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Oleanane is a triterpenoid which is common and abundant in many Late Cretaceous and Tertiary sediments, but rare in older sediments.  The observed spatial and temporal distribution of this biomarker (and the widespread occurrence of functionalized oleanoids in living monocots and eudicots) has led to oleanane’s use as a qualitative indicator of angiosperm (flowering plants) input in sediments.  However, more precise interpretations of oleanane occurrence are limited by incomplete taxonomic surveys for oleanoid natural products in living angiosperms and other seed plants.  In particular, basal-most angiosperms had not been sampled.  To examine oleanoid distribution in the base of the angiosperm tree, we sample species from the three most basal orders, Amborellales, Nymphaeales and Austrobaileyales, as well as Chloranthales, Magnoliales, Laurales, Piperales, Acorales, Alismatales, Ceratophyllales and Ranunculales.  Living material was collected, identified and air dried.  Half the sample was mounted as a voucher and the other half was crushed and cut into small fragments for analysis.  The samples were then subjected to hydrous pyrolysis, extracted, hydrogenated using an ionic reduction procedure, and separated into saturate and aromatic fractions.  The presence of oleanoids was tested using GCMS and GC-MRM-MS techniques.  The procedure was designed to mimic conditions of diagenesis and burial which transform diverse functionalized oleanoid natural products into a limited number of identifiable triterpanes, nortriterpanes, and aromatic triterpenoids in sediments.  Both oleananes and des-A-oleanane were found in all clades and most families.  A MacClade parsimony reconstruction supports the hypothesis that oleanane is ancestral in angiosperms.

Together with previous data from fossil seed plants, these results suggest that the angiosperm lineage is monophyletic and separate from other living seed plants, and related to a small group of extinct fossil seed plants.  The discovery that des-A-oleanane is common was also significance.  Previous unpublished work had shown that des-A-oleanane has a similar distribution to oleanane in sediments, but evidence for its botanical source material was lacking.  Our data clearly show that diagenesis of angiosperm source material could be the source in the geological record.

This project has involved colleagues at Stanford University as well as an undergraduate and indirectly a post-doc at IUS.  The post-doc who worked on separate paleobotanical projects was able to see the methods of plant biogeochemistry.  The undergraduate was closely involved.  Not only did she participate in the data collection, she also aided in the sampling design and interpretation of the results.  She gave one presentation at the campus research conference, and was a coauthor on a published abstract and attended the meeting of the North American Paleontological Convention where the research was presented at a symposium on Molecular Paleontology.  She has graduated with a degree in Geosciences and has obtained a job using her degree.  I hope I am able to include her in the process of writing a manuscript.  I believe that she greatly benefited by doing research and attending the conference.  I think if there had been an appropriate graduate program in the area that she would have considered graduate school and may in the future.

The funding was important for me as a provided me with the ability to have samples analyzed and to continue a long term collaboration on plant molecular fossils. The project has made excellent progress in it first of three reporting periods.  This includes analysis of 28 samples, attendance at several meetings, trips to obtain samples, and collaborative trips to Stanford to work on and discuss the results.  We anticipate an initial submission of a manuscript by the next reporting period.