Australasian Science: Australia's authority on science since 1938

Penguins Evolved After Islands Formed

New research has improved our understanding of when and why penguins evolved, and has identified two recently extinct penguins from New Zealand’s remote Chatham Islands.

In the study, published in Molecular Biology and Evolution (https://goo.gl/8kRyLS), an international team of researchers sequenced the mitochondrial genomes of all living and recently extinct penguin species. By analysing the genetic relationships of species, and using ancient fossil penguins to put a time scale on these, the team showed that many penguin species arose soon after the geological formation of islands, including those inhabiting the Antipodes and Chatham Islands, Macquarie Island, Gough Island and Galápagos Islands.

The study also confirmed that an extinct and unique crested penguin species existed on the Chatham Islands until a few centuries ago. The former existence of this species had long been suspected by study co-author Alan Tennyson of the Museum of New Zealand Te Papa Tongarewa, who had previously examined penguin bones from these islands.

The study also threw up a complete surprise, revealing that a previously unknown small subspecies of yellow-eyed penguin also once existed on the Chatham Islands. “Evidence suggests Eudyptes warhami and Megadyptes antipodes richdalei inhabited the Chatham Islands up until the last few hundred years, and became extinct only after humans arrived,” says Otago University PhD candidate Theresa Cole, who was lead author of the study. “The discovery of these two new penguins adds greatly to our understanding of how humans impacted New Zealand’s marine biodiversity in the past.”

The study was published concurrently with another led by Cole that used ancient DNA to show that prehistoric penguin bones from New Zealand included several species that no longer breed there (Molecular Phylogenetics and Evolution, https://goo.gl/R3d4jY). The researchers are now extending the study by sequencing whole genomes to explore penguin evolution and adaptation.