Atractus reticulatus ( Boulenger, 1885 )
|
publication ID |
https://doi.org/ 10.11646/zootaxa.2364.1.1 |
|
persistent identifier |
https://treatment.plazi.org/id/0390751B-3D73-FFE9-FF61-FD0FFDC5BF8E |
|
treatment provided by |
Felipe |
|
scientific name |
Atractus reticulatus ( Boulenger, 1885 ) |
| status |
|
Atractus reticulatus ( Boulenger, 1885)
Figs. 8D View FIGURE 8 , 13B View FIGURE 13
Geophis reticulatus Boulenger, 1885 ; Ann. Mag. Nat. Hist. 16(5):87.
Atractus reticulatus – Boulenger, 1894; Catalogue of the Snakes in the British Museum 2:311.
Atractus reticulatus scrocchii Alvarez, Rey & Cei, 1992 ; Boll. Mus. Reg. Sci. Nat. Torino 10(2):250.
Atractus reticulatus – Fernandes, 1996; Comun. Mus. Cienc. Tecnol. PUCRS, Sér. Zool. 8:41.
Holotype: Adult female, BMNH 1946.1 .2.7 (formerly BMNH 85.6.26.10), collected by R. von Ihering, municipality of São Lourenço do Sul (31º22’S, 51º59’W, sea level), state of Rio Grande do Sul, Brazil, (specimen examined). GoogleMaps
Diagnosis: Atractus reticulatus is distinguished from all congeners by the following combination of characters: (1) 15/15/15 smooth dorsal scale rows; (2) two postoculars; (3) loreal moderate; (4) temporals 1+2; (5) seven supralabials, third and fourth contacting orbit; (6) six or seven infralabials, first four contacting chinshields; (7) six to eight maxillary teeth; (8) usually three gular scale rows; (9) usually three preventrals; (10) 149–165 ventrals in females, 130–151 in males; (11) 19–30 subcaudals in females, 24–34 in males; (12) dorsum ground colour dark grayish brown or black, reticulating with pale colour; (13) venter immaculate creamish white; (14) moderate body size, females reaching 390 mm SVL, males 279 mm SVL; (15) tail short to moderate in females (7.8–13.5% SVL), short to long (7.9–17.1% SVL) in males; (16) moderately bilobed, semicapitate, and semicalyculate hemipenis.
Comparisons: Among all congeners, A. reticulatus shares 15 dorsal scales rows, first four infralabials contacting chinshields, six or seven maxillary teeth, pale occipital band at least on juveniles, dorsum dark brown or black, hemipenis semicapitate, semicalyculate only with A. emmeli . Atractus reticulatus differs from A. emmeli by having two or three gular scale rows, 149–163 ventrals in females and 130–151 in males, and venter immaculate creamish white (vs. four gular scale rows, 154–185 ventrals in females and 151–165 in males, and venter generally black). Atractus reticulatus is apparently close relative and occurs sympatrically with A. paraguayensis , but is easily distinguished from this species by having a moderately bilobed hemipenis and dorsal colour pattern reticulate grayish brown to black, lacking paravertebral blotches in preserved adults (vs. slightly bilobed hemipenis and dorsal colour pattern beige to pale brown usually scattered with paravertebral blotches in adults).
Description: Head twice as long as wide, slightly arched 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, broader than high, poorly visible in dorsal view; internasal moderate; internasal suture sinistral with respect to prefrontal suture; prefrontal as long as wide; supraocular sub-trapezoidal, twice as long as wide; frontal subpentagonal or sub-triangular, broader than long; 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; generally two postoculars of similar size; upper postocular occasionally longer than lower and lower higher than upper postocular; temporals 1+2; anterior temporal twice as long as wide; upper posterior temporals, three times as long as wide; seven supralabials, third and fourth contacting orbit; first two supralabials of similar size and slightly smaller than third; sixth higher and seventh supralabial longer than others; symphisial triangular, slightly broader than long; seven infralabials, first four 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; 15/15/15 smooth dorsal scale rows; dorsals lacking apical pits, supra-anal tubercles, and keels; caudal spine moderate, conical, and acuminate.
Maxillary arch: Arched in dorsal view, with six prediastemal and two postdiastemal teeth; prediastemal teeth large, closely spaced, of similar size, curved posteriorly, angular in cross session, robust at base, narrower on the apices; maxillary diastema short; postdiastemal teeth slightly smaller than last postdiastemal tooth; lateral process poorly developed, lacking posterior projection.
Colour in preservative: Dorsum of head uniformly dark brown; background of head dark brown, extending to the dorsal edges of supralabials; occasionally, dark pigment extends to labial margin through anterior edges of supralabials; mental region immaculate creamish white; venter and tail immaculate, creamish white; dorsum of body with black collar (two to four scales long); dorsal ground colour brown to dark brown, reticulating with pale brown spots; pale brown reticulations (beige or grayish brown) concentrated on the centre of each dorsal scale, with dark colour restricted to scale borders; first two dorsal scale rows generally creamish white; dorsum frequently with a dark brown vertebral line (one scale wide) along body ( Fig. 8D View FIGURE 8 ).
Juvenile colouration in preservative: Juveniles with a pale (beige) occipital band, extending generally from parietal shield to black collar.
Colour in life: Dorsum of head uniformly black; supralabials, mental region, venter, and tail creamish red; dorsal of body reticulate with creamish white to reddish brown spots (bordered with black) on the centre of scales ( Fig. 13B View FIGURE 13 ).
Hemipenis morphology (everted organs, n = 4): Retracted organ bifurcates and extends to the level of seventh subcaudal. Hemipenis moderately bilobed, semicapitate, and semicalyculate; lobes distinct and restricted to distal portion of capitulum; lobes cylindrical, with round apices; lobes generally similar in size, longer than remaining portion of capitulum; lobes and capitulum uniformly covered with spinulate calyces; calyces arranged in transverse series, constituting well defined spinulate flounces; capitulum located just at the level of sulcus spermaticus bifurcation; capitular groove well evident on the asulcate side and barely distinct on the sulcate side; capitulum of similar size to hemipenial body; sulcus spermaticus divides for about middle of organ; branches of sulcus spermaticus with centrifugal orientation, running to tip of lobes; sulcus spermaticus margins stout and narrow, bordered with spinules from the base of organ to tip of lobes; hemipenial body subcilyndrical, uniformly covered with moderate hooked spines; large spines restricted to lateral portion of sulcate side of hemipenis; basal naked pocket restricted to proximal region of hemipenial body; basal portion of hemipenis with longitudinal plicae and disperse spinules ( Fig. 14A View FIGURE 14 ).
Variation: Largest male 279 mm SVL, 42 mm CL, largest female 390 mm SVL, 47 mm CC; cauda 7.9– 17.0% (x¯ = 14.3; SD = 1.8; n = 90) SVL in males, 7.0–13.5% (x¯ = 11.2; SD = 1.4; n = 53) SVL in females; 130–151 (x¯ = 142.5; SD = 4.3; n = 98) ventrals in males, 149–163 (x¯ = 157; SD = 3.1; n = 57) in females; 24–34 (x¯ = 28.7; SD = 2.1; n = 95) subcaudals in males, 19–30 (x¯ = 24.1; SD = 2.5; n = 57) in females; 3 (n = 6 sides) or 4 (n = 55 sides) infralabials contacting chinshields; 2 (n = 10 sides) or 3 (n = 50 sides) gular scale rows; 2 (n = 3), 3 (n = 24), or 4 (n = 3) preventrals; 7–10 (x¯ = 8.1; SD = 0.6; n = 62 sides) dorsal scale rows on the level of second subcaudal; 6 (n = 1 side) or 7 (n = 24 sides) maxillary teeth; retracted hemipenis bifurcates and extends to the level of seventh to ninth subcaudal (n = 7).
Distribution: From Arceburgo (21º22’S, 46º56’W) in the state of Minas Gerais, Brazil, southeastward to Colonia Carlos Pellegrini, San Martín (28º32’S, 57º10’W) in the province of Corrientes, Argentina ( Giraudo 2001), and southward to Establecimiento Trinidad (31º02’S, 55º27’W) in the department of Rivera, Uruguay ( Carreira et al. 2004; 2005). Atractus reticulatus inhabits Pampas, Campos, southern Cerrado, and transitional zones between these vegetation types and Lowland to Lower Montane Semi-deciduous Forest between 0– 1100 m elevation ( Fig. 11 View FIGURE 11 ).
Remarks: Boulenger (1885) described Geophis reticulatus based on a specimen from “S. Lourenço” (currently São Lourenço do Sul, 31º22’S, 51º58’W) in the state of Rio Grande do Sul, Brazil. Boulenger (1894) transferred this species to the genus Atractus . Amaral (1930a) considered A. paraguayensis to be a subspecies of A. reticulatus , without discussion. Amaral (1930b) extended the range of distribution of A. r. reticulatus to Colombia, without citing any voucher specimens to support this statement. Several subsequent authors followed Amaral (1930b) in considering A. reticulatus native to Colombia (Nicéforo-Maria 1942; Prado 1945; Daniel 1949). Peters and Orejas-Miranda (1970) restricted the distribution of A. reticulatus to Paraguay and southern Brazil. Nevertheless, Pérez-Santos and Moreno (1988) still considered A. reticulatus in the Colombian fauna.
Alvarez et al. (1992) described A. reticulatus scroccchi based on 10 specimens from Santa Maria, state of Rio Grande do Sul, Brazil and San Miguel, province of Corrientes, Argentina. Alvarez et al. (1992) distinguished A. r. scrocchi from the nominal form by having a pale occipital band and more contrasting colour pattern (vs. lacking occipital band and with a less contrasting reticulate pattern in A. r. reticulatus ). Fernandes (1996) revised the A. reticulatus complex ( A. r. reticulatus , A. r. paraguayensis , and A. r. scrocchi ), considering A. paraguayensis as a full species and synonymizing A. r. scrocchi with the nominal species. Fernandes (1996) diagnosed A. paraguayensis from A. reticulatus by the holotype of the former having 165 ventrals compared to 149–163 in his sample of A. reticulatus . Fernandes (1996) established that characters employed previously to diagnose A. r. scrocchi fall within the range of ontogenetic colour variation of A. r. reticulatus . The same author restricted again the concept of A. reticulatus to the populations from southern South America, stressing that AMNH material (from Colombia) referred to A. reticulatus by Pérez-Santos and Moreno (1988) were in fact A. nicefori .
Based on additional specimens examined here, we corroborate all decisions proposed by Fernandes (1996). Although the range of ventrals in both sexes of A. paraguayensis and A. reticulatus broadly overlap, these species are easily diagnosed by dorsal colour pattern, number of maxillary teeth, and hemipenis morphology (see above and under remarks for A. paraguayensis ). A distinct feature rerported here with respect to the study of Fernandes (1996) is hemipenial morphology. We found that the organ of A. reticulatus described and ilustrated by Fernandes (1996) was only partially everted, and that this species has in fact a moderately bilobed hemipenis (see Fig. 14A View FIGURE 14 ).
| R |
Departamento de Geologia, Universidad de Chile |
No known copyright restrictions apply. See Agosti, D., Egloff, W., 2009. Taxonomic information exchange and copyright: the Plazi approach. BMC Research Notes 2009, 2:53 for further explanation.
