Michelle,
I think the Speckled or Granite line of Mex Mex are mere results of line breeding for such thing...
If you pick the best splitbanded ones out of a clutch and continue to breed for that I bet you will eventually produce a Speckled type offspring...
I know some breeders used to line breed for long nuchal stripes with Mex Mex...What happened to those? Mark Kenderdine?
Most of this line started with a German fellow (who's name I forget). Now he did frequent the Trans-Pecos so many enthusiasts thought they may have some alterna in them....River Road or Black Gap...
They have been outcrossed so many times I don't think scale counts can determine if they are pure or not....Nor DNA....
They are a hobby snake for sure....As is the black phase. Lloyd Lemke began that line and it is awesome....
Do they have Christmas Mt. Alterna in them? I don't think so....
I think Mex Mex and Alterna are decendants from one species separated now, but still show the same variability..Same goes for Greeri, Ruthveni and Thayeri...All five subspecies are decendants from one single species long ago....
That is my two cents.....
Regards,
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John Lassiter
"Poor planning and procrastination on your part does not constitute an emergency on my part....."