Re: Ruben Strikes Back

["ekaterina amalitzkaya" <eamalitz@hotmail.com>]

> difficulties--is that the theropod lineages leading up to flying birds each
> repeatedly lost flight adaptations and re-evolved the same kinds of
> adaptations for cursoriality and terrestriality convergently (e.g., small
> forelimbs, vestigial sternum, reduced hallux), and these convergences are
> misleading the cladistic analyses. At very least, this possibility has not

It appears that in wide range of Zoological contexts nowadays, aided by 
protein or nucleic acid phylogenies, morphologically less parsimonious 
suggestions are being proposed. A good case is the nesting of Turtles within 
archosaurs that would require reversal of several character states of 
traditional cladistics [could turtles be surviving aetosaurs?]. Similarly 
now nematodes have been made a sister group of the arthropods to the 
exclusion of annelids and several other taxa. This would imply that from the 
common invertebrate ancestor incourse of the origins of the new lines there 
should have been several losses of morphological features or convergent 
reinvention that unite the taxa in classical cladistic analysis.

If such scenarios are more prevelant in zoology than expected a serious 
challenge to cladistic zoology could crop up. The turtle case :if the 
protein based hypothesis turns out to be correct, could illustrate the 
relative inefficiency of cladistic approaches in higher order relationships.

In anycase given these new trends it may be worthwhile to objectively 
publish a more attenuated version of the hypothesis posted by Dinogeorge in 
more visible print- the secondary terrestriality of maniraptorans but not 
all theropods.
_EA

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