A Newly Found Anole Is Not Necessarily Good News: the Brown Anole Is a New Invader in Israel

A brown anole in its unnatural habitat; Rishon LeZion, Israel. Photo: Aviad Bar

Shai Meiri, School of Zoology & the Steinhart Museum of Natural History, Tel Aviv University
uncshai@tauex.tau.ac.il

In late April 2021, someone posted a facebook image of a lizard seen in a residence garden in Rishon LeZion, a satellite city of Tel-Aviv, Israel (approximately 31.9611N, 34.7889E). Aviad Bar, one of the best herpetologists in Israel, identified it as a brown anole (Anolis sagrei Duméril & Bibron, 1837) and went there to investigate. He found around ten lizards in that garden, and managed to catch two of them. The preliminary identification was verified, and the lizards were later deposited in the national collections at the Steinhardt Museum of Natural History, Tel Aviv University, after the Israeli Nature and Parks Authority (INPA; the governmental body in charge of protecting nature in Israel) were consulted.

Anolis sagrei is potentially very bad news. It is one of the best models for the study of evolution in nature over short time scales across the animal kingdom (a more or less random sample of works includes: Losos et al. 2004, Schoener et al. 2005, Calsbeek and Cox 2010, Losos and Pringle 2011, Stuart et al. 2014, Kamath et al. 2020, Stroud et al. 2020, Donihue et al. 2021). But it is also one of the worst reptile invaders worldwide, alongside flowerpot snakes (Indotyphlops braminus), the mourning gecko (Lepidodactylus lugubris) red-eared sliders (Trachemys scripta – we have those in Israel now too) and some Hemidactylus geckos (e.g., H. turcicus, which we may have helped to provide; H. frenatus). To date Anolis sagrei has invaded several states in continental USA (e.g., Florida, Louisiana, Texas), as well as Grand Cayman Island, Bermuda, Jamaica, Grenada, St. Vincent, the Canary Islands, multiple areas in Mexico, Belize, Honduras, Costa Rica, Panama, Ecuador, Hawaii, Taiwan, and Singapore (Sexton and Brown 1977, Kraus 2009, Norval et al. 2012, Amador et al. 2017, Capinha et al. 2017, Stroud et al. 2017, Solis et al. 2017, Batista et al. 2019).

A brown anole caught in Rishon LeZion. Photo: Aviad Bar.

Furthermore, Anolis sagrei is known to compete with native anoles, mainly Anolis carolinensis a system very frequently studied (reviewed in Kraus 2009, and see e.g., Echternacht 1999, Losos and Spiller 1999, Gerber and Echternacht 2000, Stuart et al. 2014, Kamath et al. 2020). Effects on other anoles were also suggested (Losos et al. 1993 for A. conspersus; Batista et al. 2019 for Anolis gaigei), and competition with other lizards has been hypothesized (e.g., Stroud et al. 2017, Batista et al. 2019). Thus, a new record of A. sagrei from outside its native range is no cause for a celebration.
How did A. sagrei reach Israel? One hypothesis, raised by INPA, is that eggs have been transported accidentally in shipments, likely from the USA. We know A. sagrei eggs remain viable for weeks, and can even withstand some exposure to sea water (Hsu et al. 2021). There is a plant nursery not far from the place where A. sagrei was found in Israel, and reptiles have often been accidentally transported with plant shipments (e.g., the flowerpot snake; see e.g., Perry et al. 2006, Losos 2013, Auguste et al. 2018). Indeed, a shipment of wood from Italy arriving in Israel early in 2019 contained live Podarcis siculus (specimens were transferred to the Steinhardt Museum of Natural History, and I identified them there). The USA is the #1 exporter of goods to Israel and considering A. sagrei is widespread in the US, it is a reasonable assumption.

A more plausible explanation soon emerged, however. Anolis sagrei has been in the pet trade in Israel for some time. Some third-party reports to Aviad Bar suggested that a private reptile enthusiast living in Rishon LeZion has been very successful in breeding Anolis sagrei and has simply been releasing juveniles or hatchlings into his back garden. Apparently, this has been going on for at least two and potentially 4-5 years. Thus, the source of the invasion seems to have been intentional (and illegal) introduction of individuals to nature.

The INPA asked me to write a report on potential threats posed by the brown anole and its chances of establishment and spread (Meiri 2021), then held a consultation, and commissioned Aviad Bar to survey the anole population in Rishon LeZion, and adjacent natural areas. Additionally, other Israeli herpetologists have tried to find the species around the area where it was first reported. The survey encountered some unexpected difficulties. For one, the recent horrible and useless spat of fighting between Israel and Hamas, which could and should have been avoided by both sides, caused unnecessary suffering on both, and seemed to have served only the extremely short-term purposes of “leaders” of both sides. Lizards had nothing to do with this apparently. The fighting forced the surveyors to stop the survey multiple times to take cover in shelters of complete strangers from incoming rockets. Luckily, none of them was hurt. Many people welcomed the surveyors into their garden and allowed them to look for and collect lizards. The survey (Bar 2021) was recently submitted to the INPA.

Anoles have been found in five streets in Rishon LeZion, with a maximum linear extent of ~500 m. Lizards have been found active by day on walls, fences, vegetation and on the ground, and to sleep on branches at night – typical anole behavior. Worryingly, anoles of all sizes, from adults >60 mm SVL to small hatchling-sized individuals, were found throughout the study area, strongly suggesting the lizards breed in Israel. Anolis sagrei breeds extremely fast, especially in regions where it is invasive where it matures early and reduces its already incredibly short inter-laying interval (e.g., Jensen et al. 2008, Fetters and Mcglothlin 2017). Basically, one gets the impression (or at least I do) that introduced Anolis sagrei lay eggs (almost) as fast as domestic chickens. It seems to further be helped by light pollution – growing faster and reproducing earlier where artificial lights are available at night (Thawley and Kolbe 2020) – like they are in Rishon LeZion.

Anoles were also highly abundant. Aviad (Bar 2021) found 101 anoles during his survey, and Akiva Topper and Oren Kolodny have found 28 in a single night. For comparison, the second most abundant reptile found during Aviad’s survey was the common chameleon, Chamaeleo chamaeleon – with 15 specimens. The third most abundant was the commensal (and in Israel, native) house gecko, Hemidactylus turcicus (10 animals). In fact, only 41 reptiles other than A. sagrei were found in the survey, of all species (including those identified only from tracks!). Thus in terms of abundance, A. sagrei seems to outclass all other reptiles put together by a factor of at least 2.5-to-1. That this species can be extremely abundant in places it has invaded is well known (e.g., Campbell and Echternacht 2003).

While A. sagrei has invaded many places the world over, it seems to have been confined to tropical or subtropical countries (and the subtropical parts of the USA), and this is the first report of it inhabiting higher latitudes and non-tropical climates (except perhaps some potential places in the USA). One hope expressed early was that the relatively cool Mediterranean winters prevailing in central Israel will prove detrimental for anoles. Yet, like it probably does in some cities in the USA, A. sagrei seem not to mind what goes for winters near the Mediterranean coastlines of Israel. A combination of the climatic effects of the warm puddle that is the eastern Mediterranean Sea and warm microhabitats likely found in urban residential gardens seem to allow it to easily survive the winter. Watering of said gardens likely allows it to easily survive the arid climate of the long Israeli summers (where very little rain, if any, falls in April or October, and virtually none in between). Thus, urban areas seem to present for the anoles the kind of climate and microhabitats it thrives in in its native and introduced range.

Could it spread outside of the cities? As far as we know following Aviad’s survey (Bar 2021), no anoles were found in natural areas bordering its current urban distribution. The little water available there for most of the year may preclude its establishment. But it is highly likely that, if accidentally transported, it could easily establish in habitats where abundant water is available year-round. Such as streams and pools, artificial and natural.

How much of a threat is posed by Anolis sagrei to Israeli nature is less certain. As far as I know few have tried to estimate its effect on arthropod and other prey-species communities (but see Losos 2011,2020). I certainly cannot guess it. Actual reports of Anolis sagrei impacting other vertebrate taxa seem to be confined to its effect on congenerics (even Stroud et al., 2017, only mentions potential impacts), of which Israel has none. But a super-fecund, and highly abundant, species such as the brown anole could potentially compete with other small terrestrial and arboreal lizards (and juveniles of larger species), of which the Israeli coastal plain has many (Bar et al. 2021). I can easily envision it competing with, and potentially preying on lizards such as Mediodactylus orientalis, Hemidactylus turcicus, Phoenicolacerta laevis and Heremites vittatus – at least juvenile ones (and it could easily prey on adult Ablepharus rueppellii, if it can find it in the grass and leaf litter).

Aviad Bar with other lizards he recently caught (Varanus griseus). These ones are unlikely to be harmed by any anole and in fact are totally unrelated to this story. But Aviad sent the picture to me alongside the anole photos, and it was just too good to waste.

Right now, probably 2-5 years after it first invaded, A. sagrei seems to be doing extremely well in its new introduced range in Israel – but it is still probably very localized. This means that we have a unique opportunity to deal with it before it spreads further. Our record of dealing with reptile invasions in Israel is abysmal. Few reptile species have been introduced to Israel: Cyrtopodion scabrum, Trachemys scripta and more recently (Jamison et al. 2017) Tarentola annularis (Meiri et al. 2019, Bar et al. 2021). As far as I know, no attempt has been made to stop the spread of C. scabrum and T. scripta. The story of T. annularis is even more telling. Despite being larger, meaner, and potentially far more aggressive species than A. sagrei, and being introduced to a single locality, very little has been done to try and curb its invasion. One person was employed, for a few months, to try to control what was already a population numbering in the thousands – and even this effort was stopped for lack of funding (read: being of very low perceived priority).

I hope this will not be the case with Anolis sagrei too. We have the potential to stop the invasion, still in its infancy, in its tracks. The INPA seem to have the will (and certainly has the means) to do it, and I wish them luck and perseverance. This is an outlet of anole lovers so please don’t get me wrong. I do not wish for Israel to be the next test case of fascinating scientific work on the rapid evolution of Anolis sagrei. We want to keep anoles those wonderful and lizards we read about in papers and books (e.g., Roughgarden 1995, Losos 2009). I want us to keep on having to go and find them in places we find exotic (if there is anything Rishon LeZion is not, it is exotic). I want to engage with the scientists who study them on their own turf. Let’s keep anoles in the Neotropics where they belong.


References
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Auguste, R.J., Dass, K. and Baldeo, D. 2018. Discovery of the Puerto Rican crested anole, Anolis cristatellus Duméril & Bibron, on Trinidad. Caribbean Herpetology, 63: 1-2.

Bar, A. 2021. Summary of a preliminary survey to evaluate the establishment and distribution of the species brown anole (Anolis sagrei). Report to the chief ecologist of the Israeli Nature and Parks Authority, Pazbar, Herzlia. In Hebrew.

Bar, A., Haimovitch, G. and Meiri, S. 2021. Field guide to the amphibians and reptiles of Israel. Edition Chimaira, Frankfurt Am Main. In Press.
Batista, A, Ponce, M., Garces, O., Lassiter, E. and Miranda, M. 2019. Silent pirates: Anolis sagrei Dumeril & Bibron, 1837 (Squamata, Dactyloidae) taking over Panama City, Panama. Check List 15: 455-459.
Calsbeek, R. and Cox, R. M. 2010. Experimentally assessing the relative importance of predation and competition as agents of selection. Nature 465: 613-616.
Campbell, T. S. and Echternacht, A. C. 2003. Introduced species as moving targets: changes in body sizes of introduced lizards following experimental introductions and historical invasions. Biological Invasions 5: 193-212.
Capinha, C., Seebens, H., Cassey, P., Garcia‐Diaz, P., Lenzner, B., Mang, T., Moser, D., Pysek, P., Rodder, D., Scalera, R. and Winter, M. 2017. Diversity, biogeography and the global flows of alien amphibians and reptiles. Diversity and Distributions 23: 1313-1322.
Donihue, C. M., Kowaleski, A. M., Losos, J. B., Algar, A. C., Baeckens, S., Buchkowski, R. W., Fabre, A. C., Frank, H. K., Geneva, A. J., Reynolds, R. G., Stroud, J. T., Velasco, J. A., Kolbe, J. J., Mahler, D. L. and Herrel, A. 2020. Hurricane effects on Neotropical lizards span geographic and phylogenetic scales. Proceedings of the National Academy of Sciences, USA, 117: 10429-10434.
Echternacht, A. C. 1999. Possible causes for the rapid decline in population density of green anoles, Anolis carolinensis (Sauria: Polychrotidae) following invasion by the brown anole, Anolis sagrei, in the southeastern United States. Anolis Newsletter 5: 22–27.
Fetters, T. L. and Mcglothlin, J. W. 2017. Life histories and invasions: accelerated laying rate and incubation time in an invasive lizard, Anolis sagrei. Biological Journal of the Linnean Society 122: 635-642.
Gerber, G. P. and Echternacht, A. C. 2000. Evidence for asymmetrical intraguild predation between native and introduced Anolis lizards. Oecologia 124: 599–607.
Hsu, M. H., Lin, J. W., Liao, C. P., Hsu, J. Y. and Huang, W. S. 2021. Trans-marine dispersal inferred from the saltwater tolerance of lizards from Taiwan. PLoS One, 16: e0247009.
Jamison, S., Tamar, K., Slavenko, A. and Meiri, S. 2017. Tarentola annularis (Squamata: Phyllodactylidae): a new invasive species in Israel. Salamandra 53: 299-303.
Jensen, J. B., Camp, C. D., Gibbons, W. and Elliot, M. J. 2008. Amphibians and reptiles of Georgia. University of Georgia Press, Athens.
Kamath, A., Herrmann, N. C., Gotanda, K., Shim, K. C., LaFond, J., Cottone, G., Falkner, H., Campbell, T. S. and Stuart, Y. E. 2020. Character displacement in the midst of background evolution in island populations of Anolis lizards: a spatiotemporal perspective. Evolution 74: 2250-2264.
Kraus, F. 2009. Alien reptiles and amphibians. A scientific compendium and analysis. Springer Verlag, Berlin.
Losos, J. B. 2009. Lizards in an evolutionary tree: ecology and adaptive radiation of Anoles. University of California Press, Berkeley.
Losos, J. B. and Pringle, R. M. 2011. Competition, predation and natural selection in island lizards. Nature 475: E1-E2.
Losos, J. B. and Spiller, D. A. 1999. Differential colonization success and assymmetrical interactions between two lizard species. Ecology 80: 252-258.
Losos, J. B., Marks, J. C. and Schoener, T. W. 1993. Habitat use and ecological interactions of an introduced and a native species of Anolis lizard on Grand Cayman, with a review of the outcomes of anole introductions. Oecologia 95: 525-532.
Losos, J. B., Schoener, T. W. and Spiller, D. A. 2004. Predator-induced behaviour shifts and natural selection in field-experimental lizard populations. Nature 432: 505-508.
Meiri, S., Belmaker, A., Berkowic, D., Kazes, K., Maza, E., Bar-Oz, G. and Dor, R. 2019. A checklist of Israeli land vertebrates. Israel Journal of Ecology and Evolution 65: 43-50.
Meiri, S. 2021. The brown anole in Israel, assessing the invasion pathway, establishment potential and potential threats. Report to the chief ecologist, Israel Nature and Parks Authority. In Hebrew.
Norval, G., Huang, S.-C., Mao, J.-J., Goldberg, S. R. and Slater, K. 2012. Additional notes on the diet of Japalura swinhonis (Agamidae) from southwestern Taiwan, with comments about its dietary overlap with the sympatric Anolis sagrei (Polychrotidae). Basic and Applied Herpetology, 26: 87-97.

Perry, G., Powell, R. and Watson, H. 2006. Keeping invasive species off Guana Island, British Virgin Islands. Iguana, 13: 273-277.

Roughgarden, J. 1995. Anolis lizards of the Caribbean: ecology, evolution, and plate tectonics. Oxford University Press, Oxford.
Schoener, T. W., Losos, J. B. and Spiller, D. A. 2005. Island biogeography of populations: an introduced species transforms survival patterns. Science 310: 1807-1809.
Sexton, O. J. and Brown, K. M. 1977. The reproductive cycle of an iguanid lizard Anolis sagrei, from Belize. Journal of Natural History, 11: 241-250.
Solis, J. M., Ayala-Rojas, C. G. and O’Reilly, C. M. 2017. New records for two reptiles from the Bay islands, Honduras. Mesoamerican Herpetology 4: 669-671.
Stroud, J. T., Giery, S. T. and Outerbridge, M. E. 2017. Establishment of Anolis sagrei on Bermuda represents a novel ecological threat to Critically Endangered Bermuda skinks (Plestiodon longirostris). Biological Invasions, 19: 1723-1731.
Stroud, J. T., Mothes, C. C., Beckles, W., Heathcote, R. J., Donihue, C. M. and Losos, J. B. 2020. An extreme cold event leads to community-wide convergence in lower temperature tolerance in a lizard community. Biology Letters, 16: 20200625.
Stuart, Y. E., Campbell, T. S., Hohenlohe, P. A., Reynolds, R. G., Revell, L. J. and Losos, J. B. 2014. Rapid evolution of a native species following invasion by a congener. Science 346: 463-465.
Thawley, C. J. and Kolbe, J. J. 2020. Artificial light at night increases growth and reproductive output in Anolis lizards. Proceedings of the Royal Society of London B. 287: 20191682.


New Research Explores Evolutionary History of Central and South American Anoles

The mainland ground anole Anolis tandai from Brazil. (Photo: Ivan Prates)

The mainland ground anole Anolis tandai from Brazil. (Photo: Ivan Prates)

From GW Today:

June 02, 2021

By Kristen Mitchell

A George Washington University Columbian College of Arts and Sciences Ph.D. student recently published a paper about the evolution of Central and South American anoles, a group of tropical lizards that have been historically understudied compared to their distant relatives in the Caribbean. The study was a collaboration with researchers from the Smithsonian National Museum of Natural History.

Jonathan Huie, a Ph.D. candidate in the Department of Biological Sciences, got involved in this work as an undergraduate student through a National Science Foundation research internship at the Smithsonian National Museum of Natural History. This research sparked his passion for lizards and ultimately guided him toward a doctoral program studying salamanders at GW.

Mr. Huie is lead author of the new paper, published in The Biological Journal of the Linnean Society on Wednesday. Mr. Huie spoke to GW Today about the impact of this research.

Q: Why has there historically been such a significant gap between what researchers know about Caribbean anoles and what they know about anoles found in Central and South America?
A: Most of the 400-plus species of anoles live in Central and South America, and yet the lion’s share of anole research has focused on Caribbean species. There are likely several reasons why, but ease and accessibility are definitely important factors. In the Caribbean, anoles are quite abundant and easy to find but mainland anoles are more secretive, likely because they have more predators to hide from. It’s difficult to study what you can’t see.

Another reason may be because islands themselves are excellent study systems. They’re small and easier to make sense of compared to mainland systems. There’s also a lot of them, which is ideal for replication and hypothesis testing. Lastly, science is often conducted where it’s easiest or most desirable to establish a field site so it’s probably no coincidence that many well-studied anoles occur near vacation spots.

With that said, there’s been a huge push in recent years to learn more about mainland anoles. Our study wouldn’t have been possible otherwise, but there is still a lot we don’t know about mainland anoles.

Q: What did your research reveal about how anoles in Central and South America have evolved to fill various ecological niches?
A: Anoles originated on the mainland, then they colonized the Caribbean, and eventually re-invaded the mainland. Caribbean anoles are well-known among biologists for repeatedly evolving sets of species with similar ecologies and morphologies on Cuba, Hispaniola, Jamaica and Puerto Rico. For example, some species live on thin perches like twigs and have convergently evolved short limbs and well-developed toe pads. Other species specialize in living in tree-crowns, on tree trunks, grasses and bushes. We found that when anoles diversified on the mainland the second time, they convergently re-evolved all of the same habitat specialists and morphological adaptations found in the Caribbean—but this time in Central and South America. This is fascinating given what we often believe to be true about islands and continents.

Our second main finding was that ground-dwelling anoles are really common on the mainland and have their own set of morphological adaptations. Many Caribbean anoles forage on the ground, but very few live there full-time. Mainland ground anoles, on the other hand, really took off. We hypothesized that ground anoles are common on the mainland—at least among the group that re-invaded the mainland—because most arboreal niches were already occupied by other lizards. It’s unclear why Caribbean ground anoles are not more abundant.

GW Ph.D. student Jonathan Huie (center) poses with his mentors Ivan Prates (left) and Kevin de Queiroz (right) at the Smithsonian’s National Museum of Natural History in 2018. (Photo: Smithsonian)

Q: How do your findings challenge long-held assumptions made about evolution on islands compared to mainland habitats?
A: We found that island and mainland anoles are more similar than previously thought. For a long time, it was believed that islands were hotbeds for extreme morphologies and that continents lacked the necessary conditions. In the context of anoles, island species were considered to be unique—that the relationship between habitat and morphology was fundamentally different on islands versus the mainland. However, we found strong evidence that this is not the case.

That is not to say that everything we once thought to be true is now wrong—there are still many differences between island and mainland anoles. However, our research shifts how we should view island and mainland comparisons. Our paper joins other recent studies in suggesting that the mainland is equally good at cultivating morphological diversity as island environments.

Q: How did you get involved in this research, and how did it shape the kind of research you are doing now as a Ph.D. candidate?
A: I got involved as an undergraduate National Science Foundation Research Experiences for Undergraduates (REU) intern at the Smithsonian’s National Museum of Natural History in 2018, under the co-mentorship of Ivan Prates and Kevin de Queiroz. I was a total fish geek and had never studied anoles, but I signed on to investigate the link between habitat and morphology in a handful of mainland anoles.

I measured their body proportions using the museum’s natural history collection but finished quickly. So, we started adding more and more species, and even after the internship was over, I continued to visit other natural history collections to measure even more lizards. The next thing I knew, I had looked at more than 200 species. Natural history collections like the Smithsonian were absolutely critical for this work and fostering my interests beyond fishes.

As a Ph.D. student, I am currently studying salamander limbs to better understand the type of adaptations needed to make the water-to-land transition. The kinds of questions I am interested in for my dissertation are similar to the ones we approached with the anole project. Without my internship, it’s very unlikely that I would have ended up at GW studying salamanders.

Q: How are you planning to build on this research moving forward?
A: There is still so much left to do. In our recent paper, we only published about half of the data I initially collected. We are excited to dive deeper and look at how body size influences patterns of morphological adaptation.

There’s also the other group of mainland anoles that we didn’t look at. I am interested in knowing more about how these other mainland species fit into the puzzle. Did they adapt in a similar manner as the group of mainland anoles we looked at? Or are they doing something different? We would like to know how often evolution repeats itself to produce similar outcomes.

Sex-Specific Population Differences in Resting Metabolism Are Associated with Intraspecific Variation in Sexual Size Dimorphism of Brown Anoles

Female (top) and male (bottom) brown anole. Photo courtesy Bob Reed

New literature alert!

Sex-Specific Population Differences in Resting Metabolism Are Associated with Intraspecific Variation in Sexual Size Dimorphism of Brown Anoles

In Physiological and Biochemical Zoology
Curlis, Cox, & Cox

Abstract

Sexual size dimorphism can vary in direction and magnitude across populations, but the extent to which such intraspecific variation is associated with sex and population differences in underlying metabolic processes is unclear. We compared resting metabolic rates (RMRs) of brown anole lizards (Anolis sagrei) from two island populations in the Bahamas (Eleuthera and Great Exuma) that differ in the magnitude of male-biased sexual size dimorphism. Whereas females from each population exhibit similar growth rates and body sizes, males from Great Exuma grow more quickly and attain larger body sizes than males from Eleuthera. We found that these population differences in growth of males persisted in captivity. Therefore, we predicted that males from each population would differ in RMR, whereas females would not. Consistent with this prediction, we found that RMR of males from Eleuthera was higher than that of males from Great Exuma, particularly at higher temperatures. As predicted, RMR of females did not differ between populations. Despite this apparent sex-specific trade-off between growth rate and RMR at the population level, we found a positive relationship between growth rate and RMR at the individual level. The fact that Great Exuma males maintain lower RMR than Eleuthera males, despite their greater absolute growth rates and the positive relationship between RMR and growth rate across individuals, suggests that Great Exuma males may have lower baseline metabolic demands and/or greater growth efficiency than Eleuthera males. Our results call attention to sex-specific divergence in metabolism as a potential mechanism for intraspecific divergence in sexual size dimorphism.

Read the full paper here!

Ecological Opportunity from Innovation, not Islands, Drove the Anole Lizard Adaptive Radiation

New literature alert!

Ecological Opportunity from Innovation, not Islands, Drove the Anole Lizard Adaptive Radiation

In Systematic Biology
Burress & Muñoz

Abstract

Islands are thought to facilitate adaptive radiation by providing release from competition and predation. Anole lizards are considered a classic example of this phenomenon: different ecological specialists (‘ecomorphs’) evolved in the Caribbean Greater Antilles (Cuba, Hispaniola, Jamaica, and Puerto Rico), resulting in convergent assemblages that are not observed in mainland Latin America. Yet, the role of islands in facilitating adaptive radiation is more often implied than directly tested, leaving uncertain the role of biogeography in stimulating diversification. Here, we assess the proposed “island effect” on anole diversification using Bayesian phylogenetic comparative methods that explicitly incorporate rate heterogeneity across the tree and demonstrate two cases of would-be false positives. We discovered that rates of speciation and morphological evolution of island and mainland anoles are equivalent, implying that islands provide no special context for exceptionally rapid diversification. Likewise, rates of evolution were equivalent between island anoles that arose via in situ versus dispersal-based mechanisms, and we found no evidence for island-specific rates of speciation or morphological evolution. Nonetheless, the origin of Anolis is characterized by a speciation pulse that slowed over time – a classic signature of waning ecological opportunity. Our findings cast doubt on the notion that islands catalyzed the anole adaptive radiation and instead point to a key innovation, adhesive toe pads, which facilitated the exploitation of many arboreal niches sparsely utilized by other iguanian lizards. The selective pressures responsible for arboreal niche diversification differ between islands and the mainland, but the tempo of diversification driven by these discordant processes is indistinguishable.

Read the full paper here!

How Do Anoles Get Their Colors?

A male A. distichus favillarum (a.k.a. a male Fav) extending it’s dewlap. This animal was photographed in the contact zone between orange- and yellow-dewlapped Favs.

Color and color-pattern research is a powerhouse in the study of evolution. Don’t believe me? I bet that at least one of your top five examples of evolution includes either color or color pattern. It is also very likely that some of the gene names you know by heart are from either color or color-pattern genes. Here’s an exercise: think which were the ‘textbook’ examples of evolution that you were taught in school. I’m sure that at least one of those included either color or color pattern. Here’s a famous example: Peppered moths. Another one? Deer mice. Another one? Heliconius butterflies. Another one? Coral snakes. What about color genes? Does MC1R ring a bell? Another one? ASIP (a.k.a. agouti)? Another one? Well, I should stop here before DJ Khaled sues me for copyright infringement.

Most of these early studies, however – and specially studies that attempted to unveil the genetic basis of color and color pattern – focused on melanin-based traits. The reason for this bias was simple: human color is melanin-based. This means that when these early studies took place, we knew more about the genetic basis of melanin synthesis than any other pigment by a long shot. As a consequence, melanin-based traits were ideal for candidate gene approaches – like the ones implemented in early color and color-pattern studies. As you and I know, though, the world isn’t black and white (see what I did here?). Color is all around us, and it plays all kinds of amazing roles, such as intra-specific communication (think dewlapping anoles), inter-specific communication (think dewlapping anoles), and crypsis (think non-dewlapping anoles). This means that, until recently, we didn’t have the tools to connect the genetic basis of most colorful traits to their phenotypes, specially in non-model organsisms.

Then, something happened: second generation sequencing came around. Illumina, a key player in second generation sequencing, was founded in 1998, the same year that Brazil lost the World Cup Final to France (many Brazilians, like me, think about time in four-year cycles due to the World Cup… and we don’t talk about 2014). With second generation sequencing, we could finally gather loads of data to do all kinds of glorified regressions (sorry generalized linear mixed models), and run computers for very long times so that we could try every feasible parameter combination (sorry Markov Chains) to identify candidate genes for the trait we are interested in. Connecting genotypes to phenotypes and understanding how both genotypes and phenotypes interact and change due to selection is, in fact, one of my main research interests.

I’m particularly interested in understanding the genetic basis of two phenotypes: those associated with color and color pattern, and those associated with the evolution of reproductive isolation.

Transcriptomic Analysis of Skin Color in Anole Lizards

Anolis distichus

New literature alert!

Transcriptomic Analysis of Skin Color in Anole Lizards

In Genome Biology and Evolution
de Mello, Hime, & Glor

Abstract

Color and color pattern are critical for animal camouflage, reproduction, and defense. Few studies, however, have attempted to identify candidate genes for color and color pattern in squamate reptiles, a colorful group with over 10,000 species. We used comparative transcriptomic analyses between white, orange and yellow skin in a color-polymorphic species of anole lizard to: (i) identify candidate color and color-pattern genes in squamates, and (ii) assess if squamates share an underlying genetic basis for color and color pattern variation with other vertebrates. Squamates have three types of chromatophores that determine color pattern: guanine-filled iridophores, carotenoid- or pteridine-filled xanthophores/erythrophores, and melanin-filled melanophores. We identified 13 best candidate squamate color and color-pattern genes shared with other vertebrates: six genes linked to pigment synthesis pathways, and seven genes linked to chromatophore development and maintenance. In comparisons of expression profiles between pigment-rich and white skin, pigment-rich skin upregulated the pteridine pathway as well as xanthophore/erythrophore development and maintenance genes; in comparisons between orange and yellow skin, orange skin upregulated the pteridine and carotenoid pathways as well as melanophore maintenance genes. Our results corroborate the predictions that squamates can produce similar colors using distinct color-reflecting molecules, and that both color and color-pattern genes are likely conserved across vertebrates. Furthermore, this study provides a concise list of candidate genes for future functional verification, representing a first step in determining the genetic basis of color and color pattern in anoles.

Read the full paper here!

And see the authors’ own commentary!

#DidYouAnole – Anolis vermiculatus

All anoles are amazing and unique, but some just go above and beyond others.

Anolis vermiculatus (previously seen here), the Cuban aquatic or stream anole, is a semi-aquatic anole endemic to Cuba and one of two anoles that completely lacks a dewlap (the other being Anolis bartschi).

The males can have an SVL of up to 123mm making them a large anole, and the females are smaller at 83mm. They live near streams in dense vegetation and eat (in addition to insects) plant matter, small fish, frogs, crayfish and freshwater shrimp. Like another anole, Anolis pulchellus, the Cuban aquatic anole is able to run across the surface of water to escape predators, aided by the hydrophobic skin that anoles have. Cuban stream anoles are incredibly skittish so in addition to running across the water, they may just jump into it when disturbed or threatened, staying submerged for long periods of time.

Photos: Shea Lambert

Repeated Evolution of Underwater Rebreathing in Diving Anolis Lizards

Semi-aquatic Anolis lizards have some of the most fascinating ecologies, colour patterns, and behavioural strategies in the genus (though I may be biased). Twelve of these neotropical streamside specialists are distributed across much of mainland Latin America and on the two largest islands of the Caribbean. All are rarely found more than a few meters from a stream and some have been observed to consume semi-aquatic prey (or, in the case of A. vermiculatus, even small fish and freshwater crustaceans).

Range map of all 12 semi-aquatic anole species

A riparian lifestyle is also responsible for the signature move that unites all species of semi-aquatics—escape dives! As anyone who has encountered one of these lizards in the wild can attest, semi-aquatics will readily dive underwater when approached. They can stay down for awhile too—up to 18 minutes by my count (Mexico’s A. barkeri currently holds the record). Diving anoles have attracted the attention of tropical biologists for more than half a century now (e.g., Robinson 1962; Brandon et al. 1966; Campbell 1973; González Bermúdez and Rodríguez-Schettino 1982; Birt et al. 2001; Leal et al. 2002; Henderson and Powell 2009; Muñoz et al. 2015; Herrmann 2017) and this work has begun to fill out our natural history knowledge of these enigmatic lizards. However, understandably, most work to date has focused on what these lizards are doing when they’re not in the water. And, as it turns out, there’s a lot to learn if we look below the surface…

In 2009, while studying Anolis eugenegrahami, an endangered semi-aquatic anole from Haiti, Luke Mahler and Rich Glor noticed that an individual they had just released into a clear, shallow stream proceeded to repeatedly exhale and re-inhale an air bubble as it clung to the rocky bottom. Luke and Rich had to move to their next site later that day, so weren’t able to learn more. Sadly, a follow-up field season was cancelled in the aftermath of the 2010 Haiti earthquake.

Years later, when I started my MSc thesis on aquatic anoles in at the University of Toronto, Luke shared this observation with me. When an anole does something once, another anole somewhere else usually does it convergently, so we couldn’t help but wonder whether aquatic anole species elsewhere also exhibited this apparent “rebreathing” behavior. So, when I was planning my first field season in Costa Rica, on a hunch, we purchased an oxygen microsensor, and I set out to establish whether this intriguing behaviour occurred in any other semi-aquatic anoles.

The aquatic anoles did not disappoint! During my Master’s, along with an amazing team of colleagues, I visited stream habitats in Costa Rica, Colombia, and Mexico, studying A. oxylophus, A. aquaticus, A. maculigula, and A. barkeri along with the non-aquatic anoles we were able to find at each site. I found that each of these species routinely performed the same behaviour that Luke and Rich had observed in A. eugenegrahami! We named this phenomenon “rebreathing” after the SCUBA apparatus. All of the semi-aquatics we observed performed rebreathing extensively during experimental submersions and are from five phylogenetically distinct lineages, showing a pattern of remarkable behavioural convergence!

As I was conducting these experiments, “rebreathing” was independently discovered in Anolis aquaticus by Lindsey Swierk (see image below, and Lindsey’s 2018 AA post). Lindsey is the world authority on Costa Rica’s diving anoles, and has reams of firsthand knowledge about their ecology and behavior. So we did the obvious thing when we found out about her observation – we invited her to join our project. We managed to deliver our oxygen sensor to Lindsey in Costa Rica via a colleague with overlapping travel plans, and she helped fill out our oxygen use data set for the Costa Rican diving anole species. In addition, Luke tested Anolis lynchi in Ecuador, and various non-aquatic species during fieldwork there and elsewhere (Dominican Republic, Jamaica) to help round out the data set.

A diving A. aquaticus performing rebreathing (Photo: Lindsey Swierk)

Speaking of non-aquatic anoles, what role do they play in this story? An interesting one, as it turns out. Rebreathing clearly seemed fascinating, but one possibility was that it was relatively ubiquitous and that all anoles would rebreathe if you submerged them. To find out, we did just that, carefully dunking aquatic and non-aquatic anoles alike in aquaria or buckets at our field sites.

What we discovered is that most non-aquatic anole species are indeed capable of basic rebreathing, but for the most part, they don’t rebreathe anything like the semi-aquatics do. If they rebreathed at all, non-aquatic species tended to do so only occasionally and irregularly (usually only one or a few re-inhalations). Since semi-aquatic anoles performed rebreathing extensively and consistently, while non-aquatics were capable of the basic components of rebreathing, but did not rebreathe regularly, we think consistent rebreathing may have evolved when natural selection found a new utility for a trait that all anoles possess—hydrophobic skin. The hydrophobicity of anoles’ scales is likely what enables the air bubble to adhere to the diving anoles’ heads (and thereby also enables re-inhalation).  All anoles therefore appear to be capable of forming a thin layer (or ‘plastron’) of air along their scales during submersion, but only semi-aquatics appear to make regular use of this ability (see plot below). Hydrophobic skin evolved in anoles long before it was co-opted for rebreathing in stream-dwelling species, and likely had nothing to do with the use of aquatic habitats. In this way, the innovation of underwater rebreathing apparently owes its origins to a fortuitous ‘evolutionary accident.’

Semi-aquatic anoles rebreathed more frequently than non-aquatics (from Boccia et al. 2021)

Although we observed regular rebreathing in all aquatic anole species we studied, we discovered some interesting differences in the way they go about it. There were three main locations along the head to which diving anoles would exhale bubbles (see image below). We noted some variation in the bubble positions used by semi-aquatics, perhaps indicating that are multiple ways to achieve the same rebreathing function.

Bubble positions and use percentages for five semi-aquatic anole species (Drawing credit: Claire Manglicmot)

To determine if ‘rebreathing’ was truly involved in respiration, we used our oxygen sensor to measure the oxygen concentration of the bubbles produced by diving semi-aquatics. This is not as easy as it sounds; bubbles were frequently re-inhaled quickly and diving anoles do not take kindly to being accidentally poked in the nose with a probe. But we persevered, and found that bubble oxygen levels decreased through time, consistent with the respiration hypothesis!

Experimental submersion of an A. maculigula male in Colombia; field assistant James is holding oxygen and temperature sensors ready.

We found some evidence that oxygen decrease followed an exponential decline curve, suggesting either that anoles extract some additional oxygen from the surrounding water by rebreathing (thus slowing the rate of oxygen loss from the bubble), or that metabolic rate (and thus oxygen demand) drops over time during submersion (see figure below). We compared our results to diving insects that use a similar rebreathing apparatus while submerged and found that anole oxygen use matches up well with our expectations for their sizes, and that the metabolic rate of anoles is probably too high for them to remain underwater indefinitely using oxygen captured from the water by the rebreathing bubble (the same is true for the largest diving insects).

Plots A-E show bubble oxygen concentrations through time for five species of semi-aquatic anole. Plot F shows a sham trial (in which I mimicked the bubble movements of diving anoles with a submerged syringe; no oxygen declines were observed). Plot G shows semi-aquatics (blue) and diving insect oxygen consumption rates (black) by mass. The dotted line indicates the theoretical limit of oxygen replenishment per second that could be supported by a bubble gill structure. From Boccia et al. 2021.

The consistency with which unrelated semi-aquatic anoles rebreathed suggests that rebreathing is adaptive for semi-aquatic living; however, our data currently do not allow us to favour a particular physiological functionality for this behaviour. Our top three (not mutually exclusive) hypotheses are: 1) rebreathing allows anoles to access air trapped in their head cavities or within the plastron, which might otherwise not be incorporated into their air supply; 2) the rebreathing bubble functions as a physical gill (as has been observed in diving insects), allowing diving semi-aquatics to extract some oxygen from the surrounding water; and 3) bubble exhalation and re-inhalation allows anoles to remove excess carbon dioxide which builds up during dives. We hope to investigate these possibilities during future work!

We published this work in Current Biology (Boccia et al., Repeated evolution of underwater rebreathing in diving Anolis lizards, Current Biology (2021), https://doi.org/10.1016/j.cub.2021.04.040)

See also coverage from National Geographic, the University of Toronto, and Binghamton University. Special thanks to Day’s Edge Productions who created the amazing video summary!

An A. oxylophus taking over camera duties

References

Birt RA, Powell R, Greene BD. 2001. Natural History of Anolis barkeri: A Semiaquatic Lizard from Southern México. Journal of Herpetology. 35(1):161. doi:10.2307/1566043.

Brandon RA, Altig RG, Albert EH. 1966. Anolis barkeri in Chiapas, Mexico. Herpetologica. 22(2):156–157.

Campbell HW. 1973. Ecological observations on Anolis lionotus and Anolis poecilopus (Reptilia, Sauria) in Panama. Am Mus Novit. 2516:1–29.

González Bermúdez F, Rodríguez-Schettino L. 1982. Datos etoecologicos sobre Anolis vermiculatus (Sauria: Iguanidae). Poeyana. 245:1–18.

Henderson RW, Powell R. 2009. Natural history of West Indian reptiles and amphibians. Gainesville: University Press of Florida.

Herrmann NC. 2017. Substrate availability and selectivity contribute to microhabitat specialization In two Central American semiaquatic anoles. Breviora. 555(1):1–13. doi:10.3099/MCZ33.1.

Leal M, Knox AK, Losos JB. 2002. Lack of convergence in semi-aquatic Anolis lizards. Evolution. 56(4):785–791. doi:10.1111/j.0014-3820.2002.tb01389.x.

Muñoz MM, Crandell KE, Campbell-Staton SC, Fenstermacher K, Frank HK, Van Middlesworth P, Sasa M, Losos JB, Herrel A. 2015. Multiple paths to aquatic specialisation in four species of Central American Anolis lizards. Journal of Natural History. 49(27–28):1717–1730. doi:10.1080/00222933.2015.1005714.

Robinson DC. 1962. Notes on the Lizard Anolis barkeri Schmidt. Copeia. 3:640–642.

 

Trinidadians Reflect on Their Lizards

Anolis aeneus. Photo by shanelkalicharan.

Vaneisa Baksh is an editor, writer and cricket historian for the Trinidad Saturday Express. She’s written two essays on the local lizards and along the way has chided up herpetologists for not responding to the first one. Let’s get to work!

First she writes several weeks ago, in an article entitled “The LIzards Running Up and Down”:

The first time I heard the sound, I thought a bird had flown into the house, although none of my regular feathered folk chirped like that. I searched and searched, remembering how one time a little dove had come in and had been frantically trying to escape while I tried to guide it to the open window in the kitchen. My efforts were just increasing its anxiety and I had to leave it alone to simmer down until it mercifully found its way to freedom.

This time, there was no bird and eventually, as the sound repeated itself, I spotted the culprit. It was a lizard, a gecko, and although we have co-habited in different houses since I was a child, I’d never heard one of the buggers speak. That was a couple years ago, and curious to know if this was a mutation of the creature we called “24-hours” on account of the myth that if it fell on you, it would stay there for an entire day, I went looking for information.

It turned out that these are really house-loving critters. They prefer to be indoors and are harmless, and might even be regarded as useful. I learned that they feed on insects, cockroaches, termites, wasps, flies, spiders, moths and poor butterflies. I’d decided that I would just have to get used to the unusual sound—the most apt description on Wikipedia was “tchak tchak tchak”, which it said was often sounded six to nine times in sequence. I have a way of seeing words in shapes, and maybe sounds as well. Every time I hear the gecko chirp, I would see the sound like a fairly squared-off pellet. Perhaps it is because the sounds are evenly pitched and last for roughly the same length of time. I don’t know, but I have tried to get used to it suddenly rapping into my consciousness.

At first, it was restricted to my bedroom and my study, but now it seems the lizards are everywhere. Whereas I found it an occasional interruption, now I feel there are colonies of them living in my house and even though I hardly see more than one at a time, I feel that they have taken over.

It is one thing to adjust to the sound they make—tchak tchak tchak is far more bearable than the abrasively loud grinding from the welding next door—but these discreet urban dwellers leave their little droppings everywhere. Everywhere. Not only do I have to clean them off the floors, especially at the base of the walls, but the area that really trips me is by my bedside table and on my bed. Yesterday, I washed my sheets and replaced them. As I prepared to turn in last night, I spotted the droppings on the edge of the bed. I suppose that’s why I am bringing them up now.

I would dearly like to know if other householders are experiencing this increased presence that is now forcing a whole different level of housekeeping. I have been getting faint whiffs of urine as well, and it drives me crazy, because I am washing cushion covers, curtains, sheets, everything that could be contaminated, and mopping the floors far too often.

It’s not just being finicky, which I am, but for some time now, my eyes have been unusually sensitive and gritty. While it is true that I am spending a considerable amount of time reading and writing in front of various screens, and that the presence of Saharan dust has been exacerbating things, my ophthalmologist says there is evidence of some kind of persistent irritant, or allergy affecting my eyes.

Naturally, I am mindful that it is possible that the creatures overhead who seem to like my bedroom might be doing numbers over my bed and that might be messing with my eyes. I am not trying to gross anyone out, it just seems that it is likely that there is a growing population of the lizards, which I think we also call woodslaves, and that while we might be adjusting to their presence and their noises, we might not be aware of the side effects.

I’ve never had a problem with lizards. When we were children, the whole brood of about 15 to 20 cousins on any given night would gather in my grandfather’s living room to look at television shows because nobody else had a TV.

We’d start streaming in when the news programme, Panorama, began at seven o’clock. That was when he would turn on the black and white beauty with the wooden cabinetry. Afterwards when some other show began (the real reason we were there), he would sit there with us, and if there was any sign of anything remotely inappropriate for us, like a kissing scene, he would suddenly exclaim, “Look, look, look, the lizard up there!” Naturally, we would all momentarily turn our heads away from the screen at the unexpected shout. Sometimes there was a lizard, but more often not, and he would say, “Ah, he run away!” But his distraction worked well enough, or so he thought.

Harmless enough.

But I feel something has changed. There are more, they are loud and though they love being indoors, they are not house-trained! This might sound creepy though I say it in jest, what if I am now the interloper in the house of the lizards?

—Vaneisa Baksh is an editor, writer and cricket historian.

E-mail: vaneisabaksh@gmail.com

 

And then Vanessa writes yesterday in “Welcome to the Lounge of Lizards”:

I’D hoped that bringing up the ungovernable appearance of house lizards might have elicited a response from a couple of herpetologists. Disappointingly none came; but many people shared their experiences and theories. There was much to learn from these personal stories, and they broadened my sense of community, so I want to share some titbits from a few.

I mean, here we are, locked down in our separate cubicles, not knowing anything about one another, and suddenly, we are sharing lizard tales, revealing snippets of our lives that tell us something about daily trials we have in common. It’s not something we’d chat about, and noticing that our traditionally unobtrusive house mates have become loquacious would hardly qualify as a subject for conversation—unless you have physical visitors and the lizards are contributing their five cents to the discussions. Innocuous things have to force themselves unto your radar—usually by causing some disruption—before they register on your consciousness. Like the jiggly latch on a window that you notice every time you open or close it, but never outside that moment.

Curious if these chirpy critters were mutants or had just been imported, I read of work done by Jonathan Losos, a professor of evolutionary biology and a herpetologist, whose research is mostly concerned with how lizards interact with their environment and how they have diversified. Apparently they have focused on the “evolutionary radiation” of Caribbean Anolis lizards, among others, but they are also looking at how species are adapting to urban environments.

One related study examined the impact of an invasive anole species in Dominica. Up until two decades ago, it was home to a single species until a second species arrived tucked inside a shipment of lumber. Not hard to imagine our lizards coming in by sea. I remember landing in Nevis on one of those small aircraft and as we disembarked, a scorpion scurried down the aisle as soon as the door was opened. Naturally, ­passengers let the hustler disembark first.

A 65-year-old reader sent this: “Our first house was a small ‘board-house’ with a thatched roof and termite-ridden boards. I could knock on a board to find out if it was termite-eaten by the hollow sound that emanated. Prying into the thin cover, I would find the hollow cavities. Here the house-geckos laid their eggs. Unfortunately, sometimes I would remove the eggs. The old Indian people used to call them ‘bistooyas’, the ones about three inches long, sometimes with white stripes from their eyebrows to the body.”

Quite a few people said they had been hearing the noises but couldn’t figure out the source, assuming it was some kind of night bird, and some thought they were alone in this experience.

One person said that around the same time they began hearing those sounds they noticed that “my eyes felt like I had nits in the base of my eyelashes, and the attendant discomfort… At the same time, I had noticed a reduction in small spiders, spider’s webs, and mosquitoes”.

A woman of the West included a delightful description of the upsurge of geckos. “There’s quite a lot of courtship going on between pairs, appropriately, in our bedroom, and each pair seems to play tag, with a pursuer and its quarry. Inevitably, though, they come to an agreement and tiny baby lizards pop up soon after.” She doesn’t mind them, she says, but most of the women harbour strong feelings.

“I detest those creatures. They are annoying. They feed on the insects in the house. If by chance I should see one within easy reach, I implore my husband to get rid of it, and he would hold it using a piece of cloth and throw it outside. He doesn’t harm them,” said one.

A few mentioned that peppermint infused with water makes a reasonable repellent. One had specific directions: peppermint oil may be used by soaking cotton balls and placing them on the top of shelves, inside closets, behind books and similar places. I prefer using a spray bottle, measuring half water and quarter oil and spraying in the same places. It’s been keeping them away so far and the smell becomes less pungent after a few days.” Another said she had tried it, but is worried about the larger implications.

“There is something amiss in the ecosystem. This, what can only be described as an infestation, is a new phenomenon. Is this a new and invasive species or has this lizard been blessed by depleting stock of its natural predators? I do think it is something which the scientists need to investigate. Is there something more sinister at work? And what are the implications? I have always been leery of lizards. Their presence disconcerts me. And now this is like living in some kind of mild horror story—in my own house! Lizards pop up everywhere—in the vegetable basket, in the clean-clothes basket, drop from the roof. One found its way into my glass of water; fortunately, I looked down before I sipped!”

Another said, “I agree with you totally on all that you said, and I believe that these creatures are being used for sinister purposes.”

I don’t know about that, but I enjoyed learning more, like discovering that a group of lizards is called a lounge. I imagine them lounging about our homes and I figure what better place for a lizard to lime than this country!

#DidYouAnole – Anolis transversalis


Photo: dhfischer, iNaturalist

We talked about a lot of Ecuadorean anoles last year and this week we’re revisiting South America.

Transverse anoles, Anolis transversalis, are arboreal lizards that can be found in the Eastern Amazon in Ecuador, Peru, Colombia, Brazil, Bolivia and Southern Venezuela.

These anoles are dramatically sexually dimorphic, so much so that the males were initially described as another species, A. buckleyi (O’Shaughnessy, 1880). The females have a larger banding pattern, sometimes with spots in between and are also different in colouring. The females of this species have dewlaps that are different from the males as well, being smaller and with large vertical banding. Male Transverse anoles have smaller, faint banding overlaid with spots and a larger bright yellow-green dewlap with a pattern of spots (sometimes) and small faint lateral stripes.


Photo: Fernando Ayala-Varela, iNaturalist

Transversalis anole
Photo: Santiago R Ron, BioWeb

Their differences have been noted in previous post on here as well, the differences in their dewlaps.

The average SVL of male Transverse anoles is 88mm, and females is 86mm. They actively defend their territory from other anoles.

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