It is well established that under the right conditions, the original color patterns on some aragonitic fossil mollusks can be revealed using UV light. Here we examine over 80 genera / 100 species of gastropod and bivalve that display a wide variety of spectacular UV patterns. Some of these patterns are validated by faint visible color traces.  Over 4,000 specimens that fluoresce naturally from direct sun exposure were used, with no additional preparation necessary.  They originate from two different North Carolina locations: Register Quarry (Old Dock – Lower Waccamaw Formation ~2 Ma) and Fountain Quarry, (Yorktown Formation ~4 Ma).   

We examine these two sites as they relate to each other (by species and color pattern); and as they relate to nearby North Carolina beaches with their modern extant inhabitants. 

The results have wide ranging implications – we find color patterns remaining the same, morphing over time or disappearing altogether.  We find species changing dominance, evolving, moving or going extinct.  Example: At Fountain (4Ma), Glycymeris americana is the underdog species with Tucetona subovata being the dominant large Glycymerid.   Glycymeris americana had a single color pattern.  By 2 million years later at Old Dock, the large Tucetona were gone, Glycymeris americaca was dominant and had 3 different color patterns, the Fountain pattern being recessive, a hybrid pattern being dominant and the modern extant pattern being rare.  Fast forward another 2 million years and the Fountain & hybrid patterns are completely gone and only the extant pattern remains.

There are numerous examples of specimens having the same shape and color pattern between the fossil and extant versions, but different species names, as well as the converse: specimens having the same species name, but different color patterns or morphology between the fossil and extant versions, both of which call into question existing nomenclature.

UV fossil color patterns can be an exciting new tool in helping improve our understanding of both fossil and extant classifications.  Further research will expand to include additional locations including SMR Quarry in Florida.