I believe I was the first to breed Ruthveni, but, I really was not. I believe in the mid seventies, Dallas zoo was breeding Arcifera and their animals were indeed milksnakes. L.A.Zoo(Harvey Fisher) was also breeding Arcifera but they actually had Ruthveni. So they were the first to produce those fine animals. Unfortunately, they went on the market as Arcifera.
I imagine that the evolution of the mexicana type kings was from a burrowing fossorial milk snake to a saxicolis type kingsnake. Which means the evolved into species that used habitats in and above ground level. Like rock outcrops, hollow trees, underbark, etc. For this, a wider flatter head was an advantage.
Then comes along Zonata, where some locals have milksnake heads, and others mexicana type heads.
to confuse the issue even more, I was on a field project that discussed the wide flat heads of many blairi(alterna) vs. the narrow pointed heads of individuals in the same populations(both expressed phenotypes)
We found both narrow headed individuals and wide headed individuals in all the mexicana populations that we investigated.
Bill Garska was the author, I was only a mere field guy and did not believe any of the conclusions made in the paper. hahahahahaahhahahahahahaha Simply put, there is some evolutionary confused in kings.
This is also true for cal kings as well, some populations do have wide distint heads, others more narrow and blunt. Anyway, just saying. Cheers