Published October 18, 2021. Open access.

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Western Ribbon Coralsnake (Micrurus helleri)

Reptiles of Ecuador | Serpentes | Elapidae | Micrurus | Micrurus helleri

English common names: Western Ribbon Coralsnake, Heller’s Coralsnake.

Spanish common names: Coral acintada occidental, coral de Heller.

Recognition: ♂♂ 151.7 cmMaximum distance from the snout to the tip of the tail. ♀♀ 137.5 cmMaximum distance from the snout to the tip of the tail..1 In Ecuador, the majority of true coralsnakes (genus Micrurus) can be distinguished from most, but not all, false coralsnakes by having brightly colored rings that encircle the body, small eyes that are about the same size as the post-ocular scales, and no loreal scale.1,2 This is one of four Amazonian Micrurus in Ecuador having the black rings arranged in triads, rather than in monads.1 The other three snakes are M. obscurus, M. ortoni, and M. surinamensis, all of which have less than 220 ventral scales, 4–7 rings on the tail, and lack a clear white band on the snout (more than 225 ventral scales, 8–11 rings on the tail, and distinct white snout band in M. helleri).13 The presence of complete black triads separates this species from Erythrolamprus aesculapii, a false coralsnake that, in Ecuador, has black rings arranged in dyads.4

Figure showing variation among individuals of Micrurus helleri

Figure 1: Individuals of Micrurus helleri from Ecuador: Jatun Sacha Biological Station, Napo province (); Río Yasuní, Orellana province ().

Natural history: Micrurus helleri is an uncommon terrestrial to semi-fossorial snake that inhabits pristine to heavily disturbed rainforests, which may be terra-firme or seasonally flooded.5 This species also occurs in clearings, pastures,6 orchards, and rural gardens near the forest border, usually close to bodies of water.1,3,7,8 Individuals have been seen active on soil, leaf-litter, or in water during the day or at night.1,3,7 These snakes actively forage in search of prey, which includes snakes (Amerotyphlops reticulatus, Leptodeira approximans, and species in the genus Atractus),1,8 amphisbaenians (Amphisbaena bassleri),1 lizards (Bachia trisanale),9 fish (species in the genera Synbranchus and Brachyhypopomus),8 and caecilians (Oscaecilia bassleri).8 Western Ribbon Coralsnakes rely on their warning coloration as a primary defense mechanism. Individuals are usually calm and try to flee when threatened. If disturbed, they engage in complex and seemingly erratic behavior: they hide the head beneath body coils, crawl spasmodically forward and then backward, and display their bright tails as a decoy.1,7 They are also capable of striking if provoked. Their venom is neurotoxic and, in humans, causes persistent excruciating pain, blurred vision, ptosis (drooping eyelids),2 local paralysis, and difficulty breathing and walking.10,11 In mice, the venom has been shown to have myotoxic (muscle-breaking) activity.12 In northeastern Perú, two females contained 5–6 oviductal eggs,8 but the real clutch size is not known.

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Conservation: Least Concern Believed to be safe from extinction given current circumstances.. Since it has only been recently elevated to full-species status,1,13 Micrurus helleri has not been formally included in any IUCN Red List threat category. Here, it is proposed to be included in the LC category because the species is widely distributed, occurs in major protected areas, has presumed stable populations, and is currently facing no major widespread extinction threats. The most important threat to the long-term survival of some populations is habitat destruction mostly due to mining, oil extraction, and the expansion of the agricultural frontier.1 Individuals of M. helleri also suffer from traffic mortality and direct killing at the hands of local people.1,7

Distribution: Micrurus helleri is native to the western Amazon basin and adjacent foothills of the Andes in Colombia, Ecuador (Fig. 2), Perú, and Bolivia.

Distribution of Micrurus helleri in Ecuador

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

Etymology: The name Micrurus is derived from the Greek words mikros (=small) and oura (=tail), referring to the short tail in members of this group.2 The species’ epithet helleri honors American zoologist Edmund Heller (1875–1939), who collected the holotype and participated in the Marshall Field Expedition to Perú from 1922 to 1923.9

See it in the wild: Western Ribbon Coralsnakes are usually found no more than once every few weeks at any given area. In Ecuador, the localities having the greatest number of recent observations are Jatun Sacha Biological Reserve, Yasuní Scientific Station, and the immediate environs of the town Puyo. It appears that the best way to find Western Ribbon Coralsnakes is to walk along forest trails right after sunset, especially after a warm and rainy day.

Acknowledgments: This account was published with the support of Secretaría Nacional de Educación Superior Ciencia y Tecnología (programa INEDITA; project: Respuestas a la crisis de biodiversidad: la descripción de especies como herramienta de conservación; No 00110378), Programa de las Naciones Unidas (PNUD), and Universidad San Francisco de Quito (USFQ).

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

Photographers: Jose VieiraaAffiliation: Tropical Herping (TH), Quito, Ecuador.,bAffiliation: ExSitu, Quito, Ecuador. and Sebastián Di DoménicocAffiliation: Keeping Nature, Bogotá, Colombia.

How to cite? Arteaga A (2021) Western Ribbon Coralsnake (Micrurus helleri). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: DOI: 10.47051/RGYB8672

Literature cited:

  1. Valencia JH, Garzón-Tello K, Barragán-Paladines ME (2016) Serpientes venenosas del Ecuador: sistemática, taxonomía, historial natural, conservación, envenenamiento y aspectos antropológicos. Fundación Herpetológica Gustavo Orcés, Quito, 653 pp.
  2. Campbell JA, Lamar WW (2004) The venomous reptiles of the western hemisphere. Cornell University Press, Ithaca, 774 pp.
  3. 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.
  4. Curcio FF, Scali S, Rodrigues MT (2015) Taxonomic status of Erythrolamprus bizona Jan (1863 (Serpentes, Xenodontinae): assembling a puzzle with many missing pieces. Herpetological Monographs 29: 40–64. DOI: 10.1655/HERPMONOGRAPHS-D-15-00002
  5. Duellman WE (2005) Cusco amazónico: the lives of amphibians and reptiles in an Amazonian rainforest. Cornell University Press, Ithaca, 433 pp.
  6. 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.
  7. Field notes, Reptiles of Ecuador book project.
  8. Dixon JR, Soini P (1986) The reptiles of the upper Amazon Basin, Iquitos region, Peru. Milwaukee Public Museum, Milwaukee, 154 pp.
  9. Roze JA (1996) Coral snakes of the Americas: biology, indentification, and venoms. Krieger Publishing Company, Malabar, 328 pp.
  10. Manock SR, Suárez G, Graham D, Ávila-Aguero ML, Warrell DA (2008) Neurotoxic envenoming by South American coral snake (Micrurus lemniscatus helleri): case report from eastern Ecuador and review. Transactions of the Royal Society of Tropical Medicine and Hygiene 102: 1127–1132. DOI: 10.1016/j.trstmh.2008.03.026
  11. Warrell DA (2004) Snakebites in Central and South America: epidemiology, clinical features, and clinical management. In: Campbell JA, Lamar WW (Eds) The Venomous reptiles of the Western Hemisphere. Cornell University Press, Ithaca, 709–761.
  12. Gutiérrez JM, Rojas G, da Silva Jr NJ, Núñez J (1992) Experimental myonecrosis induced by the venoms of South American Micrurus (coral snakes). Toxicon 30: 1299–1302. DOI: 10.1016/0041-0101(92)90446-c
  13. Hurtado-Gómez JP, Vargas Ramírez M, Ruiz Gómez FJ, Fouquet A, Fritz U (2021) Multilocus phylogeny clarifies relationships and diversity within the Micrurus lemniscatus complex (Serpentes: Elapidae). Salamandra 57: 229–239.

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

ColombiaCaquetáRío OrteguazaDíaz-Ricaurte & Fiorillo 2019
ColombiaCaquetáSolanoDíaz-Ricaurte & Fiorillo 2019
ColombiaCaquetáTres EsquinasiNaturalist
ColombiaCaquetáTres EsquinasiNaturalist
ColombiaCaquetáVereda El ÁguilaCortes-Ávila & Toledo 2013
ColombiaCaquetáVía antigua Neiva–HuilaDíaz-Ricaurte & Fiorillo 2019
ColombiaPutumayoMocoaDíaz-Ricaurte & Fiorillo 2019
ColombiaPutumayoPuerto AsísCampbell & Lamar 2004
ColombiaPutumayoRío GuamuésIAvH 219
ColombiaPutumayoRío PutumayoFMNH 37434
ColombiaPutumayoVereda ChuroyacoValencia et al. 2016
ColombiaPutumayoVereda San Juan de GuamuésiNaturalist
ColombiaPutumayoVereda Valle de las PalmerasIAvH-R-9212
EcuadorMorona SantiagoCentro Shuar KiimValencia et al. 2016
EcuadorMorona SantiagoLimónValencia et al. 2016
EcuadorMorona SantiagoMacasValencia et al. 2016
EcuadorMorona SantiagoMacumaValencia et al. 2016
EcuadorMorona SantiagoMetsankimiNaturalist
EcuadorMorona SantiagoPaantimValencia et al. 2016
EcuadorMorona SantiagoPakintzaValencia et al. 2016
EcuadorMorona SantiagoSan Jose de MoronaValencia et al. 2016
EcuadorMorona SantiagoSawastianOrtega-Andrade 2010
EcuadorMorona SantiagoShimpinValencia et al. 2016
EcuadorMorona SantiagoShuin MamusiNaturalist
EcuadorMorona SantiagoSucúaiNaturalist
EcuadorMorona SantiagoWisuiValencia et al. 2016
EcuadorNapoArchidonaMHNG 2413.090
EcuadorNapoBaeza–Loreto roadThis work
EcuadorNapoCentro PalmerasiNaturalist
EcuadorNapoCotundoValencia et al. 2016
EcuadorNapoGareno LodgeThis work
EcuadorNapoJatun Sacha Biological StationiNaturalist
EcuadorNapoMangochiktaValencia et al. 2016
EcuadorNapoMisahuallíValencia et al. 2016
EcuadorNapoMisahuallí, 2.6 km W ofiNaturalist
EcuadorNapoRío SunoValencia et al. 2016
EcuadorNapoTena, 9 km SW ofValencia et al. 2016
EcuadorNapoTerra Luna LodgeiNaturalist
EcuadorNapoUniversidad Estatal AmazónicaiNaturalist
EcuadorNapoWild Sumaco Wildlife SanctuaryCamper et al. 2021
EcuadorNapoYachana LodgePhoto by Douglas McMeekin
EcuadorNapoYachana ReserveValencia et al. 2016
EcuadorNapoZoo el ArcaPhoto by Diego Piñán
EcuadorOrellana10 de AgostoiNaturalist
EcuadorOrellanaAsociación San RoqueValencia et al. 2016
EcuadorOrellanaBloque 31Valencia et al. 2016
EcuadorOrellanaCampamento Apaika PetroamazonasValencia et al. 2016
EcuadorOrellanaCoca, 3 km E ofiNaturalist
EcuadorOrellanaEl Eno, environs ofiNaturalist
EcuadorOrellanaGuardianía de TambocochaValencia et al. 2016
EcuadorOrellanaJoya de los SachasValencia et al. 2016
EcuadorOrellanaNPFPhoto by Paulina Romero
EcuadorOrellanaNuevo RocafuerteiNaturalist
EcuadorOrellanaPañacochaValencia et al. 2016
EcuadorOrellanaPozo petrolero ObeValencia et al. 2016
EcuadorOrellanaPuerto Itaya, 3.5 km S ofiNaturalist
EcuadorOrellanaRío BigalGarcía et al. 2021
EcuadorOrellanaRío Yasuní, near Lake JatuncochaThis work
EcuadorOrellanaSan Jose de GuayusaiNaturalist
EcuadorOrellanaSan José de PayaminoiNaturalist
EcuadorOrellanaTiputini Biodiversity Station iNaturalist
EcuadorOrellanaYarentaro, 16 km SE ofiNaturalist
EcuadorOrellanaYasuní Scientific StationValencia et al. 2016
EcuadorPastazaCampamento K4Valencia et al. 2016
EcuadorPastazaCanelosValencia et al. 2016
EcuadorPastazaComunidad Jatun YakuValencia et al. 2016
EcuadorPastazaConamboValencia et al. 2016
EcuadorPastazaHostería SafariValencia et al. 2016
EcuadorPastazaMeraValencia et al. 2016
EcuadorPastazaMirador IndichurisiNaturalist
EcuadorPastazaNuevo Corrientes, BufeoValencia et al. 2016
EcuadorPastazaPuyoPhoto by Danilo Medina
EcuadorPastazaPuyo, 10 km N ofValencia et al. 2016
EcuadorPastazaRío HuitoyacuValencia et al. 2016
EcuadorPastazaRío PuyoiNaturalist
EcuadorPastazaSarayacuValencia et al. 2016
EcuadorPastazaSendero a Hola VidaiNaturalist
EcuadorPastazaShellValencia et al. 2016
EcuadorSucumbíosAmerica Vargas, 1 km N ofiNaturalist
EcuadorSucumbíosBosque Protector AguaricoValencia et al. 2016
EcuadorSucumbíosBrisas del Cuyabeno, 4 km N ofiNaturalist
EcuadorSucumbíosCampo Fanny 18Valencia et al. 2016
EcuadorSucumbíosEstación Amazonas OCPValencia & Garzón 2011
EcuadorSucumbíosEstación PUCE en CuyabenoValencia et al. 2016
EcuadorSucumbíosLa Selva LodgeNogueira et al. 2019
EcuadorSucumbíosLago AgrioDuellman 1978
EcuadorSucumbíosLimocochaThis work
EcuadorSucumbíosSanta CeciliaValencia et al. 2016
EcuadorSucumbíosSinangüeValencia et al. 2016
EcuadorSucumbíosTucán LodgePhoto by Harry Turner
EcuadorZamora ChinchipeLas OrquídeasThis work
EcuadorZamora ChinchipeMaycuThis work
EcuadorZamora ChinchipeReserva AtasmoiNaturalist
EcuadorZamora ChinchipeValle del QuimiBetancourt et al. 2018
PerúAmazonasAguaruna VillageMVZ 163326
PerúAmazonasPuerto GalileaUSNM 566627
PerúLoretoNuevo AndoasCampbell & Lamar 2004
PerúLoretoUllpayacuCampbell & Lamar 2004