The Middle American indigo snake (''Drymarchon melanurus''), also known commonly as the blacktail cribo, is a

species In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriate s ...

of large, non

venomous 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 ...

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 ...

in the

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 ...

Colubridae. The species is native to the southwestern

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Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

Central America Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...

, and northern

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. In addition to the

nominotypical subspecies In biological classification, subspecies is a rank below species, used for populations that live in different areas and vary in size, shape, or other physical characteristics (morphology), but that can successfully interbreed. Not all species ...

, it has four other recognized subspecies, including '' D. m. erebennus'' commonly known as the Texas indigo snake.

Description

''D. melanurus'' is a large species that can grow to a total length (including tail) of to over . This species has predominantly olive-brown glossy

dorsal scales In snakes, the dorsal scales are the longitudinal series of plates that encircle the body, but do not include the ventral scales In snakes, the ventral scales or gastrosteges are the enlarged and transversely elongated scales that extend down t ...

evolving to black at the tail. The underside is a lighter olive-yellow, olive-tan color. ''D. melanurus'' has distinctive dark markings round the eyes, a vertical dark slash just behind the jaw. and a heavy diagonal dark slash on both sides of the neck. The subspecies ''D. m. erebennus'' is predominantly solid black, though there can be lighter shaded variations.

Geographic range and habitat

The geographic range of ''D. melanurus'' extends from southern

Texas Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by ...

southwards through the Gulf Coast of Mexico, the Yucatan peninsula, Guatemala and

Belize Belize (; bzj, Bileez) is a Caribbean and Central American country on the northeastern coast of Central America. It is bordered by Mexico to the north, the Caribbean Sea to the east, and Guatemala to the west and south. It also shares a wate ...

. On the Pacific coast its range extends from Sinaloa in Mexico, southward to Guatemala, as far as Colombia,

Venezuela Venezuela (; ), officially the Bolivarian Republic of Venezuela ( es, link=no, República Bolivariana de Venezuela), is a country on the northern coast of South America, consisting of a continental landmass and many islands and islets in th ...

and

Ecuador Ecuador ( ; ; Quechua: ''Ikwayur''; Shuar: ''Ecuador'' or ''Ekuatur''), officially the Republic of Ecuador ( es, República del Ecuador, which literally translates as "Republic of the Equator"; Quechua: ''Ikwadur Ripuwlika''; Shuar: ' ...

. Its elevational distribution goes from near sea level up to around 1,900 m asl (6,230 feet). The subspecies ''D. m. erebennus'' is found in southern Texas and southwards into Mexico as far as

Veracruz Veracruz (), formally Veracruz de Ignacio de la Llave (), officially the Free and Sovereign State of Veracruz de Ignacio de la Llave ( es, Estado Libre y Soberano de Veracruz de Ignacio de la Llave), is one of the 31 states which, along with Me ...

Subspecies

There are five subspecies of ''D. melanurus'' which are recognized as being valid, including the nominate subspecies.. www.reptile-database.org. *'' Drymarchon melanurus erebennus'' *''Drymarchon melanurus melanurus'' *'' Drymarchon melanurus orizabensis'' *'' Drymarchon melanurus rubidus'' *'' Drymarchon melanurus unicolor'' ''

Nota bene (, or ; plural form ) is a Latin phrase meaning "note well". It is often abbreviated as NB, n.b., or with the ligature and first appeared in English writing . In Modern English, it is used, particularly in legal papers, to draw the atten ...

'': A trinomial authority in parentheses indicates that the subspecies was originally described in a

genus 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 nom ...

other than ''

Drymarchon ''Drymarchon'' is a genus of large nonvenomous colubrid snakes, commonly known as indigo snakes or cribos, found in the Southeastern United States, Central America, and South America. Reaching or more in length, they are among the world's larges ...

''.

Description

Geographic range and habitat

Subspecies

References

Further reading