Prof Reels In Big Evolutionary Catch

A Harvard paleontologist has discovered a fossil that represents evidence for the evolutionary transition of fish from water to land—a find some experts are calling an evolutionary missing link.

Farish A. Jenkins Jr., professor of biology and Agassiz professor of zoology, along with Neil H. Shubin, professor of organismal biology and anatomy at the University of Chicago, and Edward B. Daeschler of the Academy of Natural Sciences in Philadelphia formed the core group of scientists who made the discovery in the Canadian Arctic Archipelago.

The fossil, called Tiktaalik roseae, was found in rocks from the Devonian Age, which date back 375 million years. The organism’s gills identify it as a fish, but it lacks the piscatorial characteristic of a neck that is connected to the shoulder girdle, Jenkins said. The fish’s front fin contains identifiable wrist bones and features that resemble fingers, he added.

“It fills a gap in our understanding,” Jenkins said. “We knew about lobed-fin fish, we knew about early tetrapods, but how do you turn lobed-fin fish into tetrapods? This fish is beginning to turn into a tetrapod, giving us real insight on anatomical evolutionary transformation.”

Tetrapods are land animals with limbs.

Comprising 10 individuals, with three “really good” specimens, the fossils are important in their fin/limb skeletons, true necks, and head shapes.

“This is not just some esoteric branch of the history of life, this is our branch, that part of the branch which we share with...everything with limbs,” said Shudin, who was advised by Jenkins while attending graduate school at Harvard.

“By uncovering this creature, and other creatures, we’re understanding a major trunk of our evolutionary past.”

The field explorations were conducted in the summers of 1999,