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FW: The Paleontological Society of Washington



Greetings, folks!

Back from SVP, which was quite good (although truth be told, it did not
feature any of the mind-bending sort of new information that some meetings
have contained).

More on that later.  First, a message for the Washington area members of the
list: announcement of this month's Paleo Soc. of Washington meeting:
------------------
The Paleontological Society of Washington

Presents

"Plant Exudates or the gooey stuff that some plants ooze"*

by

Dr. Jorge Santiago-Blay
Smithsonian NMNH Department of Paleobiology


Wednesday, October 16, 2002
7:30 PM

In the Cooper Room, National Museum of Natural History


Meet at the Constitution Avenue lobby at 5:30 PM to join us for dinner.

Non-Smithsonian visitors will be escorted to the room at
7:00 and 7:25


*  Abstract
Fossilized plant resin, or amber, is notable in having exquisitely
preserved organisms or parts of them. Additionally, some features of the
biology of these organisms are traceable to the Lower Cretaceous (ca. 130
Ma). Resins, complex mixtures of carbon-rich molecules insoluble in water,
have been produced by numerous ancestral vascular plants, including the
Medullosales, since as early as the Middle Carboniferous (ca. 305 Ma). Of
all plant exudates, including resins, latexes, and gums, distributed in over
509+ genera and 137+ plant families, it appears that only resins occur in
geologic deposits. Nevertheless, the botanical source of many ancient resins
remains obscure. As the chemical nature of resins may vary with plant
species, the characterization of modern resins by different physicochemical
techniques are used to establish the likely botanical origin of ancient
resins. However, ancient resins are seldom associated with taxonomically
diagnostic plant organs or tissues. C-13 SSNMR is a state-of-the-art
research tool that generates spectra (or signatures) of solids. This
technique is the only method that can distinguish the botanical sources of a
wide variety of ancient and modern resins. Our analyses use a tiny amount of
the solid resin (< 0.5 gram) and are non-destructive. Peaks in different
regions of the spectra represent different kinds of chemical bonds,
distinguished by their resonances, present in the sample. Data from these
resins will be presented from three research areas of evolutionary
paleobiology. First, the refinement of our knowledge of fossil and modern
plant resins by generating a library of C-13 SSNMR chemical signatures for
them. Second, from a chemical library of exudate samples, the identification
and reconstruction of resiniferous forests can take into account varied
plant species that may have been diachronous sources in the same general
locality. Third, given the large number of modern resin samples at hand from
closely-related plants, there is a basis for commenting on their
classification.  These chemical approaches provide an alternative and
complementary methodology for reconstructing resin-producing forests,
particularly for lineages with extant representatives.

We are in need for additional plant exudates from all over the World, to
continue our studies. Please, contact me (blayj@nmnh.si.edu) if you wish to
help us. Thank you.


Jonathan G. Wingerath
Paleobotany Collections Specialist
Department of Paleobiology
Smithsonian Institution
P.O. Box 37012
NMNH, Room E-213, MRC-121
Washington, D.C. 20013-7012

telephone:  202-357-4470
fax:             202-786-2832
------------------------------------

                Thomas R. Holtz, Jr.
                Vertebrate Paleontologist
Department of Geology           Director, Earth, Life & Time Program
University of Maryland          College Park Scholars
                College Park, MD  20742
http://www.geol.umd.edu/~tholtz/tholtz.htm
http://www.geol.umd.edu/~jmerck/eltsite
Phone:  301-405-4084    Email:  tholtz@geol.umd.edu
Fax (Geol):  301-314-9661       Fax (CPS-ELT): 301-405-0796