Atractus wagleri

Passos, Paulo & Arredondo, Juan C., 2009, Rediscovery and redescription of the Andean earth-snake Atractus wagleri (Reptilia: Serpentes: Colubridae), Zootaxa 1969, pp. 59-68 : 60-64

Atractus wagleri

( Figures 1–4 )

Atractus wagleri Prado, 1945 ; Ciencia ( Mexico): 6:61.

Holotype: Female, MLS 228, from Humbo (05º36’N, 74º16’W, ca. 1000 m), Boyacá Department of Colombia, collected on 1948 by Hermanos of La Salle order. Presumed lost (see discussion).

Diagnosis: Atractus wagleri is distinguished from all congeners by the 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 contacting chinshields; (7) six or seven maxillary teeth; (8) generally four gular scale rows; (9) four or five preventrals; (10) 174–180 ventrals in females, 157–174 in males; (11) 43–44 subcaudals in females, 46–56 in males; (12) dorsal ground colour in preservative cream-red with an irregular vertebral black stripe connected to lateral black blotches, constituting complete bands anteriorly and decreasing in size posteriorly; (13) venter black with paraventral region cream; (14) moderate body size, females reaching 437 mm SVL and males 445 mm SVL; (15) moderate tail length in females (13.6–15.3% SVL) and long in male (21.61% SVL); (16) hemipenis moderately bilobed, semicapitate, and semicalyculate.

Comparisons: Among all congeners, Atractus wagleri occur parapatrically and shared a suite combination of characters with A. sanguineus : 17 dorsal scale rows, more than 170 ventrals in both sexes, more than 40 subcaudals in males, seven upper and lower labials, first three infralabials contacting chinshields, seven or eight maxillary teeth, long tail in males, dorsum with blotches decreasing in size posteriorly, and venter generally most black. Atractus wagleri differs from A. sanguineus in having 43–44 subcaudals in females and paravertebral blotches constituting bands anteriorly (vs. 29–38 subcaudals in females and paravertebral blotches never forming bands, except for occasionally a black collar on neck, anteriorly). The only other species of Atractus occurring parapatrycally with A. wagleri at Cordillera Oriental of Colombia is A. crassicaudatus . Atractus wagleri can be easily distinguished from A. crassicaudatus by having 174–180 ventrals in females, 43–44 subcaudals in females and 46–56 in males, and tail 21.61% SVL in males, 13.6–15.3% SVL in females (vs. 147–170 ventrals in females; 21–33 subcaudals in males and 14–26 in females; tail 11.0–17.1% SVL in males, 8.0–13.7% in females).

Description (based on 3 new specimens; 2 males, 1 female): Head twice as long as wide, flattened in lateral view, round in dorsal view; snout truncate in lateral view, round in dorsal view; rostral subtriangular in frontal view, broader than high, little visible in dorsal view; internasal as long as wide; internasal suture sinistral with respect to prefrontal suture; prefrontal longer than wide; supraocular subtrapezoidal, slightly longer than wide; frontal subpentagonal, broader than long; parietal about twice as long as wide; nasal divided; nostril located between prenasal and postnasal; prenasal twice as high as long; postnasal about twice as high as long, higher than prenasal; loreal long, contacting second and third supralabials; pupil round; two postoculars of similar length; upper postocular about twice as high as lower postocular; temporals 1+2; anterior temporal twice as long as high; upper posterior temporal elongate, three times as long as wide; seven supralabials, third and fourth contacting orbit; second supralabial higher than first and smaller than third; third higher and seventh longer than remaining supralabials; symphisial subtriangular, four times broader than long; seven infralabials, first three contacting chinshields; first pair of infralabials in contact behind symphisial, preventing symphisial/chinshields contact; chinshields three times as long as wide; three or four gular scale rows; four or five preventrals; 17/17/17 smooth dorsal scale rows; dorsals lacking apical pits, supra-anal tubercles, and keels; caudal spine short, robust, and rhomboid.

Maxillary arch: Arched in dorsal view, with four or five prediastemal and two or three postdiastemal teeth; prediastemal teeth large, curved downward, decreasing gradually in size posteriorly, angular in cross section, robust at base, and narrower at apices; maxillary diastema short; postdiastemal teeth slightly smaller than last prediastemal tooth.

Colour pattern in preservative: Dorsum of head black, covered with small beige dots above internasals, nasals, loreal, and prefrontals; background of head black to dorsal margins of supralabials; black descending postocular stripe reaching dorsal edge of sixth and anterior ventral margin of seventh supralabial; temporal region pigmented with irregular beige spots; median region of supralabials cream-white, except for sixth and seventh scales; mental region cream-white, occasionally with disperse black dots; preventrals uniformly cream; venter predominantly cream-white with irregular black dots for first 15 ventrals; venter becomes uniformly black before 15th ventral, except for lateral margin of scales uniformly cream-white; tail black with lateral portion of subcaudals cream-white; dorsal ground colour of body black anteriorly, with cream-white complete transverse bands (one scale long), alternated on flanks; black interspaces (three to four scales long), reaching paraventral region; pale transverse bands of opposite sides connected middorsally only anteriorly, up to a point level with 20th ventral; pale transverse bands increase in size at midbody (two scales long), with black interspaces reducing gradually in size, restricted to paravertebral region (two scales long); posterior to midbody region, dorsal ground colour becomes cream-red with black vertebral line (two scales wide), breaking up to for black paravertebral blotches; flanks with round black blotches (two scales long) at the level of third and fourth scale rows; paraventral region with irregular small black blotches, constituting a barely defined lateral stripe above first two dorsal scale rows; paraventral blotches occasionally connected to paravertebral ones ( Figs. 1–2 ).

Colour pattern in life: Dorsum of head black with yellow dots above internasals, nasals, loreal, prefrontal, and temporal region; ventral margin of supralabials yellow; mental region and venter anteriorly creamyellow; lateral margin of ventrals cream-yellow and remaining belly uniformly black; dorsum of body black anteriorly, with yellow transverse bands; bands gradually change to reddish orange in the median third and uniformly red at posterior region of body; vertebral line and paravertebral blotches black; flanks and paraventral region with cream-red ground colour, covered with irregular black blotches ( Fig. 3 ).

Hemipenis ( Fig. 4 ; everted organs n = 2): Organ moderately bilobed, semicapitate, and semicalyculate; lobes distinct and restricted to distal portion of capitulum; lobes cylindrical with round, laterally projecting apices; lateral projections oriented centrifugally, clearly distinct from proximal region of lobes; lobes and capitulum uniformly covered with spinulate calyces; calyces progressively replaced by papillae toward tips of lobes; lobes with calyces losing vertical walls and constituting spinulate transverse flounces; transverse flounces well defined on lateral portion of asulcate side of hemipenis; asulcate side of capitulum with barely conspicuous lobular crests; capitular crotch well marked on both sides of hemipenis; capitulum similar in size to hemipenial body, located at the level of sulcus spermaticus bifurcation; sulcus spermaticus bifurcates in the mid portion of the organ; branches of sulcus spermaticus centrifugal, reaching lobe apices; margins of sulcus spermaticus stout and narrow along hemipenial body, and moderately expanded in the capitular region; hemipenial body subcylindrical, covered with moderate hooked spines; basal naked pocket restricted to basal portion of hemipenial body; proximal portion of hemipenis with longitudinal plicae and disperse spinules.

Variation (3 new specimens plus Prado's data on female holotype): Largest male SVL 445 mm, CL 96 mm; largest female SVL 437 mm, CL 67 mm; tail 21.6% SVL in male, 13.6–15.3% (n = 2) SVL in females; 157–174 (n = 2) ventrals in males, 174–180 (n = 2) in females; 45–56 (n = 2) subcaudals in males, 43–44 (n = 2) in females; 3 (n = 1 side) or 4 (n = 5 sides) gular scale rows; 4 (n = 2) or 5 (n = 1) preventrals; 8 (n = 4 sides) or 9 (n = 2 side) dorsal scale rows in the level of second subcaudal; 6 (n = 2 sides) or 7 (n = 4 sides) maxillary teeth; 4.5–9.0 mm midbody diameter.

Distribution: Western versant of Cordillera Oriental of Colombia, from Floridablanca (07º03’53’’N, 73º05’23’’W) in Santander Department to Humbo (05º36’N, 74º16’W) in Boyacá Department. Atractus wagleri has been found in sub-Andean Tropical Forest at elevations of 740–1200 m ( Fig. 5 ).

Remarks: Prado (1945) cited the type locality of A. wagleri as Humbo (Boyacá), Colombia. Subsequently, some authors cited Muzo as the proper type locality of the species (Medem, 1965; Pérez-Santos & Moreno, 1998). This contradiction is probably because Humbo (05º36’N, 74º16’W) was a small town included originally in the boundaries of Muzo (05º32’N, 74º06) municipality. However, the municipality of Muzo was redefined and now does not contain Humbo, which is located instead within Quípama (05º31’N, 74º11’W) municipality (J. Lynch, pers. comm.).

Figures

FIGURE 3. General view of Atractus wagleri (MHUA 14504) in life.

FIGURE 4. Sulcate (left) and asulcate (right) views of the hemipenis of Atractus wagleri (MHUA 14504). Scale = 10 mm.

FIGURE 5. Geographical distribution of Atractus sanguineus and Atractus wagleri. Open symbols correspond to respective type localities of the species.

FIGURES 1 – 2. Dorsal (1) and ventral (2) views of Atractus wagleri (MHUA 14504) from San Vicenti de Chucurí. SVL 445 mm, CL 96 mm.