Joined: Mar. 2005
Re 'homologous frogs with vastly different DNA'
I thought the word "homologous" referred to features or traits. Applying it to whole organisms doesn't make sense to me.
With frogs having different DNA, the question would be is that consistent with the length of time since those frog species separated from their last common ancestor. That would (I think) be shortly after the first appearance of amphibians (i.e., it would probably precede the first appearance if anything close to reptilian, let along mammalian or avian).
On marsupial vs. placentals, I recall some discussion of that fairly recently, I think either in one of the threads on the AtBC forum or on the Panda's Thumb blog; the time of that split might still be an actual controversy.