North Island Fossils: the Glenn Massey Penguin
Penguin fossils are plentiful and well-studied on the South Island of New Zealand, but they have remained rare on the North Island. Only a few specimens have been reported, and the king of them all in the Glenn Massey Penguin. Indeed, this specimen is one of the largest penguins ever discovered.
The Glenn Massey penguin is from the early Oligocene, being roughly 30 million years old. Three bones are all that we have – a femur, tibiotarsus and tarsometatarsus. These bones from the thigh, shin and ankle of the penguin. When the fossil was found, many parts of the bones had already been eroded out of the rock and lost. In order to partially reconstruct these elements, a cast was taken from the natural impressions left in the rocks. Together, the bones and casts reveal a very large, rather primitive penguin. Whether it belongs to a known species or not remains unresolved. Based on the age and massive size of the bones, they could belong to Pachydyptes ponderosus. Unfortunately, that species is only known from flipper and pectoral girdle elements, so there is no direct point of comparison. Regardless of species, the Glenn Massey Penguin is an impressive fossil and demonstrates that a wide range of penguin species lived on the North Island as well as the South Island during the Oligocene.
Reference: Grant-Mackie, J.A., and G.G. Simpson. 1973. Tertiary penguins from the North Island of New Zealand. Journal of the Royal Society of New Zealand 3: 441–452.