They also used to be found on the island of Mauritius, but were extirpated there due to human influence and foraging pigs in particular.

Two monotypic genera are recognized, but only a single species is extant (not extinct).

[2] Bolyeriidae appear to be most closely related to the Asian genus Xenophidion.

[1] Both of these monotypic genera once inhabited Mauritius and/or a number of islands around it.

However, Bolyeria hasn't been reported since 1975 and is believed to be extinct, while Casarea is known to survive only on Round Island.