Very nice Mark!
And the underlying textbook "splendida" pattern in that one that is also found in many other nigrita is something that I have always found EXTREMELY interesting to say the least.
As you know, the only reason you don't see more of that in most MBK's is because most of the very limited gene pool in the hobby have been bred to display more solid black(even as hatchlings).
I have seen pics of a few that anyone in the entire WORLD would swear in court were 100% splendida as hatchlings, only to find they grew into absolutely solid black animals well within their first year of maturing.
Who the heck knows if these are simply a melanistic form of MBK as they gradually range south. A clinal variant of sorts similar to the brooks king for example.
I am quite sure this will continue to puzzle the scientific herp world for some time to come.
I would bet a dollar to a donut that if more wild one's were hunted in their more southern Sonaran range, one would see far more individuals with a very pronounced splendida pattern too.
BTW, the "Mesa/Schofield" scale thing was funny as heck!!..LMAO!!!!!
~Doug
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"a snake in the grass is a GOOD thing" 
my website -serpentinespecialties.webs.com