RESURRECTING THE SHARK

Excavating the history of the “one-in-a-billion buzz saw shark.”

Ewing (The Great Alaska Nature Factbook: A Guide to the State’s Remarkable Animals, Plants, and Natural Features, 2011 etc.) begins her complex, excessively detailed tale with the invitation by an artist friend, Ray Troll, to attend an exhibit titled “The Whorl Tooth Sharks of Idaho,” which featured his work. The author was captivated by a life-size reconstruction on exhibit at the museum featuring a “bizarre extinct shark, Helicoprion,” a prehistoric creature that hunted the oceans some 270 to 280 million years ago. Ewing describes the fossil as a “big brown slab of rock” that was “about the size of a bicycle wheel” and bore the imprint of a logarithmic spiral. In 1993, while conducting research, Troll, a “paleo-fish enthusiast,” had visited the Natural History Museum of Los Angeles and became intrigued by the Helicoprion fossil he found in the basement; he began sketching his vision of how the now-extinct shark might have looked when it was alive. Another fossil was discovered in 2010 in the basement of the Idaho Museum of Natural History by an Idaho State student who was cataloging Ice Age mammals. Ewing relates that find to an earlier discovery of the Helicoprion in the 1880s, which occurred in Russia and was described in an 1899 monograph. The author labels this the dawn of the discipline of paleoecology, when researchers established “the geological ground rule that unique fossil sets in rock layers succeed one another.” The fossil set off a debate among scientists about what the fossil represented, “a spiral of teeth” or “a fin spine.” By 1905, there were 44 scholarly papers from the United States, Russia, Europe, and Japan that contributed to the debate; in 1912, it was ultimately resolved in favor of the teeth hypothesis.

A carefully annotated scientific detective story that suffers from an overabundance of detail but benefits from 24 pages of lively photos.