I aquired a pair of granites last year and produced those two babies this spring. they are a morph of the checkered garters (T. marcianus), it is a proven recessive gene, the original granite was found in the wild, not sure exactly who found the original granite in the wild, but I think Scott Felzer had aquired it last year, not sure if he sold it or still has it, he would know more about the background.
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Jeff Benfer
gartersnakemorph.com