Spheniscus predemersus

Spheniscus predemersus is an extinct species of penguin. It is known only from the diagnostic humerus bones (though other material might belong to it too), South African Museum specimens L6510, L12887A and the fragmentary "Site 1/1968" humerus. They were found in Late Pliocene rocks in a quarry at Langebaanweg, South Africa.

The species was apparently closely related to the African Penguin and may have been its direct ancestor; apart from some minor details, the chief difference is that it was smaller than the extant species, about 60cm long overall. On the other hand, additional bones suggest that there were at least 2 species of penguins in South Africa in the Late Pliocene, with S. predemersus being the smaller one. Thus, it may alternatively have been a sister taxon of the extant species, both being derived from a common ancestor. What is clear, however, is that of all penguins living or extinct that have been described to date, S. predemersus is the species closest to the African Penguin. The binomen references this fact: pre- = "before", demersus = the binomen of the African Penguin.