Re: parallel cladogenesis

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

    Parallel cladogenesis is very difficult to document even among living 
organisms, so documenting it in the Mesozoic fossil record would be next to 
impossible given our present technology.
    The most likely occurences of parallel cladogenesis involving dinosaurs 
would probably have been with certain parasites, such as lice.  Lice are 
often very clade specific when it comes to their hosts, so when cladogenesis 
occurred among dinosaur hosts, their lice could have often diverged in 
cladogenic fashion in parallel.  Many clades of lice and other 
dinosaur-specific parasites probably went extinct with their hosts at K-T.   
But as I said above, documenting this would be next to impossible even if we 
did have a fossil record for lice in the Mesozoic.
    Parallel cladogenesis can also occur between plants and the organisms 
which eat and/or pollinate them, but it hard to imagine this happening with 
dinosaurs (except perhaps some dinosaur descendants like hummingbirds).  If 
you had an intimate dinosaur-plant relationship something like pandas and 
bamboo, I suppose it might be conceivable (but not very likely).
    As for a dinosaur-dinosaur case of parallel cladogenesis, that too 
seems very unlikely.  Even if a dinosaur predator specialized in a certain 
small clade of
dinosaur prey, it's very difficult to imagine cladogenesis in one resulting 
in cladogenesis in other (especially if the juveniles of the predator didn't 
also feed exclusively on juveniles of that same clade of dinosaur prey).  
Seems very improbable.
    But back to the parasites, I just wonder if one could indirectly infer 
some possible cases of broad parallel cladogenesis by studying Family taxa 
of a parasite (external or internal) in living birds, crocs, and perhaps 
lepidosaurs.  Inference from such phylogenetic bracketing would be tricky, 
but it would be a whole lot more feasible than getting it directly from the 
fossil record.  An interesting subject to think about.
          ---- Cheers, Ken
*****************************************
Jordan Mallon wrote (on 12 Mar 2002):
> Just curious as to whether or not there are examples of parallel 
> cladogenesis in the Dinosauria?  Maybe something relating to the Mesozoic 
> Arms Race?
> I just learned about this concept recently and was wondering how it might 
> apply to my favourite group of animals.


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