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Re: origin of bats (yet another combined answer)



----- Original Message -----
From: "David Peters" <davidpeters@att.net>
Sent: Sunday, June 22, 2008 2:03 PM
Subject: Re: origin of bats/reply to J. Headden

When pre-bats became inverted bipeds their hands were no longer involved in locomotory matters. That freed the hands, as in pterosaurs and birds, to become something else. In the case of birds, foldable raptorial instruments and origins for flight feathers. In the case of pterosaurs, foldable display, flapping and gliding instruments.

Just get over this hump and you'll see the light.

How did you arrive at this scenario, and why is it more parsimonious than any alternatives?


Here's the most obvious alternative: the hands were _not_ freed first, but passed from having one function to having two functions to having one function again. Hands of early eumaniraptorans were used for both grasping and flight, hands of early bats were used for both climbing and flight. The hands of extant bats are still used for both climbing and flight, even though they use different fingers for these different tasks.

Why should anything start to hang from branches by its feet alone when the hands are perfectly useful for that task? Where's the selective advantage in that? Why should a climber -- as opposed to a folivore -- start hanging at all? I think you have a "then a miracle happens" step in your flow chart. (As is, IMHO, commonly the case with evolutionary scenarios. Anyone's.)

And then you talk about "seeing the light". You come across as pretty naive...

----- Original Message -----
From: "David Peters" <davidpeters@att.net>
Sent: Sunday, June 22, 2008 2:20 PM
Subject: Re: origin of bats/suspect trees?

You're slipping back into DNA-land.

Why shouldn't he?

It's like I'm an astronomer and I find a new star. I tell other astronomers to point their telescopes at that star and look for themselves. All I'm doing is showing you new taxa to consider.

This is what I don't get. You keep acting as if a phylogenetic analysis were something that one can just write up in an afternoon and have a tree in the evening. No. No. No. A morphological phylogenetic analysis of this size is at the very least a chapter in a PhD thesis. (Rather more in this case because no previous attempts exist, other than the *Maelestes* paper.) It is an incredible lot of work. Hard work.


If you want to look at those new taxa in a new light, you'll know that someone else has pioneered the way and you can test the hypothesis. If you find it valid, great. If you find objections, please report them -- but _after_ you've done your analysis.

Report your analysis first. As in "publish it". We can only guess at the most likely objections so far!


I think you'll find the outgroups I have proposed for bats to have a fairly cosmopolitan diet, as would be expected because bats likewise vary widely, but chiefly fruit and insects.

AFAIK, all stem-bats were rather strict insectivores, judging from their dentitions; frugivory came later. Have I missed something?