Published September 26, 2021. Updated November 30, 2023. Open access. Peer-reviewed.

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Coloma’s Lightbulb-Lizard (Riama colomaromani)

Reptiles of Ecuador | Sauria | Gymnophthalmidae | Riama colomaromani

English common name: Coloma’s Lightbulb-Lizard.

Spanish common name: Lagartija minadora de Coloma.

Recognition: ♂♂ 14.2 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=6.5 cm. ♀♀ 18.3 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=8.4 cm..1,2 Lightbulb-lizards are easily distinguishable from other lizards by their fossorial habits and extremities so short that the front and hind limbs cannot reach each other.1,3 Riama colomaromani differs from other members of its genus by having a glossy black to bluish-brown dorsum with small white or yellow spots along the flanks, blackish ventral surfaces, and a reddish iris (Fig. 1).1,2 This species differs from its congener R. unicolor by having a black tail underside, rather than red with thin black longitudinal lines.1 Males of R. colomaromani differ from females by having 7–9 females pores, instead of only one.1

Figure showing variation among individuals of Riama colomaromani

Figure 1: Individuals of Riama colomaromani from Sigchos, Cotopaxi province, Ecuador. j=juvenile.

Natural history: Riama colomaromani is a rarely seen lizard that nevertheless occurs in high densities in some select microhabitats of Andean ecosystems ranging from pristine high evergreen montane forests and cloud forests to pastures nearby forest border.4,5 This reptile has semi-fossorial habits, being found under rocks, buried under soft dark soil, or in dirt walls among roots and rotten logs.1,2 All individuals have been found close to roads in transformed landscapes characterized by pastures and secondary vegetation.1,2 Most of these sites can be far from water, but some of them are close to ditches, small waterfalls, and ponds.2 When dug up or otherwise exposed, individuals of R. colomaromani will quickly flee underground. If captured, they may bite or readily shed the tail. Coloma’s Lightbulb-Lizards are susceptible to high temperatures, dying if exposed to the sun or even if handled for longer than just a few seconds.2

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Conservation: Endangered Considered to be facing a high risk of extinction in the near future..6 Riama colomaromani is listed in this category because, at the time of the assessment in 2019,6 its distribution area was estimated to be under 2,500 km2 and the species was only known to occur in four localities, all of them affected heavily by habitat destruction due to agricultural expansion and active mining concessions.6 Although ten localities of occurrence are reported here (Appendix 1), none of these represent a major distribution extension, and the species’ estimated extent of occurrence (Fig. 2), though larger than previously thought, is still smaller than the 5,000 km2 threshold needed to qualify for a less threatened category. Fortunately, some R. colomaromani populations in Pichincha province are in protected areas: Bosque Protector Verdecocha, Reserva Biológica Yanacocha, and Bosque Protector el Cedral.

Distribution: Riama colomaromani is endemic to an area of approximately 3,630 km2 along the Pacific slopes of the Andes in northwestern Ecuador (Fig. 2).

Distribution of Riama colomaromani in Ecuador

Figure 2: Distribution of Riama colomaromani in Ecuador. The star corresponds to the type locality: Chillogallo–Guajalito road, Pichincha 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 girl’s names to use on reptiles.710 The specific epithet colomaromani honors Ecuadorian biologist Luis Coloma, in recognition of his innumerable contributions to increasing herpetological knowledge in Ecuador.1

See it in the wild: Coloma’s Lightbulb-Lizards are recorded rarely unless actively searched for by digging in areas of soft soil or by turning over rocks and logs. They can be found at a rate of about 3–12 individuals per day of sampling in humid areas having remnants of native vegetation in private reserves such as Bosque Protector Verdecocha and Reserva Biológica Yanacocha.

Acknowledgments: Special thanks to Daniela Franco and María Jose Quiroz for finding some of the specimens of Riama colomaromani pictured in this account.

Authors: Miguel Ángel Méndez-GaleanoaAffiliation: Grupo de Biodiversidad y Sistemática Molecular, Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá, Colombia. and Alejandro ArteagabAffiliation: Tropical Herping (TH), Quito, Ecuador.

Academic reviewer: Jeffrey D CampercAffiliation: Department of Biology, Francis Marion University, Florence, USA.

Photographer: Jose VieiradAffiliation: Tropical Herping (TH), Quito, Ecuador.,eAffiliation: ExSitu, Quito, Ecuador.

How to cite? Méndez-Galeano MA, Arteaga A (2023) Coloma’s Lightbulb-Lizard (Riama colomaromani). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: DOI: 10.47051/TKDS5945

Literature cited:

  1. 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
  2. Field notes, Reptiles of Ecuador book project.
  3. 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.
  4. MECN, JOCOTOCO, ECOMINGA (2013) Herpetofauna en áreas prioritarias para la conservación: el sistema de reservas Jocotoco y Ecominga. Museo Ecuatoriano de Ciencias Naturales, Quito, 408 pp.
  5. Yánez-Muñoz M, Meza-Ramos P, Ramírez S, Reyes-Puig J, Oyagata L (2009) Anfibios y reptiles del Distrito Metropolitano de Quito (DMQ). In: Yánez-Muñoz MH, Moreno-Cárdenas PA, Mena-Valenzuela P (Eds) Guía de campo de los pequeños vertebrados del Distrito Metropolitano de Quito (DMQ). Museo Ecuatoriano de Ciencias Naturales (MECN), Quito, 9–52.
  6. Cisneros-Heredia DF (2019) Riama colomaromani. The IUCN Red List of threatened species. Available from: DOI: 10.2305/IUCN.UK.2019-3.RLTS.T50950484A50950493.en
  7. 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.
  8. 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.
  9. 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.
  10. 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 colomaromani in Ecuador (Fig. 2). Go to the section on symbols and abbreviations for a list of acronyms used. Asterisk (*) indicates type locality.

EcuadorCotopaxiSigchosPhoto by Luis Coloma
EcuadorCotopaxiSigchos, 10 km NW ofThis work; Fig. 1
EcuadorImbaburaLa DeliciaKizirian 1996
EcuadorImbaburaSanta RosaGalarza-Verkovitch 2020
EcuadorPichinchaBosque Protector El CedralPhoto by Luis Coloma
EcuadorPichinchaChillogallo, 19.8 km W of*Kizirian 1996
EcuadorPichinchaReserva Biológica YanacochaYánez-Muñoz et al. 2013
EcuadorPichinchaZurolomaReptiles of Ecuador book database