Published November 6, 2021. Open access.

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Aquatic Coralsnake (Micrurus surinamensis)

Reptiles of Ecuador | Serpentes | Elapidae | Micrurus | Micrurus surinamensis

English common names: Aquatic Coralsnake, Amazonian Aquatic Coralsnake.

Spanish common names: Coral acuática, coral de agua.

Recognition: ♂♂ 126.2 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=111.5 cm. ♀♀ 135 cmMaximum distance from the snout to the tip of the tail..1,2 In Ecuador, the majority of true coralsnakes can be distinguished from most, but no all, false coral snakes 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.3,4 In the Amazon rainforest of Ecuador, Micrurus surinamensis is unmistakable due to its robust body, black rings arranged in triads, and red head cap with each scale outlined in black (Fig. 1).4 It is also unique among coral snakes in having the eyes and nostrils oriented dorsally, an adaptation for aquatic living.1 The presence of complete black triads separates this species from the Aesculapian False-Coralsnake (Erythrolamprus aesculapii), which, in Ecuador, has black rings arranged in dyads.5

Figure showing variation among individuals of Micrurus surinamensis

Figure 1: Individuals of Micrurus surinamensis from Reserva Río Bigai () and from an unknown locality (), Orellana province, Ecuador.

Natural history: Micrurus surinamensis is an uncommon snake that inhabits pristine to heavily disturbed rainforests, which may be terra-firme or seasonally flooded,4 but also ventures into clearings, rural gardens, and houses near the forest border.6,7 Aquatic Coralsnakes are active at night, especially between sunset and midnight,3,8 but occasionally also during the day.3,7 They are semi-aquatic, which means individuals are usually, but not exclusively, found in or along slow-moving rivers, streams, swamps, ponds (including artificial tilapia ponds),3 and lagoons.3,911 They also forage on mud, leaf-litter, and even on vegetation.4,6 Juveniles have been seen coiled on vines and shrubs 1.35–1.38 m above the ground.12,13 These snakes forage actively above and below the water surface in search of prey. Their diet includes primarily swamp eels (Synbranchus marmoratus),4,14 knifefish (Gymnotus carapo4,15,14 and Sternopygus macrurus16), armored catfish (Callichthys callichthys),4,8,11 and other species of bony fishes,4,11 but also lizards7 and snakes (Atractus major6 and Erythrolamprus reginae17). An instance of predation was recorded in Brazil in which the snake slowly approached and seized the fish, bit the prey, and released it after envenomation. The ingestion process initiated after 10 minutes.8 Aquatic Coralsnakes rely on their warning coloration as a primary defense mechanism. Individuals are usually calm and try to flee when threatened.2 If disturbed, they engage in complex and seemingly erratic behavior: they hide the head beneath body coils, crawl spasmodically forward and then backward, flatten their body dorso-ventrally, and display their bright tails as a decoy.36 They are also capable of striking if provoked. Aquatic Coralsnakes are proteroglyphous and venomous (LD50The median lethal dose (LD50) is a measure of venom strength. It is the minium dosage of venom that will lead to the deaths of 50% of the tested population. 0.2–0.4 mg/kg).18 The venom appears to have evolved mainly to immobilize aquatic prey,18,19 since it is more lethal to fish than to mice, snakes, or amphisbaenians.18 The venom is mostly neurotoxic2022 with little or not myotoxic (muscle breaking) activity,23 and the yield per bite is higher (up to 160 mg or 0.16 cc) than that of other Amazonian coralsnakes.2 In humans, it causes paresthesia (a burning or prickling sensation), blurred vision, muscle paralysis, difficulty breathing, and even death by respiratory arrest.2,24,25 Gravid females of M. surinamensis have been found to contain 5–12 eggs, and clutches of 8–13 eggs have been reported.3,2 The hatchlings measure 33–35 cm in total length.26

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Conservation: Least Concern Believed to be safe from extinction given current circumstances..2729 Micrurus surinamensis is included in this 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.27 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. Individuals of M. surinamensis also suffer from traffic mortality and direct killing at the hands of local people.3

Distribution: Micrurus surinamensis is widely distributed throughout Amazonia, occurring in Bolivia, Brazil, Colombia, Ecuador (Fig. 2), French Guiana, Guyana, Perú, and Suriname.

Distribution of Micrurus surinamensis in Ecuador

Figure 2: Distribution of Micrurus surinamensis in Ecuador. The type locality is Suriname. 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 genus.4 The species epithet surinamensis refers to the type locality: Suriname.4

See it in the wild: Aquatic Coralsnakes are usually found no more than once every few weeks at any given locality. In Ecuador, the areas having the greatest number of recent observations are Sani Lodge, Yasuní Scientific Station, and Jatun Sacha Biological Reserve. It appears that the best way to find Aquatic Coralsnakes is to walk along forest streams and swamps right after sunset, especially after a warm and rainy day.

Special thanks to Pieter Staarink for symbolically adopting the Aquatic Coralsnake and helping bring the Reptiles of Ecuador book project to life.

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

Photographers: Jose VieirabAffiliation: Tropical Herping (TH), Quito, Ecuador.,cAffiliation: ExSitu, Quito, Ecuador. and Amanda QuezadaaAffiliation: Khamai Foundation, Quito, Ecuador.

How to cite? Arteaga A (2021) Aquatic Coralsnake (Micrurus surinamensis). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: DOI: 10.47051/TZUI8784

Literature cited:

  1. 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.
  2. Silva Haad JJ (1994) Los Micrurus de la Amazonia Colombiana. Biología y toxicología experimental de sus venenos. Colombia Amazónica 7: 1–76.
  3. 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.
  4. Campbell JA, Lamar WW (2004) The venomous reptiles of the western hemisphere. Cornell University Press, Ithaca, 774 pp.
  5. 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
  6. Field notes, Reptiles of Ecuador book project.
  7. Martins M, Oliveira ME (1998) Natural history of snakes in forests of the Manaus region, Central Amazonia, Brazil. Herpetological Natural History 6: 78–150.
  8. Morais DH, Ávila RW, Kawashita-Ribeiro RA, Carvalho MA (2011) Squamata, Elapidae, Micrurus surinamensis (Cuvier, 1817): new records and distribution map in the state of Mato Grosso, Brazil, with notes on diet and activity period. Check List 7: 350–351.
  9. Silva Haad JJ, Rodríguez RA (1985) Las serpientes Micrurus de la Amazonía Colombiana. Amazonía 85: 26–28.
  10. Duellman WE (2005) Cusco amazónico: the lives of amphibians and reptiles in an Amazonian rainforest. Cornell University Press, Ithaca, 433 pp.
  11. Roze JA (1996) Coral snakes of the Americas: biology, indentification, and venoms. Krieger Publishing Company, Malabar, 328 pp.
  12. Hartdegen RW, Aucone B (2001) Natural history notes: Micrurus surinamensis surinamensis (NCN): arboreality. Herpetological Review 32: 264.
  13. Bertão Dávila PE, Takahashi HS, Oshiro Barbosa MH (2014) Micrurus surinamensis (Aquatic Coralsnake): behavior. Herpetological Review 45: 340.
  14. Schmidt KP (1952) The Surinam coral snake Micrurus surinamensis. Fieldiana: Zoology 34: 25–34.
  15. Bean BA (1924) A curious fish trap. Copeia 1924: 57–58.
  16. Tavares-Pinheiro R, Souza Melo F, Martins Barbosa de Figueiredo VA, Ribeiro Sanches P, Costa Anaissi JS, Salviano Santana MM, Oliveira-Souza AE, dos Santos Reis T, Lima Rebelo G, Vasconcelos Melo FT, Costa-Campos CE (2021) “In living color”: predation by the coralsnake Micrurus surinamensis (Cuvier, 1816) (Serpentes: Elapidae) on a knifefish in the eastern Amazon, Brazil. Herpetology Notes 14: 755–758.
  17. Pinto RR, Gomes M, Carvalho Jr R (2011) Micrurus surinamensis (Aquatic Coralsnake): ophiophagy. Herpetological Review 42: 441.
  18. da Silva Jr NJ, Aird SD (2001) Prey specificity, comparative lethality and compositional differences of coral snake venoms. Comparative Biochemistry and Physiology Part C 128: 425–456. DOI: 10.1016/s1532-0456(00)00215-5
  19. Sanz L, de Freitas-Lima LN, Quesada-Bernat S, Graça-de-Souzab VK, Soares AM, Calderón LdA, Calvete JJ, Caldeira CAS (2019) Comparative venomics of Brazilian coral snakes: Micrurus frontalis, Micrurus spixii spixii, and Micrurus surinamensis. Toxicon 166: 39–45. DOI: 10.1016/j.toxicon.2019.05.001
  20. Olamendi-Portugal T, Batista CVF, Restano-Cassulini R, Pando V, Villa-Hernandez O, Zavaleta-Martínez-Vargas A, Salas-Arruz MC, Rodríguez de la Vega RC, Becerril B, Possani LD (2008) Proteomic analysis of the venom from the fish eating coral snake Micrurus surinamensis: novel toxins, their function and phylogeny. Proteomics 8: 1919–1932. DOI: 10.1002/pmic.200700668
  21. Terra AL, Moreira-Dill LS, Simoes-Silva R, Monteiro JR, Cavalcante WL, Gallacci M, Barros NB, Nicolete R, Teles CB, Medeiros PS, Zanchi FB, Zuliani JP, Calderon LA, Stabeli RG, Soares AM (2015) Biological characterization of the Amazon coral Micrurus spixii snake venom: Isolation of a new neurotoxic phospholipase A2. Toxicon 103: 1-11. DOI: 10.1016/j.toxicon.2015.06.011
  22. Cecchini AL, Marcussi S, Silveira LB, Borja-Oliveira CR, Rodrigues-Simioni L, Amara S, Stábeli RG, Giglio JR, Arantes EC, Soares AM (2005) Biological and enzymatic activities of Micrurus sp. (Coral) snake venoms. Comparative Biochemistry and Physiology Part C 140: 125–134. DOI: 10.1016/j.cbpb.2004.11.012
  23. da Rocha Oliveira F, Nogueira Noronha MdD, Lopez Lozano JL (2017) Biological and molecular properties of yellow venom of the Amazonian coral snake Micrurus surinamensis. Revista da Sociedade Brasileira de Medicina Tropical 50: 365–373. DOI: 10.1590/0037-8682-0408-2016
  24. 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.
  25. de Oliveira Pardal PP, de Oliveira Pardal JS, da Costa Gadelha MA, da Silva Rodrigues L, Feitosa DT, da Costa Prudente AL, Fan HW (2010) Envenomation by Micrurus coral snakes in the Brazilian Amazon region: report of two cases. Revista do Instituto de Medicina Tropical de São Paulo 52: 333–337. DOI: 10.1590/S0036-46652010000600009
  26. Starace F (1998) Serpents et amphisbènes de Guyane Française. Ibis Rouge Editions, Guadeloupe, 450 pp.
  27. Ines Hladki A, Ramírez Pinilla M, Renjifo J, Urbina N, Nogueira C, Gonzales L, Hoogmoed M, Schargel W, Rivas G (2019) Micrurus surinamensis. The IUCN Red List of threatened species. Available from: DOI: 10.2305/IUCN.UK.2019-3.RLTS.T44582094A44582103.en
  28. 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.
  29. Carrillo E, Aldás A, Altamirano M, Ayala F, Cisneros-Heredia DF, Endara A, Márquez C, Morales M, Nogales F, Salvador P, Torres ML, Valencia J, Villamarín F, Yánez-Muñoz M, Zárate P (2005) Lista roja de los reptiles del Ecuador. Fundación Novum Millenium, Quito, 46 pp.

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

ColombiaCaquetáEl RochalDíaz-Ricaurte & Fiorillo 2019
ColombiaCaquetáEl RubíDíaz-Ricaurte & Fiorillo 2019
ColombiaCaquetáFlorencia, 6 km NW ofiNaturalist
ColombiaCaquetáMoreliaDíaz-Ricaurte & Fiorillo 2019
ColombiaCaquetáNavarcoDíaz-Ricaurte & Fiorillo 2019
ColombiaCaquetáTres Esquinas del CaguánDíaz-Ricaurte & Fiorillo 2019
ColombiaCaquetáVereda La FlorestaDíaz-Ricaurte & Fiorillo 2019
ColombiaCaquetáVereda La ViciosaDíaz-Ricaurte & Fiorillo 2019
ColombiaCaquetáVereda Los ÁngelesDíaz-Ricaurte & Fiorillo 2019
ColombiaCaquetáVereda PoreDíaz-Ricaurte & Fiorillo 2019
ColombiaCaquetáVereda San JuanDíaz-Ricaurte & Fiorillo 2019
ColombiaPutumayoFinca San CarlosDíaz-Ricaurte & Fiorillo 2019
ColombiaPutumayoSimón BolívariNaturalist
EcuadorMorona SantiagoAmazonasValencia et al. 2016
EcuadorMorona SantiagoCentro KusutkaValencia et al. 2016
EcuadorMorona SantiagoKiimValencia et al. 2016
EcuadorMorona SantiagoKushapucusMZUA.RE.0197
EcuadorMorona SantiagoMacumaValencia et al. 2016
EcuadorMorona SantiagoPaantimValencia et al. 2016
EcuadorMorona SantiagoSantiago de TiwintzaMCZ 45782
EcuadorMorona SantiagoShuin MamusiNaturalist
EcuadorMorona SantiagoTaishaPhoto by Axel Marchelie
EcuadorMorona SantiagoTunantsValencia et al. 2016
EcuadorNapoArchidonaOnline multimedia
EcuadorNapoChontapuntaValencia et al. 2016
EcuadorNapoFinca FischerTCWC 69458
EcuadorNapoJatun Sacha Biological StationVigle 2008
EcuadorNapoLiana LodgeiNaturalist
EcuadorNapoMisahuallíKU 202957
EcuadorNapoMuyunaValencia et al. 2016
EcuadorNapoPuerto MishuallíiNaturalist
EcuadorNapoRancho JohannaTCWC 68725
EcuadorNapoSan PedroValencia et al. 2016
EcuadorNapoSinchi SachaPhoto by Ernesto Arbeláez
EcuadorNapoSuchipakari LodgeThis work
EcuadorNapoTena, 5 km SW ofValencia et al. 2016
EcuadorNapoYachana ReserveWhitworth & Beirne 2011
EcuadorNapoYuralpaThis work
EcuadorNapoZoo el ArcaPhoto by Diego Piñán
EcuadorOrellanaCampo Repsol YPFValencia et al. 2016
EcuadorOrellanaDayumaValencia et al. 2016
EcuadorOrellanaEl CocaMHNG 2249.017
EcuadorOrellanaEl Coca, 15 km W ofiNaturalist
EcuadorOrellanaLaguna de JatuncochaValencia et al. 2016
EcuadorOrellanaMargen del Río NashiñoValencia et al. 2016
EcuadorOrellanaNPFPhoto by Neshat Shoghi
EcuadorOrellanaNuevo RocafuerteValencia et al. 2016
EcuadorOrellanaPuerto MirandaiNaturalist
EcuadorOrellanaSan José de PayaminoMaynard et al. 2016
EcuadorOrellanaTiputiniUSNM 232496
EcuadorOrellanaTiputini Biodiversity Station iNaturalist
EcuadorOrellanaVía Hollín–Loreto, km 77Valencia et al. 2016
EcuadorOrellanaVía Pompeya Sur–Iro, km 86Valencia et al. 2016
EcuadorOrellanaYasuní Scientific StationThis work
EcuadorPastazaAndoasValencia et al. 2016
EcuadorPastazaAnga CochaNogueira et al. 2019
EcuadorPastazaBalsauraOrtega-Andrade 2010
EcuadorPastazaBoca del Río CapahuariValencia et al. 2016
EcuadorPastazaJuyuintzaOrtega-Andrade 2010
EcuadorPastazaKillu AllpaNogueira et al. 2019
EcuadorPastazaMontalvoValencia et al. 2016
EcuadorPastazaRío CopatazaValencia et al. 2016
EcuadorPastazaRío CorrientesUSNM 232497
EcuadorPastazaRío Pastaza Valencia et al. 2016
EcuadorPastazaRío RutunoUSNM 232499
EcuadorPastazaRío TzapinoCampbell & Lamar 2004
EcuadorPastazaShiripuno LodgeOnline multimedia
EcuadorPastazaUyuimiOnline multimedia
EcuadorPastazaUyuimiPhoto by Darwin Núñez
EcuadorSucumbíosCampo LibertadorValencia et al. 2016
EcuadorSucumbíosCampo UnitaValencia et al. 2016
EcuadorSucumbíosDurenoYánez-Muñoz & Chimbo 2007
EcuadorSucumbíosGarzacochaYánez-Muñóz & Venegas 2008
EcuadorSucumbíosLagartocochaUSNM 232495
EcuadorSucumbíosLago AgrioValencia et al. 2016
EcuadorSucumbíosPlayas del CuyabenoValencia et al. 2016
EcuadorSucumbíosReserva de Producción Faunística CuyabenoFMNH 2008
EcuadorSucumbíosRío AguaricoNogueira et al. 2019
EcuadorSucumbíosSan Pablo de KantesiyaValencia et al. 2016
EcuadorSucumbíosSan Pedro de los CofanesiNaturalist
EcuadorSucumbíosSani LodgeThis work
EcuadorSucumbíosSanta CeciliaDuellman 1978
PeruAmazonasAguaruna VillageMVZ 163331
PeruAmazonasCaterpizaUSNM 566631
PeruAmazonasHuampamiUSNM 316654
PeruAmazonasTeniente PingloUSNM 566634
PeruLoretoAguas NegrasFMNH 2008
PeruLoretoPuerto Nuevo de Parinari, 7 km S ofiNaturalist
PeruLoretoReserva Nacional Pacaya SamiriaiNaturalist
PeruLoretoZona de Reserva GüepiiNaturalist