Monday, May 25, 2009

Researchers model super-strong fish jaws

A new study reveals that Dunkleosteus terreli, a schoolbus-sized ancient fish, had one of the most powerful bites in history: its jaws exerted maximum forces of about 7,495 newtons, or half the weight of a VW beetle.

Today, only the great white shark and a few types of alligators beat out the Dunkleosteus for bite-force. Dunkleosteus is a better biter than any other reported fish species, as well as modern mammals like the spotted hyena, whose jaws are built to cut through bone. (T-rexes, according to models, still had a stronger bite than Dunkleosteus.)

Dunkleosteus is a species of placoderm—giant armored fish that lived during the Devonian period (415-360 mya). Placoderms provide an early and relatively well-preserved example of vertebrate jaw development, so studying their function may teach us more about the evolution of vertebrate feeding, in general.

Researchers based their computerized model of a Dunkleosteus jaw on a simple four-bar linkage mechanism—essentially four rigid rods connected in a square—combined with “landmark morphological data” (details from the actual fossils?). By analyzing their model’s skull and jaw movements, they were able to draw conclusions about the giant fish’s jaw speed, rotation, and force.

They found that Dunkleosteus opened its mouth by moving both its upper and lower jaw (most animals only drop their lower jaw). They also discovered that the fish had unusually high jaw-opening speed, and (as mentioned above) an incredibly strong bite.

This combination of characteristics means that Dunkleosteus could “potentially eat anything in its ecosystem, including other placoderms.”

Aside from being a badass animal with an awesome name, my interest in biodesign makes Dunkleosteus especially exciting to me. A fundamental problem in the world of human engineering is how to generate big forces efficiently. Animals, and natural selection, deal with the same issue. I think that a huge amount can be learned from these kinds of models, and from a better understanding of how natural selection has, over millions of years, “approached” the problems we deal with as humans today.

Read the "science news" article here; the abstract it references here; or an open-access article by the same authors here.


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