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Re: Livezey and Zusi's big bird morph analysis [...]

What really makes me raise an eyebrow is that Livezey and Zusi not
only find a grebe/loon clade, but also a owl/falconiform clade

This one, however, is also found by the last few molecular analyses, as well as by Mayr taking *Messelastur* and the like into account.

I hadn't seen it show up in the molecular analyses; I'll take a look at that. I was aware that Mayr found a raptorial clade using Messelastur and company. However, Mayr's analyses seem to have a similar trend wherein the analyses consistently find groups previously considered "convergent" to be sister taxa instead (such as penguins and plotopterids). When that keeps happening consistently, I start to question character choices. He could be right on the money, I admit, I'm just a bit cautious about it at present.

a falconiform clade including cathartids

What's so bad about that one?

There isn't anything bad about it, per se. The problem is same as mentioned above; ie. the shear number of clades previously considered functionally convergent that this new analysis finds to be closely related. It could be that, indeed, all of those homoplastic hypotheses were incorrect. I remain skeptical at present, however, because it seems a bit suspect that *all* of those clades would end up being closely related after all. It increases the likelihood that many of the characters they are using carry a high degree of functional signal. And I do admit to a certain degree of personal bias; as rampant as functional convergence is in most groups, I suppose I've always expected to see similar trends in birds. I have no qualms about it being shown otherwise, though. More tests with expanded versions of the new dataset should help give weight one way or the other. Until then, I'm a bit skeptical but still very impressed with the work that went into the Livezey and Zusi tree.


--Mike H.