"not"-lonely Dan Janzen
kinman2 at YAHOO.COM
Thu Mar 25 09:59:35 CST 2004
Rich Pyle wrote:
The real "problem", as I see it, is as you say: the information gaps (and the unwillingness of some ardent cladisticians to acknowledge that such gaps can compromise the integrity of their inferred phylogenies).
I totally agree. The one, two punch that ruffles the most feathers is (1) refusal to accept even occasional, explicit, paraphyletic taxa; and (2) as stated above, the integrity of inferred phylogenies. The latter can be due not only to information gaps, but is often also due to additional shortcomings (abusing what information we do have), such as misrooting, character choice, ignoring trees that are not "the best" tree, and various other pitfalls that have also been discussed before.
But let me emphasize that the information gap problem varies greatly from group to group. In the Diptera, the gap will be largely filled in a decade or less, as molecular sequences (and whole genomes) become available. Whether we should then abandon a paraphyletic Nematocera is up to dipterists. I personally think it has more value than some formal clade names (e.g., Eremoneura and Muscomorpha sensu lato). These and additional intermediate clades (that will no doubt be proposed in the future) are better encoded and referred to informally.
Now, for a group in which the information gap will be a problem for many, many decades to come----reptiles. What some vertebrate paleontologists have done to reptile classification is inexcusable. Trying to formally cladify it decades before sufficient information will be available is embarrassing, confusing, destabilizing, and just generally a black-eye for cladistic methodology. This is even true for the dinosaurs, which are "relatively" well-known (compared to many other fossil reptile groups), and it will be one of Phylocode's major blunders from the very start this summer. In order to avoid a paraphyletic Class Reptilia, a very high price will be paid by the entire systematics community (but vertebrate zoologists in particular), not to mention inconvenience to millions of non-scientists. I will probably be ranting against that unnecessary mess, in particular, until the day I die (and at 53 years of age, I don't feel like an "old" fuddy-duddy yet). :-) The irony is that where we most need formal paraphyly is where strict cladism is most entrenched (herpetology). Zealous herpetologists have also made quite a mess of Class Amphibia (clade Amphibia is very restricted now). Too bad they can't be more like the dipterists.
------- Ken Kinman
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