Published December 9, 2021. Open access.

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Variable Worm-Lizard (Amphisbaena varia)

Reptiles of Ecuador | Amphisbaenia | Amphisbaena varia

English common name: Variable Worm-Lizard.

Spanish common names: Pudridora del Chocó, pudridora, culebra ciega de la costa (Ecuador); lagarto gusano moteado, lagartija gusano, tatacoa (Colombia); lagarto de dos cabezas (Panamá).

Recognition: ♂♂ 42.4 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=40.4 cm..1 The Variable Worm-Lizard (Amphisbaena varia) is a unique reptile, neither lizard nor snake, it belongs to the suborder Amphisbaenia.2,3 It can be easily distinguished by the presence of the following two features: white or light pink background color with very dense black markings that resemble a checkerboard and scales arranged in rings around the body.4,5 The eyes of this species are small, vestigial, but functional; hence the local name culebra ciega (which means “blind snake”). In western Ecuador, there is no other snake or lizard that looks remotely similar to A. varia.

Figure variation among individuals of Amphisbaena varia

Figure 1: Individuals of Amphisbaena varia from Durango () and Gualpí (), Esmeraldas province, Ecuador.

Natural history: RareTotal average number of reported observations per locality less than ten..1,6 Amphisbaena varia is a fossorial and primarily nocturnal reptile that spends most of the time in galleries built by the animal itself.1 Variable Worm-Lizards come to the surface only occasionally, especially during twilight or at night. Some individuals have been seen moving on soil or leaf-litter during the day, particularly when their underground burrows are flooded by rains.1,7 One individual was found in a presumably self-made burrow under a large stump.1 Amphisbaena varia can be found in old growth to moderately disturbed rainforests, as well as in clearings, urban and peri-urban areas, plantations,1,7 compost bins in rural gardens,7 and inside houses.8 This reptile has an extremely muscular body that allows it to dig its own tunnels. It also has a rectilinear form of locomotion that resembles the way a worm moves.9 As a defense mechanism, Variable Worm-Lizards react by trying to flee or bury themselves quickly. If captured, they contract their body, bite,1 or shed the tail.7 There is a record of an Anchor Coralsnake (Micrurus ancoralis) preying upon an individual of this species.10 Amphisbaena varia is an oviparous species, but the nesting sites are not known. Other Amphisbaena lay eggs inside the nests of ants or termites.11

Conservation: Least Concern Believed to be safe from extinction given current circumstances..12,13 Amphisbaena varia is listed this category because it is widely distributed, especially in areas that have not been heavily affected by deforestation, like the Colombian Pacific coast, and it is unlikely to be declining fast enough to qualify for a more threatened category. However, the species could suffer local population declines due to habitat destruction and the excessive use of pesticides that decimate insect populations, such as ants or termites, which perhaps are crucial in the life cycle of A. varia. Vehicular traffic is another source of mortality for Variable Worm-Lizards.1,7 Given their terrestrial habits and their low ability to move on the ground, these animals cannot easily dodge cars and are frequently run over.

Distribution: Amphisbaena varia occurs in the Mesoamerican lowlands of eastern Central America, the Chocó region of northwestern South America, and the valleys of the rivers Magadalena and Cauca in Colombia. The species occurs from central Panama to southwestern Ecuador, where it has been recorded at elevations between 6 and 1090 m (Fig. 2).

Distribution of Amphisbaena varia in Ecuador

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

Etymology: The name Amphisbaena is a Latin word used to refer to a “fabulous serpent having a head at each end.”14 In this species, the head and the tail are very similar, which can give the illusion that the animal is advancing backwards. The specific epithet varia comes from the Latin word varius, which means “diverse.” It probably refers to the varied dorsal pattern across individuals of this species.

See it in the wild: Variable Worm-Lizards are difficult to see in Ecuador. Individuals are found no more than once or twice every few months at any given locality. Encounters usually take place after heavy rains when the lizards emerge from their burrows The area having the greatest number of recent observations in Ecuador is the immediate surrounding of the town Puerto Quito, Pichincha province.

Acknowledgments: Special thanks to Lina Parra for helping compile some of the information used in this account. Thanks to Matteo Espinosa, Eric Osterman, and Frank Pichardo for their help finding this species in the field.

Special thanks to Tim Paine for symbolically adopting the Variable Worm-Lizard and helping bring the Reptiles of Ecuador book project to life.

Click here to adopt a species.

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

Editor: Alejandro ArteagacAffiliation: Biodiversity Field Lab, Khamai Foundation, Quito, Ecuador.

Photographers: Jose VieiraaAffiliation: Tropical Herping (TH), Quito, Ecuador.,bAffiliation: ExSitu, Quito, Ecuador. and Sebastián Di DoménicodAffiliation: Keeping Nature, Bogotá, Colombia.

How to cite? Vieira J (2021) Variable Worm-Lizard (Amphisbaena varia). 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/YXFM2018

Literature cited:

  1. Ray JM (2015) Amphisbaena varia (Linnaeus, 1758) (Amphisbaenia: Amphisbaenidae): new distributional records from western Panamá. Herpetology Notes 8: 191–196.
  2. Vidal N, Hedges SB (2009) The molecular evolutionary tree of lizards, snakes, and amphisbaenians. Comptes Rendus Biologies 332: 129–139.
  3. Gans C (2005) Checklist and bibliography of the Amphisbaenia of the world. Bulletin of the American Museum of Natural History 289: 1–30.
  4. Vanzolini PE (2002) A second note on the geographical differentiation of Amphisbaena fuliginosa L., 1758 (Squamata, Amphisbaenidae), with a consideration of the forest refuge model of speciation. Anais da Academia Brasileira de Ciências 74: 609–648.
  5. Yánez-Muñoz M, Meza-Ramos P, Ramírez S, Reyes-Puig J, Oyagata L (2009) Anfibios y reptiles del Distrito Metropolitano de Quito (DMQ). In: Yánez-Muñoz MH, Moreno-Cárdenas PA, Mena-Valenzuela P (Eds) Guía de campo de los pequeños vertebrados del Distrito Metropolitano de Quito (DMQ). Museo Ecuatoriano de Ciencias Naturales (MECN), Quito, 9–52.
  6. Field notes, Reptiles of Ecuador book project.
  7. Jose Vieira, field observation.
  8. Video by Cody Conway.
  9. Gans C (1969) Amphisbaenians – Reptiles specialized for a burrowing existence. Endeavor 28: 146–151.
  10. Cisneros-Heredia DF (2005) Predation upon Amphisbaena fuliginosa LINNAEUS, 1758 by Micrurus ancoralis (JAN, 1872). Herpetozoa 18: 93–94.
  11. Andrade DV, Nascimento LB, Abe AS (2006) Habits hidden underground: a review on the reproduction of the Amphisbaenia with notes on four neotropical species. Amphibia-Reptilia 27: 207–217. DOI: 10.1163/156853806777239995
  12. 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.
  13. 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.
  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 Amphisbaena varia in Ecuador (Fig. 2). Go to the section on symbols and abbreviations for a list of acronyms used.

EcuadorCotopaxiBosque Privado El Jardín de los SueñosPhoto by Christophe Pellet
EcuadorEl OroArenillasPhoto by Carlos Patricio
EcuadorEl OroCascadas de ManuelGarzón-Santomaro et al. 2019
EcuadorEl OroCordillera de ChillaYánez-Muñoz et al. 2004
EcuadorEl OroReserva Biológica BuenaventuraGarzón-Santomaro et al. 2019
EcuadorEl OroVía La Avanzada–PiñasDHMECN 594
EcuadorEsmeraldasBilsa Biological StationOrtega-Andrade et al. 2010
EcuadorEsmeraldasCanandé Biological ReserveThis work
EcuadorEsmeraldasDurangoThis work
EcuadorEsmeraldasDurango, 5.3 km NW ofOnline multimedia
EcuadorEsmeraldasGualpíThis work
EcuadorEsmeraldasPlayón de San FranciscoField notes of Luis Coloma
EcuadorEsmeraldasQuinindé, 35 km NE ofMHNG 2086.081
EcuadorEsmeraldasReserva Biológica Jevon ForestiNaturalist
EcuadorEsmeraldasSan Miguel de los BancosMHNG 2246.090
EcuadorGuayasBucayVanzolini 2002
EcuadorGuayasCampamento Quizás HoyThis work
EcuadorGuayasNaranjal, 8 km NE ofThis work
EcuadorGuayasPagua, 15 km NNE ofThis work
EcuadorGuayasRío DauleMCZ 3571
EcuadorLos RíosHacienda La ClementinaMHNG 1078.020
EcuadorLos RíosJaunechePhoto by Keyko Cruz
EcuadorLos Rios Centro Científico Río PalenqueMCZ 156878
EcuadorLos Rios PichilingueVanzolini 2002
EcuadorManabíBosque Seco Lalo LoorHamilton et al. 2005
EcuadorManabíCerro Pata de PájaroPhoto by Carlos Robles
EcuadorManabí El Carmen Torres-Carvajal et al. 2019
EcuadorManabí Reserva Jama-CoaqueLynch et al. 2016
EcuadorManabí Sube y Baja iNaturalist
EcuadorPichinchaAlluriquínMHNG 2246.092
EcuadorPichinchaHacienda EspinosaCAS 13296
EcuadorPichinchaHostería Selva VirgenThis work
EcuadorPichinchaPuerto QuitoMHNG 2246.091
EcuadorPichinchaPuerto Quito, 2 km NW ofThis work
EcuadorPichinchaPuerto Quito, 5 km E ofThis work
EcuadorPichinchaQuevedo, 10 mi W ofMSUMHE.1374
EcuadorPichinchaRancho SuamoxPhoto by Rafael Ferro
EcuadorPichinchaReserva Mashpi ShungoiNaturalist
EcuadorPichinchaSaguangalDHMECN 4491
EcuadorPichinchaSanto Domingo de los ColoradosVanzolini 2002
EcuadorPichinchaSanto Domingo de los Colorados, 18 km SE ofMCZ 156883
EcuadorSanto Domingo de los TsáchilasChorrera del DiabloField notes of Elicio Tapia
EcuadorSanto Domingo de los TsáchilasLa Unión del ToachiThis work
EcuadorSanto Domingo de los TsáchilasOtongachi ReserveThis work
EcuadorSanto Domingo de los TsáchilasRío BabaUIMNH 66649
EcuadorSanto Domingo de los TsáchilasSanto Domingo, 12 km SW ofThis work