DOI10.47051/QPYL8113

Published September 17, 2021. Open access.

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Modest Ground Snake (Atractus modestus)

Reptiles of Ecuador | Serpentes | Colubridae | Atractus | Atractus modestus

English common name: Modest Ground Snake.

Spanish common names: Tierrera modesta, culebra tierrera modesta.

Recognition: ♂♂ 38 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=32 cm. ♀♀ 37.9 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=32.8 cm..1,2 The Modest Ground Snake (Atractus modestus) differs from other snakes in its area of distribution by having a round head similar in width to the neck, small eyes, dorsal scales arranged in 17 rows at mid-body, no preocular scale, short loreal scale, and a uniform blackish to purplish brown dorsum.1–3 The belly is bright yellow in adults and pale yellowish white in juveniles. Atractus modestus is most similar to A. paucidens, a species that can be recognized by its red blotches on the anterior third of the dorsum, blackish ventral surfaces, and a long loreal scale.4 Males of A. modestus differ from females by having less ventral scales (146–173 vs 174–186), more subcaudal scales (34–45 vs 26–31), and a proportionally longer tail.1,5 Juveniles have a contrasting yellow neck band.3

Figure showing variation among adult individuals of Atractus modestus

Figure 1: Individuals of Atractus modestus from Séptimo Paraíso Lodge, Pichincha province, Ecuador.

Natural history: Generally uncommonUnlikely to be seen more than once every few months. but locally frequentRecorded weekly in densities below five individuals per locality. in Mindo. Atractus modestus is a semi-fossorial (living underground and at ground level) snake that inhabits old-growth to moderately disturbed evergreen montane and foothill forest, crops, pastures with scattered trees, and rural gardens nearby forest border.6 Modest Ground Snakes are usually seen moving on the forest floor or crossing dirt roads and trails during warm and cloudy nights, or rarely during the daytime.6 When not active, individuals are usually found hidden under logs.6 There is an unpublished photographic record of an individual of A. modestus preying upon an earthworm in Mindo.7 Modest Ground Snakes rely mostly on their cryptic coloration as a primary line of defense. If handled, individuals usually just try to flee, but they can also produce a musky and distasteful odor when grabbed.6

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Conservation: Vulnerable Considered to be facing a high risk of extinction in the mid-term future..8 Atractus modestus is listed in this category because the species’ extent of occurrence is smaller than 20,000 km2 and its habitat is declining in extent and quality due to deforestation.8 Based on maps of Ecuador’s vegetation cover published in 2012,9 an estimated ~42% of the species’ potential distribution area has already been converted to human settlements and agricultural fields. The remaining populations are also severely fragmented and few localities (6 of 19; Appendix 1) are in privately-protected areas.

Distribution: Atractus modestus is endemic to an estimated 9,768 km2 area along the Pacific foothills of the Andes in western Ecuador. The species has been recorded at elevations between 1019 and 1780 m (Fig. 2).

Distribution of Atractus modestus in Ecuador

Figure 2: Distribution of Atractus modestus in Ecuador. 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 (meaning “spindle”),10–12 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 modestus is a Latin word meaning “modest.” It probably refers to the uniform plumbeous dorsal coloration of this snake.2

See it in the wild: Throughout most of their distribution, Modest Ground Snakes are unlikely to be seen more than once every few months. However, in the town Mindo, individuals may be found almost every week. It is easier to find these snakes right after sunset during a warm night in private reserves maintained by lodges such as Yellow House Lodge, Séptimo Paraíso Lodge, and El Monte Lodge. The snakes 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.

Acknowledgments: This account was published with the support of Secretaría Nacional de Educación Superior Ciencia y Tecnología (programa INEDITA; project: Respuestas a la crisis de biodiversidad: la descripción de especies como herramienta de conservación; No 00110378), Programa de las Naciones Unidas (PNUD), and Universidad San Francisco de Quito (USFQ).

Author: Alejandro ArteagaaAffiliation: Khamai Foundation, Quito, Ecuador.

Photographer: Jose VieiraaAffiliation: Tropical Herping (TH), Quito, Ecuador.,bAffiliation: ExSitu, Quito, Ecuador.

How to cite? Arteaga A (2021) Modest Ground Snake (Atractus modestus). In: Arteaga A, Bustamante L, Vieira J, Guayasamin JM (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: www.reptilesofecuador.com. DOI: 10.47051/QPYL8113

Literature cited:

  1. Passos P, Cisneros-Heredia DF, Salazar-Valenzuela D (2007) Rediscovery and redescription of the rare Andean snake Atractus modestus. The Herpetological Journal 17: 1–6.
  2. Boulenger GA (1894) Catalogue of the snakes in the British Museum (Natural History). British Museum of Natural History, London, 382 pp.
  3. Arteaga A, Bustamante L, Guayasamin JM (2013) The amphibians and reptiles of Mindo. Universidad Tecnológica Indoamérica, Quito, 257 pp.
  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. 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
  6. Field notes, Reptiles of Ecuador book project.
  7. Photo by Anton Sorokin.
  8. Cisneros-Heredia DF (2016) Atractus modestus. The IUCN red list of threatened species. Available from: www.iucnredlist.org. DOI: 10.2305/IUCN.UK.2016-1.RLTS.T176356A50866722.en
  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 modestus in Ecuador (Fig. 2). Go to the section on symbols and abbreviations for a list of acronyms used. Asterisk (*) indicates type locality.

CountryProvinceLocalitySource
EcuadorAzuayMolleturo, 25 km W ofPassos et al. 2007
EcuadorCarchiChicalArteaga et al. 2017
EcuadorChimborazoPallatanga*Boulenger 1894
EcuadorCotopaxiLas DamasTorres-Carvajal et al. 2019
EcuadorCotopaxiPilalóPassos et al. 2007
EcuadorCotopaxiSan Francisco de Las PampasArteaga et al. 2017
EcuadorEl OroPiñasArteaga et al. 2017
EcuadorImbaburaManduriacu ReservePhoto by Ross Maynard
EcuadorPichinchaChiribogaAlmendáriz & Orcés 2004
EcuadorPichinchaEl Monte LodgePhoto by Ryan Lynch
EcuadorPichinchaFinca ElenitaThis work
EcuadorPichinchaGualeaArteaga et al. 2017
EcuadorPichinchaMindo, townThis work
EcuadorPichinchaMirador de TulipeiNaturalist
EcuadorPichinchaReserva MaquipucunaArteaga et al. 2017
EcuadorPichinchaSanta Lucía Cloud Forest ReservePhoto by Simon Maddock
EcuadorPichinchaSéptimo Paraíso LodgeThis work
EcuadorPichinchaTerreno de Eric Osterman en MindoThis work
EcuadorPichinchaYellow House LodgeThis work