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THAT DUCK-CHICKEN THING
At last, good bird discussions :-)
Darren Naish wrote:
>Olson and Feduccia have, both together (Olson and Feduccia >1980a,
1980b), and apart (Olson 1985, Feduccia 1996), argued >strongly that
there is no 'duck-chicken relationship' and that >anseriforms are
related to waders and flamingos, and that galliforms >are of a totally
unknown phylogenetic position.
Please note I did not sink into that 'ducks are charadriiforms'
nonsense. My current, shaky (which means I can change my mind at any
moment) standing on anseriform relationships is I don't have a clue.
I'm skeptical about ANY placement of Anseriformes. Most of the features
listed by Olson and Feduccia (and Feduccia earlier) are postcranial
features (non-pneumatic humerus, position of the manubrial spine etc.)
that appear to me to be rather trivial and most likely convergent. As I
can tell I am dazzling all of you with an in-depth analysis on the
Feduccia's early work on this issue was of rather different stuff than
his later work. He argued for a special common ancestor for
Anseriformes and Phoenicopteriformes with _Presbyornis_ on the way to
both groups (or flamingos?) if I recall correctly.
>This evidence must be overturned or ignored if you are
>to reject galliform-anseriform affinity, and indeed in his 1985
>review Storrs Olson openly expressed the view that, if this is what
>the DNA data reveals, it must be wrong!
I think Darren would agree with me when I say that DNA analyses are
rather unreliable. Pettigrew in one of his bat diphyly papers (in that
big bat book; I forget the date) argued that many molecular analyses are
biased towards A-T. This relates to a high metabolism.
Master of the scientific process Storrs Olson is certainly wrong in
saying this. At least I have something to back me up :)
>Cracraft, who has supported a galliform-anseriform affinity and has
>been severely critical of Feduccia and Olson's arguments to the
>contrary, points out in many of his texts that, just because a
>morphology 'looks different', it cannot be disregarded if the
>evidence indicates it to be a shared derived state. Most often,
>this is the reason Olson and Feduccia provide in their disagreement
>with the galliform-anseriform link. Matt's reasons in his
>Thanksgiving post were the same (shame on you Matt!:)) - i.e.,
>character X looks different, and therefore does not support affinity.
Olson has also been critical of Cracraft because Cracraft uses the
opposite extreme; determining relationships from superficial and mildly
similiar characters. View Cracraft's masterpiece (in bad cladistic
analysis) of ratite phylogeny.
Yeah, I'm guilty of using that method and I was well-aware of it. At
least I used some characters that do not show sign of homology; the
basipterygoid process in ducks and chickens and the mandibular cotyle in
anseriforms and galliforms.
>Galliforms and anseriforms uniquely share some special cranial
>characters not seen in other birds (an unusual retroarticular process
>being the best known) - features that indicate that they are each
>others closest relatives, even though these structures do differ in
I can concede that the retroarticular processes are similiar in the two
groups and they are possibly some of the best evidence for the
'duck-chicken' relationship in the sarcastic Olson and Feduccia sense.
However, as noted, these differ in the details and if I remember
correctly (somebody, confirm or deny) diatrymid retroarticular processes
do not show compression and similiar details. However, I would not
place much stock in this argument for diatrymids are relatively
>1997 was a particularly interesting year for this issue, as two big
>papers were published concerning it. What is important is that both
>found no support for Olson and Feduccia's theory about >_Presbyornis_
being a duck-flamingo-shorebird mosaic: it is clearly >an anseriform,
and a close relative of ducks (anatids).
When I first read about this, I was not surprised. I was not convinced
in the charadriiform-anseriform relationship (I am convinced by the
charadriiform-phoenicopterid link though) and I thought that these
'primitive' characters were convergent and not a reliable marker of
>Ericson (1997) (published in the same journal as
>Livezey's paper) relied rather more heavily on postcranial characters
>and found instead that anseriforms fell out within a huge, newly
>defined Ciconiiformes (now including Gruiformes, Charadriiformes,
>Phoenicopteriformes AND Anseriformes - even more extensive that >the
Ciconiiformes of Sibley and Ahlquist), and galliforms were the
I think that the OTHER Olson and Feduccia paper in 1980 on the
recurvirostrid relationship of phoenicopterids, nicely domolished this
>So there you go: there is general consensus, and a great deal of
>material evidence, that galliforms and anseriforms do form a clade,
>but there will continue to be dissention and argument about it.
Until I get more of a passing look at these papers (hopefully in couple
of days) I will remain unconvinced. But hey, thats what science is
Oops. Thanks Darren. I did know this of course, but for some reason I
forgot this important feature. Oh, and Darren asked whether it is found
in all owls or not; yes, this feature is found universally throughout
Tytonidae and some (most?) Strigidae to my recollection. I am pretty
sure that it correlates with the facial disks in (all?) owls; the
external ear opening and the caudally bordering paraoccipital process
both face rostrally into the facial disk. I will probably be able to
give a more definite answer tomorrow.
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