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Re: marine reptile McMenu

- Changes in ecosystem level evolutionary process driven by keystone
species (eg. something like what we see in increasingly shorter genus
life spans among plants).

Do you have a ref for this? Because I'm writing a paper on phylogenetic nomenclature right now*, and I'd like to include this as an example of how ranks meddle with people's heads -- and picking on Benton** all the time would be unfair.

You see, there is no way to tell if something is a genus. Anyone can all anything they want a genus, and nobody has a quantifiable criterion for it, so there's not even a way to tell if it's consistent within a single author's single classification. It follows logically that it is completely impossible to compare the lifespans of genera. If anything, decreasing genus lifespans tell us something about the classificatory practices of paleobotanists, but not about biology.

* Still not my long-promised definition of Aves, unfortunately.
** Has published lots of studies where he, sometimes with a coauthor or two, tried to quantify changes in biodiversity through time by counting genera, families and/or orders. He's also a famous vertebrate paleontologist, and publishes a lot. So he's the first who came to mind.