[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index][Subject Index][Author Index]

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.

> squibbons

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 
turtles.