Published October 11, 2020. Open access. | Gallery ❯ |
Unicolored Lightbulb-Lizard (Riama unicolor)
Reptiles of Ecuador | Sauria | Gymnophthalmidae | Riama | Riama unicolor
English common names: Unicolored Lightbulb-Lizard, Drab Lightbulb-Lizard.
Spanish common names: Lagartija minadora de vientre rojo.
Recognition: ♂♂ 14.5 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=6.8 cm. ♀♀ 14.5 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=6.5 cm.. Lightbulb-lizards are easily distinguishable from other lizards by their fossorial (living underground) habits and extremities so short that the front and hind limbs cannot reach each other.1,2 Adult males of Riama unicolor differ from females by having broader heads and more colorful lower flanks. Unicolored Lightbulb-Lizards differ from other Riama by having a reddish underside of the tail with thin black longitudinal lines. Other lightbulb lizards that occur nearby R. unicolor are R. colomaromani, R. simotera, and R. raneyi, but these other lizards have completely black ventral surfaces.2
Figure 1: Unicolored Lightbulb-Lizards (Riama unicolor) from La Libertad, Carchi province (), and Tabacundo–Mojanda, Pichincha province (), Ecuador. j=juvenile
Natural history: Locally commonRecorded weekly in densities above five individuals per locality.. Riama unicolor is a fossorial lizard that inhabits old-growth to heavily disturbed high evergreen montane forest and humid highland shrublands. It also occurs in areas containing a mixture of pastures, crops, and remnants of native vegetation,3,4 and even in gardens in heavily-populated urban areas such as Quito.3 Lizards of this species spend most of their lives in tunnels they excavate in areas of soft soil or under rocks, logs, debris, and flowerpots.2,3 On rare occasions, individuals have also be seen crossing roads.3 In captivity, their diet includes maggots and small insects.2 When threatened, Unicolored Lightbulb-Lizards flee into crevices. If captured, they may bite or readily shed the tail. These lizards are susceptible to high temperatures, dying if exposed to the sun or even if handled for longer than just a few seconds.2 Members of this species are preyed upon by frogs (Gastrotheca riobambae).2
Conservation: Vulnerable Considered to be facing a high risk of extinction in the mid-term future..5 Riama unicolor is listed in this category because the species has a relatively small (~6,682 km2) extent of occurrence, its habitat is severely fragmented, and it has undergone widespread observed population declines.5 An estimated 64.3% of the habitat of R. unicolor has already been destroyed,6 mostly due to encroaching human activities such as urban development, agriculture, cattle grazing, and the replacement of native vegetation with eucalyptus and pine trees.3,5 Fortunately, Drab Lightbulb-Lizards persist in urban areas despite a considerable degree of habitat modification,4 and they are among the few reptiles able to survive in Ecuador’s capital city.4
Distribution: Riama unicolor is endemic to an estimated ~6,682 km2 area in the inter-Andean valleys of northern Ecuador. The species occurs at elevations between 2022 and 3405 m (Fig. 2).
Figure 2: Distribution of Riama unicolor in Ecuador. 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 girl’s names to use on reptiles.7–10 The specific epithet unicolor is a Latin adjective that probably refers to the nearly unicolored dorsal pattern of lizards of this species.2
See it in the wild: Unicolored Lightbulb-Lizards are recorded rarely unless they are actively searched for by digging in areas of soft soil or by turning over rocks and logs. They can be found with ~20–40% certainty in humid areas having remnants of native vegetation.
Special thanks to Walter Jennings for symbolically adopting the Unicolored Lightbulb-Lizard and helping bring the Reptiles of Ecuador book project to life.
Click here to adopt a species.
Acknowledgments: Special thanks to Amanda Quezada, Frank Pichardo, Harry Turner, and Jorge Castillo for their help and companionship during the search of specimens of Riama unicolor in the field. Thanks to Diego Piñán and María Jose Quiroz for providing locality data of R. unicolor. Thanks to Andres Pérez for the post-processing of images. This account was published with the support of Secretaría Nacional de Educación Superior Ciencia y Tecnología (programa INEDITA; project: Respuestas a la crisis de biodiversidad: la descripción de especies como herramienta de conservación; No 00110378), Programa de las Naciones Unidas (PNUD), and Universidad San Francisco de Quito (USFQ).
Author: Alejandro ArteagaaAffiliation: Khamai Foundation, Quito, Ecuador.
Photographers: Jose VieiraaAffiliation: Tropical Herping (TH), Quito, Ecuador.,bAffiliation: ExSitu, Quito, Ecuador. and Alejandro ArteagaaAffiliation: Khamai Foundation, Quito, Ecuador.
How to cite? Arteaga A (2020) Unicolored Lightbulb-Lizard (Riama unicolor). In: Arteaga A, Bustamante L, Vieira J, Guayasamin JM (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: www.reptilesofecuador.com. DOI: 10.47051/PEFN1380
Literature cited:
- 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. DOI: 10.1111/j.1096-3642.2005.00145.x
- Kizirian DA (1996) A review of Ecuadorian Proctoporus (Squamata: Gymnophthalmidae) with descriptions of nine new species. Herpetological Monographs 10: 85–155. DOI: 10.2307/1466981
- Field notes, Reptiles of Ecuador book project.
- Arteaga A, Bustamante L, Guayasamin JM (2013) The amphibians and reptiles of Mindo. Universidad Tecnológica Indoamérica, Quito, 257 pp.
- Cisneros-Heredia DF, Brito J, Yánez-Muñoz M, Almendáriz A (2019) Riama unicolor. The IUCN red list of threatened species. Available from: www.iucnredlist.org. DOI: 10.2305/IUCN.UK.2019-3.RLTS.T50950566A50950573.en
- MAE (2012) Línea base de deforestación del Ecuador continental. Ministerio del Ambiente del Ecuador, Quito, 30 pp.
- 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.
- 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.
- 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.
- 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 unicolor in Ecuador (Fig. 2). Go to the section on symbols and abbreviations for a list of acronyms used.
| Country | Province | Locality | Source |
| Ecuador | Carchi | 14 km W Tulcán | Field notes of Luis Coloma |
| Ecuador | Carchi | Gruta de la Paz | Field notes of Giovanni Onore |
| Ecuador | Carchi | Huaca | Aguirre et al. 2014 |
| Ecuador | Carchi | La Libertad | This work |
| Ecuador | Carchi | Montúfar | Kizirian 1996 |
| Ecuador | Carchi | Montúfar–Atal | Sánchez-Pacheco et al. 2012 |
| Ecuador | Carchi | San Gabriel | This work |
| Ecuador | Carchi | San Gabriel–El Angel | This work |
| Ecuador | Carchi | Tulcán | This work |
| Ecuador | Carchi | Vicinities of La Libertad | This work |
| Ecuador | Imbabura | 3 km SE San Rafael | Doan 2003 |
| Ecuador | Imbabura | 7 km W Quiroga | Kizirian 1996 |
| Ecuador | Imbabura | 8 km NW Otavalo | Kizirian 1996 |
| Ecuador | Imbabura | Cahuasquí–Urcuquí | Diego Piñán |
| Ecuador | Imbabura | Chachimbiro | Kizirian 1996 |
| Ecuador | Imbabura | Cotacachi–Intag 1 | Aguirre et al. 2014 |
| Ecuador | Imbabura | Cotacachi–Intag 2 | Aguirre et al. 2014 |
| Ecuador | Imbabura | Cuicocha | Kizirian 1996 |
| Ecuador | Imbabura | Hacienda Zuleta | Photo by Anton Sorokin |
| Ecuador | Imbabura | Hostería Cusin | Field notes of Elicio Tapia |
| Ecuador | Imbabura | Imbabura-Mariano Acosta | This work |
| Ecuador | Imbabura | Islote Yerovi | Almendáriz & Orcés 2004 |
| Ecuador | Imbabura | Laguna El Cunrro | Field notes of Rafael Cárdenas |
| Ecuador | Imbabura | Perihuela | This work |
| Ecuador | Imbabura | Pimampiro | Kizirian 1996 |
| Ecuador | Imbabura | Sigsipamba | iNaturalist |
| Ecuador | Imbabura | Tabacundo–Mojanda | KU 221766 |
| Ecuador | Imbabura | Tumbabiro | Aguirre et al. 2014 |
| Ecuador | Imbabura | Urcusiqui | KU 118101 |
| Ecuador | Imbabura | Vía Cotacachi–Quiroga | iNaturalist |
| Ecuador | Pichincha | 12 km E Pifo | Kizirian 1996 |
| Ecuador | Pichincha | 2.5 km W Tabacundo | Kizirian 1996 |
| Ecuador | Pichincha | 3.8 km W Tabacundo | This work |
| Ecuador | Pichincha | 40 SE Quito | Sánchez-Pacheco et al. 2012 |
| Ecuador | Pichincha | 5.9 km W Tabacundo | Kizirian 1996 |
| Ecuador | Pichincha | Aloguincho | QCAZ 3060 |
| Ecuador | Pichincha | Between Quito and Papallacta | Kizirian 1996 |
| Ecuador | Pichincha | Bosque de Pasochoa | Field notes of Felipe Campos |
| Ecuador | Pichincha | Brazil y Zamora | Photo by Viviana Jaramillo |
| Ecuador | Pichincha | Calacalí | This work |
| Ecuador | Pichincha | Cayambe | Kizirian 1996 |
| Ecuador | Pichincha | Colegio Fernandez Madrid | iNaturalist |
| Ecuador | Pichincha | El Inca | iNaturalist |
| Ecuador | Pichincha | Hacienda Gorzon | Kizirian 1996 |
| Ecuador | Pichincha | Hacienda Olalla | Kizirian 1996 |
| Ecuador | Pichincha | Hacienda Pesillo | Almendáriz & Orcés 2004 |
| Ecuador | Pichincha | Hacienda Pichincha | QCAZ 11660 |
| Ecuador | Pichincha | km 10 Cayambe–Olmedo | Kizirian 1996 |
| Ecuador | Pichincha | La Unión | iNaturalist |
| Ecuador | Pichincha | Machachi | Sánchez-Pacheco et al. 2012 |
| Ecuador | Pichincha | Mirador de Guápulo | iNaturalist |
| Ecuador | Pichincha | Near El Crater | iNaturalist |
| Ecuador | Pichincha | Nono | María Jose Quiroz, pers. comm. |
| Ecuador | Pichincha | Paloguillo | Field notes of Juan Freile |
| Ecuador | Pichincha | Parque Metropolitano | iNaturalist |
| Ecuador | Pichincha | Parque Rumipamba | Finding Species |
| Ecuador | Pichincha | Pasochoa | Kizirian 1996 |
| Ecuador | Pichincha | PUCE | This work |
| Ecuador | Pichincha | Quito | Kizirian 1996 |
| Ecuador | Pichincha | Quito, Calle Murgeón | DHMECN 332 |
| Ecuador | Pichincha | Río Machángara | Kizirian 1996 |
| Ecuador | Pichincha | San Antonio de Pichincha | USNM |
| Ecuador | Pichincha | San Jorge Ecolodge | Photo by Clint King |
| Ecuador | Pichincha | SE Slopes Guagua Pichincha | Kizirian 1996 |
| Ecuador | Pichincha | Tabacundo | Kizirian 1996 |
| Ecuador | Pichincha | Valle de los Chillos | Kizirian 1996 |