Short Note First report on hind-toe development in Eocene Antarctic penguins

摘要

Penguins (Aves: Sphenisciformes), wing-propelled diving seabirds, use their hind limbs mainly for steering underwater and walking on land. They are digitigrade animals, although can be plantigrade in slow motion or when at rest (Simpson 1946). Their metatarsal I and two phalanges forming the hallux or hind-toe are vestigial (Fig. 1a & b). Sphenisciformes may have existed in the Cretaceous, but the oldest known fossils are from the Palaeocene. Penguins became diversified and widely distributed by the Late Eocene (Jadwiszczak 2009). Thousands of Eocene penguin bones, assignable to at least ten species, come from Seymour (Marambio) Island, Antarctic Peninsula. Other fossils from this epoch are from South America, New Zealand and Australia (Jadwiszczak 2009).