The Middle American indigo snake (Drymarchon melanurus), also known commonly as the blacktail cribo, is a species of large, nonvenomous, snake in the family Colubridae. The species is native to the southwestern United States, Mexico, Central America, and northern South America. In addition to the nominate subspecies, it has four other recognized subspecies, including D. m. erebennus, commonly known as the Texas indigo snake.^[3]

Quick Facts Conservation status, Scientific classification ...

Middle American indigo snake
Drymarchon melanurus
Conservation status
Least Concern  (IUCN 3.1)[1]
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Reptilia
Order:	Squamata
Suborder:	Serpentes
Family:	Colubridae
Genus:	Drymarchon
Species:	D. melanurus
Binomial name
Drymarchon melanurus (A.M.C. Duméril, Bibron & A.H.A. Duméril, 1854)
Subspecies
Five, see text.
Synonyms[2]
Spilotes melanurus A.M.C. Duméril, Bibron & A.H.A. Duméril, 1854 Spilotes corais melanurus — Cope, 1893 Morenoa orizabensis Dugès, 1905 Drymarchon corais melanurus — Amaral, 1929 Drymarchon melanurus — Wüster et al., 2001

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D. melanurus is a large species that can grow to a total length (including tail) of 1.80 m (6 ft) to over 2.40 m (8 ft). This species has predominantly olive-brown glossy dorsal scales 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.^[4] The subspecies D. m. erebennus is predominantly solid black, though there can be lighter shaded variations.

The geographic range of D. melanurus extends from southern Texas southwards through the Gulf Coast of Mexico, the Yucatán Peninsula, Guatemala and Belize. On the Pacific coast, its range extends from Sinaloa in Mexico, southward to Guatemala, as far south as Colombia, Venezuela and Ecuador.^[1][4] Its elevational distribution goes from near sea level up to around 1,900 m asl (6,230 feet).^[1] The subspecies D. m. erebennus is found in southern Texas and southwards into Mexico as far as Veracruz.

There are five subspecies of D. melanurus which are recognized as being valid, including the nominate subspecies.^[3][2]

• Drymarchon melanurus erebennus (Cope, 1860)
• Drymarchon melanurus melanurus (A.M.C. Dumeril, Bibron & A.H.A. Dumeril, 1854)
• Drymarchon melanurus orizabensis (Dugès, 1905)
• Drymarchon melanurus rubidus H.M. Smith, 1941
• Drymarchon melanurus unicolor H.M. Smith, 1941

Nota bene: A trinomial authority in parentheses indicates that the subspecies was originally described in a genus other than Drymarchon.