In recent years, the term “complex” has become more common in taxonomy to address groups of closely related species that are difficult to distinguish from one another. This usage reflects advances in genetic research and a better understanding of biodiversity. The “Black/grey Rat Snake Complex,” for example, signifies that the group includes multiple species or subspecies that are morphologically similar but might be genetically distinct or have different ecological roles. This addition to binomial names helps indicate that further research is needed to clarify their taxonomic status and relationships. It’s a way to acknowledge ongoing debates and complexities in species classification that might not have been apparent when binomial nomenclature was first standardized.