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These colorful 350-million-year-old fossils are different species of an aquatic sea animal known as a crinoid. Geologists from The Ohio State University discovered organic compounds sealed within the pores of these fossilized animal skeletons. The discovery of these fossils, which were uncovered in Ohio, Indiana and Iowa, has challenged the long-held belief of scientists that complex, organic molecules could not survive fossilization.
The geologists believe these fossilized crinoids, or "sea lilies," were buried quickly sometime during the Carboniferous Period, when North America was covered with vast inland seas. Isolated from the water above by layers of fine-grained sediment, their porous skeletons gradually filled with minerals, but some of the pores containing organic molecules were sealed intact. The researchers were able to extract these molecules directly from individual crinoid fossils in the lab and determined that different species of crinoid contained different molecules. The molecules appear to be aromatic compounds, called quinones, which are found in modern crinoids and other animals. Quinones sometimes function as pigments or as toxins to discourage predators.Image credit: Photo by William Ausich, courtesy of Ohio State University
