Atractus thalesdelemai Passos, Fernandes & Zanella, 2005

Passos, Paulo, Fernandes, Ronaldo, Bérnils, Renato S. & De Moura-Leite, Julio C., 2010, Taxonomic revision of the Brazilian Atlantic Forest Atractus (Reptilia: Serpentes: Dipsadidae) 2364, Zootaxa 2364 (1), pp. 1-63 : 44-46

publication ID	https://doi.org/ 10.11646/zootaxa.2364.1.1
persistent identifier	https://treatment.plazi.org/id/0390751B-3D47-FFE5-FF61-F98FFD7DBA8D
treatment provided by	Felipe
scientific name	Atractus thalesdelemai Passos, Fernandes & Zanella, 2005
status

Treatment

Fig. 15C View FIGURE 15

Atractus thalesdelemai Passos, Fernandes & Zanella, 2005 ; Herpetologica 61:210.

Atractus kangueryensis Cacciali, Villalba & Yanoski, 2007 ; South Amer. J. Herpetol. 2:84. New synonymy.

Holotype: Adult male, MNRJ 10052 View Materials , from Fazenda Corporação da Brigada Militar, municipality of Passo Fundo (28°14’S, 52°21’W, ca. 625 m), state of Rio Grande do Sul, Brazil, collected on 30 January 2001 by N. Zanella (specimen examined). GoogleMaps

Paratypes: Seven specimens, all from the municipality of Passo Fundo, state of Rio Grande do Sul: adult females ( MNRJ 10053–54 View Materials ), collected on 26–30 November 2001 by Noeli Zanella in pitfall traps, locality Fazenda Corporação da Brigada Militar ; juvenile and adult males ( MNRJ 10080–81 View Materials ) collected on 15 August 2001 and 25 August 2002, respectively by Noeli Zanella in pitfall traps, locality Fazenda Corporação da Brigada Militar ; adult female ( CRUPF 172 ), collected on 5 August 1994 by L. Portilho, locality Jardim Botânico; adult female ( CRUPF 405 ), collected on 12 October 1998 by R. Bibiano, locality Vera Cruz; adult male ( CRUPF 801 ), collected on 12 February 2001 by Nicolau Pot, locality Jardim Botânico .

Diagnosis: Atractus thalesdelemai is distinguished from all congeners by the combination of the following characters: (1) 17/17/17 smooth dorsal scale rows; (2) single postocular; (3) loreal moderate; (4) temporals 1+2; (5) six supralabials, third and fourth contacting orbit; (6) six infralabials, first three contacting chinshields; (7) generally six maxillary teeth; (8) three gular scale rows; (9) generally three preventrals; (10) 165–169 ventrals in females, 149–154 in males; (11) 22–26 subcaudals in females, 26–30 in males; (12) dorsum grayish brown, except for first two dorsal scale rows creamish white; (13) venter and tail immaculate creamish white; (14) body size moderate in females (maximum SVL 381 mm), small in males (maximum SVL 265 mm); (15) tail small in females (9.1–10.8% SVL), moderate (13.1–14.3% SVL) in males; (16) hemipenis moderately bilobed, semicapitate, and semicalyculate.

Comparisons: Among all congeners, A. thalesdelemai shares 17 dorsal scale rows, six upper and lower labials, single postocular, dorsum uniformly grayish or pale brown, and venter creamish white only with A. balzani . Atractus thalesdelemai differs from A. balzani by having maximum tail length 38 mm, 149–154 ventrals in males and 165–169 in females, 26–30 subcaudals in males and 22–26 in females, dorsum with scales paler in the posterior edges, and homogenously creamish white venter (vs. tail length 50 mm, 159 ventrals, 32 subcaudals, dorsum with scales paler in the centre, and venter yellowish speckled with brown in A. balzani ).

Description: Head twice as long as wide, flattened in lateral view, round in dorsal view; snout truncate in lateral view, round in dorsal view; cervical constriction indistinct; rostral sub-triangular in frontal view, wider than long, poorly visible in dorsal view; internasal moderate; internasal suture sinistral with respect to prefrontal suture; prefrontal longer than wide; supraocular sub-trapezoidal, twice as long as wide; frontal sub-triangular, as long as wide; parietal twice as long as wide; nasal divided; nostril located between prenasal and postnasal; prenasal and postnasal twice as high as long; loreal moderate, contacting second and third supralabials; pupil round; single postocular twice as high as long; temporals 1+2; anterior temporal twice as long as high; upper posterior temporals generally not fused into a single plate; six supralabials, third and fourth contacting chinshields; second supralabial slightly higher than first and similar in size to third; fourth supralabial higher and sixth longer than remaining supralabials; symphisial sub-triangular, twice broader than long; generally six infralabials, first three contacting chinshields; first pair of infralabials in contact behind symphisial, preventing symphisial/chinshields contact; chinshields twice longer than wide; three gular scale rows; generally three preventrals; 17/17/17 smooth dorsal scale rows; dorsals lacking apical pits, supra-anal tubercles, and keels; caudal spine moderate, robust, conical, and acuminated.

Maxillary arch: Arched in dorsal view, with five or six prediastemal and one or two postdiastemal teeth; first three teeth large, angular in cross section, robust at base, slightly narrower on the apices, curved posteriorly, of similar size, tightly spaced; remaining prediastemal teeth moderately spaced, decreasing gradually in size posteriorly; maxillary diastema moderate; postdiastemal teeth slightly smaller than last prediastemal tooth; lateral process well developed, projected posteriorly.

Colour in preservative: Dorsum of head uniformly grayish brown; background of head grayish brown to dorsal edges of supralabials; ventral margins of nasals and lower temporals occasionally creamish white; supralabials creamish white; mental region, preventrals, belly, and tail immaculate creamish white; dorsum reticulated grayish brown with pale spots, except for two first scale rows creamish white; dorsal ground colour reticulations composed by grayish brown anterior and grayish white posterior from each scale ( Fig. 15C View FIGURE 15 ).

Colour in life: Like colouration in preservative, but with first dorsal scale rows reddish white coloured.

Hemipenis morphology (everted organ, n = 2): Retracted organ bifurcates at 10 th and extends to the level of 11 th subcaudal. Hemipenis moderately bilobed, semicapitate, semicalyculate; lobes distinct and restricted to distal portion of capitulum; lobes clavate, centrifugally oriented with round apices; lobes and capitulum covered with small spinulate calyces; calyces progressively replaced with papillae toward lobe apices; capitulum with irregular calyces; horizontal walls of calyces originate calyculate flounces, occasionally restricted to lateral of sulcate side of capitulum; asulcate side of capitulum with conspicuous lobular and medial crests; capitular groove indistinct on the sulcate and slightly to well marked on the asulcate side of hemipenis; capitulum located just above sulcus spermaticus bifurcation and taller than hemipenial body; sulcus spermaticus bifurcates on the middle of the organ; sulcus spermaticus branches centrifugally oriented, running to tips of lobes; margins of sulcus spermaticus stout and narrow, bordered with spinules from the base to the lobe apices; hemipenial body sub-cylindrical, covered with moderate hooked spines; large spines concentrated on lateral portion of sulcate and distal region of asulcate side; basal naked pocket extends to distal portion of hemipenial body; basal region of with longitudinal plicae and diffuse spinules ( Fig. 14D View FIGURE 14 ).

Variation: Largest male 265 mm SVL, 38 mm CL, largest female 381 mm SVL, 38 mm CL; tail 13.1– 14.3% (n = 2) SVL in males, 6.9–10.8 % (x¯ = 9.1; SD = 1.4; n = 4) SVL in females; 149–154 (x¯ = 151; SD = 2.2; n = 4) ventrals in males, 165–169 (x¯ = 166.5; SD = 1.0; n = 4) in females; 26–30 (x¯ = 28.2; SD = 1.7; n = 2) subcaudals in males, 22–26 (x¯ = 23.5; SD = 1.8; n = 4) in females; 6 (n = 16 sides) or 4 (n = 2 sides) infralabials; 3 (n = 16 sides) or 4 (n = 4 sides) infralabials contacting chinshields; 1 (n = 1), 2 (n = 1), 3 (n = 6), or 4 (n = 1) preventrals; 9–11 (x¯ = 9.9; SD = 0.6; n = 8) dorsal scale rows on the level of second subcaudal; 6 (n = 13 sides) or 7 (n = 3 sides) maxillary teeth; 6 (n = 9 sides) or 7 (n = 5 sides) dentary teeth; retracted hemipenis bifurcates at level of eighth to 10 th and extends to ninth to 11 th subcaudal (x¯ = 9; SD = 1.25; n = 4).

Distribution: From Estancia San Isidro (26º31’S, 55º52’W) in the department of Itapúa, Paraguay, southeastward to Passo Fundo (28°14’S, 52°21) in the state of Rio Grande do Sul, Brazil. Atractus thalesdelemai inhabits plant formations composed of Campos in transition zones with Submontane Semi-deciduous and riparian forests between 100–700 m elevation ( Fig. 11 View FIGURE 11 ).

Remarks: Passos et al. (2005b) described A. thalesdelemai based on eight specimens from the municipality of Passo Fundo in the Brazilian state of Rio Grande do Sul. Recently, Cacciali et al. (2007) described A. kangueryensis based on three individuals from Kangüery, department of Itapúa, Paraguay. Cacciali et al. (2007) distinguished A. kangueryensis from A. thalesdelemai on the basis of the number of ventral scales and colour pattern nuances, and pointed out that in contrast with A. thalesdelemai , A. kangueryensis undergoes an ontogenetic colour change. Although the type-series of A. kangueryensis could not be examined in the course of this study, the characters used by Cacciali et al. (2007) to differentiate their new species from A. thalesdelemai are insufficient to recognize A. kangueryensis as distinct from the former species. First, we strongly disagree with Cacciali et al. (2007) that the species differ in number of ventral scales because the range for A. kangueryensis (165–169) overlaps that for A. thalesdelemai (151–167). Furthermore, all colouration characters used by Cacciali et al. (2007) for diagnosing A. kangueryensis (temporal region grey, only first dorsal scale rows creamish white or pink, specimens uniformly grayish brown) from A. thalesdelemai (vs. temporal region creamish white, first two dorsal scale rows creamish white, specimens uniformly reticulate with pale colour posteriorly) are encompassed by variation occurring in adults and juveniles of A. thalesdelemai (see above).

As described and illustrated by Passos et al. (2005b), the holotype of A. thalesdelemai has grayish dorsal margins only on scales of the second dorsal row, temporal region invaded with creamish white, and dorsal scales uniformly reticulate with pale colour. However, re-examination of colour pattern in both sexes and all age classes in the type-series of A. thalesdelemai , revealed also the occurrence of features employed by Cacciali et al. (2007) to distinguish it from A. kangueryensis . Moreover, as found in many Atractus species (e.g., A. reticulatus and A. trihedrurus ), the reticulate colour pattern is subject to geographic variation and can be obscured on specimens close to ecdysis or on melanic individuals (e.g., specimens from higher elevations). Furthermore, the pink colour on the first scale rows of the paratypes of A. kangueryensis , in our view, represent merely the fresh colour from recently collected specimens rather than an ontogenetic change of colour pattern, and we suspect that live specimens of A. thalesdelemai have pink on the first scale rows as is found also in many congeners (P. Passos pers. observ.). For the reasons expressed above, A. kangueryensis is placed herein in the synonymy of A. thalesdelemai .