Jenny Clack, Paleontologist

It's every paleontologist's dream to find a transitional form, something that falls between two groups that we are familiar with, that sort of links them both in terms of anatomy and lifestyle.-- Jenny Clack

At Cambridge University's Museum of Zoology, Paleontologist Jenny Clack solved one of the greatest mysteries in the history of life on Earth: how vertebrates made the transition from sea to land, from animals with fins to animals with legs. Convincing evidence that limbs evolved while tetrapods (vertebrates with four appendages) were still water-bound comes from a fossil Clack discovered in the mountains of Greenland, in 1987. She gave the 360 million year old specimen, a fossil of the creature Acanthostega, the nickname "Boris."

Her study of Boris revealed that it was a fishlike animal with limbs. "This is a specimen of an animal that could be described as a missing link, except that we have one so it's not missing," Clack says. "Its a transitional form between animals with fins that we'd call fish, and animals with legs, with fingers and toes on the end that we call tetrapods. We are tetrapods." Clack also found evidence of early tetrapods on Valencia Island, off the southwest coast of Ireland. There, she studied the fossilized tracks an early tetrapod left in the mud of the shallows of an ancient shore. She could tell from the tracks and the surrounding rocks that it was one of the early vertebrates to leave its footprints on land.

About Jenny Clack’s career

Jennifer Clack, Ph.D., is a Professor and Curator of Vertebrate Paleontology at the Cambridge University’s Museum of Zoology where she does research and teaches. Clack received a Ph.D. in Zoology from the University of Newcastle in 1984. She also holds a Graduate Certificate in Museum Studies from the University of Leicester and a M.A. from the University of Cambridge.

Clack’s research takes her into the field, and then back to her lab to study the fossils she’s collected. Her research is about early tetrapods—their origin, evolutionary development and radiation among the lobe-finned fish. Her research interests include: the timing and sequence of skeletal and other changes which occurred during the transition from water to land, the origin and relationship of the diverse tetrapods of the Late Paleozoic and the origins of the modern radiation of tetrapods. In addition to “Boris” and the earlier fossil she discovered, Clack has found and studied other early fossil tetrapods from the Devonian (416 to 315 million years ago). She has written a book, Gaining Ground: the Origin and Evolution of Tetrapods about her area of research. Clack has been dubbed “the diva of the Devonian” by the media for her expertise in evolution during that period.

Jenny Clack
Career Questions and Answers

How did you choose your present profession?
Having done my first degree, I went into museum work for seven years. After this I had the opportunity to go back to University and do a Ph.D. degree -- something I had always wanted to do. I never expected I would actually get a job in paleontology at the end of it; I expected to go back into local museums. However, I got the best of both worlds, and got a job in a museum doing paleontology!

What would you recommend for students wanting to pursue a similar career?
Persistence!

What do you like best about your profession?
Working with fossils!

What web sites and references would you recommend for viewers interested in your work that was featured in The Shape of Life series?
University of Cambridge Department of Zoology
University of Cambridge Professor Jennifer A Clack
Tetrapod World: early evolution and diversification
Tree of Life Web Project

Clack, J. A. 2012 Gaining Ground: the origin and evolution of tetrapods, Second Edition. Indiana University Press, Bloomington, Indiana.

Clack, J. A. 2009 The fin to limb transition: new data, interpretations and hypotheses from paleontology and developmental biology. Annual Review of Earth and Planetary Sciences. 37: 163-179.

Clack, J. A. 2006 The emergence of early tetrapods. Palaeogeography, Palaeoclimatology, Palaeoecology. 232, 167-189.