Published October 30, 2021. Open access. | Gallery ❯ |
Merten’s Coralsnake (Micrurus mertensi)
Reptiles of Ecuador | Serpentes | Elapidae | Micrurus | Micrurus mertensi
English common name: Merten’s Coralsnake.
Spanish common name: Coral de Mertens.
Recognition: ♂♂ 80 cmMaximum distance from the snout to the tip of the tail. ♀♀ 91.5 cmMaximum distance from the snout to the tip of the tail..1 In western Ecuador, true coral snakes (genus Micrurus) can be distinguished from most, but no all, false coral snakes by having brightly colored rings that encircle the body (rings evident on the belly), small eyes that are about the same size as the post-ocular scales, and no loreal scale.1,2 The Merten’s Coralsnake (M. mertensi) is one of three species of the genus occurring in the dry forests of southwestern Ecuador. From these, it is the only one having a tricolored pattern and black body rings arranged in monads.1,2 Micrurus mertensi can be confused with M. bocourti, but this other species has black rings arranged in triads, and the red interspaces are much wider than the black rings (red rings about the same size as the black rings in M. mertensi).1,2 Males of the Merten’s Coralsnake differ from females by having longer tails with a greater (7–9 vs 5–6) number of black rings.2 The combination of small eyes and black rings arranged in monads separates M. mertensi from the Ecuadorian Milksnake (Lampropeltis micropholis).3
Figure 1: Adult male of Micrurus mertensi from Sabiango, Loja province, Ecuador.
Natural history: UncommonUnlikely to be seen more than once every few months.. Micrurus mertensi is a terrestrial to semi-fossorial (living underground and at ground level) snake that inhabits pristine to heavily disturbed seasonally dry forests, usually close to bodies of water.1,2 This species also occurs in human-modified environments adjacent forested areas.1 Individuals have been seen active on soil, leaf-litter, or crossing roads during day or at night.1,4 These snakes forage actively in search of prey, which includes snakes (Epictia subcrotilla,5 Bothrops pictus,5 and unidentified colubrids).1 Merten’s 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.1,4 They are also capable of striking if provoked. Individuals of M. mertensi are proteroglyphous (having fixed enlarged teeth towards the front of the maxilla) and venomous. Their venom is neurotoxic and is probably lethal to humans, but no published records of envenomation exist.1
Conservation: Least Concern Believed to be safe from extinction given current circumstances.. Micrurus mertensi has not been formally included in any IUCN Red List threat category. Here, the species is proposed to be assigned to the Least Concern category following IUCN criteria6 because the species is distributed over an area greater than 10,000 km2 and is currently facing no major widespread immediate extinction threats. However, in Ecuador, the species may qualify for a threatened conservation category. Based on maps of Ecuador’s vegetation cover published in 2012,7 an estimated 42% of the native dry forest habitat of M. mertensi has already been destroyed in this country, mostly due to cattle ranching. Furthermore, vehicular traffic and the fear of snakes are also confirmed sources of mortality to individuals of this species.4 Fortunately, Peruvian populations appear to be in better shape, and a major part of the species’ range is in the Cerros Amotape National Park and Tumbes Reserved Zone.
Distribution: Micrurus mertensi is native to the Tumbesian lowlands of extreme southwestern Ecuador (provinces Azuay and Loja) and northwestern Peru. The species has been recorded at elevations between 480 m and 1904 m (Fig. 2).
Figure 2: Distribution of Micrurus mertensi in Ecuador. The type locality is Pacasmayo, Peru. See Appendix 1 for a complete list of the presence localities included in the map.
Etymology: The generic name Micrurus, which is derived from the Greek words mikros (meaning “small”) and oura (meaning “tail”), refers to the short tail in members of this genus.2 The species epithet mertensi honors European herpetologist Robert Friedrich Wilhelm Mertens (1894–1975), director of the Senckenberg Museum and author of herpetology books and papers describing new species of reptiles.2
See it in the wild: Merten’s 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 Jorupe Reserve, and the immediate environs of the town Yangana. It appears that the best way to find Merten’s Coralsnakes is to walk along forest trails or to slowly cruise dirt roads right after sunset.
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 and photographer: Alejandro ArteagaaAffiliation: Khamai Foundation, Quito, Ecuador.
How to cite? Arteaga A (2021) Merten’s Coralsnake (Micrurus mertensi). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: www.reptilesofecuador.com. DOI: 10.47051/FPAZ6837
Literature cited:
- 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.
- Campbell JA, Lamar WW (2004) The venomous reptiles of the western hemisphere. Cornell University Press, Ithaca, 774 pp.
- Peters JA (1960) The snakes of Ecuador; check list and key. Bulletin of the Museum of Comparative Zoology 122: 489–541.
- Field notes, Reptiles of Ecuador book project.
- Roze JA (1996) Coral snakes of the Americas: biology, indentification, and venoms. Krieger Publishing Company, Malabar, 328 pp.
- IUCN (2001) IUCN Red List categories and criteria: Version 3.1. IUCN Species Survival Commission, Gland and Cambridge, 30 pp.
- MAE (2012) Línea base de deforestación del Ecuador continental. Ministerio del Ambiente del Ecuador, Quito, 30 pp.
Appendix 1: Locality data used to create the distribution map of Micrurus mertensi in Ecuador (Fig. 2). Go to the section on symbols and abbreviations for a list of acronyms used.
| Country | Province | Locality | Source |
| Ecuador | Azuay | Santa Isabel | Valencia et al. 2016 |
| Ecuador | Loja | Algodonal | Campbell & Lamar 2004 |
| Ecuador | Loja | Celica | Photo by Jorge Castillo |
| Ecuador | Loja | Hacienda Juanes | Parker 183 |
| Ecuador | Loja | Jorupe Reserve | This work |
| Ecuador | Loja | Pinto Castillo | This work |
| Ecuador | Loja | Reserva Natural Rumi Wilco | Valencia et al. 2016 |
| Ecuador | Loja | Sabiango, 1 km N of | This work |
| Ecuador | Loja | Valle del Catamayo | Valencia et al. 2016 |
| Ecuador | Loja | Vilcabamba | Photo by Eduardo Zavala |
| Ecuador | Loja | Yamburara | Valencia et al. 2016 |
| Ecuador | Loja | Yangana | Valencia et al. 2016 |
| Ecuador | Loja | Yangana, 1 km S of | Valencia et al. 2016 |
| Ecuador | Loja | Yangana, 1.87 km W | iNaturalist |
| Peru | Piura | Barrios | MCZ 45913 |
| Peru | Piura | Hacienda San Martín | iNaturalist |
| Peru | Tumbes | Quebrada Faical | LSUMZ 38324 |
| Peru | Tumbes | Quebrada Los Naranjos | Tello 1998 |