Re: the tonight show

["Ken Kinman" <kinman@hotmail.com>]

Ronald,
    I was not defending the use of the term "dino-bird", and must admit I 
winced when I read that.
    However, palaeognaths are indeed one of the many cladistic 
"halfway-houses" between the Neognaths and primitive forms (like 
Archaeopteryx and dromaeosaurs).  Other halfway-houses are the extinct 
Ichthyornithiformes,  and further back the enantiornithines.
    Paleognaths are admittedly the closest of the halfway-houses to the 
Neognaths as a whole, but I think it is unnecessary quibbling to say that 
they are not an evolutionary halfway-house.  And even within Neognathae, one 
could justify saying a Galliform-Anseriform clade is a halfway house on the 
way to the sparrow (and other passeriforms).  In between these clades, 
identifying cladistic halfway-houses gets very controversial (much less 
lining them up in the correct branching order).
    A lot of evolution occurred between the first Paleognathae and the 
first passeriforms (and even more getting to today's sparrow).  The 
paleognaths found their niches, and their evolutionary rates dropped 
compared to most neognaths.  And evolutionary rates are relevant to how 
"closely" organisms are related.
                   ------Ken
P.S.  I would certainly not say a koala is "more like" a crossopterygian 
than an elephant, but Metatheria is one of the many cladistic halfway-houses 
between the sarcopterygian Order Coelacanthiformes and the mammalian Order 
Probosciformes.     I'm running late---got to run for now.  Have a nice 
Tuesday everyone!!!  :-)
********************************************************
> From: Ronald Orenstein <ornstn@home.com>
> I must disagree.  Calling a cassowary a "dino-bird" will imply to a general 
> audience not that it is marginally more like a Velociraptor than a sparrow 
> is (and I am not sure I buy this either), but that it is some sort of
> halfway-house between birds and (other) dinosaurs.  Of course it is nothing 
> of the kind.  It is a perfectly good modern bird, though a palaeognath.  
> You could just as easily say that a koala is more like a crossopterygian 
> fish than an elephant - hardly a useful statement even if, genetically, it 
> might be (marginally) true.
>
>
> --
> Ronald I. Orenstein                           Phone: (905) 820-7886
> International Wildlife Coalition              Fax/Modem: (905) 569-0116
> 1825 Shady Creek Court
> Mississauga, Ontario, Canada L5L 3W2          mailto:ornstn@home.com
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