Atractus alytogrammus

description

Description of the holotype. Male; SVL 297 mm; moderate TL 35 mm (complete; 11.8 % SVL); TTL 332 mm; head not distinct from body; body cylindrical, diameter at midbody 5.2 mm (1.8 % of SVL); head rounded in dorsal view; HL 9.41 mm (3.2 % SVL); HW 4.9 mm (65.3 % of HL); snout rounded in dorsal view, rounded in lateral view; eye diameter 1.03 mm; pupil round; interorbital distance 3.2 mm (42.7 % HL); rostro-orbital distance 2.9 mm (38.7 % HL); naso-orbital distance 1.4 mm (18.7 % HL). 17 / 17 / 17 smooth dorsal scale rows, 16 dorsal scale rows above cloaca, 9 dorsal scale rows above second subcaudal; apical pits absent; 187 ventrals; 29 / 31 divided subcaudals; some of the subcaudals fused; 4 preventrals; cloacal scute entire; rostral well visible from above, subtriangular, wider than high (rostral height 1.3 mm, rostral width 2.24 mm); two subpentagonal internasals, height 0.7 mm, width 1.04 mm; internasal suture sinistral in respect to prefrontal suture; nostril in suture of prenasal and postnasal; 1 / 1 hexagonal postnasal, length 0.7 mm, height 0.7 mm; short subrectangular loreal, approximately as high as long (loreal length 0.7 mm; loreal height 0.6 mm; ratio length / height: 1.

Two new species of Atractus from Colombia (Reptilia, Squamata, Dipsadidae)

diagnosis

Diagnosis. A species of the genus Atractus that differs from all congeners by the following combination of characters: (1) 17 smooth dorsal scale rows; (2) preocular absent; (3) loreal present, approximately as long as high; (4) temporals 1 + 2; (5) seven supralabials; (6) seven infralabials; (7) five maxillary teeth; (8) four gular scale rows; (9) four pre-ventrals; (10) 187 ventrals in single male; (11) 29 / 31 subcaudals in single male; (12) dorsum of body with longitudinal stripes; (13) venter uniformly dark gray; (14) SVL of single male 297 mm; (15) small to moderate tail length in single male (11.8 % of SVL); (16) hemipenis morphology unknown. Comparisons. Among all currently recognized congeners, Atractus alytogrammus shares a dark venter and is morphologically similar to A. steyermarki, A. nigriventris, and A. trivittatus. It differs from A. steyermarki by having a uniform dark gray venter (vs. venter pale with a midventral stripe in A. steyermarki), 187 ventrals (vs. 160 – 167 in males in A. steyermarki), and 29 / 31 subcaudals (vs. 37 – 44 in males in A. steyermarki). Atractus alytogrammus differs from A. nigriventris and A. trivitattus by having a dorsal body pattern of

Two new species of Atractus from Colombia (Reptilia, Squamata, Dipsadidae)

etymology

Etymology. The name alytogrammus is a compound noun derived from alytos (Greek for “ unbroken ”) and gramme (Greek for “ line ”) referring to the continuous dorsolateral pale stripe in this species.

Two new species of Atractus from Colombia (Reptilia, Squamata, Dipsadidae)

materials_examined

Holotype. A male, SMF 88371, collected on January 9 1957 by Federico Medem in the Serrania de la Lindosa (2.46782 °, - 72.73155 °), south of the municipality of San José del Guaviare, department of Guaviare, Colombia.

Two new species of Atractus from Colombia (Reptilia, Squamata, Dipsadidae)