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Phylogeny and Diversification of Anolis Lizards
Phylogeny and Diversification of Anolis Lizards
Anolis lizards have reached their current global distribution through rare colonization events, followed in some early cases by extensive local diversification—where one species gives rise to many others (Patton et al., 2021). From an evolutionary (phylogenetic) perspective, this process led to separate evolutionary radiations on the mainland and on the Caribbean.
Anolis lizards have reached their current global distribution through rare colonization events, followed in some early cases by extensive local diversification—where one species gives rise to many others (Patton et al., 2021). From an evolutionary (phylogenetic) perspective, this process led to separate evolutionary radiations on the mainland and on the Caribbean.
In this study, we focused on the two main evolutionary lineages of Anolis:
In this study, we focused on the two main evolutionary lineages of Anolis:
- Caribbean anoles: found in the Greater and Lesser Antilles (e.g., Puerto Rico, Cuba, Hispaniola, Jamaica)
- Mainland anoles: mostly from Central and South America
Our hypothesis was that Anolis species would be more closely related based on their geographic location than on their ecomorphs. We tested this by analyzing the DNA sequences of more than 20 Anolis species using MEGA software and labeled them by both ecomorph and location using iTOL.
Our hypothesis was that Anolis species would be more closely related based on their geographic location than on their ecomorphs. We tested this by analyzing the DNA sequences of more than 20 Anolis species using MEGA software and labeled them by both ecomorph and location using iTOL.
Our Phylogenetic Tree
Our Phylogenetic Tree
Figure 6.1 Evolutionary analysis of Anolis lizards using the Maximum Likelihood method in MEGA software. The composite phylogeny includes both mainland and Caribbean Anolis species. Tree annotations were added using iTOL, with branch colors indicating geographic distribution and symbols representing distinct ecomorphs.
Caribbean Adaptive Radiation and Ecomorphs
Caribbean Adaptive Radiation and Ecomorphs
Figure 6.2 Zoomed-in view of closely related Jamaican Anolis species. This capture highlights phylogenetic clustering among Jamaican anoles, showing their close evolutionary relationships despite occupying different ecomorph niches.
Figure 6.3 Zoomed-in view comparing phylogenetic relationships among selected Caribbean Anolis species. A. evermanni (trunk-crown) and A. cuvieri (crown-giant), both from Puerto Rico, are shown to be more closely related to each other than to A. coelestinus (trunk-ground) from Hispaniola or A. equestris (crown-giant) from Cuba, despite sharing ecomorph categories.
In the Caribbean, Anolis lizards underwent adaptive radiation—the rapid evolution of many species from a common ancestor, each adapted to different ecological roles or niches. On islands such as Cuba, Hispaniola, Jamaica, and Puerto Rico, species independently evolved into six common ecomorphs: crown-giant, trunk-crown, trunk, trunk-ground, twig, and grass-bush. Ecomorphs are groups of species with similar body shapes and behaviors, each adapted to specific habitats like tree trunks, twigs, or grass. These forms are associated with particular microhabitats, including differences in perch height, diameter, and structural complexity (Muñoz et al., 2023). This diversification led to species-rich communities through convergent evolution:
In the Caribbean, Anolis lizards underwent adaptive radiation—the rapid evolution of many species from a common ancestor, each adapted to different ecological roles or niches. On islands such as Cuba, Hispaniola, Jamaica, and Puerto Rico, species independently evolved into six common ecomorphs: crown-giant, trunk-crown, trunk, trunk-ground, twig, and grass-bush. Ecomorphs are groups of species with similar body shapes and behaviors, each adapted to specific habitats like tree trunks, twigs, or grass. These forms are associated with particular microhabitats, including differences in perch height, diameter, and structural complexity (Muñoz et al., 2023). This diversification led to species-rich communities through convergent evolution:
- The same ecomorphs evolved independently on each island.
- For example, Jamaican anoles (e.g., A. garmani, A. grahami, A. valencienni, A. lineatopus) are closely related, despite representing distinct ecomorphs (Figure 6.2).
- In Puerto Rico, A. evermanni (trunk-crown) and A. cuvieri (crown-giant) are more phylogenetically related to each other than to other species sharing their respective ecomorphs on different islands (Figure 6.3).
This pattern supports the hypothesis that geographic proximity, rather than ecomorph classification, better explains Anolis evolutionary relationships.
This pattern supports the hypothesis that geographic proximity, rather than ecomorph classification, better explains Anolis evolutionary relationships.
Caribbean Anolis speciation and expansion
Caribbean Anolis speciation and expansion
Figure 6.4 Geographic distribution of Anolis sagrei. This map illustrates the widespread introduction and expansion of A. sagrei, originally native to Cuba, across mainland regions. Retrieved from: Anolis sagrei Duméril & Bibron, 1837.
A powerful case of Anolis speciation and expansion is Anolis sagrei (trunk-ground ecomorph), originally from Cuba. It has:
A powerful case of Anolis speciation and expansion is Anolis sagrei (trunk-ground ecomorph), originally from Cuba. It has:
- Colonized regions like Florida and the Bahamas,
- Adapted to novel environments (e.g., limb length changes),
- Competed with native species such as A. carolinensis, leading to niche shifts.
This species illustrates how ecological interactions and biological invasion continue to shape evolutionary trajectories. Its widespread distribution and ecological flexibility also help explain why some Cuban anoles appear less closely related phylogenetically—they represent a more diverse and dispersive evolutionary lineage.
This species illustrates how ecological interactions and biological invasion continue to shape evolutionary trajectories. Its widespread distribution and ecological flexibility also help explain why some Cuban anoles appear less closely related phylogenetically—they represent a more diverse and dispersive evolutionary lineage.
Mainland Anoles and Recolonization
Mainland Anoles and Recolonization
The relationship between mainland and Caribbean Anolis species is explained through recolonization and adaptive radiation. According to Patton et al., Caribbean Anolis lizards recolonized the mainland, challenging the idea that island lineages are evolutionary dead ends (2021). Anolis originally evolved in South America, forming the Mainland 1 (M1) clade, before migrating to the Caribbean, where they underwent adaptive radiation into distinct ecomorphs. Later, a subset of Caribbean Anolis species, likely from the Greater Antilles (Cuba or Jamaica), recolonized Central America, giving rise to the Mainland 2 (M2) clade, which diversified across Central America and eventually reinvaded South America. Despite different evolutionary paths, both Caribbean and mainland species often show convergent evolution, developing similar traits due to similar ecological pressures. Both regions feature arboreal ectomorphs such as trunk-crown species, which live high in trees and share several adaptations, including:
The relationship between mainland and Caribbean Anolis species is explained through recolonization and adaptive radiation. According to Patton et al., Caribbean Anolis lizards recolonized the mainland, challenging the idea that island lineages are evolutionary dead ends (2021). Anolis originally evolved in South America, forming the Mainland 1 (M1) clade, before migrating to the Caribbean, where they underwent adaptive radiation into distinct ecomorphs. Later, a subset of Caribbean Anolis species, likely from the Greater Antilles (Cuba or Jamaica), recolonized Central America, giving rise to the Mainland 2 (M2) clade, which diversified across Central America and eventually reinvaded South America. Despite different evolutionary paths, both Caribbean and mainland species often show convergent evolution, developing similar traits due to similar ecological pressures. Both regions feature arboreal ectomorphs such as trunk-crown species, which live high in trees and share several adaptations, including:
- Moderate body size
- Long limbs for climbing and jumping
- Large toepads for gripping smooth surfaces
- Green coloration for camouflage in foliage
This explains how A. carolinensis (mainland) and A. evermanni (Caribbean) are both trunk-crown species that evolved similar morphologies and behaviors independently. Though mainland anoles tend to display more morphological variation due to diverse habitats and competition, they still occupy ecological roles analogous to their Caribbean relatives, often resulting in similar body forms and behaviors.
This explains how A. carolinensis (mainland) and A. evermanni (Caribbean) are both trunk-crown species that evolved similar morphologies and behaviors independently. Though mainland anoles tend to display more morphological variation due to diverse habitats and competition, they still occupy ecological roles analogous to their Caribbean relatives, often resulting in similar body forms and behaviors.
Figure 6.5 Interactive Phylogeny of Anolis illustrating both mainland (black) and Caribbean (grey) radiations. M1 represents a basal mainland clade found in northern South America and southern Central America. C denotes the Caribbean radiation. M2 indicates a derived mainland clade that originated within the Caribbean radiation and is now distributed across Central America and northern South America. Retrieved from: Testing the island effect in adaptive radiation: rates and patterns of morphological diversification in Caribbean and mainland Anolis lizards - PMC
Figure 6.6. Representative Anolis lizards from the Caribbean (A–F) and morphologically similar mainland Draconura clade species (a–f), illustrating convergent ecomorphs across regions. Caribbean species: (A) Anolis cuvieri, (B) Anolis pulchellus, (C) Anolis distichus, (D) Anolis stratulus, (E) Anolis lineatopus, (F) Anolis occultus. Mainland species: (a) Anolis petersii, (b) Anolis auratus, (c) Anolis ortonii, (d) Anolis omiltemanus, (e) Anolis bicaorum, (f) Anolis salvini. Retrieved from: (PDF) Convergent patterns of adaptive radiation between island and mainland Anolis lizards
Ecological and Evolutionary Drivers
Ecological and Evolutionary Drivers
The evolutionary patterns of Anolis lizards are shaped by a complex interplay of:
The evolutionary patterns of Anolis lizards are shaped by a complex interplay of:
- Ecological opportunity (e.g., unoccupied niches on islands),
- Competition and niche partitioning, and
- Historical contingencies (e.g., lineage history, colonization sequences).
Additionally, in the Caribbean, perch diameter tends to drive ecomorph differentiation, while on the mainland, perch height is a stronger morphological correlate (Irschick et al., 1997). Caribbean species also exhibit greater morphological disparity and faster evolutionary rates compared to their mainland counterparts.
Additionally, in the Caribbean, perch diameter tends to drive ecomorph differentiation, while on the mainland, perch height is a stronger morphological correlate (Irschick et al., 1997). Caribbean species also exhibit greater morphological disparity and faster evolutionary rates compared to their mainland counterparts.
Interactive Anolis Tree
Interactive Anolis Tree
Explore our interactive phylogenetic tree of Anolis lizards, integrating both Caribbean and mainland species. The tree was constructed using the Maximum Likelihood method and annotated with iTOL for enhanced visualization. Zoom in and expand branches to investigate evolutionary relationships among lineages. Use the control panel to highlight species by ecomorph or geographic distribution, and to temporarily label clades of interest.
Explore our interactive phylogenetic tree of Anolis lizards, integrating both Caribbean and mainland species. The tree was constructed using the Maximum Likelihood method and annotated with iTOL for enhanced visualization. Zoom in and expand branches to investigate evolutionary relationships among lineages. Use the control panel to highlight species by ecomorph or geographic distribution, and to temporarily label clades of interest.
References
References
Irschick, D. J., Vitt, L. J., Zani, P. A., & Losos, J. B. (1997). A Comparison of Evolutionary in Mainland and Caribbean Anolis Lizards. Ecology, 78(7), 2191–2203.
https://doi.org/10.2307/2265955
Muñoz, M. M., Frishkoff, L. O., Pruett, J., & Mahler, D. L. (2023). Evolution of a model system: New insights from the study of Anolis lizards. Annual Review of Ecology, Evolution, and Systematics, 54(1), 475-503.
https://doi.org/10.1146/annurev-ecolsys-110421-103306
Patton, A. H., Harmon, L. J., del Rosario Castañeda, M., Frank, H. K., Donihue, C. M., Herrelg, A., & Losos, J. B. (2021). When adaptive radiations collide: Different
evolutionary trajectories between and within island and mainland lizard clades. Proceedings of the National Academy of Sciences of the United States of America, 118(42), 1–11.
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