Date: Tue, 4 Sep 2007 21:41:49 +1200
Reply-To: Conchologists List <CONCH-L@LISTSERV.UGA.EDU>
Sender: Conchologists List <CONCH-L@LISTSERV.UGA.EDU>
From: Andrew Grebneff <andrew.grebneff@STONEBOW.OTAGO.AC.NZ>
Subject: Re: whelk nomenclature
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--></style><title>Re: [CONCH-L] whelk
nomenclature</title></head><body>
<blockquote type="cite" cite>Andrew,</blockquote>
<blockquote type="cite" cite>The<i> Busycon</i> group has been
subdivided by Ed Petuch quite extensively. </blockquote>
<div><br>
Unsurprising. (said deadpan in deep voice, pointed ears pricked)</div>
<div><br></div>
<blockquote type="cite" cite>Apparently you are unaware of this,
but if you choose to ignore it rather than refute it, your arguments
are simply outdated.</blockquote>
<div><br></div>
<div>Not at all. Petuch has created many dozens of junior synonyms. I
have issues with his work. Sorry, Ed. However I should try to get
copies of the relevant publications (I don't count on my luck if he
sees this posting...). However it appears that his 2003 book
"Cenozoic Seas" might be important to those with an interest
in SE US fossil molluscs. I just wish the title was a bit more
specific (after all, there are no NZ fossils in there).</div>
<div><br></div>
<blockquote type="cite" cite>Ed does have a tendency to name varieties
(especially if you are correct and all the modern sinistral
forms back to the Pliocene are one species), but there are at
least five named dextral<i> Busycon sensu stricto</i> species (pre
Petuch) and (as of 1994) eight species and subspecies named by
Petuch.</blockquote>
<div><br></div>
<div>Most modern workers do not accept subspecies, and the number who
do is fortunately shrinking.<br>
</div>
<blockquote type="cite" cite>By your argument they are all<i> B.
carica</i> varieties, or dextral <i>B. perversum</i>
varieties!</blockquote>
<div><br></div>
<div>All B. perversum (oldest available name). What's the problem with
this? You tell me ONE character that cannot be seen to be gradational
among all so-called species (and chirality is meaningless... ANY
species can coil either way, and in the cases of Busycon and
Amphidromus among others they do so commonly). Coiling cannot be used
as a generic trait.</div>
<div><br></div>
<blockquote type="cite" cite><i>Lindafulgur</i> Petuch 2004
includes <i>L. candelabrum</i> (Lamarck 1816)</blockquote>
<div><br></div>
<div>The holotype of B. candelabrum is a grossly abnormal shell with
huge spinal development. Other specimens attributed to this name</div>
<div><br></div>
<blockquote type="cite" cite>and<i> L. lyonsi</i> (Petuch 1987), both
from the Gulf of Mexico,<i> L. alencasterae</i> (Perriat. 1963),
Miocene, Mexico, L<i>. miamiensis</i> (Petuch, 1991), and<i> L.
lindajoyceae</i> (Petuch, 1994), both Pliocene,
Florida.</blockquote>
<div><br></div>
<div>Lindafulgur? B. candelabrum is clearly conspecific with B.
perversum... how in h--l can it belong to a different genus?</div>
<div><br></div>
<blockquote type="cite" cite><i>Busycoarctum</i> Hollister,
1958<i>,</i> includes the modern<i> B. coarctatum</i> as well as the
Pliocene<i> B. rapum (</i>Heilprin 1886), <i> B. tudiculatum</i>
(Dall 1890).</blockquote>
<div> </div>
<div>B. rapum is probably not close to B. coarctatum. I cannot find
either of my specimens of B. coarctatum (one is in a box still
unpacked after my moving house; the other is missing in inaction), but
Hollister's images are good. Comparing specimens of B. contrarium and
B. rapum which I collected in the same locality/horizon in DeSoto,
Florida in 1989, the only difference is chirality. Sculpture (rather
variable even within the one population), expansion rate, translation
along axis, proportional canal length, canal expansion/taper,
apertural shape, columellar plait, labral liration, parietal plait...
no differences. They are mirror-images of one another. B. coarctatum
does not differ in any significant way from B. rapum, other than at
specific level; that is, it is clearly not conspecific, but has no
characters which merit generic or subgeneric separation.</div>
<div><br></div>
<div>B. coarctatum may belong to a separate monotypic subgenus to
Busycon ss (eg B. perversum), but that is debatable.</div>
<div><br></div>
<blockquote type="cite" cite> <i>Sinistrofulgur,</i> which Petuch
uses as the genus of sinistral whelks, includes at least five
Pre-Petuch species, and twelve which Ed named.</blockquote>
<div><br>
See my argument about "all B. perversum" above.<br>
</div>
<blockquote type="cite" cite>These are too subdivided for my taste,
but the group has been evolving significantly separately from the
dextral forms for millions of years. </blockquote>
<div> </div>
<div>The evidence is that they have NOT been evolving separately. As I
have said, there is a full range of intergradation between character
endmorphs, and this includes both chiralities.</div>
<div><br></div>
<blockquote type="cite" cite><i>Pyruella planulatum</i> (Dall,
1890) is typical of the Petuch genus<i> Pyruella</i>, small to medium
sized dextral Pliocene forms without spines but with a shallow sutural
depression.</blockquote>
<div><br></div>
<div>I am not familiar with Pyruella (yet).</div>
<div><br></div>
<blockquote type="cite" cite>There are at least four pre-Petuch
species, and eighteen species and subspecies named by
Petuch!</blockquote>
<div><br>
And... ?<br>
</div>
<blockquote type="cite" cite><i>Fulguropsis spiratum</i> (Lamarck,
1816), which has at least twelve extinct named relatives (five not
named by Petuch) is not that closely related to<i>
Busycotypus. </i></blockquote>
<div><br></div>
<div>Shell characters say otherwise; I don't know if anyone has done
comparative anatomies, cladograms or molecular studies of the two
species in question.</div>
<div><br></div>
<blockquote type="cite" cite><i>Coronafulgur</i> Petuch, 2004, a
Miocene group of five species previously put in<i> Busycotypus,</i> is
the apparent predecessor.</blockquote>
<div><br></div>
<div>Ancestor/descendant is always a problem when one has a continuous
fossil lineage; it not only becomes impossible to separate at species
level, but at generic or even familial. It always helps when there's a
hole in the fossil record where transitional form(s) are not
preserved. If there is a relatively complete record, then an arbitrary
cutoff point must be chosen, or else all must be place in the same
single taxon; no matter how different the endmembers may be, there is
no place one can OBJECTIVELY draw a line and say "on this side is
species (or genus) X and on that side is species (or genus) Y".
This does not show up in neontology, because the lineages are not so
apparent and gradual changes cannot be tracked over time. Therefore
where it occurs punctuated evolution is the taxonomist's friend;
gradual evolution is a pain but cannot be ignored. Perhaps (brief!!)
interruptions in the fossil record are a good thing? We have the same
problem in New Zealand with, for axample, the buccinine genus
Austrofusus, both at subgeneric and specific levels. Huge old
Buccinidae, in all its glorious subfamilies (such as Melongeninae),
has been around since well before the beginning of the Cenozoic, and
has many examples of such taxonomic problems (Perissityidae in part
etc). I guess it makes things interesting, and not only in the old
Chinese meaning.</div>
<div><br></div>
<blockquote type="cite" cite>There are also other extinct genera which
should be taken into account, like<i> Spinifulgur and
Brachysycon.</i></blockquote>
<div><i><br></i></div>
<div>There will be other related genera and subgenera, such as
Echinofulgur. The furher back in time we look, the more likely we are
to find different (though obviously related, often closely) taxa. Some
such named taxa will be good, others possibly not.</div>
<div><br></div>
<div>Remember: Just because someone has published something, that does
not make it right ("It must be true; I read it in a
book!").</div>
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