Ancient African Penguin Fossils Reveal High Species Diversity Millions of Years Ago

Africa once had a lot more penguins than it does today. New research reveals that as many as four penguin species coexisted on the continent in the past.

Researchers discovered the ancient fossils while sifting through rock and sediment excavated from an industrial steel plant near Cape Town, South Africa. Jumbled together with shark teeth and other fossils, 17 penguin bone fragments were first identified and then analyzed by the scientists. They found that the fragments were pieces of backbones, breastbones, wings and legs from several extinct species of penguins that lived between 10 to 12 million years ago--that predates what was previously considered the oldest penguin fossils by 5 to 7 million years.

These ancient penguins spanned the full size spectrum for the penguins living today--one was a mere foot tall while another towered nearer to three feet. Researchers are unsure exactly why they died out, but it could have been due to dropping sea levels or other environmental changes.

Land surface reconstructions show that five million years ago, the sea level along the South African coast was as much as 295 feet higher than it is today; the water swamped low-lying areas and turned the region into a network of islands. With the increased amount of islands--and consequently, beaches--the penguins had more places to nest and breed. When sea levels dropped in the region, though, penguins likely had to contend with predators that journeyed from the mainland.

Currently, there is just one remaining species of penguin in Africa. Known as the black-footed penguin or the jackass penguin, it has a loud, donkey-like braying call. Population numbers of this species have declined by about 80 percent in just the last 50 years. Currently, it's classified as endangered.

The recent study could provide new evidence of species diversity in the past, and what may have caused the eventual decline of the now-extinct penguins.

"There's only one species left today, and it's up to us to keep it safe," said co-author, Daniel Thomas, in a press release.

The findings are published in the Zoological Journal of the Linnean Society.