Killer Bobble-Headed Penguins!

Spheniscus penguins are your basic model.  Collectively, the four living species are sometimes known as “tuxedo penguins” for their striking color patterns, which resemble a tuxedo motif just a bit more than those of other types of penguins. These four species are among the most warm-weather adapted of modern penguins, and live in Africa, South America and the Galapagos Islands. Spheniscus penguins also have a really good fossil record, with lots of skeletons discovered in the past few years in places like Peru and Chile.  Many of these specimens are very similar to the living Humboldt Penguin (Spheniscus humboldti), which plies the coasts of South America today. However, two species stand out for their remarkable appearance.

Spheniscus urbinai and Spheniscus megaramphus were discovered in the prolific fossil deposits of the Peruvian Atacama Desert (also referred to a the Sechura Desert). These penguins appear to be standard, although slightly larger, versions of the basic Spheniscus plan from the toes up the neck.  Flippers, legs, vertebrae – all these bones are not easily distinguishable from the same elements in a Humboldt Penguin to the untrained eye.  The head, though, is a different story.  These two penguins have “bobble heads” – skulls that are proportionally too big for their body. Well, too big for a normal penguin’s body anyway – no one seems to have sent a memo to Spheniscus urbinai or Spheniscus megaramphus.  Aside from the big heads, these penguins had killer beaks.  The tips, instead of being straight like many fossil penguins or lightly down-turned like most modern species, were powerfully developed into a sharp menacing hook.  This is a style of beak often seen in aeriel predators like eagles and fish-snatching birds like frigatebirds.

Skulls of a “normal” Humboldt penguin (top) and Spheniscus megaramphus (bottom).

One of the basic facts about fossil bird beaks is that they tend to tell only half the story.  That is because the bony part of the beak is covered by a layer of keratin in life.  This sheath can greatly extend the tip of the bill in some species, and Spheniscus penguins are a perfect example.  The bony beaks of these birds have a modest sharp hook at the tip.  When the sheath is added though, the tips start looking pretty fierce. Adding the keratin layer to Spheniscus urbinai and Spheniscus megaramphus would rachet up the beak from menacing to downright scary. What were these fossil species doing with there intimidating beaks? Most likely catching tough prey.  A powerful hook  would be  well suited to ripping into fish and squid, and is more useful for holding onto a larger victim than gathering up tiny things like sardines.  Whatever their ecology, the bobble-headed Spheniscus species did not make it to the present day.  After splitting off from the main Spheniscus lineage around 6 million years ago, Spheniscus urbinai and Spheniscus megaramphus enjoined a few million years of successful hunting before vanishing.

A crude rendering of the body outline of Spheniscus urbinai with a living Spheniscus penguin for scale.