Published December 13, 2021. Open access.

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Amazon Scarlet Snake (Pseudoboa coronata)

Reptiles of Ecuador | Serpentes | Colubridae | Pseudoboa | Pseudoboa coronata

English common names: Amazon Scarlet Snake, Crowned False Boa, Black-headed Scarlet Snake.

Spanish common names: Culebra amazónica escarlata, serpiente escarlata.

Recognition: ♂♂ 97.5 cmMaximum distance from the snout to the tip of the tail. ♀♀ 107.6 cmMaximum distance from the snout to the tip of the tail..1 In Ecuador, Pseudoboa coronata can be identified by having dorsal scales arranged in 17 rows at mid-body, a black head cap, and dorsal surfaces bright pinkish red in juveniles and red in older animals.2 This species exhibits a change in head coloration throughout the organism’s lifespan. Young snakes have a black head followed by a broad white cream or light yellow nuchal collar.1 Adult snakes lack the nuchal collar or is feebly visible when present. The ventral surfaces of the body and tail are white cream in juveniles and slightly light yellow in adults.1 Among Ecuadorian snakes, Drepanoides anomalus and juveniles of Clelia clelia resemble P. coronata. However, D. anomalus can be distinguished by having dorsal scales arranged in 15 rows at mid-body, tip of dorsal scales black, and a broad white nuchal collar always present that extends from the parietal scales to the fifth or seventh dorsal scale row.24 Clelia clelia differs from P. coronata by having dorsal scales arranged in 19 rows at mid-body in addition to having divided, instead of single, subcaudal scales.46

Figure showing an adult individual of Pseudoboa coronata

Figure 1: Adult individual of Pseudoboa coronata from El Edén Lodge, Orellana province, Ecuador.

Natural history: RareTotal average number of reported observations per locality less than ten.. Pseudoboa coronata inhabits semi-open to closed canopy rainforests, which may be terra-firme or seasonally flooded,5,7 as well as pastures,8 rice fields,9 and roadside vegetation. Amazon Scarlet Snakes are terrestrial and exhibit both diurnal and nocturnal activity.2,10,11 Individuals are usually seen active on the leaf-litter,7,11 soil,6,9 in water,6 or found hidden under logs and roots of large trees.1 These snakes forage actively in search of prey, which they subdue using constriction and envenomation.11 Amazon Scarlet Snakes have a generalist diet that includes primarily lizards (Ameiva ameiva,12 Tupinambis cuzcoensis,7 and skinks of the genus Copeoglossum2) and small mammals,6,10 but also birds, fish (genus Synbranchus),9 and snakes (Tantilla melanocephala).5 Crowned False Boas are opistoglyphous (having enlarged teeth towards the rear of the maxilla) and mildly venomous, which means they are dangerous to small prey, but not to humans.1 Pseudoboa coronata is oviparous. Females attain sexual maturity when they reach 67–76.1 cm in total length. The clutch size is 4–13 eggs.2,6

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Conservation: Least Concern Believed to be safe from extinction given current circumstances..13,14 Pseudoboa coronata is listed in this category mainly because the species is widely distributed, inhabits both well-preserved forests and human-modified environments, and occurs in protected areas throughout its distribution range. Therefore, P. coronata is considered to be facing no major immediate extinction threats.13 However, the destruction and fragmentation of forested environments throughout the Amazon basin can be a threat for the long-term of survival of some populations. There are records of individuals of this species killed by vehicular traffic in areas where paved roads cross through disturbed forest.2

Distribution: Pseudoboa coronata is widely distributed throughout the Amazon basin in Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname, and Venezuela.15 The species also occurs marginally in the Brazilian Cerrado.15 In Ecuador, P. coronata has been recorded at elevations between 192 and 1015 m (Fig. 2).

Distribution of Pseudoboa coronata in Ecuador

Figure 2: Distribution of Pseudoboa coronata in Ecuador. See Appendix 1 for a complete list of the presence localities included in the map.

Etymology: The generic name Pseudoboa comes from de Greek word pseudes (meaning “false”)16 and the Latin word boa (meaning “ox killer”).17 The name refers to the single subcaudal scales in snakes of this genus, a characteristic present in boas. The specific epithet coronata, which comes from de Latin word corona (meaning “crown”),16 refers to the dorsal surface of the head, which is uniformly black in adults or black followed by a white broad nuchal collar in juveniles.

See it in the wild: In Ecuador, Amazon Scarlet Snakes are recorded no more than once every few months at any given locality. Recently, individuals of Pseudoboa coronata have been sighted in Yachana Reserve, Suchipakari Lodge, and Sacha Lodge. Active snakes can be found at night by scanning the leaf-litter in primary and secondary forests. During the day, these snakes can be found under fallen logs and root systems of large tress. The rate of encounter can be enhanced by active searching as well as by removing leaf-litter, piles of leaves, and other surface objects.

Author: Teddy Angarita-SierraaAffiliation: Yoluka ONG, Fundación de Investigación en Biodiversidad y Conservación, Bogotá, Colombia.,bAffiliation: Vicerrectoría de Investigación, Universidad Manuela Beltrán, Bogotá, Colombia.

Editor: Alejandro ArteagacAffiliation: Khamai Foundation, Quito, Ecuador.

Photographer: Jose VieiradAffiliation: Tropical Herping (TH), Quito, Ecuador.,eAffiliation: ExSitu, Quito, Ecuador.

How to cite? Angarita-Sierra T (2021) Amazon Scarlet Snake (Pseudoboa coronata). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: DOI: 10.47051/IGOK8377

Literature cited:

  1. Dixon JR, Soini P (1986) The reptiles of the upper Amazon Basin, Iquitos region, Peru. Milwaukee Public Museum, Milwaukee, 154 pp.
  2. Martins M, Oliveira ME (1998) Natural history of snakes in forests of the Manaus region, Central Amazonia, Brazil. Herpetological Natural History 6: 78–150.
  3. Zaher H, Oliveira ME, Franco FL (2008) A new, brightly colored species of Pseudoboa Schneider, 1801 from the Amazon Basin (Serpentes, Xenodontinae). Zootaxa 1674: 27–37. DOI: 10.11646/zootaxa.1674.1.2
  4. Peters JA, Orejas-Miranda B (1970) Catalogue of Neotropical Squamata: part I, snakes. Bulletin of the United States National Museum, Washington, D.C., 347 pp.
  5. Duellman WE (2005) Cusco amazónico: the lives of amphibians and reptiles in an Amazonian rainforest. Cornell University Press, Ithaca, 433 pp.
  6. Duellman WE (1978) The biology of an equatorial herpetofauna in Amazonian Ecuador. Publications of the Museum of Natural History, University of Kansas 65: 1–352.
  7. Field notes, Reptiles of Ecuador book project.
  8. Cortes-Ávila L, Toledo JJ (2013) Estudio de la diversidad de serpientes en áreas de bosque perturbado y pastizal en San Vicente del Caguán (Caquetá), Colombia. Actualidades Biológicas 35: 185–197.
  9. Beebe W (1946) Field notes on the snakes of Kartabo, British Guiana, and Caripito, Venezuela. Zoologica 31: 11–52.
  10. Alencar LR, Gaiarsa MP, Martins M (2013) The evolution of diet and microhabitat use in Pseudoboine Snakes. South American Journal of Herpetology 8: 60–66. DOI: 10.2994/sajh-d-13-00005.1
  11. dos Santos-Costa MC, Maschio GF, da Costa Prudente AL (2015) Natural history of snakes from Floresta Nacional de Caxiuanã, eastern Amazonia, Brazil. Herpetology Notes 8: 69–98.
  12. Avila-Pires TCS (1995) Lizards of Brazilian Amazonia (Reptilia: Squamata). Zoologische Verhandelingen 299: 1–706.
  13. Caicedo J, Calderón M, Cisneros-Heredia DF, Ortega A, Gonzales L, Nogueira C, Schargel W, Rivas G (2013) Pseudoboa coronata. The IUCN Red List of threatened species. Available from: DOI: 10.2305/IUCN.UK.2019-3.RLTS.T203577A2768885.en
  14. Reyes-Puig C (2015) Un método integrativo para evaluar el estado de conservación de las especies y su aplicación a los reptiles del Ecuador. MSc thesis, Pontificia Universidad Católica del Ecuador, 73 pp.
  15. Nogueira CC, Argôlo AJS, Arzamendia V, Azevedo JA, Barbo FE, Bérnils RS, Bolochio BE, Borges-Martins M, Brasil-Godinho M, Braz H, Buononato MA, Cisneros-Heredia DF, Colli GR, Costa HC, Franco FL, Giraudo A, Gonzalez RC, Guedes T, Hoogmoed MS, Marques OAV, Montingelli GG, Passos P, Prudente ALC, Rivas GA, Sanchez PM, Serrano FC, Silva NJ, Strüssmann C, Vieira-Alencar JPS, Zaher H, Sawaya RJ, Martins M (2019) Atlas of Brazilian snakes: verified point-locality maps to mitigate the Wallacean shortfall in a megadiverse snake fauna. South American Journal of Herpetology 14: 1–274. DOI: 10.2994/SAJH-D-19-00120.1
  16. Brown RW (1956) Composition of scientific words. Smithsonian Books, Washington D.C., 882 pp.
  17. O’Shea M (2007) Boas and pythons of the world. New Holland Publishers, London, 160 pp.

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

ColombiaCaquetáBelén de AndaquíesUAM-R-0337
ColombiaCaquetáLa ArenosaCaldeira Costa et al. 2015
ColombiaCaquetáTres EsquinasNogueira et al. 2019
ColombiaCaquetáVereda PalmichalesUAM-R-0414
EcuadorMorona SantiagoChiguazaFugler & Walls 1978
EcuadorMorona SantiagoMacumaFugler & Walls 1978
EcuadorMorona SantiagoSantiago de MendezFugler & Walls 1978
EcuadorNapoArchidona, 1.5 km N ofNogueira et al. 2019
EcuadorNapoEl Edén LodgeThis work
EcuadorNapoJatun Sacha Biological StationVigle 2008
EcuadorNapoPuerto Barantilla, 1.5 km E ofiNaturalist
EcuadorNapoSuchipakari LodgeThis work
EcuadorNapoYachana ReserveWhitworth & Beirne 2011
EcuadorNapoYuralpaThis work
EcuadorOrellanaComunidad Bocana del SunoCaldeira Costa et al. 2015
EcuadorOrellanaEl CocaMHNG 2444.094
EcuadorOrellanaPozo CapirónNogueira et al. 2019
EcuadorOrellanaVía Pompeya Sur–Iro, km 57Nogueira et al. 2019
EcuadorOrellanaVía Pompeya Sur–Iro, km 7.8Nogueira et al. 2019
EcuadorOrellanaYasuní Scientific StationPhoto by David Salazar
EcuadorPastazaAlto CurarayFugler & Walls 1978
EcuadorPastazaArajunoNogueira et al. 2019
EcuadorPastazaBosque Protector Pablo Lopez del Oglán AltoDHMECN 3094
EcuadorPastazaComunidad Santa RosaCaldeira Costa et al. 2015
EcuadorPastazaKallanaMZUTI 5044
EcuadorPastazaPuyoFugler & Walls 1978
EcuadorPastazaRío LliquinoFugler & Walls 1978
EcuadorPastazaRío PuninoNogueira et al. 2019
EcuadorPastazaRío VillanoFugler & Walls 1978
EcuadorPastazaSumak Kawsay In SituiNaturalist
EcuadorSucumbíosSacha LodgeiNaturalist
EcuadorSucumbíosSan Pablo de KantesiyaMHNG 2398.026
EcuadorSucumbíosSanta CeciliaKU 148389
EcuadorSucumbíosZancudocochaNogueira et al. 2019
PeruAmazonasLa PozaUSNM 566603