Published February 1, 2021. Updated January 27, 2024. Open access. | Gallery ❯ |
Ángel Whorltail-Iguana (Stenocercus angel)
Reptiles of Ecuador | Sauria | Tropiduridae | Stenocercus angel
English common name: Ángel Whorltail-Iguana.
Spanish common names: Guagsa del Ángel, lagarto arcoiris de montaña.
Recognition: ♂♂ 21.4 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=8.7 cm. ♀♀ 15.5 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=7.6 cm..1,2 Stenocercus angel differs from other lizards in its area of distribution by being larger and having keeled dorsal scales with pointed ends.3 This species is similar to S. guentheri, which can be identified by having a black gular patch (absent in S. angel).1 Stenocercus chota also occurs near the known distribution of S. angel, but males of this other species have a black mid-ventral longitudinal line and females and juveniles have black blotches in the gular region.1 Furthermore, S. chota has a brown or grayish dorsal coloration (greenish in S. angel).2 Males of S. angel differ from females by being larger, more brightly colored, and having a raised middorsal crest (Fig. 1).2
Figure 1: Individuals of Stenocercus angel from Páramo del Ángel, Carchi province, Ecuador. j=juvenile.
Natural history: Stenocercus angel is a rarely seen lizard that inhabits high evergreen montane forests, humid montane shrublands, Espeletia-dominated páramos, and highland grasslands.4,5 The species prefers areas with little degree of disturbance but may as well occur at the edge of cultivated fields and pastures.6 These lizards need extended periods of direct sunlight hitting the ground in order to become active. During sunny days, when the ambient temperature is above 5°C,4 Ángel Whorltail-Iguanas bask on the ground or on Espeletia shrubs, usually near terrestrial spiny bromeliads or tall grass, which they use as shelter.1,4,6 If captured, individuals may shed the tail or bite as a method of defense and escape.6 Males of S. angel are territorial and defend areas around burrows in the ground.4 Females lay clutches of two eggs.1,4
Conservation: Vulnerable Considered to be facing a high risk of extinction in the mid-term future..7 Stenocercus angel is listed in this category, instead of Near Threatened,5 because the species meets the following IUCN Redlist8 criteria: the species’ extent of occurrence is estimated to be less than 20,000 km2, its habitat is severely fragmented, and there is continuing decline in the extent and quality of the ecosystems where it occurs. It is estimated9,10 that ~41% of the habitat of S. angel has been lost due to the expansion of the agricultural frontier and wildfires in the páramos.6 Additionally, the species occurs as fragmented populations and mostly outside protected areas, with the exception of El Ángel Ecological Reserve, Guandera Reserve, and La Bretaña Reserve. Under current scenarios of climate change, it is likely that some populations will become extinct, similar to what has been predicted for S. guentheri.11
Distribution: Stenocercus angel is native to the high Andes of southern Colombia and northern Ecuador in the upper drainage systems of the Aguarico (Atlantic drainage) and the Mira (Pacific drainage) rivers (Fig. 2).
Figure 2: Distribution of Stenocercus angel in Ecuador. The star corresponds to the type locality: El Ángel, 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.12 The specific epithet angel refers to the Páramo del Ángel, where the species was found initially.1
See it in the wild: Ángel Whorltail-Iguanas can be spotted at a rate of about once every few days at El Ángel Ecological Reserve, but only during warm sunny days.
Acknowledgments: Special thanks to Frank Pichardo and Harry Turner for locating the specimens of Stenocercus angel photographed in this account.
Authors: Amanda QuezadaaAffiliation: Tropical Herping (TH), Quito, Ecuador.,bAffiliation: Laboratorio de Herpetología, Universidad del Azuay, Cuenca, Ecuador. and Alejandro ArteagaaAffiliation: Khamai Foundation, Quito, Ecuador.
Photographer: Jose VieiraaAffiliation: Tropical Herping (TH), Quito, Ecuador.,cAffiliation: ExSitu, Quito, Ecuador.
How to cite? Quezada A, Arteaga A (2024) Ángel Whorltail-Iguana (Stenocercus angel). 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/FMJO4408
Literature cited:
- 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
- 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
- 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.
- Castro-Herrera F, Granados-Díaz H (1993) Distribución de Stenocercus guentheri (Sauria: Iguanidae) en el sur de los Andes de Colombia. Caldasia 17: 295–300.
- Cisneros-Heredia DF (2016) Stenocercus angel. The IUCN Red List of threatened species. Available from: www.iucnredlist.org. DOI: 10.2305/IUCN.UK.2016-1.RLTS.T48616468A48616481.en
- Field notes, Reptiles of Ecuador book project.
- 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.
- 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.
- IDEAM (2014) Mapa de cobertura de la tierra adaptada para Colombia.
- Andrango MB, Sette C, Torres-Carvajal O (2016) Short-term predicted extinction of Andean populations of the lizard Stenocercus guentheri (Iguanidae: Tropidurinae). Journal of Thermal Biology 62: 30–36. DOI: 10.1016/j.jtherbio.2016.09.012
- 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 angel in Ecuador (Fig. 2). Go to the section on symbols and abbreviations for a list of acronyms used. Asterisk (*) indicates type locality.
| Country | Province | Locality | Source |
| Colombia | Cauca | Hacienda Corralejas | Ayerbe et al. 2007 |
| Colombia | Cauca | Hacienda Las Guacas | Ayerbe et al. 2007 |
| Colombia | Cauca | Malvasá | Castro-Herrera & Granados-Díaz 1993 |
| Colombia | Cauca | Puracé | Ayerbe et al. 2007 |
| Colombia | Cauca | Sotará | Ayerbe et al. 2007 |
| Colombia | Cauca | Toma del Santo | Ayerbe et al. 2007 |
| Colombia | Nariño | Contadero | iNaturalist; photo examined |
| Colombia | Nariño | Cumbal | Torres-Carvajal 2007 |
| Colombia | Nariño | Funes | Torres-Carvajal 2007 |
| Colombia | Nariño | Huecada del Vergel | Ayerbe et al. 2007 |
| Colombia | Nariño | Ipiales | iNaturalist; photo examined |
| Colombia | Nariño | La Palma | iNaturalist; photo examined |
| Colombia | Nariño | Páramo de Paja Blanca | iNaturalist; photo examined |
| Colombia | Nariño | Páramo del Chiles | Bolaños 2009 |
| Colombia | Nariño | Pasto | Torres-Carvajal 2007 |
| Colombia | Nariño | Pilcuan Viejo | iNaturalist; photo examined |
| Colombia | Nariño | Quebrada de Ramos | Calderón et al. 2023 |
| Colombia | Nariño | Santa Rosa | Torres-Carvajal 2007 |
| Colombia | Nariño | Sector Las Juntas | Borja-Acosta & Galeano 2024 |
| Colombia | Nariño | Tangua | Torres-Carvajal 2007 |
| Colombia | Nariño | Túquerres | iNaturalist; photo examined |
| Ecuador | Carchi | 13.6 km vía Tulcán-Tufino | Torres-Carvajal 2000 |
| Ecuador | Carchi | Bolívar | iNaturalist; photo examined |
| Ecuador | Carchi | Bosque Los Encinos | Yánez-Muñóz 2003 |
| Ecuador | Carchi | Cocha Seca | Torres-Carvajal 2007 |
| Ecuador | Carchi | Cordillera de la Virgen Negra | Yánez-Muñoz 2005 |
| Ecuador | Carchi | El Ángel | Torres-Carvajal 2007 |
| Ecuador | Carchi | El Angel vía a Tulcan | Torres-Carvajal 2000 |
| Ecuador | Carchi | El Ángel, 1.6 km N of | Torres-Carvajal 2000 |
| Ecuador | Carchi | El Ángel, 8 km N of* | Torres-Carvajal 2000 |
| Ecuador | Carchi | El Carmelo | Torres-Carvajal 2007 |
| Ecuador | Carchi | El Frailejón | Reptiles of Ecuador book database |
| Ecuador | Carchi | El Pun | Torres-Carvajal 2007 |
| Ecuador | Carchi | Estación Biológica Guandera | Torres-Carvajal 2007 |
| Ecuador | Carchi | La Libertad, 6.7 km NW of | Reptiles of Ecuador book database |
| Ecuador | Carchi | Monte Redondo | Almendáriz & Orcés 2004 |
| Ecuador | Carchi | Páramo del Artesón | Yánez-Muñoz 2005 |
| Ecuador | Carchi | Reserva Ecológica El Ángel | This work; Fig. 1 |
| Ecuador | Carchi | Reserva La Bretaña | Reptiles of Ecuador book database |
| Ecuador | Carchi | Tulcán | iNaturalist; photo examined |
| Ecuador | Imbabura | Pimampiro | iNaturalist; photo examined |
| Ecuador | Sucumbíos | Caldera del Páramo Mirador | Torres-Carvajal 2007 |
| Ecuador | Sucumbíos | Laguna Negra | Vriesendorp et al. 2009 |
| Ecuador | Sucumbíos | Playón de San Francisco | Torres-Carvajal 2000 |
| Ecuador | Sucumbíos | Playón de San Francisco, 1 km E of | Torres-Carvajal 2007 |