Palaeeudyptes klekowskii was a species

Species

In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...

 of the extinct penguin

Penguin

Penguins are a group of aquatic, flightless birds living almost exclusively in the southern hemisphere, especially in Antarctica. Highly adapted for life in the water, penguins have countershaded dark and white plumage, and their wings have become flippers...

 genus

Genus

In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...

 Palaeeudyptes. It was approximately the size of its congener Palaeeudyptes antarcticus

Palaeeudyptes antarcticus

Palaeeudyptes antarcticus, rarely called the Narrow-flippered Penguin is the type species of the extinct penguin genus Palaeeudyptes. It was a huge species, albeit probably with a large size variation...

: somewhat larger than the Emperor Penguin

Emperor Penguin

The Emperor Penguin is the tallest and heaviest of all living penguin species and is endemic to Antarctica. The male and female are similar in plumage and size, reaching in height and weighing anywhere from . The dorsal side and head are black and sharply delineated from the white belly,...

. It is known from an extensive collection of fossil

Fossil

Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...

 bones from the Late Eocene

Eocene

The Eocene Epoch, lasting from about 56 to 34 million years ago , is a major division of the geologic timescale and the second epoch of the Paleogene Period in the Cenozoic Era. The Eocene spans the time from the end of the Palaeocene Epoch to the beginning of the Oligocene Epoch. The start of the...

 (34-37 MYA) of the La Meseta Formation on Seymour Island

Seymour Island

Seymour Island is an island in the chain of 16 major islands around the tip of the Graham Land on the Antarctic Peninsula. Graham Land is closer to continental land mass than any other part of that Antarctica. It lies within the section of the island chain that resides off the west side of the...

, Antarctica. P. klekowskii was at first not recognized as a distinct species, and despite the coexistence of two so closely related species of similar size as Palaeeudyptes gunnari

Palaeeudyptes gunnari

Palaeeudyptes gunnari was a species of the extinct penguin genus Palaeeudyptes. It was a bit smaller than its congener Palaeeudyptes antarcticus of New Zealand, standing between 110 and 125 cm high in life, approximately the size of the Emperor Penguin...

and P. klekowskii seeming somewhat improbable, the amount of fossil material suggests that the two species are indeed diagnosably different.