FW: [Birding-Aus] Taxonomy and the purpose of Species names

To: <>
Subject: FW: [Birding-Aus] Taxonomy and the purpose of Species names
From: Syd Curtis <>
Date: Wed, 12 Jul 2006 16:39:51 +1000

the message I sent to you was intended to go to Birding-AUS, but now I lost
it. Could you please forward it to Birding AUS?


From: "Frank Rheindt" <>
Date: Tue, 11 Jul 2006 04:58:31 +0200
Subject: Taxonomy and the purpose of Species names

Syd, Birding-AUS,

you are referring to a topic of on-going debate, and you will find reputable
biologists on either side of the fence-line when it comes to Biological
(BSC) vs Phylogenetic (PSC) Species Concept. I doubt that we will all come
to an accord here on Birding-AUS. However, one of the things said stands out
as a thorn in my eye, and I would therefore like to comment:

>... there is also a big debate going on on what are the correct criteria of
>deciding what is a good species, with many people switching from the old
>Biological Species Definition to the more modern Phylogenetic Species

The statement that scientists are switching from the "old" (=outdated?)
Mayrian BSC to a more "modern" PSC is by no means correct. Working as a
molecular phylogeneticist in birds myself, my personal impression is rather
the opposite, namely that the PSC was a fashionable thing of the 90s and is
slowly fading off. Most of the colleagues I have certainly favour the BSC,
and one of the most recent textbooks on speciation does not even give any
reference to the PSC.

Many people commit the mistake of blaming the BSC for cases in which
phylogenetics have shown traditional taxonomy to be wrong. Nevertheless,
while traditional taxonomy has tried to adhere to the BSC, it has never
really been consistent in it, and many authorities admit that bird taxonomy
of the 20th century simply followed a mechanistic "morphological species
concept" defined by the procedures of museum-based taxonomists. Thus it is
unfair to conceive past mistakes in classification as shortcomings of the

Both species concepts seem to have their own problems, and books have been
published about it. For example, PSC advocates are struggling to defend
their view against the assertion that we are now able to find "characters"
that delimit any random population with modern molecular methods.
Conversely, the BSC has repeatedly been attacked because it is hard to apply
with allopatric (non-overlapping) taxa.

However, I would contend that most biologists (incl myself) do not find the
"allopatry problem" insurmountable. These days, we can judge whether two
allopatric taxa are biological species or not by applying the "yardstick
approach", i.e. compare their character divergence to that between two
uncontested and definite species within the same genus.

Last but not least, while it may be true that no one species concept
satisfies all needs, it would certainly be wrong to apply them
indeliberately. We must keep in mind that among all taxonomic units (i.e.
species, genus, family, order etc) the "species" is the only one that is a
real biological phenomenon. Genus or family boundaries can be drawn at will,
and according to the whims of the biologist; however, species really exist,
i.e. they form discrete reproductive units. Otherwise all organisms on this
planet would form a continuum from humans to sponges. Mayr wrote about this
decades ago, yet none of it has lost its significance, and I think it is
more timely than ever for some of us to read up on it.

Best wishes


============Frank E. RHEINDT================

University of Melbourne


Museum Victoria - Sciences Department
GPO Box 666
Melbourne 3001

Telephone: 8341 7426
Fax: 8341 7442


>From: Syd Curtis <>
>To: bird <>
>Subject: [Birding-Aus] Taxonomy and the purpose of Species names
>Date: Tue, 11 Jul 2006 11:45:47 +1000
>G. Crompton, referred to the listing of Oyster-catcher species in a New
>Zealand field guide, and queried the absence of the South Island
>Oystercatcher - Haematopus finschi, as well as the use of slang or uncommon
>or ambiguous vernacular names, concluding, "Any thoughts on what some of
>might think is a trivial matter?"
>Notwithstanding the perhaps unseemly levity of my separate posting, I
>certainly do not regard this as a trivial matter.  Quite the contrary.  And
>I wonder if we might have some thoughts from more expert b-aus subscribers
>than I, as to the purpose of naming species.
>Our ever-informative Wim Vader in discussing G. Crompton's posting has
>... there is also a big debate going on on what are the correct criteria of
>deciding what is a good species, with many people switching from the old
>Biological Species Definition to the more modern Phylogenetic Species
>Definition. I can pontificate more about this if you want me to; suffice it
>for now to say, that the phylogenetic criteria usually allow for 'smaller
>species' than the biological criteria.
>I would certainly like to hear more from Wim on this, and to get his views
>on why we name species.
>Schodde and Mason address the latter question in the Introduction to their
>Directory of Australian Birds - Passerines, and I wonder if  it could be
>approved for that Introduction or substantial parts of it to be posted on
>b-aus.   I surmise that permission from the publisher (CSIRO Publishing)
>would be required and further it may exceed our message size-limit.  It
>would amount to free advertising for this important treatise, so the
>publisher might agree.  Perhaps our Moderator could comment?
>However, I assume short quotes from it to be in order:
>  The regional forms of Australian birds, equivalent to the Linnaean
>of the last century and the phylogenetic species of today are basal
>biodiversity units of Australia's bird fauna.  Thus information on their
>identification and distribution is crucial for effective conservation of
>Australia's bird life nationally.
>And further:
>The current biodiversity unit in use for Australian birds, whether for the
>biologist, the conservation manager, the bird watcher or the man in the
>street, is the 'species'.
>One really needs to read the whole Introduction, but it seems clear to me
>that the authors see the prime purpose of taxonomic classification as
>providing the basis for biodiversity conservation.  I hope that Wim does
>pontificate further on the old Biological Species Definition vis a vis the
>more modern Phylogenetic Species Definition.
>Schodde and Mason consider that the 'biological species' per se is not
>doing, and indeed, cannot do, the job of identifying biodiversity units in
>the Australian bird fauna at the base-line level required for the inventory
>of biodiversity.
>So why not simply adopt phylogenetic species?  I hope I'm not exceeding
>what's reasonable, with a final rather long quote:
>Because diagnosing traits can be refined to levels that pick out minor
>populations, and even molecular sequences inaccessible to field workers,
>PSC is open to varying interpretation in practice and has yet to be adopted
>by the more authoritative continental or global manuals and checklists of
>birds.  It would also bring a degree of chaos to conventional
>of the Australian avifauna.  This comes not so much from a dearth of robust
>phylogenies as from its effect in raising most present subspecies to the
>level of species, almost doubling the size of of the fauna at species
>And all 'species' would have to be re-circumscribed according to new
>criteria.  Administrative consequences in government and the legislature as
>well as biology, would be daunting.  So we prefer to keep to the
>well-established biological species concept as the base for classification.
>As is now becoming clear, no one definition of species satisfies all needs.
>"... no one definition of species satisfies all needs."  So it depends on
>the purpose for which you are using the species names.  Comments, please.
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