Paleonet: two parts of holotype [SEC=UNCLASSIFIED]

[Jere H. Lipps]

At 04:09 PM 2/10/2008, you wrote:

>These should clearly demonstrate that the term holotype should be 
>applied to an individual organism, not a part thereof.

That was one view expressed--but only when hard evidence show the 
parts are from a single individual.  Part(s) of an individual is 
legal as a holotype as The Code specifies, so it becomes a matter of 
judgment on how to deal with the many situations where different 
elements occur together or, worse, apart.   Furthermore, all fossils 
constitute only a "part" of an organism, so arguments that an 
individual organism should be a holotype is questionable at best in 
our business.  While one might think two valves go together, another 
person may not.   In fact, John, I remember standing on Shell Beach 
at Hamlin Pool, Shark Bay, in your own country, picking up valve 
after valve from millions of similar little shells and fitting them 
to one in my hand to see if I could make a "single individual".   I 
found many opposite valves that fit the one in my hand quite 
perfectly (not surprisingly since they are all about the same 
size).  I've done it in other places too, sometimes with students to 
demonstrate both the similarity and diversity of variation in 
morphology.  It's a good exercise for them because they find valves 
that fit and those that don't and hopefully learn a lesson.  It is 
one reason I suggest that two loose valves from a fossil deposit 
should always be considered to be from separate individuals.  Good 
evidence is required, such as preservation in living positions, to 
justify making separate fossil elements part of the same holotype.

A 100% certain way to preserve the species concept of an author is 
for him to designate only one element as the holotype, selected 
carefully, and others as paratypes indicating which one might be the 
matching valve along with the evidence you think it might be so.   It 
does not hurt future paleo/biologic studies to do it this way, but 
making two valves the holotype on the assumption they go together, 
which then might fail if another investigator thinks they are 
different, thus allowing him to select a lectotype.  This action 
almost always changes the original author's concept of the 
species.  We are also relegated to doing book-keeping instead of doing science.

Asking a museum scientist in another place to make a judgement on 
whether or not the two valves go together compounds the problem and 
is improper since that person is not involved in the study, and it is 
clearly a case of judgement/responsibility that should be exercised 
by the investigator in charge if he/she is trying to demonstrate 
commonality of origin.

Clearly, selecting two or more parts that requires judgement 
(assumptions) about their origin makes for more trouble than it is 
worth, unless of course there can be no doubt, as in a live specimen 
or a fully articulated fossil.  Selection of holotypes is always 
about judgement, some being relatively easy, others more 
difficult.  Why complicate future studies with decisions that can be 
messed with by future workers?   If one is a holotype and the other 
is a paratype, then the argument remains focused on variation in the 
fossils and not so much on nomenclatorial issues.

What we have demonstrated once again is that opinions exist and that 
we can make a case for our own.   That is exactly why we have rules 
for nomenclature--to allow for opinion and keep chaos at 
bay.   Everyone is well advised to carefully state their evidence and 
assumptions in species descriptions, just as in the statement of any 
other hypothesis.  They are also entitled to their own opinions on 
how to do these things, just as subsequent investigators are entitled 
to theirs to do it differently.

Jere 
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