Chocoan Blunt-headed Snake (Imantodes chocoensis)

Reptiles of Ecuador | Serpentes | Colubridae | Imantodes chocoensis

English common names: Chocoan Blunt-headed Snake, Chocoan Blunthead.

Spanish common name: Cordoncillo del Chocó.

Recognition: ♂♂ 96.7 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=66.3 cm. ♀♀ 113.5 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=82.4 cm..^1,2 Imantodes chocoensis is one of the most readily recognizable snakes in the Chocó biome. Its distinctive features include an extremely slender body, a broad and truncated head clearly differentiated from the thin neck, and bulging eyes that occupy approximately a quarter of the head’s length.^1,3 This species differs from the rest of its Ecuadorian congeners by lacking a loreal scale and by having one anal scale (two in I. cenchoa) and dorsal dark blotches that encompass two or fewer vertebral scales without extending laterally onto ventrals (Fig. 1).^1,2 Although it may resemble snakes of the genus Leptodeira, this species differs from them by having a more compact head with more prominent eyes.

Figure showing variation among individuals of Imantodes chocoensis

Figure 1: Individuals of Imantodes chocoensis from Canandé Biological Reserve, Esmeraldas province, Ecuador. j=juvenile.

Natural history: Imantodes chocoensis is a nocturnal and entirely arboreal snake that inhabits lowland rainforests.^1–5 The species has only been found in well-preserved areas. Chocoan Blunt-headed Snakes have been observed active at night, either coiled or gliding through low (10–400 cm above the ground) understory vegetation.^2–4 Snakes of the genus Imantodes in general are opisthoglyphous, meaning they have enlarged grooved teeth towards the rear of the maxilla and are considered mildly venomous. They are also noteworthy for feeding almost exclusively on anoles. In I. chocoensis, only the lizard Basiliscus galeritus has been recorded as prey item.² In the presence of a potential predator, Chocoan Bluntheads tend to flee towards vegetation, emitting fetid fluids through the cloaca as a defensive mechanism. These snakes are considered docile, rarely attempting to bite.²

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Conservation: Least Concern Believed to be safe from extinction given current circumstances..⁶ Imantodes chocoensis is listed in this category due to its extensive distribution range, exceeding 30.000 km².⁵ However, its habitat is currently facing many threats, including persistent forest loss and fragmentation due to large-scale logging and agricultural expansion.⁶ Additionally, it remains uncertain whether I. chocoensis is uniformly distributed across its estimated range or if the known localities represent isolated populations.⁶

Distribution: Imantodes chocoensis is widely distributed throughout the Chocoan lowlands of Ecuador (Fig. 2) and Colombia.

Figure 2: Distribution of Imantodes chocoensis in Ecuador. The star corresponds to the type locality: Durango, Esmeraldas province. See Appendix 1 for a complete list of the presence localities included in the map.

Etymology: The name Imantodes comes from the Latin word immanis (=enormous) and the Greek suffix -odes (=abundance),⁷ probably referring to the large size of the eyes in relation to the head. The specific epithet chocoensis refers to the Chocó, a very humid tropical biome that comprises the rainforests along the Pacific coast of northern Ecuador, Colombia, and Panamá.¹

See it in the wild: The Chocoan Blunt-headed Snake is not a common species, but there is a high probability of seeing it in protected areas such as Canandé and Tesoro Escondido reserves. These snakes can easily be spotted by scanning understory vegetation at night.

Special thanks to Beck Pryor for symbolically adopting the Chocoan Blunt-headed Snake and helping bring the Reptiles of Ecuador book project to life.

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Author: Amanda Quezada^aAffiliation: Khamai Foundation, Quito, Ecuador.

Editor: Alejandro Arteaga^aAffiliation: Khamai Foundation, Quito, Ecuador.

Photographer: Jose Vieira^bAffiliation: Tropical Herping (TH), Quito, Ecuador.^,^cAffiliation: ExSitu, Quito, Ecuador.

How to cite? Quezada A (2024) Chocoan Blunt-headed Snake (Imantodes chocoensis). 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/XLHO9932

Literature cited:

Torres-Carvajal O, Yánez-Muñoz MH, Quirola D, Smith E, Almendáriz A (2012) A new species of blunt-headed vine snake (Colubridae, Imantodes) from the Chocó region of Ecuador. Zookeys 244: 91–110. DOI: 10.3897/zookeys.244.3950
Field notes, Reptiles of Ecuador book project.
Jaramillo-Martínez AF, Valencia-Zuleta A, Castro-Herrera F (2013) Imantodes chocoensis Torres-Carvajal, Yánez-Muñoz, Quirola, Smith, and Almendáriz, 2012 (Squamata: Dipsadidae): first records from Colombia. Check List 9: 1070–1071. DOI: 10.15560/9.5.1070
Rojas-Morales JA, Escobar-Lasso S, Osorio-Ortíz A, Lozano-Ríos LA (2013) Third observation of the Chocoan blunt-headed vine snake, Imantodes chocoensis (Serpentes: Dipsadidae) for Colombia. Biota Colombiana 14: 341–344.
Missassi AFR, Costa JCL, Prudente ALC (2015) Range extension of the Chocoan blunt-headed vine snake: Imantodes chocoensis (Serpentes: Dipsadidae) in northwestern Colombia. Salamandra 51: 269–272.
Cisneros-Heredia DF (2017) Imantodes chocoensis. The IUCN Red List of threatened species. Available from: www.iucnredlist.org. DOI: 10.2305/IUCN.UK.2017-2.RLTS.T44581695A44581702.en
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 Imantodes chocoensis in Ecuador (Fig. 2). Go to the section on symbols and abbreviations for a list of acronyms used.

Country	Province	Locality	Source
Colombia	Chocó	Cerro Iró	Bonilla & Rengifo 2022
Colombia	Risaralda	Alto Amurrupá	Urrutia & Moya Robledo 2018
Colombia	Valle del Cauca	Corregimiento Pianguita-Bazán	Jaramillo-Martínez et al. 2013
Colombia	Valle del Cauca	Quebrada El Caimancito	Jaramillo-Martínez et al. 2013
Ecuador	Carchi	Río San Juan	Torres-Carvajal et al. 2012
Ecuador	Carchi	Sendero Awá	Torres-Carvajal et al. 2012
Ecuador	Carchi	Tobar Donoso, 2 km S of	iNaturalist; photo examined
Ecuador	Esmeraldas	Alto Tambo, 4 km W of	Torres-Carvajal et al. 2012
Ecuador	Esmeraldas	Canandé Biological Reserve	This work; Fig. 1
Ecuador	Esmeraldas	Durango, 4 km E of*	Torres-Carvajal et al. 2012
Ecuador	Esmeraldas	La Ganadera, 8 km NE of	iNaturalist; photo examined
Ecuador	Esmeraldas	Lote Rosero	Reptiles of Ecuador book database
Ecuador	Esmeraldas	Playa de Oro	Torres-Carvajal et al. 2012
Ecuador	Esmeraldas	Reserva Itapoa	MZUTI 3285; examined
Ecuador	Esmeraldas	Santa Rita	Torres-Carvajal et al. 2012
Ecuador	Esmeraldas	Santo Domingo de Onzole	iNaturalist; photo examined
Ecuador	Esmeraldas	Tesoro Escondido Reserve	iNaturalist; photo examined