Atractus latifrons ( Günther, 1868 ), Gunther, 1868

Almeida, Paula C., Feitosa, Darlan T., Passos, Paulo & Prudente, Ana L. C., 2014, Morphological variation and taxonomy of Atractus latifrons (Günther, 1868) (Serpentes: Dipsadidae), Zootaxa 3860 (1) : -

Atractus latifrons ( Günther, 1868)

Geophis latifrons Günther, 1868 ; Annals Magazine of Natural History 4(1):415.

Atractus latifrons— Boulenger, 1894; Catalogue of the Snake in the British Museum 3:303. Elaps herthae Ahl, 1927 ; Zwei neue Korallenschlangen der Gattung Elaps, Zoologischer Anzeiger , 70, 251–252. Atractus sp. — Silva Jr., 1993; Herpetological Natural History 1(1): 54.

Holotype. Adult male, BMNH 1946.1.6.52 (formally BMNH 67.9.17.207), collected by Hauswell in the municipality of Pebas (= Pevas, 03º20’S, 71º49’W, ca. 100 m above sea level), department of Loreto, Peru ( Figs. 10–11 ).

Diagnosis. Atractus latifrons can be distinguished from all its congeners by the following combination of characters: (1) dorsal scale rows 17/17/17; (2) postocular single; (3) loreal short, eventually fused to postnasal; (4) temporals 1+2; (5) supralabials six, third and fourth contacting orbit; (6) infralabials seven (n = 79), first four contacting chinshields (n = 80); (7) maxillary teeth five to six, lacking maxillar diastema ; (8) gular scale rows three or four; (9) preventrals three or four; (10) ventrals 145–190 in females, 134–178 in males; (11) subcaudals 24–41 in females, 20–42 in males; (12) aposematic coloration, in preservation, with three mainly patterns [bicolor in monads, tricolor in dyads, and tricolor in tetrads] intercalating black and/or white rings separated by red interspaces; (13) ventral coloration, in preservation, similar to dorsum with complete black rings intercalating by red interspaces; (14) body size moderate to large, females reaching 566 mm SVL, males 521 mm SVL; (15) caudal length moderately long in females (10.9-14.6% SVL), moderately long to long in males (13.3–20.0% SVL); (16) hemipenis moderately bilobed, slightly semicapitate, and semicalyculate.

Comparisons. Among all congeners, Atractus latifrons shares 17 dorsal scale rows at midbody and strict coral color pattern only with A. badius and A. obesus . Atractus latifrons differs from both by having snout acuminate, loreal short, prefrontals large, supralabials six, and maxillary teeth conical, lacking postdiastemal tooth (vs. truncate snout, loreal moderately long to long, prefrontals moderate, postoculars two, usually seven supralabials, and elliptic maxillary teeth with one or two postdiastemal teeth). Atractus latifrons differs from A. elaps , A. charitoae , A. franciscopaivai , and A. poeppigi by having dorsal scale rows 17 (vs. 15). Additionally, A. latifrons differs from A. franciscopaivai and A. poeppigi by having posterior temporals two, loreal eventually fused to postnasal, and dorsal coloration with black dyads intercalated by white rings and red interspaces (vs. posterior temporal single, loreal never fused to postnasal, and dorsum generally uniform black with rhomboidal blotches covering paraventral region).

Redescription of the holotype. Adult male; SVL 227 mm, CL 35.7 mm (15.7% SVL); head length 12.8 mm (5.6% SVL), head width 5.4 mm (42% head length); head height 4.7 mm. Head indistinct from body; head flattened in lateral view and sub-triangular in dorsal view; snout acuminate in lateral view and rounded in dorsal view; rostral large, well visible in dorsal view and rounded in frontal view; internasal as wide as long; internasal suture sinistral with respect to prefrontal suture; prefrontal wider than long; supraocular sub-trapezoidal in dorsal view, about twice longer than wide; frontal sub-pentagonal, longer than wide; parietal about twice longer than wide; nasal divided; nostril almost restricted to prenasal; prenasal and postnasals about twice higher than long; loreal short, about as high as long; loreal contacting second and third supralabials; pupil subelliptical; postocular single, sub-pentagonal, about twice higher than long; temporal 1+2; anterior temporal slightly longer than high; upper posterior temporals fused, about twice longer than high; supralabials six, third and fourth contacting orbit; first two supralabials with equivalent height and smaller than third and fourth supralabials; fifth supralabial higher and sixth longer than remaining supralabials; symphyseal sub-triangular, twice wider than long; first pair of infralabials preventing contact between symphyseal and chin shields; infralabials seven, first four in contact with chin shields; chin shields twice longer than wide; gular scale rows three; preventrals four; ventrals 150; subcaudal 36 in both sides; dorsal scale rows, 17/17/17, smooth and lacking apical pits; caudal spine short, robust, and conical.

Dorsum of head with black cephalic cap extending from rostral to posterior region of parietals, interrupted by a white band covering posterior part of parietals and temporals; lateral view of head black, white band covering fifth to seventh supralabials temporal and occipital scales; first four infralabials and anterior portion of chin shields black; posterior portion of fourth supralabials and two thirds of chin shields white; remaining gular region and preventrals white; body with 10 dyads, comprising 22 black rings (4–9 scales long) separated by 11 tiny white rings (1–2 scales long), broader in ventral view (3–4 scales long); dyads intercalated by 11 red rings (3–7 scales long); tail with two dyads, comprising four black rings (4–6 scales long) separated by two tiny white rings (1–2 scales long), broader in ventral view (3–4 scales long); dyads intercalated by two red rings (5–7 scales long); dorsal and lateral portions of red rings with black pigmentation in the mid–posterior region of each scale ( Fig. 10 ).

Meristic and morphometric variation. Largest male 521 mm SVL, 92 mm CL; largest female 566 mm SVL, 83 mm CL; SVL 150 –521 (x¯ = 354.6; SD = 82; n = 75) in males, 150–566 (x¯ = 372; SD = 108; n = 60) in females; CL 20–92 (x¯ = 60.4; SD = 17.7; n = 75) in males, 20–83 (x¯ = 50.2; SD = 14.9; n = 60) in females; ventrals 134–178 (x¯ = 148; SD = 7.2; n = 75) in males, 145–190 (x¯ = 158.6; SD = 8.8; n = 60) in females; subcaudals 20–42 (x¯ = 34.8; SD = 3.4; n = 75) in males, 24–41 (x¯ = 30.9; SD = 4.9) in females; infralabials 7 (n = 80 sides) or 8 (n = 8 sides); first infralabials contacting chinshields 3 (n = 6 sides), 4 (n = 77 sides) or 5 (n = 5 sides); gular scale rows 3 (n = 44 sides) or 4 (n = 44 sides); preventrals 2–4 (x¯ = 3.5; SD = 0.5; n = 45); midbody diameter 3.0– 10.2 mm (x¯ = 8.4; SD = 1.7; n = 6); dorsal scale rows in the level of second subcaudal 7–10 (x¯ = 8.4; SD = 0.9; n = 88 sides); maxillary teeth 5 (n = 58 sides) or 6 (n = 13 sides); hemipenis (in situ) bifurcates between sixth and ninth and extends at the level of seventh to 11th subcaudal (n = 14). Additional morphometric variation of the Atractus latifrons is presented in Table 1.

Variables Males Females

n Range Mean SD n Range Mean SD

CL/SVL ratio 75 0.06–0.2 0.16 0.02 60 0.08–0.2 0.13 0.02 Ventrals 75 134–178 148 7.2 60 145–190 158.6 8.8

Subcaudals 75 20–42 34.8 3.4 60 24–41 30.9 4.9

SVL 75 150–521 354.6 82 60 150–566 372 108 CL 75 20–92 60.4 17.7 60 20–83 50.2 14.9 … …continued on the next page Variables Males Females Distribution. Atractus latifrons presents a wide distribution in South America east of the Andes, occurring in the Amazonian lowlands of Colombia, Venezuela, French Guiana, Suriname, Brazil, and Peru. This species ranges from Paloemeu River, district of Marowijne in Suriname (03º21’N, 55º26’W), east to Urubichá, department of Santa Cruz in Bolivia (15º23’S, 62º57’W), and southeast to Bela Vista, state of Pará in Brazil (07º33’S, 53º18’W). Atractus latifrons occurs on the forest litter of primary Amazon rainforest, as well as secondary forest and cultivation fields ( Dixon & Soini 1977, 1986; Hoogmoed 1980; Martins & Oliveira 1993, 1999) from sea level to 300 meters elevation. Given current distribution in the literature, the range of A. latifrons is extended here to the state of Roraima in Brazil ( Fig. 11 ).

Figures

FIGURE 10. Dorsal (A) and ventral (B) views of body; and dorsal (C), ventral (D), and lateral (E) views of head of the holotype of Atractus latifrons (BM 1946.1.6.52). Scale = 10 mm.

FIGURE 11. Geographical distribution of Atractus latifrons. Open triangles correspond to literature records and squares correspond to material examined. Star indicates the type locality. Literature records are from Boulenger (1894), Dixon & Soini (1977), Gasc & Rodrigues (1980), Hoogmoed (1980), and Chippaux (1986).