but different
Our DNA study confirmed a close relationship between fairy and fulmar prions but also tossed up some unexpected results. Most surprisingly fulmar prions from different island groups were more closely related to fairy prions than they were to each other. For example, fulmar prions from the Tini Heke Snares Islands were genetically closer to fairy prions from the Tini Heke Snares Islands than they were to Rēkohu Chatham Island fulmar prions. This result indicates independent origins of the chunky ‘fulmar’ bill form on different island groups from fairy prion ancestors.
Our DNA results showed that the existing taxonomy does not reflect the evolutionary relationships within fairy and fulmar prions. Changes to the taxonomy were needed.
Combining our genetic results with the morphological and ecological differences between the different breeding colonies, we suggest the following taxonomic changes.
The prions on the Rēkohu Chatham Islands with ‘fulmar’-like bills should be recognised as a separate species (Pyramid prion; Pachyptila pyramidalis). This species is endemic to Aotearoa New Zealand (meaning it only occurs here).
The remaining fulmar prions (Pachyptila crassirostris) are also now endemic to Aotearoa New Zealand. The prions on the Australian territory of Heard Island were thought to also be fulmar prions (although this had been debated). However, our DNA data shows that these are actually fairy prions, which is how Aotearoa New Zealand has gained two endemic species, while Australia has lost a species!
In addition to recognising the Pyramid prion as a distinct species, we recommend that two subspecies be recognised for both fairy prion and fulmar prion. When combined with other recent research on MacGillivray’s prion, this means a total of ten prion taxa should be recognised (with eight as full species):
- Broad-billed prion Pachyptila vittata
- MacGillivray’s prion Pachyptila macgillivrayi
- Salvin’s prion Pachyptila salvini
- Antarctic prion Pachyptila desolata
- Thin-billed prion Pachyptila belcheri
- Pyramid prion Pachyptila pyramidalis (Chatham Islands only)
- Fairy prion Pachyptila turtur turtur
- Subantarctic fairy prion Pachyptila turtur eatoni
- Fulmar prion Pachyptila crassirostris crassirostris (Bounty and Snares Islands)
- Lesser fulmar prion Pachyptila crassirostris flemingi (Auckland Islands only)
The reasons for these changes to fairy prion and fulmar prion names are explained in full in our paper: Genomic analyses of fairy and fulmar prions (Procellariidae: Pachyptila spp.) reveals parallel evolution of bill morphology, and multiple species.