stylistic:style_transfer, linguistic:paraphrasing
Taxonomy

Pythons were historically classified as a subfamily of Boidae (called Pythoninae), but it was later determined that they are not closely related to boas despite having superficial similarities.

Almost all of the non-boine boids are frequently elevated to their own full families: Calabariidae/inae, Candoiidae/inae, Charinidae/inae, Erycidae/inae, Sanziniidae/inae, and Ungaliophiidae/inae. The taxonomy of boid snakes has been long debated, and ultimately the decision whether to assign a particular clade to a particular Linnaean rank (such as a superfamily, family, or subfamily) is arbitrary.

The subfamily Ungaliophiinae was formerly made up of four genera. Two of them (Tropidophis and Trachyboa) are actually more closely related to the American pipe snake (Anilius scytale) than to the boas, and are now placed in the family Tropidophiidae within the superfamily Amerophidia. The other two genera (Ungaliophis and Exiliboa) are the sister group of the Charina / Lichanura clade within Boidae.