Published September 16, 2021. Updated February 27, 2024. Open access.

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Short-nosed Ground Snake (Atractus microrhynchus)

Reptiles of Ecuador | Serpentes | Colubridae | Atractus microrhynchus

English common name: Short-nosed Ground Snake.

Spanish common names: Tierrera hocicorta, culebra tierrera de hocico enano.

Recognition: ♂♂ 37.1 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=30.7 cm. ♀♀ 43.5 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=39.3 cm..1,2 Atractus microrhynchus 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, and a brown dorsum with longitudinal blackish and tan lines that may be incomplete or broken into discrete spots or blotches (Fig. 1).3,4 The belly is pale orangish yellow with various degrees of dark pigment; in some individuals it is almost completely black.4 Atractus microrhynchus is extremely similar to A. cerberus, A. dunni, A. iridescens, and A. esepe, but it has not been found living alongside any of these species.3 Most, but not all, individuals of A. microrhynchus differ from A. dunni by having longitudinal lines, either complete or broken.35 Males of A. microrhynchus differ from females by having less ventral scales (133–150 vs 148–164), more subcaudal scales (32–43 vs 20–28), and a proportionally longer tail.14 Juveniles have a light yellow nape band.

Figure showing variation among adult individuals of Atractus microrhynchus

Figure 1: Individuals of Atractus microrhynchus from Séptimo Paraíso Lodge () and Santa Rosa (), Pichincha province, Ecuador. j=juvenile.

Natural history: Atractus microrhynchus is a semi-fossorial snake that inhabits old-growth to moderately disturbed cloud forests, crops, pastures, and rural gardens near forest border.3,6 This species is distributed in warm (mean annual temperature=16.1–24.4 °C) areas where the annual precipitation ranges between 981 and 2658 mm.1 Short-nosed Ground Snakes are usually seen moving on the forest floor or crossing dirt roads and trails during warm and cloudy nights.6 When not active, individuals hide under logs, rocks, boards, fallen vegetation, or in leaf-litter.6 Based on what is know about other ground snakes, the diet of this species probably includes earthworms and slugs.79 Atractus microrhynchus relies mostly on its cryptic coloration as a primary line of defense. If handled, individuals usually just try to flee, but they can also use their sharp tail tip for poking as well as flatten their body dorsoventrally to appear larger.6 In Mindo, a clutch of 2 eggs of A. microrhynchus was found in the soil alongside eggs of Dendrophidion.10

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Conservation: Near Threatened Not currently at risk of extinction, but requires some level of management to maintain healthy populations.. Atractus microrhynchus is proposed to be included in this category, instead of Vulnerable,11 because the species is more widely distributed (Fig. 2) and occurs in more localities (Appendix 1) than was thought at the time of the assessment.1,3 Thus, it no longer meets the threshold for qualifying in the threatened category. However, although the species is widespread and tolerates moderate habitat degradation, its populations are fragmented and occur over an area where most (~76%) of the forest cover has been transformed into plantations and human settlements.12 Therefore, A. microrhynchus may qualify for a threatened category in the near future if its habitat continues to be destroyed. There is no current information on the population trend of the Short-nosed Ground Snake to determine whether its numbers are declining. Fortunately, the species has been registered in nine privately protected areas and one national park.

Distribution: Atractus microrhynchus is native to an area of approximately 42,119 km2 on the Tumbesian–Chocoan corridor in western Ecuador (Fig. 2) and extreme northern Peru.

Distribution of Atractus microrhynchus in Ecuador

Figure 2: Distribution of Atractus microrhynchus in Ecuador. The star corresponds to the type locality: Guayaquil, Guayas 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),1315 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 microrhynchus comes from the Greek mikros (=small) and rhynchos (=snout).

See it in the wild: Throughout most of their distribution, Short-nosed Ground Snakes are unlikely to be seen more than once every few months. However, in the town Mindo individuals may be found 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. One two-hour targeted search in a pasture near Mindo yielded 16 individuals of this species.6

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 (2024) Short-nosed Ground Snake (Atractus microrhynchus). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: DOI: 10.47051/VOZL5507

Literature cited:

  1. Mejía Guerrero MA (2018) Revisión taxonómica de las serpientes tierreras Atractus del grupo iridescens Arteaga et al. 2017. BSc thesis, Quito, Pontificia Universidad Católica del Ecuador, 67 pp.
  2. Averill-Murray RC, Averill-Murray A (2017) A. dunni (Sleepy Groundsnake). Maximum size. Herpetologcal Review 48: 665.
  3. 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
  4. Passos P, Cisneros-Heredia DF, Rivera DE, Aguilar C, Schargel WE (2012) Rediscovery of Atractus microrhynchus and reappraisal of the taxonomic status of A. emersoni and A. natans (Serpentes: Dipsadidae). Herpetologica 68: 375–392.
  5. Savage JM (1955) Descriptions of new colubrid snakes, genus Atractus, from Ecuador. Proceedings of the Biological Society of Washington 68: 11–20.
  6. Field notes, Reptiles of Ecuador book project.
  7. Arteaga A, Bustamante L, Guayasamin JM (2013) The amphibians and reptiles of Mindo. Universidad Tecnológica Indoamérica, Quito, 257 pp.
  8. Cisneros-Heredia DF (2005) Report of molluscivory in Atractus carrioni Parker, 1930. Herpetozoa 18: 185–186.
  9. 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.
  10. Eric Osterman, pers. comm.
  11. Aguilar C, Cisneros-Heredia DF (2017) Atractus microrhynchus. The IUCN Red List of threatened species. Available from: DOI: 10.2305/IUCN.UK.2017-2.RLTS.T50951112A50951119.en
  12. MAE (2012) Línea base de deforestación del Ecuador continental. Ministerio del Ambiente del Ecuador, Quito, 30 pp.
  13. 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.
  14. Beekes R (2010) Etymological dictionary of Greek. Brill, Boston, 1808 pp.
  15. 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 microrhynchus in Ecuador (Fig. 2). Go to the section on symbols and abbreviations for a list of acronyms used. Asterisk (*) indicates type locality.

EcuadorChimborazoHuigraSavage 1960
EcuadorCotopaxiRecinto GalápagosPassos et al. 2009
EcuadorCotopaxiSan Francisco de Las PampasArteaga et al. 2017
EcuadorEl OroEl ProgresoArteaga et al. 2017
EcuadorEl OroPacha–Cerro AzulPhoto by Anton Sorokin
EcuadorEl OroReserva Biológica BuenaventuraArteaga et al. 2017
EcuadorEl OroZambo TamboArteaga et al. 2017
EcuadorEsmeraldasBilsa Biological ReserveRodríguez-Guerra 2020
EcuadorGuayasBosque Protector Cerro BlancoPhoto by Eduardo Zavala
EcuadorGuayasGuayaquil*Cope 1868
EcuadorGuayasPetrilloiNaturalist; photo examined
EcuadorLojaOlmedoArteaga et al. 2017
EcuadorLos RíosCentro Científico Río PalenqueArteaga et al. 2017
EcuadorManabíAyampe, 2 km NE ofiNaturalist; photo examined
EcuadorManabíReserva Jama CoaqueArteaga et al. 2017
EcuadorPichinchaEl Monte LodgeArteaga et al. 2013
EcuadorPichinchaFinca ElenitaReptiles of Ecuador book database
EcuadorPichinchaHostería Garceta SoliNaturalist; photo examined
EcuadorPichinchaMilpeReptiles of Ecuador book database
EcuadorPichinchaMindo, townSavage 1960
EcuadorPichinchaNanegalitoArteaga et al. 2017
EcuadorPichinchaReserva ArlequínThis work; Fig. 1
EcuadorPichinchaReserva Las GralariasArteaga et al. 2017
EcuadorPichinchaRío CintoPhoto by Lisa Brunetti
EcuadorPichinchaRoad to MindoMejía Guerrero 2018
EcuadorPichinchaSachatamia LodgePhoto by Jeff Bouton
EcuadorPichinchaSaragoza–Río CintoYánez-Muñoz et al. 2009
EcuadorPichinchaSéptimo Paraíso LodgeArteaga et al. 2013
EcuadorPichinchaTandapiArteaga et al. 2017
EcuadorPichinchaTerreno de Eric Osterman en MindoReptiles of Ecuador book database
EcuadorPichinchaVía a Santa RosaReptiles of Ecuador book database
EcuadorPichinchaYellow House LodgeArteaga et al. 2017
EcuadorSanto Domingo de los TsáchilasEstación Experimental La FavoritaArteaga et al. 2017
PeruTumbesParque Nacional Cerros de AmotapePassos et al. 2012