Atractus boulengerii

description

Description: Head twice as long as wide, arched in lateral view, rounded in dorsal view; snout truncate in lateral view, rounded in dorsal view; cervical constriction barely defined; rostral sub-triangular in frontal view, broader than high, poorly visible in dorsal view; internasal longer than wide; internasal suture sinistral with respect to prefrontal suture; prefrontal as long as wide; supraocular sub-trapezoidal, twice as long as wide; frontal pentagonal, as long as wide; parietal about 1.5 times as long as wide; nasal divided; nostril located between prenasal and postnasal; prenasal twice as high as long; postnasal as high as long; loreal long, contacting second and third supralabials; pupil round; two postoculars of similar size; upper postocular slightly longer than lower postocular; temporals 1 + 2; first temporal twice as long as high; upper posterior temporal elongate, four times as long as wide; seven supralabials, third and fourth contacting orbit; first three supralabials of similar size and lower than fourth; fifth supralabial higher than first four and lower than sixth supralabial; sixth supralabial higher and seventh longer than remaining supralabials; symphisial s

Pacific lowland snakes of the genus Atractus (Serpentes: Dipsadidae), with description of three new species

diagnosis

Diagnosis: Atractus boulengerii is distinguished from all congeners by the combination of the following characters: (1) 17 / 17 / 17 smooth dorsals; (2) two postoculars; (3) loreal long; (4) temporals 1 + 2; (5) seven supralabials, third and fourth contacting orbit; (6) six infralabials, first three contacting chinshields; (7) five maxillary teeth; (8) four gular scale rows; (9) four preventrals; (10) 176 – 189 ventrals in males; (11) 41 – 44 subcaudals in males; (12) dorsum beige with black round blotches decreasing in size posteriorly; (13) venter uniformly creamish white, tail brown pigmented on the median suture of subcaudals; (14) moderate body size, with male reaching 316 mm SVL; (15) long tail size in the male (16.8 % SVL). Comparisons: Among all congeners, A. boulengerii shares only with A. medusa sp. nov. (see below) 17 dorsal scale rows, five well-spaced maxillary teeth with a single postdiastemal tooth, more than 40 subcaudals in males, and dorsum with black nuchal collar and round body blotches decreasing in size posteriorly. Atractus boulengerii differs from A. medusa in having 176 – 189 ventrals in males, first three infralabials contacting chinshields, four gular sca

Pacific lowland snakes of the genus Atractus (Serpentes: Dipsadidae), with description of three new species

discussion

Remarks: Peracca (1896) described Atractus boulengerii and A. iridescens on the basis of two specimens from “ America Meridionali ”, without precise collection data. Boulenger (1913) associated three individuals from Peña Lisa and Condoto in the department of Chocó in Colombia with A. iridescens (see remarks of A. iridescens), but A. boulengerii remained known only from the holotype. In the course of this revision of the Pacific Atractus, we found a specimen (UV-C 6591, adult male), from the municipality of Buenaventura, department of Valle del Cauca, Colombia, which matches the original species description, except for having 176 ventrals and 41 subcaudals (vs. 189 ventrals and 44 subcaudals in the holotype of A. boulengerii). These small count differences are entirely acceptable in accordance with the pattern of variation of ventral and subcaudals reported for the genus (Savage 1960; Passos 2008), and therefore we refer herein this specimen to A. boulengerii.

Pacific lowland snakes of the genus Atractus (Serpentes: Dipsadidae), with description of three new species

distribution

Distribution: Rediscovered at the lower Anchicayá River, on the old road between Cali and Buenaventura (03 º 44 ’ N, 76 º 58 ’ W, ca. 100 m), department of Valle del Cauca, Pacific lowlands of Colombia. Atractus boulengerii apparently inhabits rainforest near sea level (Fig. 2).

Pacific lowland snakes of the genus Atractus (Serpentes: Dipsadidae), with description of three new species