Atractus maculatus ( Günther, 1858 )
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publication ID |
https://doi.org/ 10.11646/zootaxa.2364.1.1 |
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persistent identifier |
https://treatment.plazi.org/id/0390751B-3D7E-FFDF-FF61-FA47FCDDBC78 |
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treatment provided by |
Felipe |
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scientific name |
Atractus maculatus ( Günther, 1858 ) |
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Atractus maculatus ( Günther, 1858)
Fig. 2E View FIGURE 2
Isoscelis maculata Günther, 1858 ; Catalogue of the Colubrine Snakes in the British Museum: 204.
Rhabdosoma maculatum – Günther, 1858; Catalogue of the Colubrine Snakes in the British Museum: 241. (part). Atractus maculatus – Boulenger, 1894; Catalogue of the Snakes in the British Museum 2: 306. (part).
Atractus maculatus – Fernandes, Freire & Puorto, 2000; Bol. Mus. Nac. Nov. Ser. Zool. 419:2.
Holotype: Adult male, BMNH 1946.1.6.46 (formerly BMNH 51.3.12.151), without data according to Günther (1858). Boulenger (1894) and Fernandes et al. (2000) reported the specimen as from “ Brazil?”, according to the original specimen label (specimen examined).
Diagnosis: Atractus maculatus is distinguished from all congeners by the following combination of characters: (1) 17/17/17 smooth dorsal scale rows; (2) two postoculars; (3) long loreal; (4) temporals 1+2; (5) seven supralabials, third and fourth contacting orbit; (6) seven infralabials, first four contacting chinshields; (7) six to eight maxillary teeth; (8) three gular scale rows; (9) usually three preventrals; (10) 165 ventrals in the single female, 146–151 in males; (11) 19 subcaudals in female, 27–30 in males; (12) dorsum creamish yellow with wide transverse black blotches, occasionally fragmented into small dots; (13) venter uniformly creamish white; (14) moderate body size, female 284 mm SVL, males reaching 360 mm SVL; (15) tail small in female (8.1% SVL), moderate (11.3–15.6% SVL) in males; (16) hemipenis moderately bilobed, semicapitate, and semicalyculate.
Comparisons: Among all congeners, A. maculatus shares 17 dorsal scale rows, transverse wide blotches on a pale dorsum, and venter immaculate creamish white only with A. zebrinus . Atractus maculatus differs from A. zebrinus by having dorsum creamish yellow with dark blotches lacking white border, and capitulum longer than hemipenial body (vs. dorsum creamish red and dark blotches with white border and capitulum shorter than hemipenial body). Atractus maculatus occasionally shares with A. pantostictus , A. potschi , and A. ronnie dorsal colour pattern with blotches fragmented into small dots or thin transverse bands. Atractus maculatus differ from A. pantostictus by having hemipenis moderately bilobed and semicalyculate (vs. slightly bilobed and non-calyculate); from A. potschi by having 17 dorsal scale rows (vs. 15 dorsals); from A. ronnie by having 146–151 ventrals and 27–30 subcaudals in males, generally eight maxillary teeth, and hemipenis moderate bilobed and semicapitate (vs. 134–144 ventrals, 20–25 subcaudals in males, hemipenis slightly bilobed, non-capitate).
Description: Head twice as long as wide, arched in lateral view, round in dorsal view; snout truncate in lateral view, round in dorsal view; canthus rostralis well marked in lateral view; cervical constriction indistinct; rostral sub-triangular in frontal view, about twice as broad as high, poorly visible in dorsal view; internasal as long as wide; internasal suture sinistral with respect to prefrontal suture; prefrontal as long as wide; supraocular sub-trapezoidal, twice as long as wide; frontal pentagonal, as long as wide; parietal twice as long as wide; nasal divided; nostril located between prenasal and postnasal; prenasal twice as high as long; postnasal as long as wide; loreal long, contacting second and third supralabials; pupil round; two postoculars similar in size; upper postocular slightly longer than lower postocular; temporals 1+2; anterior temporal twice as long as high; upper posterior temporal elongate, about three times as long as wide; seven supralabials, third and fourth contacting orbit; second supralabial higher than first and smaller than third; sixth higher and seventh longer than remaining supralabials; symphisial triangular, three times longer than wide; seven infralabials, first four contacting chinshields; first pair of infralabials in contact behind symphisial, preventing symphisial/ chinshield contact; chinshields twice as long as wide; three gular scale rows; usually two preventrals; 17/17/ 17 smooth dorsal scale rows; dorsals lacking apical pits, supra-anal tubercles, and keels; caudal spine short, conical, and slightly acuminate.
Maxillary arch: Arched in dorsal view, with five or six prediastemal and two or three postdiastemal teeth; prediastemal teeth large, moderately spaced, similar in size, curved posteriorly, angular in cross section, robust at base, and narrower on the apices; maxillary diastema moderate; postdiastemal teeth half size of last prediastemal tooth; lateral process well developed, lacking posterior projection.
Colour in preservative: Dorsum of head creamish yellow, with dark brown or black irregular blotches on cephalic shields; head laterally creamish yellow, with dark brown blotches concentrated on orbital and occipital regions; supralabials uniform creamish white; infralabials, chinshields, gular region, and preventrals creamish white; venter and tail immaculate creamish white; dorsal ground colour of body creamish yellow, with dark brown or black transverse blotches; transverse blotches wide (six to ten scales wide and two or three scales long), equivalent to pale interspaces on vertebral region; anterior blotches rhomboid, extending to the level of fourth scale rows; posterior blotches narrower than anterior ones, diagonally oriented, and occasionally connected above vertebral region; posterior blotches reaching second dorsal scale rows; first dorsal scale rows uniformly creamish white; second and third scale rows with small black spots (half to one scale wide) placed on pale interspaces between dorsal dark blotches; spots frequently connected ventrally to wide blotches, forming barely defined irregular longitudinal stripes above dorsal margin of second or third scale rows; tail dorsally similar to body; transverse blotches occasionally fragmented into small black dots or tiny bands arranged linearly on anterior region of body. ( Fig. 2E View FIGURE 2 ).
Juvenile colouration in preservative: Juveniles and sub-adults with dorsal ground colour creamish yellow, uniformly scattered with small black dots (one scale long), usually not merged into transverse crossbands.
Hemipenis morphology (everted organ n = 1): Retracted organ bifurcates at level of ninth and extends to level of 10 th subcaudal. Hemipenis moderately bilobed, semicapitate, and semicalyculate; lobes distinct and restricted to distal portion of capitulum; lobes attenuate, centrifugally oriented, and of similar size; lobes and capitulum uniformly covered with spinulate calyces; calyces in subtransverse rows, forming well defined flounces on lateral portion of sulcate and on asulcate sides of capitulum; capitular groove well marked laterally on the asulcate side, and indistinct on the sulcate side of hemipenis; capitulum distinct, located just above sulcus spermaticus bifurcation, and about twice longer than hemipenial body; sulcus spermaticus bifurcates on the basal third of hemipenial body; branches of sulcus spermaticus with centrifugal orientation, running to apices of lobes; margins of sulcus spermaticus narrow and stout, bordered with spinules from the base of organ to tip of lobes; hemipenial body subcylindrical, uniformly covered with moderate hooked spines; basal naked pocket restricted to basal portion of hemipenial body; basal region of hemipenis with longitudinal plicae and disperse spinules ( Fig. 6C View FIGURE 6 ).
Variation: Largest male 360 mm SVL, 55 mm CL, largest female 284 mm SVL, 23 mm CL; tail 11.3– 15.6% (x¯ = 14.5; SD = 1.4; n = 3) SVL in males, 8.1% SVL in female; 146–151 (x¯ = 149.5; SD= 2.3; n = 6) ventrals in males, 165 in female; 27–30 (x¯ = 28.3; SD = 1.2; n = 6) subcaudals in males, 19 in female; 1 (n = 1), 2 (n = 1), or 3 (n = 6) preventrals; 8–10 (x¯ = 8.8; SD = 1; n = 14 sides) dorsal scales on the level of second subcaudal; 6 (n = 2 sides), 7 (n = 2 sides) or 8 (n = 4 sides) maxillary teeth.
Distribution: Atlantic Forest remnants in the states of Alagoas and Pernambuco, from Serra Talhada (07º59’S, 38º18’W) southeastward to São Miguel dos Campos (09º47’S, 36º05’W). Atractus maculatus inhabits Lowland to Submontane and Montane Rainforest between 0–500 m elevation ( Fig. 4 View FIGURE 4 ).
Remarks: Günther (1858) described the genus Isoscelis to accommodate I. maculata , diagnosing the genus by the large size of the anteriormost compared with remaining maxillary teeth. In the appendices of the same book, Günther corrected his earlier observation, proposing the synonymy of Isoscelis with Rhabdosoma . Boulenger (1894) transferred Rhabdosoma maculatum to Atractus and synonymized R. zebrinum with A. maculatus . Fernandes et al. (2000) found two allopatric and diagnosable populations under the name Atractus maculatus , revalidating Rabdosoma zebrinum Jan (as A. zebrinus ) for the populations distributed from southern Bahia to Santa Catarina and restricting A. maculatus to the species occurring in the state of Alagoas, Brazil. Besides differences in colour pattern between A. maculatus and A. zebrinus previously stressed by Fernandes et al. (2000), we found both species strongly differing in hemipenial morphology. Atractus maculatus has a hemipenis with a capitulum twice as long as the hemipenial body, whereas A. zebrinus has lobes similar in size to the hemipenial body (see Figs. 6C View FIGURE 6 and 11F View FIGURE 11 ).
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.
