Published November 17, 2020. Open access.

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Olive Marsh-Snake (Erythrolamprus fraseri)

Reptiles of Ecuador | Serpentes | Colubridae | Erythrolamprus | Erythrolamprus fraseri

English common names: Olive Marsh-Snake, Fraser’s Marsh-Snake.

Spanish common names: Culebra pantanera aceituna, culebra de Fraser.

Recognition: ♂♂ 66.8 cmMaximum distance from the snout to the tip of the tail. ♀♀ 69 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=54 cm.. The Olive Marsh-Snake (Erythrolamprus fraseri) is a medium-sized snake having an olive, olive brown, or grayish brown dorsal coloration with thin black stripes along the posterior half of the body and tail.1 Individuals of this species are distinguished from other greenish Andean diurnal snakes in southern Ecuador (particularly Chironius monticola, Dendrophidion brunneum, Leptophis occidentalis, and Mastigodryas heathii) by being smaller (total length <1 m), having contrasting black stripes on the body (not only on the tail), and by having black-checkered yellow ventral surfaces. The most similar snake in size and coloration that may approach the distribution of E. fraseri in southwestern Ecuador is E. albiventris, a snake that has a leaf-green dorsal coloration and a immaculate yellow venter.1 Young individuals of E. fraseri usually have a black nape band.

Figure showing variation among individuals of Erythrolamprus fraseri in Ecuador

Figure 1: Individuals of Erythrolamprus fraseri from Guachapala (), Azuay province, and Azogues (), Cañar province, Ecuador. a=adult, sa=subadult.

Natural history: UncommonUnlikely to be seen more than once every few months. to frequentRecorded weekly in densities below five individuals per locality.. Erythrolamprus fraseri is a diurnal and terrestrial snake that inhabits humid to dry montane shrublands, highland grasslands, high evergreen montane forests, and areas having a matrix of pastures, plantations, rural gardens, and remnants of native vegetation. Individuals occur in rural gardens, along roads, and occasionally inside houses.24 They also seem to be particularly frequent in marshes, swamps, and along streams.3,5 Most active individuals are seen during sunny hours in the morning, basking in open areas or foraging on leaf-litter, mud, or among tall grass.24 When not active, individuals hide under trunks.5 Olive Marsh-Snakes are active hunters of amphibians. Their dentition is aglyphous,6 meaning their teeth lack specialized grooves to deliver venom. Their diet is based primarily on frogs (including Gastrotheca cuencana, Pristimantis lutzae, and P. lymanni), and tadpoles of Gastrotheca.3,7 Individuals are usually calm and try to flee when threatened, relying mostly on crypsis as a primary defense mechanism. If disturbed, they may flatten their body dorsoventrally and produce a musky and distasteful odor.2

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Conservation: Near Threatened Not currently at risk of extinction, but requires some level of management to maintain healthy populations.. The status of Erythrolamprus fraseri has not yet been formally assessed by the IUCN. In this account, the species is proposed to be assigned to the Near Threatened category given that its wide distribution precludes it from being included in a threatened category.8 The main threat to the long-term survival of populations of E. fraseri is the continuing decline in the extent and quality of its habitat, mostly due to encroaching human activities such as agriculture, cattle grazing, wild fires, and the replacement of native vegetation with eucalyptus and pine trees. It is estimated that in Ecuador, ~56.2% of the natural habitat of the species has already been destroyed.9 Olive Marsh-Snakes also suffer from traffic-related mortality.4 Therefore, the species may qualify for a threatened category in the near future if these threats are not addressed. However, there is no current information on the population trend of E. fraseri to determine whether its numbers are declining.

Distribution: Erythrolamprus fraseri is native to the inter-Andean valleys and both slopes of the Andes from southern Ecuador to central Peru.1 In Ecuador, the species occurs over an estimated ~11,989 km2 area at elevations between 1845 and 2806 m (Fig. 2).

Distribution of Erythrolamprus fraseri in Ecuador

Figure 2: Distribution of Erythrolamprus fraseri 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 (meaning “red”) and lampros (meaning “brilliant”),10 refers to the bright red body rings of some snakes in this genus (such as E. aesculapii). The specific epithet fraseri honors Louis Fraser, a British zoologist and naturalist who collected the specimen on which the original description of the species was based.11

See it in the wild: In Ecuador, Olive Marsh-Snakes are recorded usually no more than once a week at any given locality. However, in areas having low vehicle traffic, such as along the Sendero Caxarumi, Loja province, individuals may be seen more frequently. The snakes may be spotted as they cross trails and roads in areas of highland shrubland, especially during the early morning.

Acknowledgments: Special thanks to Amanda Quezada, Ernesto Arbeláez, Jose Manuel Falcón, and Pablo Loaiza for providing locality data and natural history information for Erythrolamprus fraseri. 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).

Special thanks to Dr. Robert A. Thomas for symbolically adopting the Olive Marsh-Snake and helping bring the Reptiles of Ecuador book project to life.

Click here to adopt a species.

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

Photographers: Jose VieiraaAffiliation: Tropical Herping (TH), Quito, Ecuador.,bAffiliation: ExSitu, Quito, Ecuador. and Frank PichardoaAffiliation: Tropical Herping (TH), Quito, Ecuador.

How to cite? Arteaga A (2020) Olive Marsh-Snake (Erythrolamprus fraseri). In: Arteaga A, Bustamante L, Vieira J, Guayasamin JM (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: DOI: 10.47051/XXDZ6274

Literature cited:

  1. Dixon JR (1983) Systematics of the Latin American snake Liophis epinephelus (Serpentes: Colubridae). In: Rhodin AGJ, Miyamata K (Eds) Advances in herpetology and evolutionary biology. Museum of Comparative Zoology, Cambridge, 132–149.
  2. Field notes, Reptiles of Ecuador book project.
  3. Ernesto Arbeláez, pers. comm.
  4. Darwin Núñez, pers. comm.
  5. Jose Manuel Falcón, pers. comm.
  6. 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.
  7. Pablo Loaiza, pers. comm.
  8. IUCN (2001) IUCN Red List categories and criteria: Version 3.1. IUCN Species Survival Commission, Gland and Cambridge, 30 pp.
  9. MAE (2012) Línea base de deforestación del Ecuador continental. Ministerio del Ambiente del Ecuador, Quito, 30 pp.
  10. Brown RW (1956) Composition of scientific words. Smithsonian Books, Washington D.C., 882 pp.
  11. Boulenger GA (1894) Catalogue of the snakes in the British Museum (Natural History). British Museum of Natural History, London, 382 pp.

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

EcuadorAzuayChalluabambaThis work
EcuadorAzuayCuencaErnesto Arbeláez, pers. comm.
EcuadorAzuayEl ProgresoJorge Luis Romero, pers. comm.
EcuadorAzuayGuachapalaErnesto Arbeláez, pers. comm.
EcuadorAzuayGuarumalesThis work
EcuadorAzuayLuz MaríaTorres-Carvajal & Hinojosa 2020
EcuadorAzuayOñaPablo Loaiza, pers. comm.
EcuadorAzuayPauteErnesto Arbeláez, pers. comm.
EcuadorAzuaySevilla de OroUSNM 232831
EcuadorAzuayVía a JadánThis work
EcuadorBolívar7.5 km S GuarandaKU 202952
EcuadorBolívarRío TatahuazoTorres-Carvajal & Hinojosa 2020
EcuadorBolívarSan José de ChimboAMNH 17498
EcuadorCañarAzoguesThis work
EcuadorChimborazoSan Vicente de AsacotoAlmendáriz & Orcés 2004
EcuadorEl OroChillaTorres-Carvajal & Hinojosa 2020
EcuadorLoja12 km S LojaDixon 1983
EcuadorLoja7 km N LojaDixon 1983
EcuadorLojaAbra de ZamoraKU 202953
EcuadorLojaCajanumaTorres-Carvajal & Hinojosa 2020
EcuadorLojaCatamayo, on way to LojaJose Manuel Falcón, pers. comm.
EcuadorLojaCaxarumiDarwin Núñez, pers. comm.
EcuadorLojaCelica, 10 km N ofDixon 1983
EcuadorLojaCurishiroQCAZ 816
EcuadorLojaLojaAMNH 22095
EcuadorLojaLoja, 3 km E ofUSNM 232833
EcuadorLojaMadrigal del PodocarpusiNaturalist
EcuadorLojaMalacatos, cerrosJose Manuel Falcón, pers. comm.
EcuadorLojaMasaconsaMCZ 93590
EcuadorLojaPindal, on way to CelicaJose Manuel Falcón, pers. comm.
EcuadorLojaReserva TapichalacaQCAZ 6421
EcuadorLojaSan José de MacaráMZUA.RE.0079
EcuadorLojaSan LucasField notes of Felipe Campos
EcuadorLojaSan RamónDixon 1983
EcuadorLojaUtuanaMECN 2013
EcuadorLojaVia antigua Loja–ZamoraDarwin Núñez
EcuadorLojaYangana, 3 km SE ofiNaturalist
EcuadorZamora ChinchipeEstación San FranciscoMZUA.RE.0149
PeruPiuraHuancabambaDixon 1983