The Boidae, commonly known as boas or boids, are a family of nonvenomous snakes primarily found in the Americas, as well as Africa, Europe, Asia, and some Pacific islands. Boas include some of the world's largest snakes, with the green anaconda of South America being the heaviest and second-longest snake known; in general, adults are medium to large in size, with females usually larger than the males. Six subfamilies comprising 15 genera and 54 species are currently recognized.
Viperinae, or viperines, are a subfamily of vipers endemic to Europe, Asia and Africa. They are distinguished by their lack of the heat-sensing pit organs that characterize their sister group, the subfamily Crotalinae. Currently, 13 genera are recognized. Most are tropical and subtropical, although one species, Vipera berus, even occurs within the Arctic Circle. Like all vipers, they are venomous.
Hydrophiinae is a subfamily of venomous snakes in the family Elapidae. It contains most sea snakes and many genera of venomous land snakes found in Australasia, such as the taipans (Oxyuranus), tiger snakes (Notechis), brown snakes (Pseudonaja) and death adders (Acanthophis).
Henophidia is a former superfamily of the suborder Serpentes (snakes) that contains boas, pythons and numerous other less-well-known snakes.
The Natricinae are a subfamily of colubroid snakes, sometimes referred to as a family (Natricidae). The subfamily comprises 36 genera. Members include many very common snake species, such as the European grass snakes, and the North American water snakes and garter snakes. Some Old World members of the subfamily are known as keelbacks, because their dorsal scales exhibit strong keeling.
The Colubrinae are a subfamily of snakes within the family Colubridae. It includes numerous genera, and although taxonomic sources often disagree on the exact number, the Reptile Database lists 717 species in 92 genera as of September 2019. It is the second largest subfamily of colubrids, after Dipsadinae. Many of the most commonly known snakes are members of this subfamily, including rat snakes, king snakes, milk snakes, vine snakes, and indigo snakes.
Madtsoiidae is an extinct family of mostly Gondwanan snakes with a fossil record extending from early Cenomanian to late Pleistocene strata located in South America, Africa, India, Australia and Southern Europe. Madtsoiidae include very primitive snakes, which like extant boas and pythons would likely dispatch their prey by constriction. Genera include some of the longest snakes known such as Vasuki, measuring at least 11–15 metres (36–49 ft) long, and the Australian Wonambi and Yurlunggur. As a grouping of basal forms the composition and even the validity of Madtsoiidae is in a state of flux as new pertinent finds are described, with more recent evidence suggesting that it is paraphyletic as previously defined.
Colombophis is an extinct genus of snakes of the clade Alethinophidia, a group of "primitive" snakes. The genus was first recognized in the Villavieja Formation in the town of Los Mangos, part of the known fossil fauna of La Venta in the department of Huila (Colombia), in the middle Miocene. With the remains of a fossil snake was erected the species Colombophis portai in 1977, based on forty fragmentary vertebrae. These vertebrae are characterized by a low neural spine, and subdivided paradiapophysis and thin zygosphene. The vertebrae are medium to large, so the snake would measure about 1.77 metres long, similar in size to the current Boa constrictor.
The Lamprophiidae are a family of snakes found throughout much of Africa, including Seychelles. There are 89 species as of July 2022.
Colubroidea is a superfamily of snakes in the clade Colubroides that includes Colubridae, with some studies splitting Colubridae into multiple families that make up Colubroidea. Historically, Colubroidea also included other caenophidian snakes such as cobras and vipers, as these snakes form a clade. However these groups are now divided into several distinct, but related, families. Zaher et al. (2009) proposed to redefine Colubroidea for colubrids and related families, while designating Colubroides as the group containing vipers and cobras as well as colubroids. The ReptileDatabase considers Colubroidea to be composed of Colubridae and the members of its sister group, Elapoidea, and does not recognize the division of Colubridae into multiple families.
Dipsadinae is a large subfamily of colubroid snakes, sometimes referred to as a family (Dipsadidae). Species of the subfamily Dipsadinae are found in most of the Americas, including the West Indies, and are most diverse in South America. There are more than 700 member species.
Lamprophiinae is a subfamily of lamprophiid snakes, a large group of mostly African snakes, most of which were formerly classified as colubrids but which we now know are actually more closely related to elapids.
The Booidea, also known as booid snakes, are a superfamily of snakes that contains boas and other closely related boa-like snakes. As of 2017, Booidea contains 61 species, including the eponymous neotropical Boa constrictor, anacondas, and smaller tree and rainbow boas as well as several genera of booid snakes from various locations around the world: bevel-nosed boas or keel-scaled boas (Candoia) from New Guinea and Melanesia, Old World sand boas (Eryx) from Northeast Africa, the Middle East, and Southwest Asia, rubber boas (Charina) and rosy boas (Lichanura) from North America, neotropical dwarf boas (Ungaliophis) and the Oaxacan dwarf boa (Exiliboa) from Central America, Madagascan boas or Malagasy boas from Madagascar, and the Calabar python (Calabaria) from tropical West-Central Africa.
The Uropeltoidea, also known as uropeltoid snakes, are a superfamily of snakes that contains uropeltids and Asian pipesnakes.
The Amerophidia, also known as amerophidian snakes, are a superfamily of snakes that contains two families: Aniliidae and the boa-like Tropidophiidae.
The Colubroides are a clade in the suborder Serpentes (snakes). It contains over 85% of all the extant species of snakes. The largest family is Colubridae, but it also includes at least six other families, at least four of which were once classified as "Colubridae" before molecular phylogenetics helped in understanding their relationships. It has been found to be monophyletic.
Afrophidia is a clade of alethinophidian snakes comprising the groups Henophidia and Caenophidia, essentially making up the snakes people commonly associate with. The name refers to the deep split between Afrophidia and their sister taxon, Amerophidia, which originated in South American origin, and the afrophidians was recently hypothesized to represent a vicariant event of the breakup of Gondwanan South America and Africa.
The Elapoidea are a superfamily of snakes in the clade Colubroides, traditionally comprising the families Lamprophiidae and Elapidae. Advanced genomic sequence studies, however, have found lamprophiids to be paraphyletic in respect to elapids, and anywhere between four and nine families are now recognized.
Nigerophiidae is an extinct family of marine snakes known from the Late Cretaceous to the Paleogene. Species of this family were found throughout much of the former Tethys Ocean. Their taxonomic identity is uncertain due to their fragmentary remains. The earliest nigerophiid is Nubianophis from the Campanian of Sudan.
