Published June 6, 2021. Open access.

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Mountain Centipede-Snake (Tantilla insulamontana)

Reptiles of Ecuador | Serpentes | Colubridae | Tantilla | Tantilla insulamontana

English common name: Mountain Centipede-Snake.

Spanish common name: Culebra ciempiés de montaña.

Recognition: ♂♂ 24.9 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=18.2 cm. ♀♀ 40.4 cmMaximum distance from the snout to the tip of the tail..1 The Mountain Centipede-Snake (Tantilla insulamontana) may be recognized from other snakes in its area of distribution by having a round head similar in width to the neck, small eyes, no loreal scale, and a brown head cap with a pale snout tip, and dorsal pattern consisting of faint dark longitudinal lines on a uniform tan dorsum.1,2 The most similar snakes occurring in the valley of the Río Jubones are those in the genus Atractus, which have a loreal scale and lack longitudinal lines.3 The most similar species that occur near the known distribution of T. insulamontana are T. capistrata and T. melanocephala, but these other species have a much more clearly marked head cap that includes a blackish nape band (absent in T. insulamontana).1,4 Juveniles of the Mountain Centipede Snakes have a much more contrasting dorsal pattern that becomes fainter with age.

Figure showing variation among individuals of Tantilla insulamontana

Figure 1: Individuals of Tantilla insulamontana from Oña, Loja province, Ecuador. ad=adult, j=juvenile.

Natural history: RareTotal average number of reported observations per locality less than ten., but apparently more frequent during the rainy season (December–April).5,6 Tantilla insulamontana is a semi-fossorial (living underground and at ground level) snake that inhabits the dry to humid highland shrubland ecosystem. It occurs in areas areas containing a matrix of native vegetation, rural gardens, human settlements, and pastures.5,7 Mountain Centipede-Snakes have been seen active during overcast days, at dusk, or at night after a rainy day.1,5 They are seen crossing dirt roads or moving on soil, leaf-litter, among roots, rocks, or in crevices.5,6 One individual was moving at ground level besides bamboo thickets along a river.1 Inactive individuals have been found hidden under rocks,7 logs,5 buried 60 cm under soft soil,6 or in leaf-litter in banana plantations.8 There is an unpublished record of a wandering spider (Ctenidae) preying upon an individual of this species.5 Although there is no information about the diet of T. insulamontana, it is likely that it feeds primarily on centipedes, as is the case for other members of the genus.9 Camouflage and trying to to flee are the most common defense behaviors seen in this species.

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Conservation: Endangered Considered to be facing a high risk of extinction in the near future.. Tantilla insulamontana is proposed to be listed in this category, instead of Critically Endangered,10,11 because new data suggests that the species’ extent of occurrence (1,069 km2; see Appendix 1), though small, is greater than the 100 km2 required for inclusion in the more threatened category.12 Still, the specie’s habitat is under pressure due to increased human activities such as infrastructure expansion, agriculture, and livestock grazing.10 Based on maps of Ecuador’s vegetation cover published in 2012,13 an estimated ~57% of the native shrubland habitat of T. insulamontana has already been destroyed. Furthermore, Yunguilla Biological Reserve is the only protected area where the species has been reported. There is anecdotal information5 that suggests that this snake species suffer from intense traffic mortality.

Distribution: Tantilla insulamontana is endemic to an estimated 1,069 km2 area in the xeric inter-Andean valley of the Río Jubones in southern Ecuador. The species has been recorded only in Azuay, El Oro, and Loja provinces at elevations between 1023 and 2411 m (Fig. 2).

Distribution of Tantilla insulamontana in Ecuador

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

Etymology: The generic name Tantilla, which is derived from the Latin word tantillus (meaning “so little”),14 is probably a reference to the small body size of snakes of this genus. The specific epithet insulamontana is Latin, meaning “island in the mountains.” This refers to the species’ distribution, isolated in a xeric inter-Andean valley.1

See it in the wild: Mountain Centipede-Snakes are rarely encountered. Individuals are found no more than once every few months and usually only by chance. It appears the best way to find individuals is to slowly cruise through dirt roads along areas of well-preserved shrubland at dusk, during the rainy season. Another option is to flip surface objects in clearing besides these areas during the daytime.

Acknowledgments: Special thanks to José Manuel Falcón and Jorge Brito for providing locality data and information on the natural history of Tantilla insulamontana. 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.

Photographer: Jose VieiraaAffiliation: Tropical Herping (TH), Quito, Ecuador.,bAffiliation: ExSitu, Quito, Ecuador.

How to cite? Arteaga A (2021) Mountain Centipede-Snake (Tantilla insulamontana). 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/LOBL7299

Literature cited:

  1. Wilson LD, Mena CE (1980) Systematics of the melanocephala group of the colubrid snake genus Tantilla. Memoirs of the San Diego Society of Natural History 11: 5–58.
  2. Peters JA, Orejas-Miranda B (1970) Catalogue of Neotropical Squamata: part I, snakes. Bulletin of the United States National Museum, Washington, D.C., 347 pp.
  3. Savage JM (1960) A revision of the Ecuadorian snakes of the Colubrid genus Atractus. Miscellaneous Publications, Museum of Zoology, Univesity of Michigan 112: 1–184.
  4. Wilson LD (1990) Tantilla insulamontana Wilson & Mena. Catalogue of American Amphibians and Reptiles 502: 1.
  5. Jose Manuel Falcón, pers. comm.
  6. Jorge Brito, pers. comm.
  7. Field notes, Reptiles of Ecuador book project.
  8. Almendáriz A, Brito J (2011) Anfibios y reptiles. In: Albuja L (Ed) Biodiversidad de los valles secos interandinos del Ecuador. Escuela Politécnica Nacional, Quito, 41–48.
  9. Savage JM (2002) The amphibians and reptiles of Costa Rica, a herpetofauna between two continents, between two seas. The University of Chicago Press, Chicago, 934 pp.
  10. Arteaga A, Yánez-Muñoz M, Valencia J, Cisneros-Heredia DF (2017) Tantilla insulamontana. The IUCN red list of threatened species. Available from: DOI: 10.2305/IUCN.UK.2017-2.RLTS.T203317A2763862.en
  11. 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.
  12. IUCN (2001) IUCN Red List categories and criteria: Version 3.1. IUCN Species Survival Commission, Gland and Cambridge, 30 pp.
  13. MAE (2012) Línea base de deforestación del Ecuador continental. Ministerio del Ambiente del Ecuador, Quito, 30 pp.
  14. 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 Tantilla insulamontana in Ecuador (Fig. 2). Go to the section on symbols and abbreviations for a list of acronyms used. Asterisk (*) indicates type locality.

EcuadorAzuayGirón, 2 km SW ofWilson & Mena 1980
EcuadorAzuayJubonesJosé Manuel Falcón, pers. comm.
EcuadorAzuayOñaPhoto by Darwin Núñez
EcuadorAzuayPoetateThis work
EcuadorAzuayReserva Biológica YunguillaMZUA.RE.0023
EcuadorAzuayRío Minas*Wilson & Mena 1980
EcuadorAzuayRircay–LentagJosé Manuel Falcón, pers. comm.
EcuadorAzuaySanta IsabelJorge Brito, pers. comm.
EcuadorAzuaySanta MartaJosé Manuel Falcón, pers. comm.
EcuadorAzuaySulupali GrandeiNaturalist
EcuadorAzuaySulupali–AndataliaJorge Brito, pers. comm.
EcuadorAzuayTendales, nearbyJosé Manuel Falcón, pers. comm.
EcuadorAzuayVía Santa Isabel–SulupaliJosé Manuel Falcón, pers. comm.
EcuadorAzuayVicinities of SusudelThis work
EcuadorAzuayYunguillaWilson & Mena 1980
EcuadorEl OroAbañínJosé Manuel Falcón, pers. comm.
EcuadorEl OroSan FranciscoJosé Manuel Falcón, pers. comm.
EcuadorLojaOña, 2.7 km SW ofThis work
EcuadorLojaSan SebastiánJosé Manuel Falcón, pers. comm.
EcuadorLojaUchucayJorge Brito, pers. comm.