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Re: Is *Amargasaurus sattleri* a Parent Clade for Dicraeosaurines?



philidor11 wrote...
>First, any 'species' after inception is descended
>from another species...[snip]...you're exaggerating.  They look different
to us because they are
>substantially different.

    How substantially different are ring species?  How about cryptic
species?  There are lots of very closely related living species where the
line between them is not agreed upon by biologists, where morphological,
breeding isolation, or whatever criteria for definign species aren't always
100%.  The same sort of fuzziness would apply to all species if we could see
all the intermediates back to thier common ancestor.
      Where is the dividing line between your hand and your foot?  Is it at
your wrist?  Your ankle?  Your knee?  Your shoulder?  Your navel?  If
somebody was in a horrible accident that left only a severed hand with a
little bit of forearm attached, and a severed foot with a little bit of shin
bone, it makes an easy solution to that problem, but we are interested in
the whole "body".

>Actually, because new species are often created in isolated populations,
the
>opposite is true.

    Just because the big symbiotic colonies of cells we call individual
animals live in bigger groups themselves doesn't mean that they aren't big
symbiotic colonies of cells.

>From what little I know, you seem to be urging a Linnaean approach as
>contrasted with an evolutionary approach.


    Not really.  I'm just suggesting that phylogenetic taxonomy has selected
one arbitraily chosen criteria (common descent) for breaking up animals over
another because its more useful to us as people interested the big
evolutionary picture.  Again, just because its artificial doesn't mean we
shouldn't use it, because it IS useful.

LNJ
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