Published February 11, 2021. Updated January 27, 2024. Open access.

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Chota Whorltail-Iguana (Stenocercus chota)

Reptiles of Ecuador | Sauria | Tropiduridae | Stenocercus chota

English common name: Chota Whorltail-Iguana.

Spanish common name: Guagsa del Chota.

Recognition: ♂♂ 20.7 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=9.7 cm. ♀♀ 17.3 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=6.5 cm..1,2 Stenocercus chota differs from other lizards in its area of distribution by having keel-shaped dorsal scales with pointed ends.3 Stenocercus chota differs from S. guentheri by lacking a black throat patch in males and by having black blotches in the throat in females. From S. angel, it differs by having a mid-ventral longitudinal black line and by having a brownish, instead of green, coloration (Fig. 1).1,2 Males of S. chota are larger than females and have a well-developed dorsal crest.2

Figure showing variation among individuals of Stenocercus chota

Figure 1: Individuals of Stenocercus chota from Pimampiro, Ecuador. sa=subadult, j=juvenile.

Natural history: Stenocercus chota is a diurnal and terrestrial lizard restricted to areas of dry highland shrubland.1,4 The species usually occurs in open areas with shrubby vegetation both in undisturbed areas as well as along roads or in pastures, rural gardens, houses, and plantations.1,5 Chota Whorltail-Iguanas are active during sunny hours, basking on large rocks or on the ground.1 If disturbed, individuals retreat into holes in the substrate, between rocks, or under bushes, fallen logs, branches, or thorny shrubs.1,5 If captured, they may shed the tail or bite. There are unpublished observations of snakes (Drymarchon melanurus and Mastigodryas pulchriceps) preying upon individuals of this species.1 Females lay clutches of two eggs.1

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Conservation: Vulnerable Considered to be facing a high risk of extinction in the mid-term future..6,7 Although Stenocercus chota is considered a common species adapted to human-modified environments,8 it meets the IUCN Red List criteria9 to be included in the Vulnerable, instead of the Least Concern,8 category: the species’ extent of occurrence is less than 2,000 km2, its habitat is severely fragmented, and there is continuing decline in the extent and quality of the ecosystem where it occurs. It is estimated that ~57% of the habitat of S. chota has been transformed into a matrix of human settlements, pastures, and agricultural fields.10 Additionally, the species is not found within protected areas.8

Distribution: Stenocercus chota is endemic to an area of approximately 702 km2 in the xeric inter-Andean valley known as El Chota, the headwaters of the Río Mira in northern Ecuador (Fig. 2).

Distribution of Stenocercus chota in Ecuador

Figure 2: Distribution of Stenocercus chota in Ecuador. The star corresponds to the type locality: Chota, Carchi province. See Appendix 1 for a complete list of the presence localities included in the map.

Etymology: The generic name Stenocercus, which comes from the Greek words stenos (=narrow) and kerkos (=tail), refers to the laterally-compressed tail in some members of this genus, which contrasts with the dorsally flattened tail of other Tropiduridae.11 The specific epithet chota refers to the Valle del Chota, inhabited by this species.1

See it in the wild: Chota Whorltail-Iguanas can be seen with almost complete certainty during strongly sunny days in areas having adequate vegetation cover throughout El Chota Valley. The best time to look for members of this species is during the first hours after sunrise, when the lizards are active and approachable.

Acknowledgments: Special thanks to Frank Pichardo and Harry Turner for helping locate the specimens of Stenocercus chota photographed in this account.

Authors: Amanda QuezadaaAffiliation: Tropical Herping (TH), Quito, Ecuador.,bAffiliation: Laboratorio de Herpetología, Universidad del Azuay, Cuenca, Ecuador. and Alejandro ArteagacAffiliation: Khamai Foundation, Quito, Ecuador.

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

How to cite? Quezada A, Arteaga A (2024) Chota Whorltail-Iguana (Stenocercus chota). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: DOI: 10.47051/AZYE5437

Literature cited:

  1. Torres-Carvajal O (2000) Ecuadorian lizards of the genus Stenocercus (Squamata: Tropiduridae). Scientific Papers Natural History Museum, The University of Kansas 15: 1–38. DOI: 10.5962/bhl.title.16286
  2. Torres-Carvajal O (2007) A taxonomic revision of South American Stenocercus (Squamata: iguania) lizards. Herpetological Monographs 21: 76–178. DOI: 10.1655/06-001.1
  3. Peters JA, Donoso-Barros R (1970) Catalogue of the Neotropical Squamata: part II, lizards and amphisbaenians. Bulletin of the United States National Museum, Washington, D.C., 293 pp.
  4. Torres-Carvajal O, Pazmiño-Otamendi G, Salazar-Valenzuela D (2019) Reptiles of Ecuador: a resource-rich online portal, with dynamic checklists and photographic guides. Amphibian & Reptile Conservation 13: 209–229.
  5. Field notes, Reptiles of Ecuador book project.
  6. 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.
  7. 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.
  8. Cisneros-Heredia DF, Reyes-Puig C, Brito J, Yánez-Muñoz M (2017) Stenocercus chota. The IUCN Red List of threatened species. Available from: DOI: 10.2305/IUCN.UK.2017-2.RLTS.T50950651A50950654.en
  9. IUCN (2001) IUCN Red List categories and criteria: Version 3.1. IUCN Species Survival Commission, Gland and Cambridge, 30 pp.
  10. MAE (2012) Línea base de deforestación del Ecuador continental. Ministerio del Ambiente del Ecuador, Quito, 30 pp.
  11. Duméril AMC, Bibron G (1837) Erpétologie générale ou Histoire Naturelle complète des Reptiles. Librairie Encyclopédique de Roret, Paris, 571 pp. DOI: 10.5962/bhl.title.45973

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

EcuadorCarchiAmbuquí–Monte Olivo roadTorres-Carvajal 2007
EcuadorCarchiEl Chota, 5 km E of*Torres-Carvajal 2007
EcuadorCarchiLa ConcepciónTorres-Carvajal 2000
EcuadorCarchiSalinas, 10.4 km N ofUSNM 201126; VertNet
EcuadorImbabura28 km N Rio TaguandoMVZ 178428; VertNet
EcuadorImbaburaAmbuquíTorres-Carvajal 2007
EcuadorImbaburaAmbuquí–Monte olivo roadTorres-Carvajal 2000
EcuadorImbaburaAmbuquí, 2.3 km W ofReptiles of Ecuador book database
EcuadorImbaburaCahuasquíPhoto by Diego Piñán
EcuadorImbaburaEl JuncalTorres-Carvajal 2005
EcuadorImbaburaFinca El DescansoiNaturalist; photo examined
EcuadorImbaburaFinca San Ignacio AltoTorres-Carvajal 2007
EcuadorImbaburaIbarraUIMNH 91615; VertNet
EcuadorImbaburaLa DolorosaiNaturalist; photo examined
EcuadorImbaburaLa PrimaveraiNaturalist; photo examined
EcuadorImbaburaMira, 2 km E ofiNaturalist; photo examined
EcuadorImbaburaMirador del Codor, way toReptiles of Ecuador book database
EcuadorImbaburaPablo ArenasDiego Piñán, pers. comm.
EcuadorImbaburaPimampiro, 1.5 km W ofThis work; Fig. 1
EcuadorImbaburaPimampiro, 1.7 km NW ofReptiles of Ecuador book database
EcuadorImbaburaPlaya de la CruzPhoto by Diego Piñán
EcuadorImbaburaQuebrada CruzhuaicPhoto by Luis Coloma
EcuadorImbaburaQuebrada de la VertienteTorres-Carvajal 2007
EcuadorImbaburaQuebrada HierbabuenaOnline multimedia
EcuadorImbaburaRío AmarilloReptiles of Ecuador book database
EcuadorImbaburaRío AmbiReptiles of Ecuador book database
EcuadorImbaburaRío ChotaTorres-Carvajal 2007
EcuadorImbaburaSalinasTorres-Carvajal 2000
EcuadorImbaburaSan Blas, UrcuquíiNaturalist; photo examined
EcuadorImbaburaTumbabiroTorres-Carvajal 2000
EcuadorImbaburaTumbabiro, 1.9 km E ofReptiles of Ecuador book database
EcuadorImbaburaTunas y Cabras LodgeReptiles of Ecuador book database
EcuadorImbaburaUniversidad YachayiNaturalist; photo examined
EcuadorImbaburaUrcuquí, 4 km E ofiNaturalist; photo examined
EcuadorImbaburaValle del ChotaTorres-Carvajal 2000