ISOLATION & CHARACTERIZATION OF ORGANIC MOLECULES FROM MISSISSIPPIAN-AGED CRINOIDS

In examples of exceptional preservation, fossil crinoids (phylum Echinodermata) from the same locality display species-specific color preservation. It was this feature that motivated Christina O’Malley and William Ausich to consider the potential for using coloration as a means of tracking phylogeny. These colors are produced by light absorbing chromophores in organic molecules and have been recognized as polyaromatic hydrocarbons. The Soxhlet extraction method was employed to isolate organic molecules that had been preserved in the calcite stereom of the crinoids. Ultraviolet visible (UV-Vis) light spectroscopy and Orbitrap electrospray ionization mass spectrometry (ESI-MS) were used in this study to further elucidate the identity of these organic molecules, while also assessing the feasibility of utilizing these molecules as biomarkers to track phylogeny. Organic molecules extracted from fossil material were compared to extracts from modern echinoderm analogues in order to determine the most plausible identities. Results indicated that the organic molecules preserved in Paleozoic crinoids are distinct from those identified in Mesozoic crinoids. These differences may be attributed to biological differences between the different crinoid taxa, but most likely are associated with the different geologic settings that the crinoids were deposited in.