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 species^2,3 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.

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 Arteaga^aAffiliation: Khamai Foundation, Quito, Ecuador.

Photographer: Jose Vieira^bAffiliation: 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: www.reptilesofecuador.com. DOI: 10.47051/IHRR1793

Literature cited:

Field notes, Reptiles of Ecuador book project.
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
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
Photo by Paul Pina.
MAE (2012) Línea base de deforestación del Ecuador continental. Ministerio del Ambiente del Ecuador, Quito, 30 pp.
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.

Country	Province	Locality	Source
Ecuador	Azuay	Chilcaplaya	MZUA.RE.0046; photo examined
Ecuador	El Oro	Balsas	MNNG 2413.053; collection database
Ecuador	El Oro	El Progreso	MHNG 2413.052; collection database
Ecuador	El Oro	Humedal La Tembladera	Garzón-Santomaro et al. 2019
Ecuador	El Oro	La Cuca	Torres-Carvajal & Terán 2021
Ecuador	El Oro	La Victoria	iNaturalist; photo examined
Ecuador	El Oro	Machala	iNaturalist; photo examined
Ecuador	El Oro	Machala, 10 km SE of	Albuquerque & Fernandes 2022
Ecuador	El Oro	Pasaje, 20 km E of	Albuquerque & Fernandes 2022
Ecuador	El Oro	Planta Paraíso	iNaturalist; photo examined
Ecuador	El Oro	Represa Tahuin	Garzón-Santomaro et al. 2019
Ecuador	El Oro	Reserva Militar Arenillas	iNaturalist; photo examined
Ecuador	El Oro	Rosa Delia plantation	Albuquerque & Fernandes 2022
Ecuador	El Oro	Salatí	iNaturalist; photo examined
Ecuador	El Oro	Tenguel	iNaturalist; photo examined
Ecuador	Guayas	Bosque Aventura	iNaturalist; photo examined
Ecuador	Guayas	Capeira	Photo by Eduardo Zavala
Ecuador	Guayas	Cerro de Hayas	Reptiles of Ecuador book database
Ecuador	Guayas	Cerro Masvale	Torres-Carvajal & Terán 2021
Ecuador	Guayas	Chongón	Reptiles of Ecuador book database
Ecuador	Guayas	Durán	Albuquerque & Fernandes 2022
Ecuador	Guayas	Guayaquil*	Günther 1859
Ecuador	Guayas	Isla Santay	Cruz-García et al. 2023
Ecuador	Guayas	La Aurora	iNaturalist; photo examined
Ecuador	Guayas	Lomas De Sargentillo	iNaturalist; photo examined
Ecuador	Guayas	Milagro, 3 mi E of	Albuquerque & Fernandes 2022
Ecuador	Guayas	Via a la Costa	Photo by Jean Thomas Bujard
Ecuador	Loja	Alamor–Arenillas road	Torres-Carvajal & Terán 2021
Ecuador	Loja	Macará–Larama	Reptiles of Ecuador book database
Ecuador	Loja	Reserva Jorupe	Reptiles of Ecuador book database
Ecuador	Los Ríos	Dole María Jose	iNaturalist; photo examined
Ecuador	Los Ríos	Hacienda Delia Margarita	iNaturalist; photo examined
Ecuador	Manabí	Canuto, 3.5 km N of	Photo by Regdy Vera
Ecuador	Manabí	Chone	Photo by Regdy Vera
Ecuador	Manabí	Poza Honda	Photo by Lisa Brunetti
Ecuador	Manabí	Quinta Zambrano Alcívar	Photographic record by Regdy Vera
Ecuador	Manabí	Río Ayampe	Torres-Carvajal et al. 2021
Ecuador	Manabí	Santa Ana, 9 km SE of	iNaturalist; photo examined
Ecuador	Santa Elena	Salinas	Photo by Ernesto Arbeláez
Ecuador	Santa Elena	Villa Curia	iNaturalist; photo examined
Perú	Cajamarca	Río Zaña	Albuquerque & Fernandes 2022
Perú	Piura	Canchaque, 1.5 km E of	Albuquerque & Fernandes 2022