Atractus schach (BOIE, 1827)
Can you confirm these amateur observations of Atractus schach?
|Higher Taxa||Colubridae (Dipsadinae), Colubroidea, Caenophidia, Alethinophidia, Serpentes, Squamata (snakes)|
|Common Names||Schach's Ground Snake|
|Synonym||Brachyorrhos schach BOIE 1827: 540|
Brachyorrhos Schach — WAGLER 1830
Calamaria badia — SCHLEGEL 1837: 35 (part.)
Rabdosoma badium — DUMÉRIL, BIBRON & DUMÉRIL 1854: 95 (part.)
Rabdosoma badium — GÜNTHER 1858 (part.)
Atractus badius var. D — BOULENGER 1894
Atractus badius — HOOGMOED 1979
Atractus schach — HOOGMOED 1980
Atractus schach — DA CUNHA & DO NASCIMENTO 1983: 16
Atractus schach — STARACE 1998: 136
Atractus schach — PASSOS et al. 2007
Atractus schach — WALLACH et al. 2014: 80
Atractus schach — MELO-SAMPAIO et al. 2019
|Distribution||French Guiana, Guyana, Suriname|
Type locality: Guyane, restricted to Mamadam (4° 56’ N, 55° 33’ W; 33 m above sea level), Saramaca River, Sipaliwini, Suriname, by HOOGMOED 1980.
|Types||Lectotype: RMNH 119a, a 192 mm male ("Ancien Cabinet"of RMNH, 1820), designated by Hoogmoed, 1980: 34.|
|Diagnosis||Diagnosis. Atractus schach is distinguished from all congeners by the following combination of characters: (1) smooth dorsal scale rows 17/17/17; (2) postoculars two; (3) loreal moderately long; (4) temporal formula 1 þ 2; (5) supralabials seven, third and fourth contacting eye; (6) infralabials eight, first four contacting chinshields; (7) maxillary teeth seven; (8) gular scale rows three; (9) two preventrals; (10) ventrals 148–150 in females, 142–151 in males; (11) subcaudals 19–21 in females, 25–32 in males; (12) in preservative, dorsum olive brown with a series of black regular bands until midbody when becomes alternated dark greyish brown blotches separated by a vertebral line; (13) in preservative, venter cream with two parallel rows of sepia dots or square spots; (14) small body size in female (maximum 260 mm SVL) and in male (maximum 275 mm SVL); (15) moderately long tail both in female (10–11.3% SVL) and male (10–14% SVL); (16) hemipenis strongly bilobed, slightly semicapitate and semicalyculate (MELO-SAMPAIO et al. 2019: 213).|
Comparisons. We restricted the comparisons by geographic proximity due to regionalization and putative endemism of GS snake. Thus, Atractus schach differs from A. aboiporu sp. nov., A. elaps, A. latifrons, A. insipidus, A. tamessari, and A. trilineatus by having 17 dorsal scale rows (vs. 15 dorsal scale rows). Regarding the GS species with 17 dorsal scales rows, Atractus schach differs from A. badius in its dorsal olive-brown colouration with greyish brown transversal bands, and cream to buff ventral colouration with scattered sepia dots (vs. ‘coral colour pattern’ with black diads separated by cream bands, venter immaculate cream anteriorly, followed by square dark brown dots from midbody to posterior region of belly). Atractus schach is distinguished from A. flammigerus by SVL < 300mm in both sexes and absence of keeled dorsal scales near cloaca (vs. adult SVL > 300 mm and presence of keels on dorsal scale rows in A. flammigerus); from A. torquatus by having SVL < 300mm in both sexes two postoculars and < 33 subcaudals (vs. one postocular and 34–47 subcaudals in females, 35–53 in males in A. torquatus from GS; Passos & Prudente, 2012); from A. zidoki by having dorsal scales without apical pits and supra-cloacal tubercles, olive-brown dorsum with dark greyish brown bands and bilobed hemipenis (vs. presence of apical pits and/or supracloacal tubercles on the dorsal scales, light brown dorsum with longitudinal series of paravertebral spots and unilobed hemipenis in A. zidoki). For the comparisons between A. schach and the new species see section ‘comparisons’ respectively for each species (MELO-SAMPAIO et al. 2019: 213).
|Comment||Not listed in PETERS & OREJAS-MIRANDA 1970.|
Distribution: not in Brazil (Amazonas, Acre, Pará), nor in Peru (Loreto) fide MELO-SAMPAIO et al. 2019.
Similar species: A. snethlageae, A. flammigerus.
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