Here is a brief overview of some of the most unique African bush viper subspecies and variations:

• Green bush viper (Atheris squamigera): The green bush viper is the most common and widespread species of African bush viper. It is found in a variety of rainforest habitats, from lowland swamps to montane forests. Green bush vipers are known for their bright green coloration, which can range from a light lime green to a deep emerald green.
   
• Black bush viper (Atheris matildae): The black bush viper is a rare and elusive snake that is found in the rainforests of Cameroon and Nigeria. It is characterized by its jet-black coloration and its large, triangular head. Black bush vipers are apex predators in their environment and prey on a variety of small mammals, birds, and reptiles.
   
• Horned bush viper (Atheris ceratophora): The horned bush viper is a unique snake that is found in the rainforests of West Africa. It is characterized by the pair of horns that protrude from its head. Horny bush vipers are ambush predators and use their camouflage and horns to their advantage when hunting prey.
   
• Norris's bush viper (Atheris norrisi): Norris's bush viper is a rare and endangered snake that is found in the rainforests of Cameroon. It is characterized by its bright yellow coloration and its black dorsal stripe. Norris's bush vipers are threatened by habitat loss and fragmentation.
   
• Blue bush viper (Atheris chlorechis): The blue bush viper is a recently discovered species that is found in the rainforests of the Democratic Republic of the Congo. It is characterized by its bright blue coloration and its large, triangular head. Blue bush vipers are apex predators in their environment and prey on a variety of small mammals, birds, and reptiles.
   

African bush vipers are a diverse group of venomous snakes that are found in the rainforests of Central and West Africa. They are known for their bright green coloration, which allows them to blend in seamlessly with their surroundings. There are 14 recognized subspecies of African bush vipers, each with its own unique features.

Some of the most unique African bush viper subspecies and variations include the green bush viper, black bush viper, horned bush viper, Norris's bush viper, and blue bush viper. These snakes are fascinating creatures that play an important role in the rainforest ecosystem.