Published August 19, 2023. Updated May 16, 2024. Open access.

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Western Parrot-Snake (Leptophis occidentalis)

Reptiles of Ecuador | Serpentes | Colubridae | Leptophis occidentalis

English common name: Western Parrot-Snake.

Spanish common name: Serpiente loro occidental.

Recognition: ♂♂ 161 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=94.6 cm. ♀♀ 123.9 cmMaximum distance from the snout to the tip of the tail..1,2 Leptophis occidentalis can be identified from other green diurnal snakes in the Ecuadorian Tumbesian region by having keeled dorsal scales arranged in 15 rows at mid-body, a unique color pattern, and no loreal scale.2 The dorsum is bright emerald green with no markings other than a short black postocular stripe (Fig. 1).2,3 In juveniles, there is a bright yellow ventrolateral stripe on the anterior third of the body.1 This species is usually confused with L. bocourti and L. depressirostris, but the former has black speckling on the dorsum and the latter has a loreal scale.2,3

Figure showing variation among individuals of Leptophis occidentalis

Figure 1: Individuals of Leptophis occidentalis from Guayas province, Ecuador: Cerro de Hayas (); Chongón (). j=juvenile.

Natural history: Leptophis occidentalis is an uncommon snake that occurs in old-growth seasonally dry forests as well as in gallery forests, pastures with scattered trees, dry shrublands, savannas, plantations, and peri-urban areas.1 Western Parrot-Snakes are most often seen active at ground level or on low vegetation during the day, either basking or actively foraging.1 They also venture into rural houses. At night, they roost on understory vegetation or on ceilings up to 3 m above the ground.1 Parrot snakes in general are active hunters having an opisthoglyphous dentition, meaning they have enlarged teeth towards the rear of the maxilla and are mildly venomous.1 So far, only frogs (Pristimantis achatinus4) have been recorded as prey items of L. occidentalis. The main defense mechanism of Western Parrot-Snakes is to flee quickly, although they can also inflate the neck and open the mouth aggressively to appear bigger and intimidating. They are also known to strike with little provocation.1

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Conservation: Near Threatened Not currently at risk of extinction, but requires some level of management to maintain healthy populations.. Leptophis occidentalis has only recently been recognized as a full species2,3 and its conservation status has not yet been formally evaluated by the IUCN. Here, it is proposed to be included in the Near Threatened category. The rationale is that, although the species is widely distributed and tolerates moderate habitat degradation, its populations are fragmented and occur over an area where ~80% of the forest cover has been transformed into pastures, plantations, and human settlements.5 Furthermore, snakes of this species suffer from intense persecution.1 Therefore, L. occidentalis may qualify for a threatened category in the near future if these threats are not addressed.

Distribution: Leptophis occidentalis is native to the Tumbesian lowlands and adjacent foothills of the Andes in southwestern Ecuador (Fig. 2) and extreme northwestern Perú.

Distribution of Leptophis occidentalis in Ecuador

Figure 2: Distribution of Leptophis occidentalis 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 generic name Leptophis comes from the Greek words leptos (=thin) and ophis (=serpent)6 and probably refers to the body shape of parrot snakes in general. The specific epithet occidentalis is a Latin word meaning “of the west.”6 It refers to the distribution of this species, west of the Andes.

See it in the wild: In Ecuador, Western Parrot-Snakes are found at a rate of about once every few weeks in areas having adequate canopy cover, such as at Bosque Protector Cerro Blanco and Manglares Churute Ecological Reserve. Although diurnal, these snakes are most easily spotted sleeping on vegetation along forest trails at night.

Acknowledgments: Special thanks to Regdy Vera for providing locality data of Leptophis occidentalis.

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

Photographer: Jose VieirabAffiliation: Tropical Herping (TH), Quito, Ecuador.,cAffiliation: ExSitu, Quito, Ecuador.

How to cite? Arteaga A (2023) Western Parrot-Snake (Leptophis occidentalis). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: DOI: 10.47051/IHRR1793

Literature cited:

  1. Field notes, Reptiles of Ecuador book project.
  2. Albuquerque NR, Fernandes DS (2022) Taxonomic revision of the parrot snake Leptophis ahaetulla (Serpentes, Colubridae). Zootaxa 5153: 001–069. DOI: 10.11646/zootaxa.5153.1.1
  3. Torres-Carvajal O, Terán C (2021) Molecular phylogeny of Neotropical Parrot Snakes (Serpentes: Colubrinae: Leptophis) supports underestimated species richness. Molecular Phylogenetics and Evolution 164: 107267. DOI: 10.1016/j.ympev.2021.107267
  4. Photo by Paul Pina.
  5. MAE (2012) Línea base de deforestación del Ecuador continental. Ministerio del Ambiente del Ecuador, Quito, 30 pp.
  6. 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 Leptophis occidentalis in Ecuador (Fig. 2). Go to the section on symbols and abbreviations for a list of acronyms used. Asterisk (*) indicates type locality.

EcuadorAzuayChilcaplayaMZUA.RE.0046; photo examined
EcuadorEl OroBalsasMNNG 2413.053; collection database
EcuadorEl OroEl ProgresoMHNG 2413.052; collection database
EcuadorEl OroHumedal La TembladeraGarzón-Santomaro et al. 2019
EcuadorEl OroLa CucaTorres-Carvajal & Terán 2021
EcuadorEl OroLa VictoriaiNaturalist; photo examined
EcuadorEl OroMachalaiNaturalist; photo examined
EcuadorEl OroMachala, 10 km SE ofAlbuquerque & Fernandes 2022
EcuadorEl OroPasaje, 20 km E ofAlbuquerque & Fernandes 2022
EcuadorEl OroPlanta ParaísoiNaturalist; photo examined
EcuadorEl OroRepresa TahuinGarzón-Santomaro et al. 2019
EcuadorEl OroReserva Militar ArenillasiNaturalist; photo examined
EcuadorEl OroRosa Delia plantationAlbuquerque & Fernandes 2022
EcuadorEl OroSalatíiNaturalist; photo examined
EcuadorEl OroTengueliNaturalist; photo examined
EcuadorGuayasBosque AventuraiNaturalist; photo examined
EcuadorGuayasCapeiraPhoto by Eduardo Zavala
EcuadorGuayasCerro de HayasReptiles of Ecuador book database
EcuadorGuayasCerro MasvaleTorres-Carvajal & Terán 2021
EcuadorGuayasChongónReptiles of Ecuador book database
EcuadorGuayasDuránAlbuquerque & Fernandes 2022
EcuadorGuayasGuayaquil*Günther 1859
EcuadorGuayasIsla SantayCruz-García et al. 2023
EcuadorGuayasLa AuroraiNaturalist; photo examined
EcuadorGuayasLomas De SargentilloiNaturalist; photo examined
EcuadorGuayasMilagro, 3 mi E ofAlbuquerque & Fernandes 2022
EcuadorGuayasVia a la CostaPhoto by Jean Thomas Bujard
EcuadorLojaAlamor–Arenillas roadTorres-Carvajal & Terán 2021
EcuadorLojaMacará–LaramaReptiles of Ecuador book database
EcuadorLojaReserva JorupeReptiles of Ecuador book database
EcuadorLos RíosDole María JoseiNaturalist; photo examined
EcuadorLos RíosHacienda Delia MargaritaiNaturalist; photo examined
EcuadorManabíCanuto, 3.5 km N ofPhoto by Regdy Vera
EcuadorManabíChonePhoto by Regdy Vera
EcuadorManabíPoza HondaPhoto by Lisa Brunetti
EcuadorManabíQuinta Zambrano AlcívarPhotographic record by Regdy Vera
EcuadorManabíRío AyampeTorres-Carvajal et al. 2021
EcuadorManabíSanta Ana, 9 km SE ofiNaturalist; photo examined
EcuadorSanta ElenaSalinasPhoto by Ernesto Arbeláez
EcuadorSanta ElenaVilla CuriaiNaturalist; photo examined
PerúCajamarcaRío ZañaAlbuquerque & Fernandes 2022
PerúPiuraCanchaque, 1.5 km E ofAlbuquerque & Fernandes 2022