DOI10.47051/JTSZ4676

Published June 10, 2026. Updated September 2, 2026. Open access.

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Muchmores’ Lightbulb-Lizard (Riama muchmoreorum)

Reptiles of Ecuador | Sauria | Gymnophthalmidae | Riama muchmoreorum

English common name: Muchmores’ Lightbulb-Lizard.

Spanish common name: Lagartija minadora de los Muchmore.

Recognition: ♂♂ 14.8 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=6.5 cm. ♀♀ 17.1 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=8.0 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 Muchmores’ Lightbulb-Lizard (R. muchmoreorum) is the sole representative of its genus within its known geographic range and is readily distinguished from the syntopic Pholidobolus macbrydei by its dark brown dorsum lacking longitudinal dorsal stripes (Fig. 1).1 From the similar, but allopatric R. jenningsi and R. stigmatoral, it differs by having a checkerboard ventral pattern (instead of dark brown). Riama muchmoreorum exhibits little sexual dimorphism, with males differing from females primarily by having a broader head and a more vibrant ventral blotch coloration.1

Figure showing variation among individuals of Riama muchmoreorum

Figure 1: Individuals of Riama muchmoreorum from the Zhoray–Mazar road, Cañar province, Ecuador. j=juvenile.

Natural history: Riama muchmoreorum is a rarely encountered, semi-fossorial lizard that, so far, has only been recorded in a single agricultural mosaic environment consisting of pastures, crops, living fences, and remnants of high evergreen montane forest.1 Muchmores’ Lightbulb-Lizards have been found under rocks, dirt clods, as well as in crevices in dirt walls as much as 50 cm underground. The species can be found living in syntopy with Pholidobolus macbrydei.1 Like its congeners, R. muchmoreorum 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: Data Deficient There is inadequate information to make an assessment of extinction risk..1 Riama muchmoreorum is recommended for this category because the species belongs to a poorly studied genus of lizards and is known only from a single locality along a river valley (Río Mazar) on the eastern slopes of the Ecuadorian Andes. At this locality, most of the native cloud forest habitat has been converted to pastures. However, there is insufficient data to estimate whether this recently discovered lizard species is actually restricted to an area no greater than 10 km2 or if it is more widespread.1

Distribution: Riama muchmoreorum is known only from the type locality, an area known as La Libertad, slightly outside the Reserva Mazar, along the Zhoray–Mazar road. The locality is in the valley of Río Mazar, on the upper watershed of the Río Paute in Cañar province (Fig. 2). The species has only been recorded along a 1 km stretch of road at elevations of 2,664–2,765 m above sea level.

Distribution of Riama muchmoreorum in Ecuador

Figure 2: Distribution of Riama muchmoreorum in Ecuador. The star corresponds to the type locality: Zhoray–Mazar road, Cañar province.

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 in honor of Lile Muchmore and her family. Born into a family deeply committed to conservation and advocating for the voiceless, Lile has been an enduring source of inspiration. The Muchmore family played a pivotal role in supporting the expedition that led to the discovery of this remarkable burrowing lizard.1

Where to observe: Individuals of Riama muchmoreorum may be found at the type locality by actively searching under rocks and dirt clods or by digging in friable soils along the edge of pastures near the forest edge.

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) Muchmores’ Lightbulb-Lizard (Riama muchmoreorum). 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/JTSZ4676

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.