Published June 7, 2022. Updated December 12, 2023. Open access.

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Keel-bellied Shade-Lizard (Alopoglossus atriventris)

Reptiles of Ecuador | Sauria | Alopoglossidae | Alopoglossus atriventris

English common names: Keel-bellied Shade-Lizard, Blackbelly Shade-Lizard, Black-bellied Forest-Lizard.

Spanish common names: Lagartija sombría ventrinegra, lagartija sombría de vientre quillado.

Recognition: ♂♂ 14.7 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=5.5 cm. ♀♀ 13.2 cmMaximum distance from the snout to the tip of the tail. Snout–vent length=5.2 cm..1,2 The Keel-bellied Shade-Lizard (Alopoglossus buckleyi) is a small, brownish lizard that can be distinguished from other Amazonian leaf-litter lizards by having strongly keeled dorsal scales arranged in oblique rows on the dorsum and arms3,4 and by the absence of occipital and postparietal scales.5 Within its distribution area, A. atriventris is often confused with A. buckleyi, A. carinicaudatus, and A. copii, from which it differs by having granular neck scales and keeled ventral scales.2,68 Alopoglossus buckleyi differs from Loxopholis parietalis by its larger size, lack of red ventral coloration in adult males, and parietal scales not forming a semicircle.6,9 Adult males of the Blackbelly Shade-Lizard can be differentiated from adult females by having a black belly (light cream in females) in which each keel is white, giving a dashed line effect.1,8,9

Figure showing variation among individuals of Alopoglossus atriventris

Figure 1: Individuals of Alopoglossus atriventris from Gareno, Napo province () and Yasuní Scientific Station, Orellana province (), Ecuador.

Natural history: Alopoglossus atriventris is a frequently encounteredRecorded weekly in densities below five individuals per locality. lizard in old-growth to moderately disturbed lowland rainforests, logged forests, swamps,10 and shaded plantations in Ecuador.6,11 This species appears to prefer terra-firme forests rather than seasonally flooded forests.12 Keel-bellied Shade-Lizards are active during sunny or cloudy days, especially between 10:00 am and 3:00 pm, with a peak of activity in the late morning.12,13 They usually move among the leaf-litter at the base of large stumps and buttress roots, but they also climb tree trunks less than a meter high.9,12 Although these lizards spend most of their life in the shade,10 they bask occasionally in the sunlight that filters through the rainforest canopy.12 At night, they hide under leaf-litter or under logs.14 The diet in this species is primarily (up to 94.3% based on volume) composed of small (around 6.6 mm long) spiders, grasshoppers, crickets, and cockroaches.9,12,13 The diet includes at least 12 additional prey items ranging from springtails and mites to pseudoscorpions, millipedes, and mollusks.12,13 Predators of A. atriventris include the vipers Bothrocophias hyoprora, Bothrops brazili, and B. taeniatus.10 Parasites include tapeworms and nematodes.15 The primary defense strategy of these jittery lizards is their camouflage and fleeing into the leaf-litter when disturbed; they may also shed the tail or bite if captured.14 The clutch size in this species consists of two eggs.9,10

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Conservation: Least Concern Believed to be safe from extinction given current circumstances..11,16,17 Alopoglossus atriventris is included in this category mainly on the basis of the species’ wide distribution, presence in protected areas, and presumed large stable populations.11 In the Brazilian Amazonia, about 48% of the occurrence area of A. atriventris is inside protected areas and about 98% of its original forest habitat is still standing.18 The status in Ecuador is similar. Based on the most recent maps of vegetation cover of the Amazon basin,19 the majority (~90%) of the species’ habitat in Ecuador remains forested. Thus, A. atriventris is considered to be facing no major immediate extinction threats.

Distribution: Alopoglossus atriventris is native to an area of approximately 935,081 km2 in the Amazon basin of Brazil, Colombia, Ecuador (Fig. 2), and Peru.18

Distribution of Alopoglossus atriventris in Ecuador

Figure 2: Distribution of Alopoglossus atriventris in Ecuador. The star corresponds to the type locality: Lago Agrio. See Appendix 1 for a complete list of the presence localities included in the map.

Etymology: The generic name Alopoglossus, which is derived from the Greeks words alopekia (=bare) and glossa (=tongue),20 refers to the tongue of lizards of this genus, which lacks scale-like papillae.3,21 The specific epithet atriventris, which is derived from the Latin words atra (meaning “black”) and ventris (meaning “belly”), refers to the ventral coloration of the adult males in this species.1

See it in the wild: Even though they are not the most common leaf-litter lizard wherever they occur, Keel-bellied Shade-Lizards can be seen with relative ease in forested areas throughout the species’ area of distribution in Ecuador. These shy reptiles may be spotted during the daytime by scanning the leaf-litter in areas of filtered sunlight reaching the forest floor. At night, they may be located by searching under leaf-litter and logs. In Ecuador, some of the best places to observe Keel-bellied Shade-Lizards are Yasuní Scientific Station and forest trails around Laguna Grande in Cuyabeno Reserve.

Special thanks to Kurt A Radamaker and S. King for symbolically adopting the Keel-bellied Shade-Lizard and helping bring the Reptiles of Ecuador book project to life.

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Author: Jose VieiraaAffiliation: Tropical Herping (TH), Quito, Ecuador.,bAffiliation: ExSitu, Quito, Ecuador.

Editor: Alejandro ArteagacAffiliation: Khamai Foundation, Quito, Ecuador.

Photographers: Jose VieiraaAffiliation: Tropical Herping (TH), Quito, Ecuador.,bAffiliation: ExSitu, Quito, Ecuador. and Alejandro ArteagacAffiliation: Khamai Foundation, Quito, Ecuador.

How to cite? Vieira J (2022) Keel-bellied Shade-Lizard (Alopoglossus atriventris). In: Arteaga A, Bustamante L, Vieira J (Eds) Reptiles of Ecuador: Life in the middle of the world. Available from: DOI: 10.47051/KFJT2146

Literature cited:

  1. Duellman WE (1973) Descriptions of new lizards from the upper Amazon basin. Herpetologica 29: 228–231.
  2. Köhler G, Hans-Helmut D, Veselý M (2012) A contribution to the knowledge of the lizard genus Alopoglossus (Squamata: Gymnophthalmidae). Herpetological Monographs 26: 173–188. DOI: 10.1655/HERPMONOGRAPHS-D-10-00011.1
  3. Harris DM (1994) Review of the teiid lizard genus Ptychoglossus. Herpetological Monographs 8: 226–275. DOI: 10.2307/1467082
  4. Ribeiro-Júnior MA, Choueri E, Lobos S, Venegas P, Torres-Carvajal O, Werneck F (2020) Eight in one: morphological and molecular analyses reveal cryptic diversity in Amazonian alopoglossid lizards (Squamata: Gymnophthalmoidea). Zoological Journal of the Linnean Society 190: 227–270. DOI: 10.1093/zoolinnean/zlz155
  5. Castro Herrera F, Ayala SC (1988) Saurios de Colombia. Unpublished, Bogotá, 692 pp.
  6. Avila-Pires TCS (1995) Lizards of Brazilian Amazonia (Reptilia: Squamata). Zoologische Verhandelingen 299: 1–706.
  7. Camper JD, Torres-Carvajal O, Ron SR, Nilsson J, Arteaga A, Knowles TW, Arbogast BS (2021) Amphibians and reptiles of Wildsumaco Wildlife Sanctuary, Napo Province, Ecuador. Check List 17: 729–751.
  8. Duellman WE (1978) The biology of an equatorial herpetofauna in Amazonian Ecuador. Publications of the Museum of Natural History, University of Kansas 65: 1–352.
  9. Vitt LJ, De la Torre S (1996) A research guide to the lizards of Cuyabeno. Pontificia Universidad Católica del Ecuador, Quito, 165 pp.
  10. Dixon JR, Soini P (1986) The reptiles of the upper Amazon Basin, Iquitos region, Peru. Milwaukee Public Museum, Milwaukee, 154 pp.
  11. Calderón M, Perez P, Avila-Pires TCS, Aparicio J, Moravec J (2019) Alopoglossus atriventris. The IUCN Red List of threatened species. Available from: DOI: 10.2305/IUCN.UK.2019-2.RLTS.T44578076A44578081.en
  12. Vitt LJ, Ávila-Pires TCS, Espósito MC, Sartorius SS, Zani PA (2007) Ecology of Alopoglossus angulatus and A. atriventris (Squamata, Gymnophthalmidae) in western Amazonia. Phyllomedusa 6: 11–21. DOI: 10.11606/issn.2316-9079.v6i1p11-21
  13. Vitt LJ, Zani PA (1996) Organization of a taxonomically diverse lizard assemblage in Amazonian Ecuador. Canadian Journal of Zoology 74: 1313–1335.
  14. Field notes, Reptiles of Ecuador book project.
  15. Goldberg SR, Bursey C, Vitt LJ (2007) Parasite communities of two lizard species, Alopoglossus angulatus and Alopoglossus atriventris, from Brazil and Ecuador. Herpetological Journal 17: 269–272.
  16. Reyes-Puig C (2015) Un método integrativo para evaluar el estado de conservación de las especies y su aplicación a los reptiles del Ecuador. MSc thesis, Pontificia Universidad Católica del Ecuador, 73 pp.
  17. 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.
  18. Ribeiro-Júnior MA, Amaral S (2016) Diversity, distribution, and conservation of lizards (Reptilia: Squamata) in the Brazilian Amazonia. Neotropical Biodiversity 2: 195–421. DOI: 10.1080/23766808.2016.1236769
  19. MapBiomas Amazonía (2022) Mapeo anual de cobertura y uso del suelo de la Amazonía. Available from:
  20. Brown RW (1956) Composition of scientific words. Smithsonian Books, Washington D.C., 882 pp.
  21. Boulenger GA (1885) Catalogue of the lizards in the British Museum. Taylor & Francis, London, 497 pp.

Appendix 1: Locality data used to create the distribution map of Alopoglossus atriventris in Ecuador (Fig. 2). Go to the section on symbols and abbreviations for a list of acronyms used. Asterisk (*) indicates type locality.

EcuadorOrellanaBloque 31Libro PetroAmazonas
EcuadorSucumbíosSani LodgeReptiles of Ecuador book database
ColombiaCaquetáAguacateGutiérrez-Lamus et al. 2020
ColombiaCaquetáFlorencia Online multimedia
ColombiaCaucaSerranía de los ChurumbelosHernández-Morales et al. 2020
ColombiaPutumayoMocoaHernández-Morales et al. 2020
ColombiaPutumayoMocoa, 10 km S ofDuellman 1973
Colombia PutumayoEntre los Ríos Churuyaco y RumiyacoIAvH-R-4882
Colombia PutumayoJardín de Sucumbios, 3 km NE ofICN 8044
Colombia PutumayoParque Nacional Natural La PayaIAvH-R-5784
EcuadorMorona SantiagoCusuimeOrtega-Andrade 2010
EcuadorMorona SantiagoLos TayosKöhler et al. 2012
EcuadorMorona SantiagoMirador de la VirgenCarvajal-Campos & Pazmiño-Otamendi 2020
EcuadorMorona SantiagoShuin MamusiNaturalist; photo examined
EcuadorNapoGareno LodgeReptiles of Ecuador book database
EcuadorNapoJatun Sacha Biological StationReptiles of Ecuador book database
EcuadorNapoLiana LodgeReptiles of Ecuador book database
EcuadorOrellanaCampo ObeCarvajal-Campos & Pazmiño-Otamendi 2020
EcuadorOrellanaCampo ShiripunoPhoto by Néstor Acosta
EcuadorOrellanaIndillama SurField notes of Ana María Velasco
EcuadorOrellanaParcela botánicaReptiles of Ecuador book database
EcuadorOrellanaPozo Amo 2Ribeiro-Júnior & Amaral 2016
EcuadorOrellanaPozo IroTorres-Carvajal et al. 2019
EcuadorOrellanaPozo petrolero Daimi IKöhler et al. 2012
EcuadorOrellanaPrimaveraiNaturalist; photo examined
EcuadorOrellanaPuerto YuturiKöhler et al. 2012
EcuadorOrellanaRio YasuníiNaturalist; photo examined
EcuadorOrellanaSaladero Río TiputiniReptiles of Ecuador book database
EcuadorOrellanaSan José de PayaminoMaynard et al. 2016
EcuadorOrellanaVía Pompeya Sur–Iro, km 107Photo by Morley Read
EcuadorOrellanaVía Pompeya Sur–Iro, km 72Torres-Carvajal et al. 2019
EcuadorOrellanaYasuni Scientific StationReptiles of Ecuador book database
EcuadorOrellanaYuca SurReptiles of Ecuador book database
EcuadorPastazaBalsauraOrtega-Andrade 2010
EcuadorPastazaBataburo LodgeOnline multimedia
EcuadorPastazaCampamento K10Photo by Jorge Valencia
EcuadorPastazaCampamento K4Torres-Carvajal et al. 2019
EcuadorPastazaCampo VillanoOnline multimedia
EcuadorPastazaCanelosOrtega-Andrade 2010
EcuadorPastazaChichirotaDuellman 1973
EcuadorPastazaComunidad KurintzaPhoto by Diego Paucar
EcuadorPastazaDestacamento Militar ShionaAvila-Pires 1995
EcuadorPastazaHuito MolinoOnline multimedia
EcuadorPastazaJuyuintzaOrtega-Andrade 2010
EcuadorPastazaKurintzaOrtega-Andrade 2010
EcuadorPastazaLorocachiRibeiro-Júnior & Amaral 2016
EcuadorPastazaMontalvoAvila-Pires 1995
EcuadorPastazaMoreteUSNM 163439
EcuadorPastazaNuevo GolondrinaKöhler et al. 2012
EcuadorPastazaParacachiDuellman 1973
EcuadorPastazaPavacachiPhoto by Graham Bailey
EcuadorPastazaPozo Garza 1Köhler et al. 2012
EcuadorPastazaPozo Petrolero MisiónKöhler et al. 2012
EcuadorPastazaRío ConamboKöhler et al. 2012
EcuadorPastazaRío HuiyayacuHernández-Morales et al. 2020
EcuadorPastazaRío Pastaza Köhler et al. 2012
EcuadorPastazaRío PindoDuellman 1973
EcuadorPastazaSarayacuDuellman 1973
EcuadorPastazaShiripuno LodgeiNaturalist; photo examined
EcuadorPastazaUNOCAL Base CampRibeiro-Júnior & Amaral 2016
EcuadorSucumbíosEstación PUCE CuyabenoKöhler et al. 2012
EcuadorSucumbíosGüeppicilloYánez-Muñoz & Venegas 2008
EcuadorSucumbíosLagartocochaUsma et al. 2016
EcuadorSucumbíosLago Agrio*Duellman 1973
EcuadorSucumbíosLaguna GrandeTorres-Carvajal & Lobos 2014
EcuadorSucumbíosLimoncocha Biological ReserveKU 183506
EcuadorSucumbíosPañacochaiNaturalist; photo examined
EcuadorSucumbíosSanta Elena iNaturalist; photo examined
EcuadorSucumbíosShushufindiiNaturalist; photo examined
EcuadorSucumbíosTarapoaiNaturalist; photo examined
EcuadorSucumbíosTerritorio Cofán DurenoYánez-Muñoz & Chimbo 2007
PeruLoretoRío TigreKöhler et al. 2012
PeruLoretoRío YuvinetoMNHN 1978.2343; collection database
PeruLoretoShiviyacuKöhler et al. 2012