DOI10.47051/FQBG6954

Published January 3, 2021. Updated March 2, 2024. Open access.

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Olive Ground Snake (Atractus roulei)

Reptiles of Ecuador | Serpentes | Colubridae | Atractus roulei

English common names: Olive Ground Snake, Roule’s Ground Snake.

Spanish common names: Tierrera olivácea, culebra tierrera de Roule.

Recognition: ♂♂ 45.1 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=39.7 cm. ♀♀ 47.1 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=43.7 cm..1 Atractus roulei can be recognized by its round head similar in width to the neck, small eyes, dorsal scales arranged in 15 rows at mid-body, and olive brown dorsum (Fig. 1).1,2 The other co-occurring ground snakes are A. microrhynchus and A. paucidens, both of which have dorsal scales arranged in 17 rows at mid-body and have either a brown dorsum with a series black of spots or a uniform black dorsum with a series of red blotches on the anterior third of the body.2–4 Atractus roulei differs from A. michaelsabini by having a uniform olivaceous dorsal pattern rather than one in which each scale is outlined in a thin black line, and by having the prefrontal scale not in contact or barely in contact with the postnasal scale (broadly in contact in A. michaelsabini).1

Figure showing an adult female individual of Atractus roulei

Figure 1: Individuals of Atractus roulei from near Tixán, Chimborazo province, Ecuador.

Natural history: Atractus roulei is a semi-fossorial snake that occurs in comparatively high densities in remnants of dry montane shrublands, irrigated pastures, and agricultural fields.1–3 Based on what is known about the diet of other Atractus, this species probably feeds on earthworms or slugs.4,5 Olive Ground Snakes have been found hidden under rocks and logs during the daytime.6 When exposed, their defensive behavior consists mainly of trying to flee. Also, when an individual is handled, it can use its sharp tail-tip for poking.6

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Conservation: Vulnerable Considered to be facing a high risk of extinction in the mid-term future..8 Atractus roulei is listed in this category because the species’ extent of occurrence is estimated to be much less than 3,000 km2 (Fig. 2) and its habitat is severely fragmented and declining in extent and quality due to deforestation.8 It is noteworthy that A. roulei is not present in protected areas and all localities where the species has been recorded are in heavily human-modified areas. Approximately 74% of the forest cover throughout the species’ potential distribution area has been destroyed, mostly due to the expansion of the agricultural frontier.1

Distribution: Atractus roulei is endemic to an area of approximately 2,474 km2 along the western slopes of the Andes in central Ecuador (Fig. 2).

Distribution of Atractus roulei in Ecuador

Figure 2: Distribution of Atractus roulei in Ecuador. The star corresponds to the type locality: Alausí, Chimborazo 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),9–11 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 roulei honors French zoologist Louis Roule (1861–1942), chair of zoology at the Muséum National d’Histoire Naturelle (MNHN) in Paris.12

See it in the wild: Olive Ground Snakes can be found with almost complete certainty around the towns Tixán and Alausí, Chimborazo province. A search that includes turning over rocks and logs in pastures near remnants of native vegetation usually results in 2–5 individuals.

Authors: Duvan ZambranoaAffiliation: Universidad del Tolima, Ibagué, Colombia. and Alejandro ArteagabAffiliation: Tropical Herping (TH), Quito, Ecuador.

Photographer: Jose VieiracAffiliation: Tropical Herping (TH), Quito, Ecuador.,dAffiliation: ExSitu, Quito, Ecuador.

How to cite? Zambrano D, Arteaga A (2024) Olive Ground Snake (Atractus roulei). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: www.reptilesofecuador.com. DOI: 10.47051/FQBG6954

Literature cited:

  1. Arteaga A, Quezada A, Vieira J, Guayasamin JM (2022) Leaving no stone unturned: three additional new species of Atractus ground snakes (Serpentes, Colubridae) from Ecuador discovered using a biogeographical approach. ZooKeys 1121: 175–210. DOI: 10.3897/zookeys.1121.89539
  2. Arteaga A, Mebert K, Valencia JH, Cisneros-Heredia DF, Peñafiel N, Reyes-Puig C, Vieira-Fernandes JL, Guayasamin JM (2017) Molecular phylogeny of Atractus (Serpentes, Dipsadidae), with emphasis on Ecuadorian species and the description of three new taxa. ZooKeys 661: 91–123. DOI: 10.3897/zookeys.661.11224
  3. Savage JM (1960) A revision of the Ecuadorian snakes of the Colubrid genus Atractus. Miscellaneous Publications, Museum of Zoology, Univesity of Michigan 112: 1–184.
  4. Passos P, Mueses-Cisneros JJ, Lynch JD, Fernandes R (2009) Pacific lowland snakes of the genus Atractus (Serpentes: Dipsadidae), with description of three new species. Zootaxa 2293: 1–34. DOI: 10.5281/zenodo.191476
  5. 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.
  6. Cisneros-Heredia DF (2005) Report of molluscivory in Atractus carrioni Parker, 1930. Herpetozoa 18: 185–186.
  7. Field notes, Reptiles of Ecuador book project.
  8. Cisneros-Heredia DF, Almendáriz A (2017) Atractus roulei. The IUCN Red List of threatened species. Available from: www.iucnredlist.org. DOI: 10.2305/IUCN.UK.2017-2.RLTS.T176360A54445808.en
  9. 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.
  10. Beekes R (2010) Etymological dictionary of Greek. Brill, Boston, 1808 pp.
  11. Duponchel P, Chevrolat L (1849) Atractus. In: d’Orbigny CD (Ed) Dictionnaire universel d’histoire naturelle. MM. Renard, Martinet et Cie., Paris, 312.
  12. Despax R (1910) Mission géodésique de l’Équateur. Collections recueillies par M. le Dr. Rivet. Liste des Ophidiens et description des espèces nouvelles. Bulletin du Muséum National d’Histoire Naturelle 16: 368–376. DOI: 10.5962/bhl.part.20432

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

CountryProvinceLocalitySource
EcuadorAzuay Chaucha, 2 km SW ofArteaga et al. 2022
EcuadorAzuay Hierba BuenaPassos et al. 2022
EcuadorAzuay Hierba MalaPassos et al. 2022
EcuadorAzuay Loma del TamboArteaga et al. 2022
EcuadorAzuay Luz María, 10–15 km E ofArteaga et al. 2022
EcuadorAzuay Miguir, 10 km E ofArteaga et al. 2022
EcuadorAzuay MolleturoArteaga et al. 2022
EcuadorAzuay San Antonio de ChauchaArteaga et al. 2022
EcuadorBolívarAbove BalzapambaArteaga et al. 2017
EcuadorBolívarGuaranda, 7.5 km S ofSavage 1960
EcuadorBolívarSan José de ChimboSavage1960
EcuadorCañarHuatacónArteaga et al. 2022
EcuadorChimborazoAlausí valleySavage 1960
EcuadorChimborazoAlausí*Despax 1910
EcuadorChimborazoTixán, 1 km S ofArteaga et al. 2017
EcuadorChimborazoTixán, 2 km SW ofArteaga et al. 2022
EcuadorChimborazoTixán, 4.9 km S ofArteaga et al. 2022