[4] Two other genera (Ungaliophis and Exiliboa) were once considered to be tropidophiids but are now known to be more closely related to the boids, and are classified in the subfamily Ungaliophiinae.

This family is confined to the neotropics, mainly in Hispaniola, Jamaica, and the Cayman Islands, with the greatest diversity being in Cuba, where new species are still being discovered.

[1] Fossils of 10 extinct species in five genera[6] from the Paleocene, Eocene, and Oligocene of Europe, Africa, and North and South America have been assigned to the Tropidophiidae, although all of them are probably actually either ungaliophiines or stem afrophidians.

Two genera, Falseryx and Rottophis, both from the Oligocene of western Europe, have some similarities with living tropidophiids[7] as well as with ungaliophiines, but for the most part their skulls are poorly preserved, leaving paleontologists to work on just their vertebrae.

Paleogene erycines dominated the snake fauna of North America prior to the Miocene explosion of colubroids, but as far as we know all of these species were much more closely related to modern rosy and rubber boas than they were to tropidophiids.