Published August 2, 2023. Updated December 3, 2023. Open access.

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Ringed Spinytail-Iguana (Enyalioides annularis)

Reptiles of Ecuador | Sauria | Hoplocercidae | Enyalioides annularis

English common names: Ringed Spinytail-Iguana, Ringed Manticore.

Spanish common name: Mantícora de anillos.

Recognition: ♂♂ 31.2 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=13.7 cm. ♀♀ 24.2 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=11.8 cm..1,2 Enyalioides annularis is unmistakable among lizards in its area of distribution by having spines on the dorsal surface of the hind limbs and a thick tail with greatly enlarged, projecting, spinous scales (Fig. 1).1,2 Males are larger, more robust, and more brightly colored than females.1,2 This species coexists with other dwarf iguanas that are similar in size and coloration (E. microlepis and E. praestabilis), but these other wood lizards lack spines on the tail.3

Figure showing variation among individuals of Enyalioides annularis

Figure 1: Individuals of Enyalioides annularis from Arutam, Pastaza province, Ecuador. sa=subadult.

Natural history: Enyalioides annularis is an extremely rare dwarf iguana that inhabits pristine foothill rainforests as well as remnants of gallery forest in a matrix of pastures.1,2 Ringed Spinytail-Iguanas are diurnal, terrestrial, and gregarious.1,2 They live in self-dug burrows in colonies along walls of compact soil, with no more than one animal per hole.2 The burrows are about 20 cm in diameter, 1–3 m deep, and may be at ground level or above the ground. Most of the day, the lizards sit motionless in front of the entrances to their burrows and carefully observe their surroundings.2 If an insect or spider approach, the manticores can be surprisingly quick and take the prey with one well-aimed leap.2 Then the lizard returns to its post at the cave entrance. When disturbed, individuals quickly flee into the burrows, inflate their body, and lock themselves strongly against the tunnel walls using their spiny scales.1 Females lay clutches of 2–5 eggs inside the burrows.1,2

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Conservation: Vulnerable Considered to be facing a high risk of extinction in the mid-term future..4 Enyalioides annularis is listed in this category primarily on the basis of the species’ limited extent of occurrence (originally estimated to be under 20,000 km2, but see below), low population densities, fragmented distribution, and ongoing decline in the extent and quality of the upper Amazonian landscape.4 Since E. annularis is a burrowing specialist that exhibits high site fidelity, it is unlikely to recolonize areas following extirpation.4 Previously sampled colonies at Canelos and Bobonaza are now deserted.5 In Bobonaza and Arutam, local people report hunting these iguanas for food.5 Despite this, Arutam is still one of the last strongholds for the iguana.

Distribution: Enyalioides annularis is native to an area of approximately 24,893 km2 along the Amazonian slopes of the Andes in Ecuador (Fig. 2) and Colombia.

Distribution of Enyalioides annularis in Ecuador

Figure 2: Distribution of Enyalioides annularis in Ecuador. The star corresponds to the type locality: Canelos, Pastaza province. See Appendix 1 for a complete list of the presence localities included in the map.

Etymology: The generic name Enyalioides, which comes from the Latin words Enyalius (a genus of neotropical lizards) and the suffix oides (=similar to), refers to the similarity between lizards of the two genera. The specific epithet annularis (=ringed in Latin) refers to the ringed tail.6

See it in the wild: Ringed Spinytail-Iguanas used to be locally common in some parts of the Ecuadorian Amazon, but healthy colonies are now extremely difficult to find. Vagrant individuals are reported from time to time around Arutam, Arajuno, and Macuma, but these observations probably correspond to individuals displaced by deforestation.

Acknowledgments: Special thanks to Søren Hoff Brøndum and Linda Vargas for helping us locate the two individuals of Enyalioides annularis pictured in Fig. 1.

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

Photographer: Amanda QuezadabAffiliation: Tropical Herping (TH), Quito, Ecuador.,cAffiliation: Laboratorio de Herpetología, Universidad del Azuay, Cuenca, Ecuador.

How to cite? Arteaga A (2023) Ringed Spinytail-Iguana (Enyalioides annularis). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: DOI: 10.47051/ATHX1802

Literature cited:

  1. Torres-Carvajal O, Etheridge R, de Queiroz K (2011) A systematic revision of Neotropical lizards in the clade Hoplocercinae (Squamata: Iguania). Zootaxa 2752: 1–44. DOI: 10.11646/zootaxa.2752.1.1
  2. Köhler G, Seipp R, Moya S, Almendáriz A (1999) Zur Kenntnis von Morunasaurus annularis (O’Shaughnessyi 1881). Salamandra 35: 181–190.
  3. Torres-Carvajal O, de Queiroz K, Etheridge R (2009) A new species of iguanid lizard (Hoplocercinae, Enyalioides) from southern Ecuador with a key to eastern Ecuadorian Enyalioides. ZooKeys 27: 59–71. DOI: 10.3897/zookeys.27.273
  4. Cisneros-Heredia DF (2016) Morunasaurus annularis. The IUCN Red List of threatened species. Available from: DOI: 10.2305/IUCN.UK.2016-1.RLTS.T203069A2759780.en
  5. Field notes, Reptiles of Ecuador book project.
  6. O’Shaughnessy AWE (1881) An account of the collection of lizards made by Mr. Buckley in Ecuador, and now in the British Museum, with descritions of the new species. Proceedings of the Zoological Society of London 49: 227–245.

Appendix 1: Locality data used to create the distribution map of Enyalioides annularis in Ecuador (Fig. 2). Go to the section on symbols and abbreviations for a list of acronyms used. Asterisk (*) indicates type locality.

ColombiaCaucaVilla IguanaTorres-Carvajal et al. 2011
ColombiaPutumayoDesembocadura Río IndiyacoTorres-Carvajal et al. 2011
ColombiaPutumayoEstación de bombeo GuamuézTorres-Carvajal et al. 2011
ColombiaPutumayoPuerto LimónTorres-Carvajal et al. 2011
ColombiaPutumayoRío GuamuésiNaturalist; photo examined
EcuadorMorona SantiagoCentro Shuar KenkuimTorres-Carvajal et al. 2011
EcuadorMorona SantiagoCentro Shuar KiimTorres-Carvajal et al. 2011
EcuadorMorona SantiagoCentro Shuar MutinzaTorres-Carvajal et al. 2011
EcuadorMorona SantiagoCusuimeOrtega-Andrade 2010
EcuadorMorona SantiagoMacumaiNaturalist; photo examined
EcuadorMorona SantiagoValle del Río SantiagoOnline multimedia
EcuadorNapoCampamento Codo BajoTorres-Carvajal et al. 2011
EcuadorPastazaAlto CurarayKöhler et al. 1999
EcuadorPastazaAlto Río ArajunoWiens and Etheridge 2003
EcuadorPastazaAlto Río ConamboVan Denburgh 1912
EcuadorPastazaArutamKöhler et al. 1999
EcuadorPastazaBobonazaTorres-Carvajal et al. 2011
EcuadorPastazaBosque Protector Yawa JeeKöhler et al. 1999
EcuadorPastazaCanelos*O’Shaughnessyi 1881
EcuadorPastazaPalora, 30 km E ofiNaturalist; photo examined
EcuadorPastazaRío HuiyayacuUSNM 200796; VertNet
EcuadorPastazaRío LliquinoUSNM 200804; VertNet
EcuadorPastazaRío OglánKöhler et al. 1999
EcuadorPastazaRío PucayacuUSNM 200811; VertNet
EcuadorPastazaRío VillanoUSNM 200813; VertNet
EcuadorSucumbíosLumbaqui, 15 km ENE ofTorres-Carvajal et al. 2011
EcuadorSucumbíosReserva Ecológica Cofán BermejoBorman et al. 2007