A question about passeriform birds

Related to my earlier question about grasses...

The passeriform group, aka the 'perching birds' or 'songbirds', is the largest group of birds today, right? It comfortably outnumbers all other bird groups combined, and includes most of the birds we see every day (sparrows, robins, starlings) and most of the birds we think of when we think 'bird'.

Now, the earliest passerine fossils are from the upper Eocene, but the group is probably much older than that. There are swallow-like _Paleospiza_ fossils from the Oligocene. But the molecular evidence suggests that the group didn't undergo major radiation until well into the Miocene... at which point it began its rise to the dominance that it enjoys today. Most of the major passerine

The radiation of passerines in the Miocene was pretty dramatic. I would assume that they were relatively rare way back in the Eocene, and would not expect to find them in the Paleocene at all (although one never knows). The three toes pointing forward makes perfect sense to me, since they bend forward a whole lot more than they do backward. And if you saw them walking up trunks of trees a lot (like many woodpeckers), two forward and two backward would make more sense, but I can't think of many passeriforms that live and move much like woodpeckers.

You're sure right about the fossil record of small birds... apparently _Paleospiza_ is the *only* passeriform fossil for about 15 my.

But the molecular evidence is trickling in and giving some hints about who diverged from whom, and when. Or so I'm told.

Okay, no argument there.

(blinking in bemusement) Really? I had no idea. I was using a birdwatcher's guideline with the toes.

Er, what exactly is 'bundled sperm', anyway?

(Please keep in mind that I'm not, not, not a biologist. So I'm going to be asking what may be some fairly stupid questions.)

[concerning the reasons for passeriform radiation]

Okay... would you have any idea when this was debated? I do have access to a good library.

Er, having more species than all other birds combined doesn't count?

We do? We don't?

What's wrong with comparing them to, well, to all other birds? IIRC it's something like 3500 passeriform species, 2100 non-passeriform.

I have enough statistics to know what a null model is, but you lost me with the random markov branching.

Okay. Well, I guess I can live with that.

Doug M.

I think you're on to something there, but there are other factors. How do you account for the diversity in Passerine diets ? Could that have been driven by a reliance on song ? Or could it have been another element in the drive to speciate ?

John M.

I don't want to get involved in the bickering over the meaning of 'significant'. However, I have not studied passeriform phylogeny recently, and have a quick question. Is the following classification outline a fairly good representation of the main phylogeny (numbers show the main cladistic sequence): PASSERIFORMES 1 Acanthisittidae 2 Eurylaimidae and other suboscines 3 Menuridae 4 'core oscine group' of families And if Acanthisittidae turns out to share synapomorphies with suboscines, we could change the coding to reflect this: 1 Acanthisittidae B Eurylaimidae and other suboscines 2 Menuridae 3 'core oscine group' of families