March of the Fossil Penguins

Fossil penguin discoveries and research

IPC Roundup 2: Big Spheniscus

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Peru has yielded some  amazing penguin fossils.  In the deep past, over 30 million years ago, we have evidence of such wonders as the spear-beaked Icadyptes salasi and the feathered penguin “mummy” Inkayacu paracasensis. Closer to the present, roughly eleven million years ago, we start to see the first records of modern penguin genera turn up, sometimes as spectacularly well-preserved fossils. During the paleontology section of the International Penguin Conference, we heard about exciting new Spheniscus specimens from Martín Chávez, a PhD student at the University of Bristol.

The penguin genus Spheniscus includes four living species, which are the most warm-weather tolerant of the living penguins.  Fossil evidence suggests this group of penguins first evolved in coastal South America, later spreading  across the Atlantic to South Africa and across the Pacific to the Galápagos Islands.  Fossils from Peru reveal the earliest glimpses of this lineage. Spheniscus muizoni is the oldest crown clade, or modern-type, penguin known at 11-13 million years in age.

Skeletal outlines of a modern Humboldt Penguin and the extinct Spheniscus megaramphus by Martín F. Chávez Hoffmeister.

Skeletal outlines of a modern Humboldt Penguin and the extinct Spheniscus megaramphus by Martín F. Chávez Hoffmeister. Click to see more reconstructions by this scientist.

Martín Chávez presented a study of several new specimens representing multiple extinct Spheniscus species. Two of the most impressive extinct Spheniscus species are the “bobble-headed” penguins Spheniscus urbinai and Spheniscus megaramphus. For many years, we have known that Spheniscus urbinai was a “tough” penguin with a robust postcranial skeleton. However, Spheniscus megaramphus has been known formally only from the holotype skull for the past decade.  Nearly complete skeletons have recently come to light – Martín showed in his presentation that this species was even bigger and more powerfully built than Spheniscus urbinai He also showed off some excellent artwork in the form of skeletal reconstructions of these penguins.  Side by side with a modern penguin, the differences really stand out.  These penguins were larger and armed with more heavily constructed beaks than any modern species of Spheniscus, and surely took bigger prey than the anchovies preferred by the Humboldt Penguins that frequent Peruvian coastlines today. Closer examination of skulls from Peru even suggests there may have been multiple megaramphus-type” species.  So the picture of penguin diversity in the last few million years continues to improve.

References:

Chávez Hoffmeister, M.F. 2013. The Peruvian Neogene penguins. Abstracts of the 8th International Penguin Conference: 32.

Chávez Hoffmeister, M.F. 2013. A review of the Peruvian Neogene penguins. PalAss Newsletter 81: 62-66.

Written by Dan Ksepka

September 16, 2013 at 10:07 am

Posted in Uncategorized

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