DELTA and paleobotany

Tue Mar 15 13:53:09 CST 1994

For a while, it was trendy to mention in research papers the brand name
of the computer on which the paper was written.  This seems foolish now,
since we all know about these tools of the trade, but it is still a good
way to bring valuable new tools, such as computerized taxonomic keys, to
the attention of others in your field.

My current project uses DELTA (and the paper will say so) as follows:

Many fossil plant taxa are insertae sedis in the botanical record, but
there is always some evidence to help place a fossil species in relation
to other taxa, at some level.  The usual procedure is to use an almost
intuitive sense based on personal experience, if you are experienced, or
the experience of a specialist, if you know one, or by laborious browsing
through one of the standard classification schemes, such as Cronquist's.
This last approach is tremendously simplified (though it may still be
intellectually challenging) by employing DELTA with the new ANGIO key.

How?  In an iterative process.  First, consider the characters given
in ANGIO, and decide which ones you can determine for your fossil (this
step may help you discover characters that you had overlooked).  Then
determine as far as possible the relevant character states.  Then plug
these in, in various combinations, perhaps stepwise, into DELTA, in the
identification mode, and observe which families match the data you have.
This may help you refine your morphological and anatomical description,
and provide some hints for further inspection of the fossil material.

Early fossils, in particular, may lack defining apomorphic characters
that help restrict affinity to a single family or order, yet they may
have "gestalt" similarities.  Using DELTA adds a degree of objectivity
and discipline to the hard task of perceiving "meaningful" similarity.

Yale Peabody Museum readers:  DELTA is installed on drive D: of the PC
in the lab next to Larry Gall's office.

        Una Smith                       smith-una at

Department of Biology, Yale University, New Haven, CT  06520-8104  USA

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