In response to Troy, I will only simply quote what I said in the other forum, since Troy had no answer to what I said there in response to his picture of a snake without the silvery gray iris.



Me:

"I will not, for the time being, contest troy h's claim that someone has collected an alterna without a silvery gray iris. I will instead try to figure out what such a find, if it were authentic, would do to my theory of how L. mexicana transformed into L. alterna.



Of course, if it were a fake, then it would not change my theory. Assuming, however, that it is real, I will see what effects it will have on my theory.



1. It is a mutant. Mutations happen sooner or later. If it is a mutant then it has no effect on my theory. In fact, it supports my contention that the silvery gray iris (or iris color in general) in L. alterna is a selectively neutral character that became fixed because of founder effect speciation, because the ancestor of L. alterna went through a genetic bottleneck when its population crashed at the end of the last ice age, when west Texas turned from woodland into desert.



2. It is an individual L. mexicana that is from a remnant, previously unknown population of L. mexicana in Texas. Even if that is the case, it only proves my hypothesis that L. mexicana once existed in Texas and that it is now absent from most of its original range, including the site where van Devender found vertebral material in packrat middens. My theory is one that is consistent with the fossil record. If anyone has an alternative theory, they still would have to explain how alterna originated and where and how it replaced L. mexicana if the formation of the Chihuahuan Desert was not the cause of such replacement.



3. It is an alterna that has reverted to the ancestral condition in iris color. That possibility, once again, does not affect my theory since it supports my contention that L. mexicana once existed in west Texas and that it has since been replaced by L. alterna. A reversion to an ancestral condition simply proves that L. alterna is derived from L. mexicana, which is my theory.



If none of these scenarios would falsify my hypothesis, then what would? Since my theory is a scientific one, it makes predictions, which are in turn falsifiable. One prediction made by my theory is that genetic variation among the many different populations of L. alterna is low, much lower than the amount of variation among different populations of, say, L. mexicana or L. pyromelana. Hence a finding that L. alterna genetic variation is high would indeed falsify my theory.



Hence I am quite amused to see troy h do the online equivalent of a victory dance (and his comrades dancing along with him) even though his finding that a Davis Mountain L. alterna with a non-silvery gray iris, even if it were authentic, really has no effect on my theory of the origin and evolution of L. alterna."



PS I really would like Troy to explain how the silvery gray iris evolved in L. alterna, if the ancestor of L. alterna did not suffer a population crash and then went through a genetic bottleneck. Tell us how the silvery gray iris is apparently so adaptive that it has replaced the ancestral golden brown iris completely (with but one possible exception) over the entire range of L. alterna.

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