Phenotypic Divergence and Dwarf Morphotypes in a Closed Poecilia sphenops Lineage.

The closed Poecilia sphenops lineage examined in this study shows progressive phenotypic divergence across approximately nine to ten generations under stable aquarium conditions. The population originated from a reduced founder group and currently consists of nineteen individuals distributed across generations G8–G10. Two chromatic lines, black and orange mottled, remained stable throughout the lineage, while the orange phenotype developed progressively stronger mottling patterns in recent gener