Paleonet: two parts of holotype [SEC=UNCLASSIFIED]

[leigh van valen]

As in many kinds of situations, one has to distinguish between the ontic 
(what exists) and the epistemic (our inference as to what exists.)  A 
type is an individual, but the author may be mistaken in associating 
elements of the claimed holotype.  These elements are then syntypes and 
a lectotype should be chosen from among them.  It happens.  Yes, it's 
better practice to designate a single element, but we have to live with 
cases where this isn't done.
  -Leigh

Jere H. Lipps wrote:
> 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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