Santa Cruz Lava-Lizard

Reptiles of Ecuador | Sauria | Tropiduridae | Microlophus | Microlophus indefatigabilis

Spanish common name: Lagartija de lava de Santa Cruz.

Recognition: ♂♂ 23.2 cm ♀♀ 17.9 cm. Microlophus indefatigabilis is the only lava lizard known to occur on Baltra, Santa Cruz, Seymour Norte, and 13 of the surrounding islets of these islands. Males and females of this species differ from each other in size, shape, and coloration. Adult males are easily recognized by their raised middorsal crest. They also have a brown body with scattered black and white blotches, as well as a distinctive red and black throat and a black chest. Adult females usually have a mostly uniform brownish body, bright orange face, and a black mark at shoulder level.

Natural history: Extremely common. Microlophus indefatigabilis is a diurnal lizard that inhabits volcanic rock areas, dry shrublands, dry grasslands, deciduous forests, and urban areas.1 Santa Cruz Lava-Lizards bask and move over areas of 64–1,377 m2 mostly (up to ~99% of the time) on rocks, but also on soil, leaf litter, shrubs, cacti, and walls up to 2.5 m above the ground.1–4 They move into the shade during hot midday hours, sitting on surfaces that have not been heated by the sun.2 At night, M. indefatigabilis sleeps on rocky outcrops1 or hides among rocks, beneath soil, and under leaf litter.2,3

Male Santa Cruz Lava-Lizards are faster and have greater stamina than females.5,6 They also keep harems and are able to defend only about 20% of their overall home range territories,3,4 which they guard by performing pushup displays and fighting with intruders.1 They defend themselves by fleeing into crevices, shedding the tail, and biting.1 Lizards that occur in habitats with relatively little vegetation cover have greater levels of sprint speed, endurance, and wariness.5–7 Individuals of Microlophus indefatigabilis are generalist foragers and the most frugivorous (that is, feeding on fruits) of the Galápagos lava lizards.8 Their diet includes fruits, seeds, flowers, insects (termites, beetles, flies, maggots, ants, caterpillars, moths, antlions, aphids, leaf hoppers, and grasshoppers), crustaceans, spiders, scorpions, centipedes, Mourning Geckos (Lepidodactylus lugubris), members of their own species, and their own shed skin.1,2,8,9 In urban areas, Santa Cruz Lava-Lizards have been observed opportunistically feeding on breadcrumbs, macaroni, meat scraps, and dog food,2 although this is not a natural behavior. Santa Cruz Lava-Lizards obtain water from their diet and by drinking precipitation that accumulates on leaves.2 Predators include hawks, owls, herons, mockingbirds, snakes (both Pseudalsophis dorsalis and P. steindachneri), and housecats.10–12

The breeding season of the Santa Cruz Lava-Lizard peaks in Februay and March, but may start in November. Females lay 1–6 eggs per clutch2,13 in 20 cm deep nests14 that are excavated on loose soil or sand usually close to rocks or vegetation.15 They protect their nests from potential predators and from other females.15

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Conservation: Least Concern.16 There is no conclusive evidence that Microlophus indefatigabilis is undergoing population declines.16 Santa Cruz Lava-Lizards are abundant and occur on three islands and 13 islets. However, immediate threats include invasive predators,11 road traffic,10 and the loss of habitat due to agriculture.

Distribution: The Santa Cruz Lava-Lizard is endemic to an estimated 773 km2 area on Baltra, Santa Cruz, and Seymour Norte islands, as well as 13 of their surrounding islets (Caamaño, Dahpne Major, Edén, Guy Fawkes Este, Guy Fawkes Norte, Guy Fawkes Oeste, Guy Fawkes Sur, Mosquera, Plaza Norte, Plaza Sur, Punta Bowditch Norte, Punta Bowditch Sur, and Venecia).1,17 Galápagos, Ecuador.

Distribution of Microlophus indefatigabilis Distribution of Microlophus indefatigabilis in and around Santa Cruz Island

Etymology: The generic name Microlophus, which comes from the Greek words mikros (meaning “small”) and lophos (meaning “crest”), refers to the reduced dorsal crest in another lava lizard species (M. peruvianus).18 The specific epithet indefatigabilis refers to Santa Cruz, previously known as Indefatigable Island.

See it in the wild: Santa Cruz Lava-Lizards can be seen year-round with ~100% certainty at most tourism sites on and around Santa Cruz Island, including Daphne Major, Plaza Sur, and Seymour Norte islands. The best time to look for and photograph the lizards is during the first hours after sunrise or right before sunset.

Authors: Alejandro Arteaga,aAffiliation: Tropical Herping (TH), Quito, Ecuador. Gabriela Aguiar, and Juan M GuayasaminbAffiliation: Laboratorio de Biología Evolutiva, Universidad San Francisco de Quito (USFQ), Quito, Ecuador.,cAffiliation: Galapagos Science Center, Galápagos, Ecuador.,dAffiliation: Centro de Investigación de la Biodiversidad y Cambio Climático, Universidad Tecnológica Indoamérica, Quito, Ecuador.

Academic reviewers: Edgar Benavides, John Rowe, and Cruz Márquez.

Photographers: Jose VieiraaAffiliation: Tropical Herping (TH), Quito, Ecuador.,eAffiliation: ExSitu, Quito, Ecuador. and Alejandro ArteagaaAffiliation: Tropical Herping (TH), Quito, Ecuador.

How to cite? Arteaga A, Aguiar G, Guayasamin JM (2020) Microlophus indefatigabilis. 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

Literature cited:

  1. Field notes, Reptiles of Ecuador book project.
  2. Stebbins RC, Lowenstein JM, Cohen NW (1967) A field study of the lava lizard (Tropidurus albemarlensis) in the Galápagos Islands. Ecology 48: 839–851.
  3. Rowe JW, Martin CE, Clarck DL (2019) Habitat use and spatial ecology of three Microlophus lizard species from Santa Cruz and San Cristóbal islands, Galápagos, and the coastal dry forest of Machalilla, Ecuador. Herpetological Review 50: 43–51.
  4. Stone P, Baird T (2002) Estimating lizard home range: the Rose Model revisited. Journal of Herpetology 36: 427–436.
  5. Snell HL, Jennings RD, Snell HM, Harcourt S (1988) Intrapopulation variation in predator-avoidance performance of Galápagos lava lizards: the interaction of sexual and natural selection. Evolutionary Ecology 2: 353–369.
  6. Miles DB, Snell HL, Snell HM (2001) Intrapopulation variation in endurance of Galápagos lava lizards (Microlophus albemarlensis): evidence for an interaction between natural and sexual selection. Evolutionary Ecology Research 3: 795–804.
  7. Jordan MA, Snell HL, Snell HM, Jordan WC (2005) Phenotypic divergence despite high levels of gene flow in Galápagos lava lizards (Microlophus albemarlensis). Molecular Ecology 14: 859–867.
  8. Hervías-Parejo S, Heleno R, Rumeu B, Guzmán B, Vargas P, Olesen JM, Traveset A, Vera C, Benavides E, Nogales M (2018) Small size does not restrain frugivory and seed dispersal across the evolutionary radiation of Galápagos lava lizards. Current Zoology 65: 353–361.
  9. Lewbart GA, Valle CA, Muñoz-Perez JP (2017) Microlophus indefatigabilis (Lava Lizard) diet. Herpetological Review 48: 851–852.
  10. Tanner D, Perry J (2007) Road effects on abundance and fitness of Galápagos lava lizards (Microlophus albemarlensis). Journal of Environmental Management 85: 270–278.
  11. Konecny MJ (1987) Food habits and energetics of feral house cats in the Galápagos Islands. Oikos 50: 24–32.
  12. Townsend CH (1930) The Astor Expedition to the Galápagos Islands. Bulletin of the New York Zoological Society 33: 135–155.
  13. Van Denburgh J, Slevin JR (1913) Expedition of the California Academy of Sciences to the Galápagos Islands, 1905-1906. IX. The Galapagoan lizards of the genus Tropidurus with notes on iguanas of the genera Conolophus and Amblyrhynchus. Proceedings of the California Academy of Sciences 2: 132–202.
  14. Carpenter CC (1970) Miscellaneous notes on Galápagos lava lizards (Tropidurus: Iguanidae). Herpetologica 26: 377–386.
  15. Burger J (1993) Colony and nest site selection in lava lizards Tropidurus ssp. in the Galápagos Islands. Copeia 1993: 748–754.
  16. Márquez C, Cisneros-Heredia DF (2016) Microlophus indefatigabilis. The IUCN red list of threatened species. Available from: www.iucnredlist.org
  17. Jordan MA, Snell HL (2008) Historical fragmentation of islands and genetic drift in populations of Galápagos lava lizards (Microlophus albemarlensis complex). Molecular Ecology 17: 1224–1237.
  18. Frost DR (1992) Phylogenetic analysis and taxonomy of the Tropidurus group of lizards (Iguania: Tropidurudae). American Museum Novitates 3033: 1–68.