Paleonet: Deadline for submitting GSA 2009 sessions-- January 6th!

argo at u.washington.edu argo at u.washington.edu
Wed Dec 24 22:56:53 GMT 2008


Hi Rowan and colleagues - 
Pardon the mass mailing.

Would anyone out there be willing to contribute to something along the lines of reconciling biostratigraphy and paleobiology?  In all of our fields the dominant paradigm of the last two centuries, using fossils to break up time, created species concepts so narrowly drawn that they worked to break up rock units (sometimes), but surely are not grounded in any biological reality.  In my own group, ammonoids and nautiloids, it is clear that there are far too many taxa oversplit at the species level, split so fine that only one or two specialists can  recognize them.  Because ammonoids hatched with a tiny calcified gas bag, and surely floated with currents, it can be predicted that there should be relatively few species, that speciation was difficult. Because nautiloids hatched large and lived benthically, it can be predicted that since any water depth greater than implosion depth would functionally 
segregate populations, that there should be many species.  Modern Biology seems to bear both predictions out.  Jim Bonacum of Illinois has now shown that what we call "Nautilus pompilius" may be 10-25 separate, sibling species.   Each separated island group has its own.  And the closest analogue to ammonoid reproduction, the coleoid Spirula, has but one species world-wide.  Using morphometrics on shell characters, I can show that the index ammonite Baculites is  oversplit by an order of magnitude -

I do not know what to call such a session - Putting Biology into Biostratigraphy? or something?  But I know it is needed.

Professor Peter D Ward
Dept of Biology
The University of Washington
Seattle, 98195
206-543-2962  ( Office )







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