Anery is almost to designer morphs, what salt is for cooking. They are a key ingredient in many morphs like; snow, ghost, pearl and mooglow.
There are two types of anerystic mutations. Type I will become brownish with age, and type II will stay more or less gray.
The two are not compatible. Unfortunately not much is known about the heritage of ths morph. On regular basis they turn up in imported stock and captive bred wild type to wild type litters.
Anerys are also referred to as "black albinos" because their pigment composion is opposite to the albino boa. Albinos lack melanin which is black pigment, and anerythristics lack erythrin which is red pigment. Therefore the name anerythristic; "an" = wothout and "erythri" = red.
This trait is a simple recessive color mutation.