DOI10.47051/OQSQ9559

Published July 17, 2024. Updated June 30, 2025. Open access.

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Boursier’s Spot-lipped Snake (Saphenophis boursieri)

Reptiles of Ecuador | Serpentes | Colubridae | Saphenophis boursieri

English common names: Boursier’s Spot-lipped Snake, Spotted Genuine Snake.

Spanish common names: Culebra labio pintado de Boursier, culebra manchada de Boursier.

Recognition: ♂♂ 66.5 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=49.3 cm. ♀♀ 77.9 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=60.9 cm..14 Saphenophis boursieri is a small brown snake that can be identified by having black-spotted enamel white lips, with the spots sometimes coalescing into a sinuous line.14 The dorsum is rich yellowish brown with a black ocular-lateral stripe (Fig. 1).14 The ventral surfaces are bright golden yellow with black pigment on the anterior border of each scale. This species can be found living alongside Erythrolamprus albiventris, a predominantly green snake that has immaculate throat and lips.3

Figure showing variation among individuals of Saphenophis boursieri

Figure 1: Juveniles of Saphenophis boursieri from Arlequín Reserve, Pichincha province, Ecuador.

Natural history: Saphenophis boursieri is a rarely seen terrestrial snake that occurs naturally in semi-open areas and clearings within old-growth cloud forests and high evergreen montane forests.35 The species also occurs in pastures and along roadsides.3 Boursier’s Spot-lipped Snakes are typically active at ground level during overcast and drizzly days,5 but individuals have also been seen active during sunny days.3,4 Their foraging occurs on leaf-litter, grass, bare soil, or gravel along dirt roads.35 The diet of this species consists primarily of amphibians,5 but also includes lizards of the genus Riama and insect larvae.4 The typical defense behavior in this harmless snake consists of musking while exposing the bright yellow tail underside.5 Three gravid females contained 5–7 eggs,4 which probably corresponds to the actual clutch size.

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Conservation: Near Threatened Not currently at risk of extinction, but requires some level of management to maintain healthy populations..6 Saphenophis boursieri is listed in this category because, at the time of the assessment in 2013, the species was believed to have a wide distribution in Colombia, Ecuador, and presumably even Perú. However, the actual extent of occurrence of S. boursieri is probably no greater than 3,000 km2, with records outside Ecuador corresponding to different species. Although small, the area where the species occurs in Ecuador is comparatively well-preserved, with approximately 72% of the forest cover still intact. The species has been recorded in 14 privately protected areas.

Distribution: Saphenophis boursieri is endemic to an area of approximately 2,582 km2 along the western slopes of the Andes in northern Ecuador (Fig. 2).

Distribution of Saphenophis boursieri in Ecuador

Figure 2: Distribution of Saphenophis boursieri in Ecuador. The star corresponds to the approximate type locality near Quito, Pichincha province. See Appendix 1 for a complete list of the presence localities included in the map.

Etymology: The genus name Saphenophis comes from the Greek words saphenes (=evident) and ophis (=snake).7 The species is named in honor of Mr. Boursier de La Rivière, a French explorer who is thought to have collected the holotype.3

See it in the wild: Boursier’s Spot-lipped Snakes are recorded at a rate of about once a month along the old Nono–Mindo road, especially during drizzly days.

Special thanks to John Sullivan for symbolically adopting the Boursier’s Spot-lipped Snake and helping bring the Reptiles of Ecuador book project to life.

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Author: Alejandro ArteagaaAffiliation: Fundación Khamai, Reserva Arlequín, Ecoruta Paseo del Quinde km 56, Santa Rosa de Mindo, Pichincha 171202, Ecuador.

Photographer: Amanda QuezadaaAffiliation: Fundación Khamai, Reserva Arlequín, Ecoruta Paseo del Quinde km 56, Santa Rosa de Mindo, Pichincha 171202, Ecuador.

How to cite? Arteaga A (2025) Boursier’s Spot-lipped Snake (Saphenophis boursieri). 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/OQSQ9559

Literature cited:

  1. Myers CW (1973) A new genus for Andean snakes related to Lygophis boursieri and a new species (Colubridae). American Museum Novitates 2522: 1–37.
  2. Myers CW (1969) South American snakes related to Lygophis boursieri: A reappraisal of Rhadinaea antioquiensis, Rhadinaea tristriata, Coronella whymperi, and Liophis atahuallpae. American Museum Novitates 2385: 1–27.
  3. Arteaga A, Bustamante L, Guayasamin JM (2013) The amphibians and reptiles of Mindo. Universidad Tecnológica Indoamérica, Quito, 257 pp.
  4. Cisneros-Heredia DF (2005) Saphenophis boursieri. Habitat, reproduction and diet. Herpetological Review 36: 71.
  5. Field notes, Reptiles of Ecuador book project.
  6. Cisneros-Heredia DF, Bolívar W, Velasco J, Arredondo JC (2017) Saphenophis boursieri. The IUCN Red List of threatened species. Available from: www.iucnredlist.org. DOI: 10.2305/IUCN.UK.2017-2.RLTS.T44581808A44581817.en
  7. Brown RW (1956) Composition of scientific words. Smithsonian Books, Washington D.C., 882 pp.

Appendix 1: Locality data used to create the distribution map of Saphenophis boursieri in Ecuador (Fig. 2). Go to the section on symbols and abbreviations for a list of acronyms used.

CountryProvinceLocalitySource
EcuadorCotopaxiLas PampasArteaga et al. 2013
EcuadorImbaburaJunín, 4 km NE ofiNaturalist; photo examined
EcuadorImbaburaNeblina Bird LodgeiNaturalist; photo examined
EcuadorImbaburaReserva Siempre VerdeArteaga et al. 2013
EcuadorImbaburaSan AntonioCisneros-Heredia 2005
EcuadorPichinchaAlaspungoValencia et al. 2017
EcuadorPichinchaBellavista LodgeArteaga et al. 2013
EcuadorPichinchaBosque La VictoriaYánez-Muñoz et al. 2009
EcuadorPichinchaChespiiNaturalist; photo examined
EcuadorPichinchaChoco Birds ReserveiNaturalist; photo examined
EcuadorPichinchaCordillera del SaloyaYánez-Muñoz et al. 2009
EcuadorPichinchaEl CedralArteaga et al. 2013
EcuadorPichinchaGuantopungo–YunguillaValencia et al. 2017
EcuadorPichinchaGuarumos–NonoiNaturalist; photo examined
EcuadorPichinchaHacienda Las PalmasYánez-Muñoz et al. 2009
EcuadorPichinchaLa Unión–Río CintoYánez-Muñoz et al. 2009
EcuadorPichinchaLlamboArteaga et al. 2013
EcuadorPichinchaNono–Nanegalito, km 5Valencia et al. 2017
EcuadorPichinchaQuebrada frutillasiNaturalist; photo examined
EcuadorPichinchaReserva ArlequínThis work; Fig. 1
EcuadorPichinchaReserva OreothraupisiNaturalist; photo examined
EcuadorPichinchaReserva Orquideológica PahumaArteaga et al. 2013
EcuadorPichinchaSanta Lucía Cloud Forest ReserveSavit 2006
EcuadorPichinchaSanta Lucía Reserve, 3 km NE ofArteaga et al. 2013
EcuadorPichinchaTambo Tanda LodgeArteaga et al. 2013
EcuadorPichinchaTambo Tanda lodge, 1 km E ofiNaturalist; photo examined
EcuadorPichinchaTamboquindeYánez-Muñoz et al. 2009
EcuadorPichinchaTandayapa, 3.5 km SW ofiNaturalist; photo examined
EcuadorSanto Domingo de los TsáchilasBosque Protector Río GuajalitoCisneros-Heredia 2005
EcuadorSanto Domingo de los TsáchilasLa FavoritaArteaga et al. 2013
EcuadorSanto Domingo de los TsáchilasLas PalmerasArteaga et al. 2013
EcuadorSanto Domingo de los TsáchilasMiligaliMyers 1973