Upon the slopes of Volcán Wolf lives one of Earth’s rarest and most ecologically unique reptiles. Charles Darwin missed the Galápagos pink land iguana (Conolophus marthae) on his 1835 Galápagos voyage, a species whose evolution remains puzzling (Figure 1)(Gentile et al. 2009). Darwin’s Galápagos observations were central to his ideas about evolution, making this species’ absence significant to its modern evolutionary mystery. C. marthae is critically endangered and endemic to Isabela Island, with only about 200 adults estimated to remain (Galápagos Conservation Trust 2026; Gargano et al. 2024). These researchers later found that these iguanas migrate up Volcán Wolf to use geothermal heat to incubate their eggs, an unusual trait among their Conolophus relatives. However, genetic studies indicate that the pink iguana lineage split from other Galápagos land iguanas potentially before Isabela Island and Volcán Wolf even existed, making their presence on this young volcano an evolutionary mystery (Gentile et al. 2009).
The island’s invasive feral cats prey on this species, and the eruption of Volcán Wolf in 1982 threatened the population of C. marthae (Gargano et al. 2024). During rescue efforts, researchers struggled to locate nesting grounds until tracking females during the 2019–2020 reproductive season revealed nests located on a small plateau inside Volcán Wolf’s caldera, ~400 meters below the rim. Females travelled over 2 kilometres from their usual habitat to reach these sites. After laying eggs, C. marthae females only guard their nests for 2 days to a week; an unusually short period for iguanas.
The question of how C. marthae came to live on Volcán Wolf becomes more interesting considering its evolutionary history. The Galápagos has three main terrestrial Conolophus species: C. subcristatus, C. pallidus and C. marthae (Paradiso et al. 2025). Using RADseq data, Paradiso et al. (2025) estimated that iguanas colonized the Galápagos ~10 mya. These scientists believe that within this period, C. marthae diverged from C. subcristatus through allopatric speciation after the emergence of Isabela Island ~0.57 mya (Figure 2). This timing supports recent allopatric speciation after Isabela’s emergence, indicating that this volcano played a role in their distinctive evolutionary habits. However, mitochondrial DNA evidence from Gentile et al. (2009) suggest that C. marthae split from other Conolophus species ~5.7 mya, before Isabela Island emerged. This earlier divergence suggests that these species may have adapted to its volcanic environment after becoming genetically distinct.
The evolutionary history of C. marthae remains uncertain. Recent research suggests they diverged from other land iguanas after the emergence of Isabela Island, while earlier genetic evidence suggests a much older split (Paradiso et al. 2025). These conflicting estimates and its unusual nesting behaviour make C. marthae an evolutionary puzzle. If Darwin had encountered this species, its unique traits may have provided another example of how isolation and environmental pressures shape evolution. More than a century later, C. marthae still raises questions about its origins, adaptations, and connection to Volcán Wolf. If only Darwin had explored a bit further.
References
Bustamante, Lucas. “Galapagos Iguanas Given Strongest Protection Possible.” IFAW, December 3, 2025. https://www.ifaw.org/press-releases/galapagos-iguanas-given-strongest-protection-possible.
Gargano, Marco, Giuliano Colosimo, Lorenzo Garizio, Paolo Gratton, Gregory A. Lewbart, Glenn P. Gerber, Pierpaolo Loreti, et al. 2024. “Locating Nesting Sites for Critically Endangered Galápagos Pink Land Iguanas (Conolophus Marthae).” Animals 14 (12): 1835. https://doi.org/10.3390/ani14121835.
Galápagos Conservation Trust. “Galápagos Pink Land Iguana.” Galápagos Conservation Trust, July 16, 2026. https://Galápagosconservation.org.uk/species/Galápagos-pink-land-iguana/.
Gentile, Gabriele, Anna Fabiani, Cruz Marquez, Howard L. Snell, Heidi M. Snell, Washington Tapia, and Valerio Sbordoni. 2009. “An Overlooked Pink Species of Land Iguana in the Galápagos.” Proceedings of the National Academy of Sciences of the United States of America 106 (2): 507–511. https://doi.org/10.1073/pnas.0806339106
Paradiso, Cecilia, Paolo Gratton, Emiliano Trucchi, Julia López-Delgado, Marco Gargano, Lorenzo Garizio, Ian M. Carr, Giuliano Colosimo, Christian Sevilla, Mark E. Welch, Mohd Firdaus-Raih, Mohd Noor Mat-Isa, Simon J. Goodman, and Gabriele Gentile. 2025. “Genomic Insights into the Biogeography and Evolution of Galápagos Iguanas.” Molecular Phylogenetics and Evolution 204: 108294. https://doi.org/10.1016/j.ympev.2025.108294
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