Iridescent Ground Snake

description

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

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

diagnosis

Diagnosis: Atractus iridescens is distinguished from all congeners by combination of the following characters: (1) 17 / 17 / 17 smooth dorsal scale rows; (2) two postoculars; (3) loreal long; (4) temporals 1 + 2; (5) seven supralabials, third and fourth contacting orbit; (6) seven infralabials, first three or four contacting chinshields; (7) six or seven maxillary teeth; (8) generally four gular scale rows; (9) three preventrals; (10) 135 – 144 ventrals in females, 135 – 150 in males; (11) 25 – 37 subcaudals in females, 33 – 38 in males; (12) dorsum reddish brown scattered with small and irregular dark blotches; (13) venter beige with a median line comprised of small black dots; (14) moderate body size, single subadult female with 170 mm SVL, males reaching 353 mm SVL; (15) long tail in females (16.4 – 17.6 % SVL) and males (14.2 – 18.9 % SVL); (16) hemipenis moderately bilobed, slightly semicapitate, and non-calyculate. Comparisons: Atractus iridescens is distinguished from all congeners, except A. typhon by having a lateral projection on the base of the hemipenis. Atractus iridescens differs from A. typhon by having 17 dorsal scale rows at midbody, 135 – 150 ventrals in males, do

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

discussion

Remarks: Peracca (1896) described A. iridescens based on a specimen from “ America Meridionali ” (= South America) without precise collection data. Boulenger (1913) associated the name with three specimens collected at Peña Lisa, Condoto in the department of Chocó, Colombia. Analyses of data and photographs of the holotype of A. iridescens corroborate Boulenger’s identification. We report herein three additional specimens extending the species’ distribution about 500 km south. We found another specimen (CSJ 563) that may be referable to A. iridescens, but it is labelled as coming from “ San Pedro ”, a municipality on the other side of the Andes. There are at least five localities named San Pedro in the department of Antioquia, Colombia, and it is very likely that the specimen came from San Pedro de Urabá (08 º 17 ’ N, 76 º 23 ’ W, ca. 200 m), on the northern portion of the Pacific lowlands of Colombia. If this record would be considered, the species range would extend 300 km north from Nuqui. However, the colour pattern of this specimen is poorly preserved and its identity cannot be properly established, thus we prefer not to include this doubtful record of A. iridescens until furt

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

distribution

Distribution: Pacific lowlands of Colombia from Nuqui (05 º 43 ’ N, 77 º 16 ’ W) west of Condoto (05 º 08 ’ N, 76 º 39 ’ W) in the department of Chocó south to Barbacoas (01 º 39 ’ N, 78 º 10 ’ W) in the department of Nariño. Atractus iridescens inhabits rainforest at elevations of 50 – 150 m (Fig. 6).

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