Atractus atlas PASSOS, SCANFERLA, MELO-SAMPAIO, BRITO & ALMENDARIZ, 2018
Can you confirm these amateur observations of Atractus atlas?
|Higher Taxa||Colubridae (Dipsadinae), Colubroidea, Caenophidia, Alethinophidia, Serpentes, Squamata (snakes)|
|Common Names||E: Atlas Ground Snake|
S: Culebra Tierrera del Atlas
|Synonym||Atractus atlas PASSOS, SCANFERLA, MELO- SAMPAIO, BRITO & ALMENDARIZ 2018|
Atractus sp. — ALMENDARIZ et al. 2014
|Distribution||Ecuador, elevation 1800–2100 m|
Type locality: Rio Blanco (03°55’2.08’’S 78°30’9.81’’W, ca. 1850 m elevation), Paquisha, municipality of Paquisha, province of Zamora-Chinchipe, Ecuador
|Types||Holotype: MEPN 14203, adult female, collected on July 26 2011 by Ana Almendáriz, Jorge Brito, Juan Hurtado and Jorge Puchaicela (Figs. 1–2). Paratypes: Three adult females from southeastern slopes of Ecuadorian Andes: (DHMECN 2972) collected on May 2005 by Juan Carlos Ronquillo at Guayzimi Alto (04°06’20.7”S 78°46’05.7”W; ca. 2100 m asl ), Parroquía Guayzimi, province of Zamora- Chinchipe; (QCAZ 14946) from Reserva Biológica Cerro Plateado (04o36’20’’S 78o52’30’’W; ca. 1700 m asl), and (DHMECN 12361) collected on July 5 2014 by Jorge Brito and Victor León at Zúñac (02o11’48’’S 78o18’58’’W; ca. 1900 m asl), Parque Nacional Sangay, Cantón Morona, both in the province of Morona Santiago. Quantitative variation of the type-series of Atractus atlas is presented in Table I in Passos et al. 2018.|
|Diagnosis||Diagnosis: Atractus atlas can be 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, contacting second to fourth supralabials; (4) temporal formula usually 1+2; (5) supralabials eight, fourth and fifth contacting eye; (6) infralabials eight, first four contacting chinshields; (7) maxillary teeth eight; (8) gular scale rows usually four; (9) preventrals usually four; (10) ventrals 158–169 in females; (11) subcaudals 28– 33 in females; (12) in preservative, dorsum yellow ocher with a series of alternating black bands (2–3 scales long), connected or not to the opposite band on the vertebral region; (13) ventral surface of body mostly pale buff scattered with conspicuous black marks (blotches, spots and dots); (14) maximum body size moderate in females 820 mm SVL; (15) tail size moderately long in females (12.2–15.0% SVL); (16) midbody diameter in females 18.0–21.4 mm.|
Comparisons: Among all congeners, Atractus atlas is similar to A. gigas Myers and Schargel 2006, A. serranus Amaral 1930, A. torquatus Duméril, Bibron and Duméril 1854, A. touzeti Schargel et al. 2013, and A. trihedrurus Amaral 1926 in having: SVL > 600 mm, midbody diameter > 18.0 mm, dorsal scales rows 17/17/17, supralabials and infralabials eight, postoculars two, maxillary teeth eight, dorsum with banded pattern, and ventral surface of body light with several black marks or mostly black. Atractus atlas differs from all of them except for A. torquatus and A. touzeti in having a banded dorsum in adult specimens (vs. adults uniformly greyish brown to black in A. gigas, A. serranus and A. trihedrurus); from A. torquatus in having two postoculars, 28–33 subcaudals in females, and ventral surface of body mostly darker or heavily marked with irregular black blotches (vs. usually one postocular, subcaudals 34– 47, and belly mostly creamish white scattered with dark brown dots or irregular rhomboidal spots); from A. touzeti in having head width < 55% head length and dorsum with a series of alternating dark brown to black bands (2–3 scales long), connected or not to the opposite band on the vertebral region (vs. head width > 66% head length and dorsum with tiny pale cross-bands [one scale long] edged by black borders [half to one scale long], separating the pale color from the brown ground color). Moreover, Atractus atlas differs from A. gigas in having eight supra- and infralabials, second to fourth supralabials contacting loreal, fourth to fifth supralabials contacting eye, first four infralabials contacting chinshields (vs. supra- and infralabials usually seven, second and third infralabials contacting loreal, third to fourth supralabials contacting eye, first three infralabials contacting chinshield) (Fig. 4). In addition, we refer to Table I for other diagnostic features of the A. atlas with respect to A. touzeti, and to comparisons with other congeners for which we have recorded specimens above 500 mm SVL (see Passos et al. 2010a, Table I).
|Comment||Habitat: Mountain rainforest; the holotype (MEPN 14203) was found resting under leaf litter. This forest formation usually remains cloudy in the early hours of the morning, afternoons, or even all day long, depending on the season, and is comprised by trees of 15–20 m covered with bryophytes, bromeliads and abundant moss. The plant layer sits on a plateau of sandstone, and grows on a substrate of very acid sand soil poor in nutrients.|