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Re: The Future is Wild
Original Message by Mickey Mortimer
> I don't see what your problem with this is. Assuming terrestrial
> vertebrates went extinct (and what an extinction that would be), something
> would recolonize land. [...] Though I could picture annelids,
> arthropods or any number of other invertebrate phyla becoming the main
> clade of large terrestrial animals, cephalopods do seem well equipped for
> the job (octopuses already have cartilaginous braincases after all).
I didn't know that. Now it sounds quite a lot better. What's missing is a
genetic trick that triggers braincase formation everywhere in the body...
could be feasible. Hm. In the meantime arthropods and snails would inherit
the earth. Eurypterid-sized scorpions with book lungs... :-)
> As for design
> constraints, who could have guessed Pikaia would be the ancestor of
> reptiles 200 million years after it existed?
Nitpicking alert! I couldn't, because there was at least one real vertebrate
in the Early Cambrian of China. :-)
Hou Xianguang, Richard J. Aldridge, David J. Sieter, Derek J. Siveter & Feng
Xianghong: New evidence on the anatomy and phylogeny of the earliest
vertebrates, Proc. R. Soc. Lond. B 269, 1865 -- 1869 (2002)
Is about a new specimen that shows that *Myllokunmingia* and *Haikouichthys*
are the same. The former name is selected as having priority.
And of course, *Branchiostoma* has those lateral "metapleural folds" that are
probably homologous to paired fins. At least as a larva it also has an eye
that is homologous to our two, in addition to the pineal & parietal ones. So,
in hindsight at least, it's not so hard to guess.
Wouldn't even need an endoskeleton as long as they don't get too heavy. :-)
Well, what I do have a problem with are 4-winged birds. And sauropod-sized