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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 
issue.   

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 
>the details. 

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 
specialized birds.  

>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 
relationship.  

>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 
>sister-group.

I think that the OTHER Olson and Feduccia paper in 1980 on the 
recurvirostrid relationship of phoenicopterids, nicely domolished this 
notion.  

>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 
about.  

OWL EARS

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.  

Matt Troutman 
m_troutman@hotmail.com


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