Re: Jeholornis

[David Marjanovic <david.marjanovic@gmx.at>]

> >Abstract:  The recently reported Jeholornis represents the only known 
> >bird with a complete long skeletal tail except for Archaeopteryx. 
>  
> Does _Rahonavis_ not count because its tail isn't completely known, or  
> because it isn't a "bird"? 
 
As it says, in rather convulsed words: because the only known specimen has 
a skeletal tail that is long but not complete. :-) 
 
> Are there any other feathers preserved?  Two or four wings?  :) 
 
Two. The impressions are rather faint, though, and I only saw them on one 
of the two specimens... 
 
> >We conclude  that the common ancestor of birds must have a more 
> >primitive tail  than that in Archaeopteryx, 
> >confirming the side branch >position of 
> >Archaeopteryx in the early avian evolution. 
 
OK, this isn't news... those who thought that Archie was a direct ancestor 
of the living birds have become quite rare. 
 
> Should that be said about _Archaeopteryx_ when _Jeholornis_ is clearly a  
> side-branch? 
 
If 
 
+--+--Archie 
|  `--*Jeholornis* 
`--Avebrevicauda 
 
, then yes. (Maybe I should better write it as a phylogram, like this: 
 
      ,----------------Archie 
   ,-+ 
--+   `--*Jeholornis* 
  `----------------Avebrevicauda 
 
.) If 
 
+--Archie 
`--+--*Jeholornis* 
   `--short-tailed birds 
 
, then, too, because then Archie may have reduced its tail independently 
from the really short-tailed birds. 
 
While I am at it, what should I choose as an outgroup for an analysis of 
the above problem, without having to make a 500-character coelurosaur 
analysis out of it? 
 
>  Which tail shape allows for better flight ability? 
 
May I hazard the guess that this depends on how you want to fly. :-) And 
that's not taking sexual selection into account -- several studied species 
of living birds have tail shapes that are a compromise between natural and 
sexual selection. 

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