The fossil record is rife with convergence, parallelisms...but when you look at the anatomy, many structures betray this...icthyosaurs have many features that indicate their reptilian heritage, camels and litopterns many others (litopterns have completely different braincases and the molar teeth are not selenodont like artiodactyls like camels for example)...so, I suppose its not IMPOSSIBLE, but its pretty dang un parsimonious...
Still, I like unlikely things, that's why I liked comics when I was a kid...
But WHY does the flame dragon have an opposable thumb or the thought beast project images from a third party's view?
Re: parallel evolution: Yes, on Earth, in similar circumstances, similar forms have developed to fill the same needs.
We have two problems with that for humanoid aliens in general and Kryptonians and Daxamites in particular.
First, those alien environments tend to be far different than any Terrestrial ones. Even all other things being the same, that danged high-G would at the very least tend to produce shorter, more heavily-muscled beings instead of the virtually indistinguishable from us humanoids. They even tend to look more physically imposing than we do instead of being smaller.
Second, they're demonstrably able to interbreed with us in numerous stories from various eras of Superman. Sharks and dolphins may have developed similar forms due to parallel evolution but they certainly cannot interbreed with each other just the same.
I maintain that this must be evidence of
design for the Daxamite/Kryptonian species (or perhaps, subspecies). That ability to interbreed is evidence that all such humanoids are subspecies of a larger species of humanity, depending on how one defines 'species'. This is further supported by the strange super-powers they possess outside their native environments which are highly unlikely to evolve for an environment they've never experienced, and the incredible Daxamite coincidence of a lead vulnerability on a virtually lead-free planet.
Flame dragons having opposable thumbs is no more mysterious than raccoons having similar ones on Earth. Worse comes to worst, we could suggest design here, but those darn 'coons tend to make me dismiss this as not that important.
The mere existence of Thought Beasts, not even mentioning their showing third person POV, is a glaring example of design. In the fictional DCU, no way could such a bizarre creature naturally evolve since that darn screen seems to be more of a liability than an advantage. I suppose if the creatures could deceive others with the screen, like Earth life uses mimicry, then it might somehow work. But it's clear how the things are portrayed that they tend to display exactly what's on their minds. Perhaps the third person POV is evidence that they might be partly telepathic, linking with others in their presence. I see the Thought Beast as the DCU equivalent of the Babel Fish: Glaring evidence of someone designing them since they don't have a logical way to have evolved by themselves.
