[2-part post combined.  BIG]
 
Q: " I *know * that skunks were reclasified.  I just can't find the
documentation.  Bob, Hopefully you will have some direction for me."
 
A: Do you know how many off-color jokes I could make with "have some
direction for me?"  I will be strong"I will be strong".
 
Ok, this is about skunks, but similar problems exist with ferrets and
polecats, so a discussion of both could be in order.  The article that
started the skunk stink was:
 
Dragoo, J. W., and R. L. Honeycutt.  1997 Systematics of mustelid-like
carnivores.  Journal of Mammalogy 78:426-443.
 
Many people read this and immediately thought the authors had proved
skunks belong to a family separate from the other mustelids.  Indeed,
dozens of newspaper articles, skunk owners, and even wildlife agencies
proclaimed skunks to no longer belong to the Family Mustelidae subfamily
Mephitinae, but now formed a new Family, the Mephitidae.  I have no doubt
that Dragoo and Honeycutt believes they have shown strong evidence to
reclassify the skunks, but I don't think they wrote an article that
proved it.  In fact, a careful reading of Dragoo and Honeycutt suggests
they DIDN'T SAY skunks should be in their own family at all!  All they
really say is that their studies illuminate problems with current
classification and some of the problems would be resolved if the skunk
subfamily was elevated to a family position.  Read it for yourself:
 
"If the Mustelidae are to be treated as a monophyletic group, then
the skunks need to be reclassified.  The solution is to elevate the
subfamily, Mephitinae (Bonaparte, 1845), to a distinct family, the
Mephitidae."
 
All "monophyletic group" means is that all forms in the family have a
single common ancestor, meaning all mustelids (members of the Family
Mustelidae: otters, polecats, weasels, badgers, skunks, etc.) can be
traced back to a single ancestral line.  This is nothing more than the
same type of genealogy done when you trace your ancestors back to your
great, great grandfather.  Dragoo and Honeycutt suggest keeping the
skunks within the Family Mustelidae makes it a polyphyetic group (more
than one ancestral line; it is like having two great, great grandfathers
on your father's side when you can only have one).  Modern taxonomists
suggest any lineage that results in a polyphyetic group is in error and
should be rejected; you simply cannot have two great, great grandfathers
on your father's side.  The solution, as Dragoo and Honeycutt suggested
it, is to elevate the Mephitinae to their own family, the Mephitidae.
 
The line, "The solution is to elevate the subfamily, Mephitinae
(Bonaparte, 1845), to a distinct family, the Mephitidae," was interpreted
by many to say the need for such a reclassification was proved.  But was
it?  Certainly, Dragoo and Honeycutt did some great research and
supported conclusions and questions brought out by other scientists.
But did they prove it?
 
I don't think so.  You have to understand there is a difference between
being right and proving something.  For example, I know I am right when
I say the consumption of refined carbohydrates causes insulinoma in
ferrets, but it isn't proved (it will be, and pretty soon, too!).
Likewise, Dragoo and Honeycutt brought up some very interesting
questions, but did their paper prove the point?
 
Not according to a recently published paper:
 
Sato, J. J., T. Hosoda, M. Wolsan and H. Suzuki.  2004 Molecular
Phylogeny of Arctoids (Mammalia: Carnivora) with Emphasis on Phylogenetic
and Taxonomic Positions of the Ferret-badgers and Skunks.  Zoological
Science 21:111-118.
 
This is what they say:
 
"Our analysis also strongly supports an outgroup position of the skunks
to a clade containing Procyonidae and the nonmephitine Mustelidae
(causing Mustelidae, as traditionally circumscribed, to be paraphyletic).
This position of the skunks agrees with results of most previous genetic
studies.  However, it is contradicted by known morphological evidence
from both living and fossil taxa, as well as genetic evidence from
protein electrophoresis.  These consistently support the traditional
placement of the skunks within the monophyletic Mustelidae (recently
in a close relationship to Lutrinae).  Therefore, we consider the
recent elevation of the skunks to the level of family as premature, and
recommend that this clade be left at the subfamily level (Mephitinae)
within the family Mustelidae, pending further evidence."
 
What the second paper says is that the genetic evidence supports the
idea the skunks are a distinct group that may be distinct from the
other mustelids, but it also says that other lines of evidence suggests
otherwise.  Sato etal's position is that until more evidence is
uncovered, you should not suggest moving the skunks into their own
family.  Good advice.
 
So, one article says skunks belong in a separate family, the other says
no.  Who is right?  Well, to answer the question, lets look at the
polecats and ferrets.  In 1999, Davison etal did genetic studies and
came to the conclusion that the genetic relationships between polecats
and ferrets were too close for determining the ancestor.  Sato etal
2003 confirmed that ferrets and polecats were too close to determine
an ancestor.  Of interest in both of the papers is the discussion of
the relationship between the polecats and the European mink (Mustela
lutreola).  Based on one type of genetic test, Davison etal suggested
that the European mink might be a sister species to putorius.  Based
on another type of test, Sato etal suggested the difference was due to
interspecific mitochondrial introgression that is, hybridization between
the polecats and the European mink.  Those are two different conclusions
based on two different tests, both done correctly.
 
Have you figured out the problem with the original skunk study yet?  You
are right; it was not the study, it was the precipitous dash to the
conclusion.  As soon as the Dragoo and Honeycutt paper came out, people
were busting a gut to amend the mustelid phylogenetic tree.  No one
seemed to want to wait for the next step in the process, which is for
someone else to test or confirm the findings.  And now there is the Sato
etal 2004 paper saying the elevation of the skunks to a new family is
premature.
 
One thing that may not be apparent to those that do not deal with matters
of species taxonomy is that ALL concepts, except the actual animals
themeselves, are artificial.  There is really no such thing as a
subspecies, or a family, or even of a genus.  In the real world, there
are only specieseverything else is artificial, constructed by humans to
understand the relationships between different types of animals.  So, the
argument about how skunks fit in with the other mustelids, or the exact
relationship between the polecats and ferrets, is actually an argument of
evolution.  What is being asked is, "At what point did the skunks break
away from the other mustelids, who was the common ancestor, and how do
they fit in with the other carnivores?" These are arguments of history,
ancient history actually, not of what skunks actually are.  Skunks are
skunks are skunks, and knowing or not knowing their exact position in
the scheme of life does not change that one simple fact.
 
This is the bottom line.  Dragoo and Honeycutt implied in 1997 that
skunks should be placed in their own family.  Sato etal in 2004 said that
change is premature.  Someone else will in some other year say something
else.  Then they will be revised, and so on and so on and so on.  Who
knows what will be said in 50 years, but even then, skunks will be
skunks.  We will understand their history better, but they will still
be skunks.
 
Oh, just for the record and to make this more ferret related.  I
mentioned earlier that neither Davison etal 1999 nor Sato etal 2003 could
determine the ancestor of the domesticated ferret.  Both touched on the
reason for this: introgression (hybridization).  This hybridization could
be European polecat (Mustela putorius) to steppe polecat (Mustela
eversmannii), it could be from one or both of the polecats to the ferret
(Mustela furo), or it could be any combination of hybridization.  But it
gives us a major clue to the domestication of the ferret.  Think about
it, and I will discuss ferret domestication in depth in a couple of days.
 
I've been gone for a long time, and I am very, very behind in some
important stuff.  I'm trying to get stuff done as soon as I can, and I
will post more on the FML as I catch up.
 
Bob C  [log in to unmask]
[Posted in FML issue 4722]