Palaeoapterodytes ictus is an extinct species of penguin from the late Oligocene or early Miocene of Argentina, the only member of its genus. Its fossil remains, consisting of only of a severely worn proximal part of a humerus, were found in the Patagonia Formation.
Ameghino named his genus Apterodytes (meaning "wingless diver", later emended to "ancient wingless diver" as the original name was preoccupied) because he mistakenly believed that this species lacked functional wings (the name is not to be confused with Aptenodytes, the modern emperor and king penguins). In this he seemingly overlooked the effects of taphonomy, and I will simply relay the summation of Lambrecht (1933), as translated from German by Simpson (1972):
Simpson (1972) concluded that the meagre remnant assigned to this genus was unidentifiable (though, contrary to Brodkorb (1963), it was evidently not a junior synonym of Palaeospheniscus), and left Palaeoapterodytes to sink into nomen dubium status.
Simpson, G. G. 1972. Conspectus of Patagonian fossil penguins. American Museum Novitates 2488: 1-37.