The feathers that made up the body contour of the bird have large shafts, and the primaries along the edge of the wings are short and undifferentiated.

The feathers were well enough preserved that researchers Julia Clarke, Liliana D'Alba and Ali J. Altamirano were able to perform analysis of melanosomes.

Large penguins, including the species Perudyptes devriesi and Icadyptes salasi, had been described from the area the previous year.

[3] The first evidence of melanosomes in fossilized feathers was published in late 2008, being reported from an Early Cretaceous bird.

[5] This discovery gives insight into how the evolutionary history of Inkayacu has affected the morphology of its extant descendants.

The large tightly packed melanosomes within the cells of living penguins gives the feathers added rigidity, which may be an adaptation for coping with the stresses of underwater flight.

However, it is also possible that the melanosomes of modern penguins do not give them an advantage underwater, since the feathers on their undersides are primarily white, lacking the rigidity of melanin.