‘Missing link’ penguin fossil shows how they evolved after dinosaurs went extinct

CNN  — 

Penguins weren’t always the petite, tuxedo-sporting birds we know and love today. Once, giant penguins the size of humans reigned supreme.

But how did they evolve into the creatures living in Antarctica? Scientists have discovered fossils that act like the missing link for their evolution – and it all happened after the dinosaurs went extinct.

Fossils from five partial skeletons were found on the Chatham Islands near New Zealand’s South Island. The fossils were found in the remote area during excavations from 2006 to 2011. The group was led by Monash University palaeontologist Jeffrey Stilwell.

The fossils belong to the newly discovered species Kupoupou stilwelli, the oldest known penguin that’s similar in size to modern penguins. Its name is derived from the indigenous Moriori people of the Chatham Islands. Kupoupou means “diving bird” in their language, Te Re Moriori. Stilwelli is in honor of Stilwell’s discovery.

This penguin lived around 60 to 62.5 million years ago, after the mass extinction event that claimed the dinosaurs 66 million years ago. The oceans were tropical and subtropical then, with no polar ice cap at the South Pole.

A study detailing an analysis of the fossils published Monday in the journal Palaeontologia Electronica.

“Next to its colossal human-sized cousins, including the recently described monster penguin Crossvallia waiparensis, Kupoupou was comparatively small – no bigger than modern King Penguins, which stand just under 1.1 meters [3.6 feet] tall,” said Jacob Blokland, study author and a PhD palaeontology candidate at Flinders University. “Kupoupou also had proportionally shorter legs than some other early fossil penguins. In this respect, it was more like the penguins of today, meaning it would have waddled on land.”

Like modern penguins, this ancient one performed best underwater. It was also the first penguin found to be similar in both hind limb and foot shape to modern penguins, Blokland said.

Ancient penguin fossils have been found on South Island’s eastern coast, which is 497 miles from the Chatham Islands. This discovery causes researchers to question how they’re linked. Researchers also found remnants of a larger penguin species on the remote archipelago, but there wasn’t enough material to name it.

These smaller penguins may have been swimming alongside their larger counterparts. And the fossils support the idea that penguins evolved quickly after the dinosaurs went extinct.

“We think it’s likely that the ancestors of penguins diverged from the lineage leading to their closest living relatives – such as albatross and petrels – during the Late Cretaceous period, and then many different species sprang up after the dinosaurs were wiped out,” said Paul Scofield, study author and Flinders University professor. “It’s not impossible that penguins lost the ability to fly and gained the ability to swim after the extinction event of 66 million years ago, implying the birds underwent huge changes in a very short time. If we ever find a penguin fossil from the Cretaceous period, we’ll know for sure.”

Earlier this year, fossils belonging to “monster penguin” Crossvallia waiparensis were found in Waipara, near the city of Christchurch on New Zealand’s South Island. It stood more than five feet tall, weighed more than the average human and lived between 56 million and 66 million years ago.

Recent discoveries have also uncovered other large creatures that lived in New Zealand, including the world’s largest parrot, the large flightless moa bird, a giant eagle and a giant burrowing bat.