By Veronique Greenwood

New York Times News Service

For thousands of years, penguins have darted through the waters of the southern oceans, chasing fish and surfacing to nest on islands and landmasses sprinkled from the Galápagos to the Antarctic.

Today, there are about 20 penguin species, ranging from the playful Adelie to the stately Emperor. There once were other penguins, including a previously unknown subspecies of dwarf yellow-eyed penguin in New Zealand.

You won’t be seeing it any time soon. It’s extinct, apparently wiped out by humans hundreds of years ago.

“We suspect that these Megadyptes penguins were on their way to becoming a full new species,” said Theresa Cole, a graduate student at University of Otago in New Zealand and co-author of a paper about this bird and another newly discovered extinct subspecies of crested penguin. “But they just didn’t get a chance, because people ate them.”

Cole and her colleagues sequenced DNA from many penguin species and built a family tree of the waddling birds living and dead.

The resulting research, published Tuesday in the journal Molecular and Biological Evolution, led to the discovery of these two subspecies.

It suggests that the same island environments that resulted in such diversity in the penguin family can also be linked to doom for some as they eventually came into contact with hungry human settlers.

With their family tree, Cole and her fellow researchers set out to understand when it was that these birds started to diverge from each other.

The researchers linked the tree to the dates assigned to fossilized penguins, and from that, they were able to deduce the rough timing of the penguins’ radiation into different species over millions of years.

That revealed something intriguing. Many penguins are native to specific volcanic islands, which arose relatively quickly from solidified lava. Often, the researchers found, the appearance of new penguin species was closely tied in time to the appearance of those penguins’ native islands.

In other words, before the islands formed, the species that call them home today did not exist. Rather, these species came into being when penguins from elsewhere popped out of the sea near the new patches of earth, began to make a new life for themselves, and slowly evolved into a new species.

The dwarf yellow-eyed penguin and the new crested penguin were natives of the Chatham Islands in southern New Zealand. The dwarf penguin was genetically very similar to the yellow-eyed penguins that roam New Zealand’s mainland. The little creatures were even smaller than the yellow-eyed penguins, which are only a couple of feet tall.

The bones of both penguins have been found in trash heaps that date to when humans arrived in the Chatham Islands. Circumstances suggest the animals were cooked and eaten, and soon went extinct.

In recent years, penguin numbers around the world have plummeted. One recent study projected that by 2060, the yellow-eyed penguins still living in New Zealand may join their dwarf relatives in extinction, unless an effort is made to preserve them.