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Superregnum: Eukaryota
Regnum: Animalia
Subregnum: Eumetazoa
Cladus: Bilateria
Cladus: Nephrozoa
Superphylum: Deuterostomia
Phylum: Chordata
Cladus: Craniata
Subphylum: Vertebrata
Infraphylum: Gnathostomata
Superclassis: Tetrapoda
Cladus: Reptiliomorpha
Cladus: Amniota
Classis: Reptilia
Cladus: Eureptilia
Cladus: Romeriida
Subclassis: Diapsida
Cladus: Sauria
Infraclassis: Lepidosauromorpha
Superordo: Lepidosauria
Ordo: Squamata
Subordo: Serpentes
Infraordo: Caenophidia
Superfamilia: Colubroidea

Familia: Colubridae
Subfamilia: Colubrinae
Genus: Gyalopion
Species (2): G. canumG. quadrangulare

Gyalopion Cope, 1860: 241, 243

Type species: Gyalopion canum Cope, 1860, by monotypy.
Primary references

Cope, E.D. 1860. Catalogue of the Colubridae in the Museum of the Academy of Natural Sciences of Philadelphia, with notes and descriptions of new species. Part 2. Proceedings of the Academy of Natural Sciences of Philadelphia 12: 241–266. BHL Reference page.


Uetz, P. & Hallermann, J. 2021. Gyalopion . The Reptile Database. Accessed on 16 May 2018.

Vernacular names
English: Hooknose Snakes

Gyalopion is a genus of small nonvenomous colubrid snakes. Species in the genus Gyalopion are commonly referred to as hooknose snakes, and are native to the southwestern United States and Mexico.


The following species and subspecies are recognized:

Gyalopion canum Cope, 1860 – western hook-nosed snake
Gyalopion quadrangulare (Günther, 1893) – desert hook-nosed snake
Gyalopion quadrangulare desertorum (Taylor, 1936)
Gyalopion quadrangulare quadrangulare (Günther, 1893)

Nota bene: A binomial authority or trinomial authority in parentheses indicates that the species or subspecies was originally described in a genus other than Gyalopion.
Geographic range

G. canum is found in the United States (Arizona, New Mexico, Texas), and in Mexico (Chihuahua, Coahuila, Durango, Jalisco, Michoacán, Nuevo León, San Luis Potosí, Sonora, Zacatecas).[1]

G. quadrangulare is found in the United States (Arizona), and in Mexico (Sinaloa, Sonora).[2]

Hooknose snakes prefer shortgrass prairie habitats.

Dorsally, the base color of hook-nosed snakes is light brown, which is overlaid with darker brown crossbands. The ventral color is white or cream-colored. The most distinguishing feature of hook-nosed snakes is an upturned snout, which has a concave rostral scale, as opposed to hognose snakes which have a keeled rostral scale. Species of Gyalopion rarely grow beyond 25.5 cm (10 inches) in total length (including tail).

Hooknose snakes are nocturnal and secretive snakes, generally found hiding under rocks, or buried in the soil.

The primary diet of hook-nosed snakes consists of spiders and centipedes.

Species in the genus Gyalopion are oviparous.

"Gyalopion canum ". The Reptile Database.

"Gyalopion quadrangulare ". The Reptile Database.

Further reading

Cope ED (1860). "Catalogue of the Colubridæ in the Museum of the Academy of Natural Sciences of Philadelphia, with notes and descriptions of new species. Part 2". Proc. Acad. Nat. Sci. Philadelphia 12: 241–266. (Gyalopion, new genus, p. 243).

External links

Herps of Texas: Gyalopion canum


Biology Encyclopedia

Reptiles Images

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