Adults of B. neuwiedi average in total length, but may grow to as much as. Head scalation includes 7-11 keeledintrasupraoculars, 9-13 sublabials and seven to eight supralabials, the second of which is not fused with and usually separated from the prelacunal. Two rows of small scales usually separate the subocular and fourth supralabial scales. At midbody the 22-29 rows of dorsal scales are strongly keeled. The ventral scales number 158-179 and 164-185 in males and females, respectively, while the subcaudal scales are divided and number 39-56 or 34-51 in males or females. The color pattern consists of a brown or dark-brown ground color overlaid with a series of 16-27 dark brown or black dorsolateral blotches. The blotches are edged in white and may be trapezoidal, triangular, subtriangular, or headphone-shaped and oppose each other middorsally. The belly is white or yellow with gray speckling. Juveniles have a white tail tip.
Geographic range
The species B. neuwiedi is found in South America east of the Andes and south of approx. 5°S, including Brazil, Bolivia, Paraguay, Argentina and Uruguay. According to Vanzolini, the type locality given is "provincia Bahiae".
Bothrops neuwiedi is one of the main causes of snakebite in Argentina: between 1960 and 1975, according to Esteso, 80% of the approximately 500 cases reported each year were attributed to B. n. diporus. In a review of the symptoms in all 18 bite cases for this species admitted to the hospital in São Paulo between 1975 and 1992, Jorge and Ribeiro found all suffered pain, 83% had swelling, 50% had bruising, 17% had necrosis, 12% developed coagulopathy and 5% had abscesses, can also cause high blood pressure and collapse. In a case in Germany, a 36-year-old snake keeper was bitten on the finger and developed hemorrhagic "necrosis" of the afflicted digit and swelling that extended onto the hand. Five hours after being bitten, his blood had a normal platelet count, but was incoagulable with a reduced fibrinogen concentration, elevated fibrin degradation products and D-dimer. Three different antivenins, Soro Antibotropico-Crotalico, Soro Antibotropico-Laquetico and Soro Botropico, can be used to treat bites from this species. All three are manufactured by the Instituto Butantan in Brazil and contain specific antibodies to counteract the effects of the venom.
Subspecies
Taxonomy
Formerly twelve subspecies were recognized by Peters and Orejas-Miranda, Campbell and Lamar, and Golayet al.. A revision by Silva elevated five taxa to full species: B. diporus, B. lutzi, B. matogrossensis, B. pauloensis, B. pubescens; and identified one unnamed new species. In some cases, intergradation may occur. Together, these are referred to as the Bothrops neuwiedi complex.
