Nav: Home

New islands, happy feet: Study reveals island formation a key driver of penguin speciation

February 05, 2019

Ever since Darwin first set foot on the Galapagos, evolutionary biologists have long known that the geographic isolation of archipelogos has helped spur the formation of new species.

Now, an international research team led by Theresa Cole at the University of Otago, New Zealand, has found the same holds true for penguins. They have found the first compelling evidence that modern penguin diversity is driven by islands, despite spending the majority of their lives at sea.

"We propose that this diversification pulse was tied to the emergence of islands, which created new opportunities for isolation and speciation," said Cole.

Over the last 5 million years, during the Miocene period, (particularly within the last 2 million years), island emergence in the Southern Hemisphere has driven several branches on the penguin evolutionary tree, and also drove the more recent influence of human-caused extinctions of two recently extinct penguin species from New Zealand's Chatham Islands.

"Our findings suggest that these taxa were extirpated shortly after human settlement on the Chatham Islands," said Cole. "These findings thus potentially represent important new examples of human-driven, Holocene extinction in the Pacific."

"While our results reinforce the importance of islands in generating biodiversity, they also underscore the role of humans as agents of biodiversity loss, especially via the extinction of island-endemic taxa," said Cole. As many of the bones were from middens, our results provide direct evidence that our newly discovered extinct taxa was hunted by humans."

The publication appears in the advanced online edition of the journal Molecular Biology and Evolution.

About 20 modern penguin species exist, from the Antarctic emperor penguin, the forest dwelling Fiordland penguin and the tropical Galapagos penguin. A fossil record of more than 50 species can trace back penguin history to more than 60 million years ago - indicating that penguin diversity may have once been much higher than today.

Using historical skin samples and subfossils from natural history museums, along with blood samples, the researchers performed the largest survey to date, across all penguin taxa.

The team tested their island hypotheses using 41 near-complete mitochondrial genomes, representing all extant and recently extinct penguin taxa. They calibrated their mitogenomic evolution to make an evolutionary clock based on the fossil record.

"By using well-justified fossil calibrations, we resolve the timing and mechanisms of modern penguin diversification," said Cole.

They found that the two largest-bodied and most polar-adapted penguins are sister to all other living penguins. The DNA evidence also showed that genetically similar penguin species may be at the earlies stages of diversification.

The study provides important new data and perspectives to the debate on the origins of penguin diversity. It will also help better understand the role of islands as drivers of speciation to other animals and marine life.

The new taxa have been named Eudyptes warhami and Megadyptes antipodes richdalei after John Warham and Lance Richdale, pioneers in penguin biology.
-end-


Molecular Biology and Evolution (Oxford University Press)

Related Penguins Articles:

Finding new homes won't help Emperor penguins cope with climate change
Unlike other species that migrate successfully to escape the wrath of climate change, a new study shows that dispersal may help sustain global Emperor penguin populations for a limited time, but, as sea ice conditions continue to deteriorate, the 54 colonies that exist today will face devastating declines by the end of this century.
New Zealand's mainland yellow-eyed penguins face extinction unless urgent action taken
In a newly published study in the international journal PeerJ, scientists have modeled factors driving mainland yellow-eyed penguin population decline and are calling for action to reduce regional threats.
Time-lapse cameras provide a unique peek at penguins' winter behavior
Not even the most intrepid researcher wants to spend winter in Antarctica, so how can you learn what penguins are doing during those cold, dark months?
Antarctic penguin colony repeatedly decimated by volcanic eruptions
One of the largest colonies of gentoo penguins in Antarctica was decimated by volcanic eruptions several times during the last 7,000 years according to a new study published in the journal Nature Communications.
In times of plenty, penguin parents keep feeding their grown offspring
A research team led by University of Washington biology professor Dee Boersma reports that fully grown Galapagos penguins who have fledged -- or left the nest -- continue to beg their parents for food.
The oldest fossil giant penguin
Together with colleagues from New Zealand, Senckenberg scientist Dr. Gerald Mayr described a recently discovered fossil of a giant penguin with a body length of around 150 centimeters.
Climate change and fishing create 'trap' for penguins
Endangered penguins are foraging for food in the wrong places due to fishing and climate change, new research shows.
Endangered African penguins are falling into an 'ecological trap'
As the climate changes and fisheries transform the oceans, the world's African penguins are in trouble, according to researchers reporting in Current Biology on Feb.
How natural selection acted on 1 penguin species over the past quarter century
University of Washington biologist Dee Boersma and her colleagues combed through 28 years' worth of data on Magellanic penguins to search for signs that natural selection -- one of the main drivers of evolution -- may be acting on certain penguin traits.
Climate change may shrink Adélie penguin range by end of century
Climate has influenced the distribution patterns of Adélie penguins across Antarctica for millions of years.

Related Penguins Reading:

Best Science Podcasts 2019

We have hand picked the best science podcasts for 2019. Sit back and enjoy new science podcasts updated daily from your favorite science news services and scientists.
Now Playing: TED Radio Hour

Anthropomorphic
Do animals grieve? Do they have language or consciousness? For a long time, scientists resisted the urge to look for human qualities in animals. This hour, TED speakers explore how that is changing. Guests include biological anthropologist Barbara King, dolphin researcher Denise Herzing, primatologist Frans de Waal, and ecologist Carl Safina.
Now Playing: Science for the People

#532 A Class Conversation
This week we take a look at the sociology of class. What factors create and impact class? How do we try and study it? How does class play out differently in different countries like the US and the UK? How does it impact the political system? We talk with Daniel Laurison, Assistant Professor of Sociology at Swarthmore College and coauthor of the book "The Class Ceiling: Why it Pays to be Privileged", about class and its impacts on people and our systems.