Hypsiglena jani, commonly known as the Texas night snake or the Chihuahuan night snake, is a small species of mildly venomous snake in the subfamily Dipsadinae of the family Colubridae. The species is native to the southwestern United States and adjacent northeastern Mexico.
Etymology The epithet, jani, is in honor of Italian taxonomist Giorgio Jan.Beolens, Bo; Watkins, Michael; Grayson, Michael (2011). The Eponym Dictionary of Reptiles. Baltimore, Maryland: Johns Hopkins University Press. xiii + 296 pp. . (Hypsiglena jani, p. 133).
Description H. jani grows from in total length (including tail), record .Conant R (1975). A Field Guide to Reptiles and Amphibians of Eastern and Central North America, Second Edition. Boston: Houghton Mifflin. xviii + 429 pp. + Plates 1-48. (hardcover), (paperback). (Hypsiglena torquata texana, p. 217 + Plate 33 + Map 170). It is typically a light gray or tan in color, with dark brown or dark gray blotching down the back,Powell R, Conant R, Collins JT (2016). Peterson Field Guide to Reptiles and Amphibians of Eastern and Central North America, Fourth Edition. Boston and New York: Houghton Mifflin Harcourt. xiv + 494 pp., 47 plates, 207 figures. . (Hypsiglena jani, pp409410 + Plate 39). and has an unmarked underside. It has smooth dorsal scales. The eye has a vertically elliptical pupil. H. jani is rear-fanged, and is considered to be venomous, though it is not dangerous to humans.
Behavior As the common names imply, H. jani is a primarily nocturnal snake.
Diet The diet of H. jani consists of primarily lizards, but it will also eat smaller snakes and occasionally soft bodied insects.
Habitat H. jani prefers semi-arid habitats with rocky soils.
Reproduction H. jani is an oviparous species that breeds in the spring rainy season, laying 4–6 eggs that take approximately 8 weeks to incubate before hatching. The eggs average long by wide. The hatchlings are about in total length.Wright AH, Wright AA (1957). Handbook of Snakes of the United States and Canada. Ithaca and London: Comstock Publishing Associates, a division of Cornell University Press. 1,105 pp. (in 2 volumes) (Hypsiglena torquata texana, pp. 326–330, Figure 101 + Map 30 on p. 315).
Geographic range H. jani ranges from southern Kansas to southern Colorado, and south throughout New Mexico, the western half of Texas to central Mexico.
Subspecies Three subspecies are recognized as being valid, including the nominotypical subspecies. Hypsiglena jani dunklei Hypsiglena jani jani Hypsiglena jani texana
Nota bene: A trinomial authority in parentheses indicates that the subspecies was originally described in a genus other than Hypsiglena.
References
Further reading Dugès A (1865). "Du Liophis janii". Mémoires de l'Académie des Sciences et Lettres de Montpellier 6: 32–33. (Liophis jani, new species). (in French). Stejneger L (1893). "Annotated List of the Reptiles and Batrachians Collected by the Death Valley Expedition in 1891, with Descriptions of New Species". North American Fauna 7: 159–228. (Hypsiglena texana, new species, p. 205). Tanner WW (1944). "A Taxonomic Study of the Genus Hypsiglena ". Great Basin Naturalist 5 (3 & 4): 25–92. (Hypsiglena dunklei, p. 48; H. ochrorhynchus janii, pp. 48–51; and H. o. texana, pp. 51–54).
External links Herps of Texas: Hypsiglena jani