Think of a species (ONLY ONE SPECIES) the individuals all live in the same environment, share the same sentience level BUT are divided into "A", "B" and "C" races which have different number of limbs, eyes, natural weapons, etc.
For example A has tentacles, B has bird legs and feet, C has horse legs, this sort of different.
They are able to interbreed and have fertile hybrid offspring, but the hybridization would last only for one generation, like if A and B have an offspring, it will be an hybrid AB, now if AB has offspring with A, all their children will be pure A, if AB has offspring with B, their children will pure B.
If an AB breeds with C, their offspring will be AC or BC hybrids. (AB +AB = 25% chance of pure A 25% chance of pure B, 50% chance AB hybrid).
Are aliens that have this sort of genetics, crazy different appearances, and only 1 generation lasting hybrids, possible?
Can this be explained by epi-genetics?
Is this possible at all?