Colubridae (, commonly known as colubrids , from la, coluber, 'snake') is a
family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
of
snake
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 j ...
s. With 249
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 ...
, it is the largest snake family. The earliest species of the family date back to the
Oligocene
The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but ...
epoch. Colubrid snakes are found on every continent except Antarctica.
Description
While most colubrids are not
venom
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 ...
ous (or have venom that is not known to be harmful to humans) and are mostly harmless, a few groups, such as genus ''
Boiga
''Boiga'' is a large genus of rear-fanged, mildly venomous snakes, known commonly as cat-eyed snakes or simply cat snakes, in the family Colubridae. Species of the genus ''Boiga'' are native to southeast Asia, India, and Australia, but due to ...
'', can produce medically significant injuries. In addition, the
boomslang
The boomslang (, , or ; ''Dispholidus typus'') is a large, highly venomous snake in the family Colubridae.
Taxonomy and etymology
Its common name means "tree snake" in Afrikaans and Dutch – ''boom'' meaning "tree", and ''slang'' meaning "sn ...
Rhabdophis
''Rhabdophis'' is a genus of snakes in the subfamily Natricinae of the family Colubridae. Species in the genus ''Rhabdophis'' are generally called keelback snakes, and are found primarily in Southeast Asia.
Toxicity
''Rhabdophis'' is often tho ...
'' have caused human fatalities.
Some colubrids are described as opisthoglyphous (often called "rear-fanged"), meaning they have elongated, grooved teeth located in the back of their upper jaws. It is likely that opisthoglyphous dentition evolved many times in the history of snakes and is an evolutionary precursor to the fangs of vipers and elapids, which are located in the front of the mouth.
Classification
In the past, the Colubridae were not a natural group, as many were more closely related to other groups, such as elapids, than to each other. This family was historically used as a "
wastebasket taxon
Wastebasket taxon (also called a wastebin taxon, dustbin taxon or catch-all taxon) is a term used by some taxonomists to refer to a taxon that has the sole purpose of classifying organisms that do not fit anywhere else. They are typically define ...
" for snakes that do not fit elsewhere. Until recently, colubrids were basically colubroids that were not elapids, viperids, or '' Atractaspis''.
However, recent research in molecular phylogenetics has stabilized the classification of historically "colubrid" snakes and the family as currently defined is a
monophyletic
In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic ...
clade, although additional research will be necessary to sort out all the relationships within this group. As of May 2018, eight subfamilies are recognized.
Dipsadinae
Dipsadinae is a large subfamily of colubroid snakes, sometimes referred to as a family (Dipsadidae). They are found in most of the Americas, including the West Indies, and are most diverse in South America. There are more than 700 species.
Dip ...
– 100 genera (sometimes given as family
Dipsadidae
Dipsadinae is a large subfamily of colubroid snakes, sometimes referred to as a family (Dipsadidae). They are found in most of the Americas, including the West Indies, and are most diverse in South America. There are more than 700 species.
Dips ...
)
Grayiinae
''Grayia'' is a genus of snakes, commonly referred to as African water snakes, in the family Colubridae. The genus, which is native to tropical Africa, is the only genus in the colubrid subfamily Grayiinae.
''Grayia'' species are relatively poo ...
Calamariinae
The Calamariinae are a subfamily of colubrid snakes, commonly known as reed snakes, that are found in southern and southeastern Asia. They are most diverse in Indonesia, especially Sumatra and Borneo. The subfamily contains 90 species in seven ge ...
– seven genera
Ahaetuliinae
The Ahaetuliinae are a subfamily of the snake family Colubridae that was erected in 2016 and comprises five genera containing 63 species (''Ahaetulla'' 7 species ''Chrysopelea'' species ''Dendrelaphis'' 5 species ''Dryophiops'' speciesand ' ...
These taxa have been at one time or another classified as part of the Colubridae, but are now either classified as parts of other families, or are no longer accepted because all the species within them have been moved to other (sub)families.
*Subfamily
Aparallactinae
The Atractaspididae (atractaspidids) are a family of venomous snakes found in Africa and the Middle East, commonly called mole vipers, stiletto snakes, or burrowing asps. Currently, 12 genera are recognized.
Description
This family includes many ...
(now a subfamily of Lamprophiidae, sometimes combined with
Atractaspidinae
The Atractaspididae (atractaspidids) are a family of venomous snakes found in Africa and the Middle East, commonly called mole vipers, stiletto snakes, or burrowing asps. Currently, 12 genera are recognized.
Description
This family includes many ...
)
*Subfamily Boiginae (now part of Colubrinae)
*Subfamily Boodontinae (some of which now treated as subfamily
Grayiinae
''Grayia'' is a genus of snakes, commonly referred to as African water snakes, in the family Colubridae. The genus, which is native to tropical Africa, is the only genus in the colubrid subfamily Grayiinae.
''Grayia'' species are relatively poo ...
of the new Colubridae, others moved to family Lamprophiidae as part of subfamilies
Lamprophiinae
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.
Lamprophiine snakes are small t ...
Pseudoxyrhophiidae
The Pseudoxyrhophiidae is a family of elapoid snakes, found mostly in Madagascar. They were formerly placed as a subfamily of the Lamprophiidae, but have been more recently identified as a distinct family.
It contains about 22 genera in two ...
, which are now sometimes treated as families)
*Subfamily Dispholidinae (now part of Colubrinae)
*Subfamily Homalopsinae (now family Homalopsidae)
*Subfamily Lamprophiinae (now a subfamily of Lamprophiidae)
*Subfamily Lycodontinae (now part of Colubrinae)
*Subfamily Lycophidinae (now part of Lamprophiidae)
*Subfamily Pareatinae (now family Pareidae, sometimes incorrectly spelled Pareatidae)
*Subfamily Philothamninae (now part of Colubrinae)
*Subfamily
Psammophiinae
Psammophiidae is a family of elapoid snakes. They were formerly placed as a subfamily of the Lamprophiidae, but have been more recently identified as a distinct family.
Genera
It contains 8 genera:
* '' Dipsina'' Jan, 1862
* ''Hemirhagerrhis'' ...
(now a subfamily of Lamprophiidae)
*Subfamily Pseudoxyrhophiinae (now a subfamily of Lamprophiidae)
*Subfamily Xenoderminae (now family
Xenodermidae
Xenodermidae is a family of snakes native to East Asia, South Asia, and Southeast Asia. All species in the family Xenodermidae are small or moderately sized snakes, never more than but typically less than in total length (including tail). ...
, sometimes incorrectly spelled Xenodermatidae)
*Subfamily
Xenodontinae
Xenodontinae is a subfamily of snakes in the family Colubridae.
The subfamily Xenodontinae encompasses a number of rear-fanged ( opisthoglyphous), mildly venomous snake genera found in South America and the Caribbean. Members of the subfamily X ...
(which many authors put in
Dipsadinae
Dipsadinae is a large subfamily of colubroid snakes, sometimes referred to as a family (Dipsadidae). They are found in most of the Americas, including the West Indies, and are most diverse in South America. There are more than 700 species.
Dip ...
/
Dipsadidae
Dipsadinae is a large subfamily of colubroid snakes, sometimes referred to as a family (Dipsadidae). They are found in most of the Americas, including the West Indies, and are most diverse in South America. There are more than 700 species.
Dips ...
)
Fossil record
The Pliocene (
Blancan
The Blancan North American Stage on the geologic timescale is the North American faunal stage according to the North American Land Mammal Ages chronology (NALMA), typically set from 4,750,000 to 1,806,000 years BP, a period of .Ringold Formation of Adams County, Washington has yielded fossils from a number of colubrids including ''
Elaphe pliocenica
''Elaphe'' is a genus of snakes in the family Colubridae. ''Elaphe'' is one of the main genera of the rat snakes, which are found in many regions of the northern hemisphere. ''Elaphe'' species are medium to large constrictors by nature. Althoug ...
'', ''
Elaphe vulpina
''Pantherophis vulpinus'', commonly known as the foxsnake or the eastern fox snake, Crother BI (editor) (2008). ''Scientific and Standard English Names of Amphibians and Reptiles of North America North of Mexico''. Society for the Study of A ...
'', ''
Lampropeltis getulus
''Lampropeltis getula'', commonly known as the eastern kingsnake, Conant R (1975). ''A Field Guide to Reptiles and Amphibians of Eastern and Central North America, Second Edition''. (First published in 1958). Boston: Houghton Mifflin Company. 42 ...