| Inkayacu Temporal range: Late Eocene | |
|---|---|
| |
| An artist's illustration of Inkayacu paracasensis | |
| Scientific classification | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Chordata |
| Class: | Aves |
| Order: | Sphenisciformes |
| Family: | Spheniscidae |
| Genus: | †Inkayacu Clarke, 2010 |
| Species: | †I. paracasensis |
| Binomial name | |
| †Inkayacu paracasensis Clarke, 2010 | |
Inkayacu ("King of the Water" in Quechua) is an extinct genus of large penguins that lived in what is now Peru during the Late Eocene, approximately 36 million years ago. The genus consists of one species, I. paracasensis.
Discovery[]
The holotype specimen of Inkayacu was discovered in 2008 on the southern coasts of Peru. It consisted of a nearly complete skeleton, including fossilized feathers, the first known for penguins. A study of the melanosomes (pigment contained in organelles in the feathers) indicates that they were gray or reddish-brown in color. The main difference between its brown feathers and that of its modern counterparts is that it had ellipsoidal melanosomes.
Description[]
Although Inkayacu was a fairly basal penguin, its morphology closely resembled its more advanced extant relatives. It, along with other extinct penguins from Peru, are known as the 'giant penguins' due to their large size, with Inkayacu reaching a height of about 1.5 meters and a mass of around 57 kg (125 lbs); in comparision, the largest living penguin — the emperor penguin — is only about 1.2 meters tall and 30 kg (66 lbs) large on average, making Inkayacu among the largest penguins yet described.
Inkayacu feather melanosomes are long and narrow, similar to those of most birds. Most modern penguins have melanosomes that are similar in length to those of the Inkayacu, but are broader. This means that while modern penguins have black or white feathers, Inkayacu apparently had gray or reddish brown feathers. Despite the differences in the melanosomes, Inkayacu's feathers were similar to those of living penguins in all other respects.
Paleobiology[]
As a penguin, Inkayacu inhabited the seas of Peru during the Eocene, with its paddle-like limbs allowing for an aquatic lifestyle. While the feathers of extant penguins had tightly packed melanosomes within their cells that grant increased rigidity to cope with the stresses of underwater locomotion, Inkayacu had smaller melanosomes in lesser quantities, which may have suggested that it did not swim deeply, instead preferring to stay close to shallower waters.