Published March 20, 2022. Updated February 16, 2024. Open access.

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Atlas Ground Snake (Atractus atlas)

Reptiles of Ecuador | Serpentes | Colubridae | Atractus atlas

English common name: Atlas Ground Snake.

Spanish common name: Tierrera Atlas.

Recognition: ♀♀ 92.6 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=82 cm..1 In its area of distribution, the Atlas Groundsnake (Atractus atlas) can be recognized by having a round head similar in width to the neck, small eyes, large body size, and a dorsal pattern consisting of dark bands on a yellowish to ochre ground color (Fig. 1).1 Atractus atlas may be distinguished from other large-bodied banded Amazonian ground snakes base on its cloud forest distribution and its yellowish ground color.1,2 However, individuals in the Cerro Plateado area, where no other ground snake species are known, have a uniform dorsal coloration. This species differs from A. touzeti by having broader and more contrasting dorsal bands, whereas in the latter the bands are pale, narrow, and on a dark-brown ground color.1,3

Ilustration of an adult female of Atractus atlas

Figure 1: Illustration of an adult female of Atractus atlas from Río Blanco, Zamora Chinchipe province, Ecuador.

Natural history: Atractus atlas is an extremely rare semi-fossorial snake that inhabits the montane cloud forest ecosystem, an area in which the canopy reaches 20–30 m and where there trees are covered with bryophytes, bromeliads, and abundant moss.1 One individual was found resting under the leaf-litter using the morning sun to raise its body temperature in a forest clearing.1 Others were hiding under logs or crossing roads during drizzles.1,4 Based on what is know about other ground snakes,26 the diet of A. atlas probably includes earthworms and slugs. The defensive behavior of A. atlas is unknown, although, when threatened, similar Amazon ground snakes usually try to flee and use their camouflage to hide.7,8

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Conservation: Vulnerable Considered to be facing a high risk of extinction in the mid-term future.. Atractus atlas is a recently described species; therefore, its conservation status has not yet been formally evaluated by the IUCN. Here, it is proposed to be included in the Vulnerable category because the species has a limited (~4,944 km2; Fig. 2) extent of occurrence, it is known to exist at no more than 10 localities, and the populations in Zamora Chichipe province are under severe threat from large-scale mining and agricultural development. Fortunately, the majority (~94%) of the species’ potential distribution holds continuous areas of pristine forest and ~52% of this area is inside two national parks and four ecological reserves.9 The most important threat to the long-term survival of A. atlas is forest destruction due to mining and the expansion of the agricultural frontier.

Distribution: Atractus atlas is endemic to an area of approximately 4,944 km2 along the Amazonian slopes of the Andes of southeastern Ecuador (Fig. 2).

Distribution of Atractus atlas in Ecuador

Figure 2: Distribution of Atractus atlas in Ecuador. The star corresponds to the type locality: Río Blanco, Paquisha, Zamora Chinchipe province. See Appendix 1 for a complete list of the presence localities included in the map.

Etymology: The name Atractus, which is a latinization of the Greek word άτρακτος (=spindle),1012 probably refers to the fact that snakes of this genus have a uniform width throughout the body and a narrow tail, resembling an antique spindle used to spin fibers. The specific epithet atlas is the name of the titan that, according to Greek mythology, supports the entire world on his shoulders.1 The name refers to the large body size of the species.1

See it in the wild: Only seven records of Atractus atlas have been reported, which makes this an extremely rare species. The Reserva Biológica Cerro Plateado as well as the type locality (Río Blanco, Paquisha) are probably the best localities to find these elusive snakes. Individuals may be located by scanning the forest floor and leaf-litter along trails at night or by looking under rocks and logs in pastures nearby forest border.

Author: Duvan ZambranoaAffiliation: Universidad del Tolima, Ibagué, Colombia.

Editor: Alejandro ArteagabAffiliation: Khamai Foundation, Quito, Ecuador.

Illustrator: Valentina Nieto Fernández

How to cite? Zambrano D (2022) Atlas Ground Snake (Atractus atlas). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: DOI: 10.47051/ERFC3087

Literature cited:

  1. Passos P, Scanferla A, Melo-Sampaio PR, Brito J, Almendariz A (2018) A giant on the ground: another large-bodied Atractus (Serpentes: Dipsadinae) from Ecuadorian Andes, with comments on the dietary specializations of the goo-eaters snakes. Anais da Academia Brasileira de Ciências 91: e20170976. DOI: 10.1590/0001-3765201820170976
  2. Melo-Sampaio PR, Passos P, Prudente ALC, Venegas PJ, Torres-Carvajal O (2021) Systematic review of the polychromatic ground snakes Atractus snethlageae complex reveals four new species from threatened environments. Journal of Zoological Systematics and Evolutionary Research 00: 1–30. DOI: 10.1111/jzs.12453
  3. Schargel WE, Lamar WW, Passos P, Valencia JH, Cisneros-Heredia DF, Campbell JA (2013) A new giant Atractus (Serpentes: Dipsadidae) from Ecuador, with notes on some other large Amazonian congeners. Zootaxa 3721: 455–474. DOI: 10.11646/zootaxa.3721.5.2
  4. Jorge Brito, pers. comm.
  5. Cisneros-Heredia DF (2005) Report of molluscivory in Atractus carrioni Parker, 1930. Herpetozoa 18: 185–186.
  6. Balestrin RL, Di-Bernardo M, Moreno AG (2007) Feeding ecology of the neotropical worm snake Atractus reticulatus in southern Brazil. The Herpetological Journal 17: 62–64.
  7. Martins M, Marques OAV, Sazima I (2008) How to be arboreal and diurnal and still stay alive: microhabitat use, time of activity, and defense in neotropical forest snakes. South American Journal of Herpetology 3: 58–67. DOI: 10.2994/1808-9798(2008)3[58:HTBAAD]2.0.CO;2
  8. Martins M, Oliveira ME (1998) Natural history of snakes in forests of the Manaus region, Central Amazonia, Brazil. Herpetological Natural History 6: 78–150.
  9. MAE (2012) Línea base de deforestación del Ecuador continental. Ministerio del Ambiente del Ecuador, Quito, 30 pp.
  10. Woodward SP, Tate R (1830) A manual of the Mollusca: being a treatise on recent and fossil shells. C. Lockwood and Company, London, 750 pp.
  11. Beekes R (2010) Etymological dictionary of Greek. Brill, Boston, 1808 pp.
  12. Duponchel P, Chevrolat L (1849) Atractus. In: d’Orbigny CD (Ed) Dictionnaire universel d’histoire naturelle. MM. Renard, Martinet et Cie., Paris, 312.

Appendix 1: Locality data used to create the distribution map of Atractus atlas in Ecuador (Fig. 2). Go to the section on symbols and abbreviations for a list of acronyms used. Asterisk (*) indicates type locality.

EcuadorMorona SantiagoLaguna el EnmascaradoJorge Brito, pers. comm.
EcuadorMorona SantiagoParque Nacional SangayPassos et al. 2019
EcuadorTungurahuaBosque Protector La CandelariaMarco Reyes, pers. comm.
EcuadorZamora ChinchipeGuayzimi AltoPassos et al. 2019
EcuadorZamora ChinchipeAlto MachinazaiNaturalist
EcuadorZamora ChinchipePaquisha*Passos et al. 2019
EcuadorZamora ChinchipeReserva Biológica Cerro PlateadoPassos et al. 2019