Scientists have unveiled details about a fossil of possibly the tallest ever penguin.
One of two new fossilised species, Kairuku grebneffi, found by New Zealand, may have been almost five feet (1.3m) tall - the height of some humans. Almost intact skeletons of Kairuku grebneffi and Kairuku waitaki were discovered at least 20 years ago, but have been studied by a team of scientists and a report written by lead author Daniel Ksepka, from North Carolina State University, America.
He says, "It is thrilling to see a completely new type of penguin turning up in the fossil record. Kairuku joins a cadre of extinct forms including the 'proto-penguin' Waimanu, spear-billed penguins, and tiny divers."
There have now been more than 50 species of extinct penguins found - most in New Zealand - and each one helps scientists discover more information.
The new species that were named Kairuku as it is translated as 'food diver' in Maori, date back around 27 million years. They were shaped differently to other penguins, living or dead, were slim, with long flippers and sturdy rear limbs.
The fossils were actually discovered on field trips in Waitaki, New Zealand, looking for whales and dolphin fossils sometime between the 1970s and 1990s.
The discoveries mean the area is a vital source of marine fossils, says geology professor Dr Ewan Fordyce, from the University of Otago, Dunedin, in New Zealand, who originally found the penguin fossils.
Although researchers have been examining penguin fossils for over 150 years, the current discoveries are among the best ever, Daniel Ksepka says.
Up to now, 10 species of extinct penguins, consisting of different sizes and shapes, have been found in deposits of a similar age.
The shallow, warm sea and remote coastal areas would have been ideal for the penguins to feed and nest.
Other scientists working on the project, which is published in the Journal of Vertebrate Paleontology, include current Otago student Ewan Fordyce and former students Craig Jones and Tatsuro Ando.
The team's findings, New Fossil Penguins (Aves, Sphenisciformes) from the Oligocene of New Zealand reveal the Skeletal Plan of Stem Penguins, are available online from the Journal of Vertebrate Paleontology.