Great White Shark Evolution Debate

A significant debate is currently underway in the scientific community over the evolution of the Great White shark, and Chuck Ciampaglio, Ph.D., an assistant professor of geology at the Wright State University Lake Campus, is right in the middle of it. The issue is if the Great White, one of the most feared predators of the sea, evolved from the huge prehistoric megalodon shark or if its ancestry rests with the mako shark.

"Most scientists would probably say the Great Whites evolved from the megalodon line, which existed from two million to twenty million years ago. They were huge sharks, approximately the length of a Greyhound bus and possessing teeth that were up to six inches long," explains Ciampaglio.

"However, our research, which is based on analyzing fossils of several hundred shark teeth, shows that the Great White shares more similarities with the mako shark." He added that because sharks regularly replace their teeth, it is relatively easy to obtain tooth samples through fossil field work along the Atlantic seaboard.

Ciampaglio acknowledges that people seem to have a fascination with sharks. "The general public seems to like sharks, and maybe this is because they bring out the fears of our childhood, when they were perceived as scary monsters," he explained.

His interest in sharks is apparent when entering his office. The door and walls have pictures of shark teeth, and there are posted references to fossils and a geological time table.

The research scientist makes imprints of the teeth, then digitizes the picture to establish grids of different combinations that are analyzed by a sophisticated computer program. He even uses an electron microscope to view different serration designs of shark teeth.

"Our analysis of their teeth shows that Great White and mako sharks have very similar tooth growth trajectories, while those of the great white and megalodon are not similar. Analysis of both the root and entire tooth also shows a remarkable similarity in all four tooth positions under study for both the Great White and mako shark. Serration densities possess a strong similarity between the Great White and makos, where the serration densities between the Great White and megalodon exhibit sharp differences. In summary, our morphological (form and structure) evidence strongly supports the theory that the Great White is descended from the prehistoric mako group."

Ciampaglio said the Great White sharks, which can reach a size of nearly 25 feet and possess two-inch teeth, have been a major research subject of his for the past four years. He holds a doctorate from Duke in paleontology, the study of prehistoric life forms. His academic background also includes master’s degrees in zoology and geology and a bachelor’s degree in physics and chemistry. "My work looks at large scale changes of life over time and how things like mass extinction affect the course of life," he said.

Ciampaglio discussed his shark research findings at recent Geological Society of America meetings in Mississippi and Colorado. A scholarly journal article on the subject is pending.

The geologist joined the Lake Campus faculty two years ago, and one of the reasons he selected Wright State was the extensive opportunity for fossil research in this region of Ohio.

Source: www.divenews.com and Wright State University