Published April 29, 2024. Open access.

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Pygmy Marsh-Snake (Erythrolamprus pygmaeus)

Reptiles of Ecuador | Serpentes | Colubridae | Erythrolamprus pygmaeus

English common name: Pygmy Marsh-Snake.

Spanish common name: Culebra pantanera pigmea.

Recognition: ♂♂ 23.2 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=19.4 cm. ♀♀ 24.7 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=20.7 cm..1 Erythrolamprus pygmaeus is the smallest species of its genus and can be identified by having a unique coloration. The dorsum is grayish-brown with a series of dorsolateral oblique bars followed by a series of black spots or blotches, thereafter continuing as a lateral stripe on each side of the body ending at the tip of the tail (Fig. 1).14 No other snake in the Ecuadorian Amazon has this pattern. The ventral surfaces are immaculate white.1 The head is uniformly olive-brown followed by a black nuchal band.14 This species differs from E. chrysostomus, E. lamonae, and E. reginae by lacking black marks on the belly.5 From Taeniophallus brevirostris, it differs by lacking undulating cream dorsolateral bands.6

Figure showing a juvenile individual of Erythrolamprus pygmaeus

Figure 1: Juvenile of Erythrolamprus pygmaeus from Parque Miraflores, Huila department, Colombia.

Natural history: Erythrolamprus pygmaeus is an extremely rare diurnal and terrestrial to semi-aquatic snake that inhabits rainforests, which may be terra-firme or seasonally flooded.1,3 The species also occurs in disturbed areas such as open fields and crops, but usually not far from the forest border or from water bodies.1,3,7 The swamp snake is diurnal and typically dwells on the leaf-litter, but most other aspects of its natural history remain unknown. Its dentition is aglyphous, meaning the teeth lack specialized grooves to deliver venom.8 In Brazil, remnants of insects were found in the hindgut of a specimen, presumably the result of secondary ingestion of a frog.3 There is a recorded instance of predation on an individual of E. pygmaeus by the coralsnake Micrurus obscurus.1 When threatened, the Pygmy Marsh-Snake expands the neck and anterior part of the body, creating a kind of hood.4 A gravid female in Ecuador laid a clutch of four eggs.7

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Conservation: Least Concern Believed to be safe from extinction given current circumstances..9 Erythrolamprus pygmaeus is listed in this category mainly on the basis of the species’ wide distribution, occurrence in protected areas, and presumed large stable populations. Therefore, the species is considered to be facing no major immediate extinction threats.

Distribution: Erythrolamprus pygmaeus is widely distributed throughout the Amazon basin in Brazil, Colombia, Ecuador (Fig. 2), Peru, and Venezuela.

Distribution of Erythrolamprus pygmaeus in Ecuador

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

Etymology: The name Erythrolamprus, which comes from the Greek words erythros (=red) and lampros (=brilliant),10 refers to the bright red body rings of some snakes in this genus (such as E. aesculapii). The specific epithet pygmaeus is a Latin word meaning “dwarf.”10 It refers to the size of this species, the smallest among its genus.

See it in the wild: In Ecuador, Pygmy Marsh-Snakes are recorded no more than once every few years. The area having the greatest number of observations of this species is the environs of the town Macuma. Active snakes can be found by walking along forest trails during the day.

Authors: Tatiana Molina-Moreno,aAffiliation: Departamento de Biología, Universidad de los Llanos, Villavicencio, Colombia. Sophia Hurtado,bAffiliation: Universidad ICESI, Cali, Colombia. Andrés F. Aponte-Gutiérrez,cAffiliation: Grupo de Investigación en Ciencias de la Orinoquía, Universidad Nacional de Colombia sede Orinoquía, Arauca, Colombia.,dAffiliation: Fundación Biodiversa Colombia, Bogotá, Colombia. and Alejandro ArteagaeAffiliation: Tropical Herping (TH), Quito, Ecuador.

Photographer: Duvan ZambranofAffiliation: Universidad del Tolima, Ibagué, Colombia.

How to cite? Molina-Moreno T, Hurtado S, Aponte-Gutiérrez AF, Arteaga A (Erythrolamprus pygmaeus). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: DOI: 10.47051/MWQG1008

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. Cope ED (1868) An examination of the Reptilia and Batrachia obtained by the Orton Expedition to Equador and the Upper Amazon, with notes on other species. Proceedings of the Academy of Natural Sciences of Philadelphia 20: 96–140.
  3. Martins M, Oliveira ME (1998) Natural history of snakes in forests of the Manaus region, Central Amazonia, Brazil. Herpetological Natural History 6: 78–150.
  4. Kawashita-Ribeiro RA, de Carvalho VT, de Lima AC, Ávila RW, de Fraga R (2011) Morphology and geographical distribution of the poorly known snake Umbrivaga pygmaea (Serpentes: Dipsadidae) in Brazil. Phyllomedusa 10: 177-182.
  5. Dixon JR (1989) A key and checklist to the neotropical snake genus Liophis with country lists and maps. Smithsonian Herpetological Information Service 79: 1–40. DOI: 10.5479/si.23317515.79.1
  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. Social media post by Alex Bentley.
  8. Hurtado-Gómez JP (2016) Systematics of the genus Erythrolamprus Boie 1826 (Serpentes: Dipsadidae) based on morphological and molecular data. PhD thesis, Universidade de São Paulo, 62 pp.
  9. Caicedo JR, Calderón M, Ines Hladki A, Ramírez Pinilla M, Renjifo J, Rivas G, Urbina N, Nogueira CC (2019) Erythrolamprus pygmaeus. The IUCN Red List of threatened species. Available from: DOI: 10.2305/IUCN.UK.2019-3.RLTS.T44581678A44581687.en
  10. 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 Erythrolamprus pygmaeus in Ecuador (Fig. 2). Go to the section on symbols and abbreviations for a list of acronyms used.

ColombiaCaquetáSanto DomingoiNaturalist; photo examined
ColombiaCaucaSanta RosaLondoño et. al. 2023
ColombiaPutumayoMocoaDunn 1944
ColombiaPutumayoReserva La Isla EscondidaiNaturalist; photo examined
ColombiaPutumayoRío GuamuezBentley & Brown 2023; SiB
EcuadorLimoncochaReserva Biológica LimoncochaTorres-Carvajal & Hinojosa 2020
EcuadorMorona SantiagoAmazonas, 3 mi E ofiNaturalist; photo examined
EcuadorMorona SantiagoMacasMHNG 2397.058; collection database
EcuadorMorona SantiagoRío MacumaiNaturalist; photo examined
EcuadorNapoEl SaladoKU 155509; VertNet
EcuadorNapoEstación Biológica Jatun SachaVigle 2008
EcuadorNapoJondachiiNaturalist; photo examined
EcuadorNapoYachana ReserveReptiles of Ecuador book database
EcuadorOrellanaRío Bigal Biological ReserveGarcía et al. 2021
EcuadorOrellanaRío HuataracoUSNM 233067; VertNet
EcuadorPastazaAvícola IsabeliNaturalist; photo examined
EcuadorPastazaCanelosUSNM 233069; VertNet
EcuadorPastazaMeraiNaturalist; photo examined
EcuadorPastazaMontalvoMSH data; collection database
EcuadorPastazaReserva TamandúaPhoto by Jorge Flores
EcuadorPastazaRío TigreDal Vechio 2015
EcuadorPastazaSarayacuOrtega-Andrade 2010
EcuadorPastazaSumak Kawsay In SituBentley et al. 2021
EcuadorSucumbíosEl ReventadorMHNG 2397.059; collection database
EcuadorZamora ChinchipeZamoraDal Vechio 2015
PeruAmazonasYutupisDal Vechio 2015
PeruLoretoAngoterosDal Vechio 2015
PeruLoretoCentro UniónTCWC 41426; VertNet
PeruLoretoMishanaTCWC 42111; VertNet
PeruLoretoMoroponTCWC 40545; VertNet
PeruLoretoRío MarañónDal Vechio 2015
PeruLoretoSan JacintoKU 222202; VertNet