DOI10.47051/JAGJ2066

Published June 10, 2026. Updated August 28, 2026. Open access.

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Jennings’ Lightbulb-Lizard (Riama jenningsi)

Reptiles of Ecuador | Sauria | Gymnophthalmidae | Riama jenningsi

English common name: Jennings’ Lightbulb-Lizard.

Spanish common name: Lagartija minadora de Jennings.

Recognition: ♂♂ 18.9 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=8.0 cm. ♀♀ 16.6 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=7.0 cm..1 Lightbulb-lizards (Riama) are easily distinguished from other sympatric lizards by their fossorial habits and extremely reduced extremities, where the fore- and hind limbs are too short to meet when adpressed against the body.2,3 The Jennings’ Lightbulb-Lizard (R. jenningsi) is the sole representative of its genus within its known geographic range and is readily recognized by its stocky body and uniformly dark brown dorsum lacking major conspicuous markings such as lines or ocelli (Fig. 1).1 From the similar, but allopatric R. stigmatoral, it differs by having a shiny black belly without bright reddish, orange, or cream spots along the flanks.1 From R. muchmoreorum, it differs by having a uniformly black or dark brown belly (vs. checkerboard ventral pattern). Adult males of R. jenningsi differ from females by their larger size, broader heads, and by the occasional broken ochraceous dorsolateral stripe.1

Figure showing variation among individuals of Riama jenningsi

Figure 1: Individuals of Riama jenningsi from Azuay province, Ecuador: Santa Ana (); Guachapala (). j=juvenile.

Natural history: Riama jenningsi is a rarely encountered, semi-fossorial lizard that, so far, has only been recorded in agricultural landscapes consisting of a matrix of pastures, crops, living fences, and remnants of high evergreen montane forest.1 Jennings’ Lightbulb-Lizards have been found under rocks, logs, dirt clods, and other surface objects in pastures as well as in crevices in dirt walls along roads. As many as four individuals have been found under the same stone, alongside clutches of two eggs.1 When unearthed or exposed, individuals rapidly attempt to retreat underground; if handled, they may bite or employ caudal autotomy to shed the tail.4 Like its congeners, R. jenningsi exhibits extreme stenothermy, rendering it vulnerable to thermal stress—rapidly succumbing to elevated temperatures if exposed to direct sunlight or handled continuously for more than a few seconds.4

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Conservation: Endangered Considered to be facing a high risk of extinction in the near future..1 Riama jenningsi is recommended for this category because the species is known only from a small (here estimated to be under 500 km2) area of forest patches that continues to decline in extent and quality due to the expansion of the agricultural frontier. Only seven localities are known (Appendix 1); they lack connectivity between them and none of them are protected.

Distribution: Riama jenningsi is endemic to an area of approximately 226 km2 along the watershed of the Río Paute in Azuay and Cañar provinces, southeastern Ecuador (Fig. 2).

Distribution of Riama jenningsi in Ecuador

Figure 2: Distribution of Riama jenningsi in Ecuador. The star corresponds to the type locality: Guachapala, Azuay province. See Appendix 1 for a complete list of the presence localities included in the map.

Etymology: The generic name Riama does not appear to be a reference to any feature of this group of lizards, but a matter of personal taste. John Edward Gray usually selected girls’ names to use on reptiles.5–8 The species is named after Walter Jennings, a tireless conservationist and naturalist who supports and served on the board of the Jocotoco Foundation. Most of the new lizard species described in this work are now in the process of being protected thanks to Walt and his wife Linda.1

Where to observe: Riama jenningsi is rarely encountered unless researchers actively target its microhabitat by searching under rocks, logs, dirt clods, and other surface objects in pastures near remnants of native forest. In the environs of Guachapala and Santa Ana in Azuay province, intensive sampling efforts yield a predictable encounter rate of approximately 8–10 individuals per day of dedicated fieldwork.

Author: Alejandro ArteagaaAffiliation: Fundación Khamai, Reserva Arlequín, Ecoruta Paseo del Quinde km 56, Santa Rosa de Mindo, Pichincha 171202, Ecuador.

Photographer: Jose VieirabAffiliation: Tropical Herping (TH), Quito, Ecuador.,cAffiliation: ExSitu, Quito, Ecuador.

How to cite? Arteaga A (2026) Jennings’ Lightbulb-Lizard (Riama jenningsi). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: www.reptilesofecuador.com. https://doi.org/10.47051/JAGJ2066

Literature cited:

  1. Arteaga A, Tovar-Ortiz A, Vieira J, Bringsøe H, Quezada A, Camper J, Harris K (2026) Six new species of lizards (Riama, Sauria, Gymnophthalmidae) from the high Andes of Ecuador. In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador. Second Edition. Khamai Foundation & Tropical Herping, Quito, 1082–1119. https://doi.org/10.47051/GZNM5526
  2. Doan TM, Castoe TA (2005) Phylogenetic taxonomy of the Cercosaurini (Squamata: Gymnophthalmidae), with new genera for species of Neusticurus and Proctoporus. Zoological Journal of the Linnean Society 143: 405–416. https://doi.org/10.1111/j.1096-3642.2005.00145.x
  3. Kizirian DA (1996) A review of Ecuadorian Proctoporus (Squamata: Gymnophthalmidae) with descriptions of nine new species. Herpetological Monographs 10: 85–155. https://doi.org/10.2307/1466981
  4. Field notes, Reptiles of Ecuador book project.
  5. Gray JE (1831) Description of a new genus of ophisaurean animal, discovered by the late James Hunter in New Holland. Treuttel, Würtz & Co., London, 40 pp.
  6. Gray JE (1831) A synopsis of the species of the class Reptilia. In: Griffith E, Pidgeon E (Eds) The animal kingdom arranged in conformity with its organization. Whittaker, Treacher, & Co., London, 1–110.
  7. Gray JE (1838) Catalogue of the slender-tongued saurians, with descriptions of many new genera and species. Annals and Magazine of Natural History 1: 274–283.
  8. Gray JE (1845) Catalogue of the specimens of lizards in the collection of the British Museum. Trustees of the British Museum, London, 289 pp.

Appendix 1: Locality data used to create the distribution map of Riama jenningsi in Ecuador (Fig. 2). Asterisk (*) indicates type locality.

CountryProvinceLocalitySource
EcuadorAzuayCruz y AntenasSánchez-Pacheco et al. 2017
EcuadorAzuayGuachapala*Arteaga et al. 2026
EcuadorAzuaySan Vicente, camino a las antenasSánchez-Pacheco et al. 2017
EcuadorAzuaySanta AnaArteaga et al. 2026
EcuadorAzuaySevilla de OroSánchez-Pacheco et al. 2012
EcuadorCañarIglesia de BibliánSánchez-Pacheco et al. 2017
EcuadorCañarJatumpambaArteaga et al. 2026