The two fossil penguins Inkayacu and Icadyptes were actually quite different despite living in similar areas and having similar ecologies.The pigments of the feathers of the penguins have been identified, tentatively but with few caveats, and this allows us to differentiate between the animals when feather impressions and melanosomes are present to identify the colors of the feathers. Icadyptes is similar to extant king and emperor penguins as far as we can tell in plumage. They appear to have had a few areas of yellow and black feathering but were mostly covered in white feathers Darker back feathers make deeper diving a realistic ecological impact on the way of life of Icadyptes. The darker black would allow for the penguins to be camouflaged from above when at deeper depths and their white feathers would have added to their camouflage from below as they would have blended in better with the lighter water nearer the surface. Drawing these conclusions we can say that it is likely that Icadyptes dove deeper than Inkayacu to feed. Sharks and contemporary mammals (I cannot seem to find an evolutionary appearance of Leopard Seals, but we can assume that they would have loved giant penguins given how much they love extant penguins) of the deeper waters would have preyed upon the penguins, making that camouflage necessary. Inkayacu, on the other hand, has been hypothesized to have been a brown to rusty red color below and black or a dark grey above. Again, the black or dark grey color would camouflage the penguins against the deeper waters, but the rusty color would not provide much camouflage against many backdrops. This line of evidence is used to argue that Inkayacu
is a shallow swimming penguin; there are melanosome related reasons as to why this is a possibility, but we can leave these at rest for the time being. At the moment, simply appreciate that there are two colorations hypothesized for the two penguins and that each color scheme denotes attributes of each species. The two disparate ecological niches would mean that the two penguins could live in the same area and feed on different prey without destroying the food sources of one another. It is an interesting system with two interesting and differently colored taxa represented.