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Re: Reduced Consensus (Was: Afrotheria revisited)



----- Original Message ----- From: "Mike Taylor" <mike@indexdata.com>
Sent: Friday, March 23, 2007 6:06 PM


And because everyone uses unweighted characters, something as
gross as this difference in cervical morphology is worth no more
than, say an unobtrustive process on the lateral face of the
distal part of pedal phalange II-2.  I tell you, it's a sick
world out there.

This argument certainly has to be taken seriously, but it has its limits. Eike recently told us about some birds where it turned out that there was a lot of phylogenetic signal in the colour of the animals, while beak shape converges and reverses as it pleases. It's not easy to guess a priori which features are favoured by stabilising selection.


Then there's reweighting (aka a posteriori weighting). I like its effects on my (ancient, tiny) bird analysis: without it I got *Patagopteryx* around the base of Euornithes -- probably due to a few features that may well be due to its flightlessness and may therefore not have been present in all of its ancestors --, while after reweighting it jumped closer to the crown than *Yixianornis*, IIRC. While partially circular, it's much easier to defend than a priori weighting.

BTW, the singular is "phalanx"... though originally it referred to all digits as a whole, the meaning of the Greek word being "army (hoplites lined up in rows)".