To the naked eye, fossilized seashells lack the colorful patterns of their living counterparts. But ultraviolet light can reveal some of their unique hues using a new method described by San Jose State University geologist Jonathan Hendricks on April 1 in PLOS ONE.
While examining 4.8-million- to 6.6-million-year-old cone snail shells from the Dominican Republic, Hendricks found that under UV light the organic compounds in the shells fluoresce — though it’s unclear which specific compounds are doing the fluorescing. Using images taken under UV light, Hendricks re-created the shells’ pigmentation, compared the patterns and identified snail species. Out of 28 species, 13 are previously unknown, and one fossil shell even sports polka dots.