Common names: Mauritius snakes, Round Island boas, splitjaw snakes.

The Bolyeriidae are a family

Family (biology)

In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...

 of snakes native to Mauritius

Mauritius

Mauritius , officially the Republic of Mauritius is an island nation off the southeast coast of the African continent in the southwest Indian Ocean, about east of Madagascar...

 and a few islands around it, especially Round Island

Round Island (Mauritius)

Round Island is an uninhabited islet 22.5 kilometers north of Mauritius. It has an area of 1.69 square kilometers and a maximum elevation of 280 meters...

. In the past they also occurred on the island of Mauritius

Mauritius

Mauritius , officially the Republic of Mauritius is an island nation off the southeast coast of the African continent in the southwest Indian Ocean, about east of Madagascar...

, but were extirpated there due to human influence and foraging pigs in particular. These snakes were formerly placed in the Boidae, but are now classed as a separate family. Currently, two monotypic

Monotypic

In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...

 genera are recognized, but only a single species is extant.

Genera

Genus	Taxon author	Species	Common name	Geographic range
Bolyeria Bolyeria The Round Island Burrowing Boa is an extinct species of snake in the Bolyeriidae family, in the monotypic genus Bolyeria, which was endemic to Mauritius. The species was last seen on Round Island in 1975. No subspecies are currently recognized.-Description:It reached about 1 m in length and... T	Gray John Edward Gray John Edward Gray, FRS was a British zoologist. He was the elder brother of George Robert Gray and son of the pharmacologist and botanist Samuel Frederick Gray .... , 1842	1	Round Island burrowing boa	Mauritius Mauritius Mauritius , officially the Republic of Mauritius is an island nation off the southeast coast of the African continent in the southwest Indian Ocean, about east of Madagascar... .
Casarea Casarea The Round Island Boa , also known as the Round Island Keel-scaled Boa, is a snake in the Bolyeriidae family, in the monotypic genus Casarea. It is also the only extant member of the family Bolyeriidae, and is endemic to Round Island, Mauritius...	Gray, 1842	1	Round Island ground boa	Mauritius.

^T) Type genus

Type genus

In biological classification, a type genus is a representative genus, as with regard to a biological family. The term and concept is used much more often and much more formally in zoology than it is in botany, and the definition is dependent on the nomenclatural Code that applies:* In zoological...

.

Both of these monotypic gena 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 Casarae is presently known to survive only on Round Island

Round Island (Mauritius)

Round Island is an uninhabited islet 22.5 kilometers north of Mauritius. It has an area of 1.69 square kilometers and a maximum elevation of 280 meters...

.