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Re: THAT DUCK-CHICKEN THING
>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.
You may be thinking of Juncitarsus, which Olson and Feduccia consider a
"shorebird-flamingo mosaic" (see Feduccia's book at p. 208), a view
supported by Stefan Peters.
>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.
Not to mention his suggestion that loons, grebes and hesperornithiforms
were related (though that was a while back.....)
>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
Without checking specimens, let me remind you that the retroarticular
process serves, among other things, as the insertion point for m. depressor
mandibulae, the chief jaw-opening muscle in birds. Birds which open their
mouths against force may have large, well-developed processes. You can see
this in filter-feeders like flamingos, or in birds that use the beak for
"gaping" - that is, spreading apart materials to expose food. Meadowlarks
have a pretty big process, for example, and use it to spread vegetation
apart on the ground as they forage, and the South American Scarlet-headed
Blackbird, or "Federal", which uses a beak like a chisel to split open
thick-stemmed bulrushes, has an immense process approaching that of a
flamingo in proportion. IOW, beware of convergence!
>I think that the OTHER Olson and Feduccia paper in 1980 on the
>recurvirostrid relationship of phoenicopterids, nicely domolished this
Ah. This is, of course, the Juncitarsus paper. I confess, though, I am
not so sure about comparing flamingos to the living Banded Stilt, a
communal breeder with somewhat flamingo-like behaviour that is surely a
case of convergence. The fossil evidence is interesting, though.
Ronald I. Orenstein Phone: (905) 820-7886
International Wildlife Coalition Fax/Modem: (905) 569-0116
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