San Jose State University researcher Dr Jonathan Hendricks has used ultraviolet (UV) light to reveal and characterize the original shell coloration patterns of 28 cone snail species from three Neogene coral reef-associated deposits from the Cibao Valley, northern Dominican Republic.
Fossil cone shells and their original colors, from top to bottom rows: Conasprella stenostoma, Conus lombardii, and C. carlottae. Image credit: Jonathan Hendricks / San Jose State University; adapted by Sci-News.com.
Cone snails – which include three small genera, Profundiconus, Californiconus, and Conasprella, and one large genus, Conus – are one of the most well-studied groups of marine animals, and are represented by over 700 extant species.
The diverse shell coloration patterns of these snails, which all belong to the venomous neogastropod family Conidae, have caused them to be coveted by shell collectors for centuries, and these patterns have even been the subjects of studies by computer modelers.
Unlike their modern relatives, fossil cone shells often appear white and without a pattern when viewed in regular visible light.
By placing these shells under UV light, the organic matter remaining in the shells fluoresces, revealing the original coloration patterns of the once living animals. However, it remains unclear which compounds in the shell matrix are emitting light when exposed to UV rays.
Using this technique, Dr Hendricks of the San Jose State University’s Department of Geology was able to view and document the shell coloration patterns of 28 different cone snail species that lived between 6.6 and 4.8 million years ago, 13 of which had not been previously described.
Determining the coloration patterns of the ancient shells may be important for understanding their relationships to modern species.
The scientist compared the preserved patterns with those of modern Caribbean cone snail shells and found that many of the fossils showed similar patterns, indicating that some modern species belong to lineages that survived in the Caribbean for millions of years.
“A striking exception in this study was the newly described species Conus carlottae, which has a shell covered by large polka dots, a pattern that is apparently extinct among modern cone snails,” said Dr Hendricks, who is the author of the paper published in the journal PLoS ONE.
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Hendricks JR. 2015. Glowing Seashells: Diversity of Fossilized Coloration Patterns on Coral Reef-Associated Cone Snail (Gastropoda: Conidae) Shells from the Neogene of the Dominican Republic. PLoS ONE 10 (4): e0120924; doi: 10.1371/journal.pone.0120924
