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Re: parallel cladogenesis

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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