I object to the idea that we have only two choices in regard to speciation:
the PSC and the BSC. I object to the BSC because as a theory, it has
nothing whatever to say about possibly related taxa that are not sympatric.
People have come up with suggestions (eg Schodde & Mason's in the
Directory of Australian Birds: Passerines that if two taxa are similar and
differ in one dimension, they are subspecies; if they differ in several
dimensions, they are species), which seem sensible, but have nothing to do
with the BSC! A number of accepted cases of interbreeding between forms
that are accepted as good species (eg Baltimore and Bullock's Orioles in
North America) seem to contradict outright the BSC. Equally, I reject the
PSC because it denies the facts of differences in degree of relationship.
As long as they are diagnosable, it says that two taxa that show a 1%
genetic difference are as much two good species as two that differ by 8%.
This is nonsense!
So with the albatrosses, we can use Schodde and Mason's criteria, but I
would prefer to rely on DNA sequencing. If the degree of genetic
difference between D.exulans and D.antipodensis is comparable to the
difference between T.chrysostoma and T.bulleri, then the first two are good
species. If it is notably less then they differ as subspecies.
Given the facts of albatross breeding, and in particular, the fidelity of
birds to their natal island, I would not be in the least surprised if they
turn out to be good species.
John Penhallurick
Associate Professor John M. Penhallurick<>
Canberra, Australia
Phone BH( 61 2) 6201 2346 AH (61 2) 62585428
FAX (61 2) 6258 0426
Snail Mail Division of Communication and Education,
University of Canberra,A.C.T.2601, AUSTRALIA
OR (Private) PO Box 3469, BMDC, BELCONNEN, ACT 2617, AUSTRALIA
"I'd rather be birding!"
"Vivat,crescat,floreat Ornithologia" Hartert,Vog.pal.Fauna,p.2016.
"The market where possible,the state where necessary"(Margaret Thatcher)
"Sunt lacrimae rerum." Virgil, Aeneid,i,462.
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