Bothrops neuwiedi subtriangular, or headphone-shaped and oppose each other middorsally. The belly is white or yellow with gray speckling. Juveniles have a white tail tip. This species is found in South America east of the Andes and south of approx. 5°S, including Brazil (southern Maranhão, Piauí, Ceará, Bahia, Goiás, Mato Grosso, an isolated population in Amazonas, Rondônia and all southern states), Bolivia, Paraguay, Argentina (Catamarca, Córdoba, Corrientes, Chaco, Entre Ríos, Formosa, Jujuy, La Pampa, La Rioja, Mendoza, Misiones, Salta, San Juan, San Luis, Santa Fe, Santiago del Estero and Tucumán) and Uruguay. According to Vanzolini (1981), the type locality given is ""provincia
Formosa Province up to 45 °C The tropical weather is characterized with uniform annual rains in the east (1000 mm annual), while in the rest of the country winter is a drier season (80 mm). The humidity variation results in the jungle vegetation on one side, and the Chaqueño forest in the other. The limit with the Salta Province is known as the "Impenetrable" ("Impenetrable"). Formosa's protected areas are the Río Pilcomayo National Park and the Formosa National Reserve. Coincidentally, part of the province is the antipode to northern Taiwan, which was also known as "Formosa". (Taiwan was named "Formosa" by European