The Tropidophiidae, common name dwarf boas or thunder snakes, are a

family Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...

nonvenomous Venom or zootoxin is a type of toxin produced by an animal that is actively delivered through a wound by means of a bite, sting, or similar action. The toxin is delivered through a specially evolved ''venom apparatus'', such as fangs or a sti ...

snakes Snakes are elongated, limbless, carnivorous reptiles of the suborder Serpentes . Like all other squamates, snakes are ectothermic, amniote vertebrates covered in overlapping scales. Many species of snakes have skulls with several more joi ...

found from Mexico and the West Indies south to southeastern Brazil. These are small to medium-sized

fossorial A fossorial () animal is one adapted to digging which lives primarily, but not solely, underground. Some examples are badgers, naked mole-rats, clams, meerkats, and mole salamanders, as well as many beetles, wasps, and bees. Prehistoric eviden ...

snakes, some with beautiful and striking color patterns. Currently, two living

genera Genus ( plural genera ) is a taxonomic rank used in the biological classification of living and fossil organisms as well as viruses. In the hierarchy of biological classification, genus comes above species and below family. In binomial nomenclat ...

, containing 34 species, are recognized. Two other genera (''

Ungaliophis :''Common names: bromeliad boas, banana boas, neotropical dwarf boas.'' ''Ungaliophis'' is a genus of dwarf boas found from southern Mexico to Colombia. Currently, two species are recognized. Geographic range Found from the Pacific coastal plai ...

'' and ''

Exiliboa :''Common names: Oaxacan dwarf boa.'' ''Exiliboa'' is a monotypic genus created for the non-venomous dwarf boa species ''Exiliboa placata'', which is endemic to southern Mexico. No subspecies are currently recognized. Description ''E. placata'' ...

'') were once considered to be tropidophiids but are now known to be more closely related to boids, and are classified in the subfamily

Ungaliophiinae Ungaliophiinae is a subfamily of booid snakes containing two genera, ''Ungaliophis'' (two species) and ''Exiliboa'' (one species). They are small constrictors that are found in Central and South America from southern Mexico to Colombia. They eat ...

. There are a relatively large number of fossil snakes that have been described as tropidophiids (because their vertebrae are easy to identify), but which of these are more closely related to ''Tropidophis'' and ''Trachyboa'' and which are more closely related to ''Ungaliophis'' and ''Exiliboa'' is unknown.

Description

This family is confined to the neotropics, mainly in

Hispaniola Hispaniola (, also ; es, La Española; Latin and french: Hispaniola; ht, Ispayola; tnq, Ayiti or Quisqueya) is an island in the Caribbean that is part of the Greater Antilles. Hispaniola is the most populous island in the West Indies, and th ...

, Jamaica, and the

Cayman Islands The Cayman Islands () is a self-governing British Overseas Territory—the largest by population in the western Caribbean Sea. The territory comprises the three islands of Grand Cayman, Cayman Brac and Little Cayman, which are located to the ...

, with the greatest diversity being in Cuba, where new species are being discovered. These snakes are relatively small, averaging to about in total length (including tail). Messelophis ermannorum 02

Behavior

Most species spend their day burrowed underground or under vegetation, surfacing only at night or when it rains. Some species are arboreal and are often seen hiding in bromeliads in trees.

Color change

The dwarf boas can change color from light (when they are active at night) to dark (inactive in the day). This color change is brought about by the movement of dark pigment granules.

Defensive behavior

When threatened, tropidophiids coil up into a tight ball. A more peculiar defensive behavior is their ability to bleed voluntarily from the eyes, mouth, and nostrils.

Distribution and habitat

They are found from southern Mexico and Central America, south to northwestern South America in

Colombia Colombia (, ; ), officially the Republic of Colombia, is a country in South America with insular regions in North America—near Nicaragua's Caribbean coast—as well as in the Pacific Ocean. The Colombian mainland is bordered by the Car ...

, (Amazonian) Ecuador, and Peru, as well as in northwestern and southeastern Brazil, and also in the West Indies.

Fossils

Fossils of ten extinct species in five genera from the Paleocene, Eocene, and Oligocene of Europe, Africa, & 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 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. The only unequivocal tropidophiid fossils are from the Pleistocene of Florida (in English, with an abstract in Spanish). and the Bahamas.

Genera

^T Type genus.

Cited references

External links

Tropidophiidae at ''Life is Short but Snakes are Long''
{{Taxonbar, from=Q1006104 Taxa named by Leo Brongersma Snake families