It’s been a while since we’ve looked at an anole from South America, so why not go all the way over to an an anole that is probably at the highest elevation an anole species has ever been found: Anolis heterodermus, the Flat Andes anole!
Anolis heterodermus lizards are arboreal and can be found on montane elevations in Colombia and Ecuador at about 2,600 m (8,530 ft). As you can guess, living at an such an elevation should be too cold for a lizard, but the Flat Andes anole is ok with this. They have been found to have wider preferred and body temperature ranges than expected for anoles and have adapted to take advantage of the limited hours of sun that the area gets (Méndez-Galeano & Calderón-Espinosa, 2017).
These anoles are large rich green to olive lizards with males being slightly larger than females at 85.4mm and 85mm respectively. They have wide banding on their bodies and both males and females have a patch on their tails that have been observed to change from red to blue throughout the day. This patch is larger in males (Beltrán, 2019) and is another sign of sexual dimorphism in this species. Their dewlaps are pink striped.
More on Anolis heterodermus from the pages of Anole Annalshere.
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.
Costa Rica field team, 2017
Colombia field team, 2018
Mexico field team & friends, 2018
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)
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.
This week’s anole is one of three recorded species of anoles with a proboscis, the Pinocchio Anole, or Ecuadorian Horned Anole. The other two proboscid species being Anolis phyllorhinus and Anolis laevis.
Anolis proboscis has been featured on this website several times and is well loved here, so you may already know that only the males have the proboscis.
They are capable of raising and lowering their appendages and use it for attracting mates. They move their heads side to side in displays referred to as ‘proboscis flourishing’ (Quirola et al. 2017). Males also stimulate females during courtship, by rubbing the nape of their necks with the appendage. The horn can’t be used as a weapon for fighting other males as it is very flexible, capable of folding right over (Losos et al. 2012), but they display their horns during these interactions, raising them, most likely to appear larger and more intimidating to the rival male. Their dewlaps are small, which is common in anoles with other physical signals, but more research is needed into the uses of the appendage to further confirm its uses.
Female Pinocchio Anole, photo by Nelson Apolo, iNaturalist
The Pinocchio Anole males, unlike other proboscid anoles, are born with a small horn. Why do they have the horn so early? We don’t know… yet!
This anole is very hard to find, actually even being assumed extinct after going unseen by locals and visiting scientists alike, after specimens were collected in 1966, until accidentally being spotted by a birdwatching group in 2005 when a male crossed the road. They typically prefer dense vegetation but on occasion may be found active on the ground. Pinocchio Anoles are endangered, and only found in the protected forest reserves that make up their range in Ecuador, where they are endemic.
Some people think that the anoles with brown colouring and patterns are too drab or boring but honestly I appreciate their ability to blend in almost seamlessly to their habitats. The Blotchbelly Anole is another one of those, usually brown, sometimes with light patterning or a tan line down its back.
The males have a unique burnt sienna coloured dewlap, while the females of this species have no dewlap. Blotchbelly anoles appear to be twig anoles and they inhabit lowland forests in Ecuador and Colombia.
The anole gets its name due to the spotting (but not blotches) on its belly. Female Blotchbelly Anoles may be slightly larger than the males with a recorded length of 124-140 mm (Arteaga 2013), and the males at 120-129 mm.
Found from northwestern Ecuador to central Colombia, Anolis lyra is a trunk anole that gets its name (Lyre Anole) from the lyre shape on the back of its head.
As it is sympatric with several other Ecuadorean anoles, it helps that this one has distinct features, like the marking on its head and its very distinct dewlap that is red in males with a dark central spot, and grey-white in females (also with the spot). They have an SVL of about 77mm (males) and 73mm (females).
Hey! Hope everyone has been having a good month so far!
As we all know it is October, my favourite time of year, and I am trying to bring you anoles that can fit the season. For now, here’s an anole whose female has an orange and black dewlap, the official unofficial colours of Halloween.
Anolis lososi is an Ecuadorean anole that tends to be found in open areas of forest.
The anoles are usually about 55-60 mm (SVL) and have bands on their tails and limbs. Their colouring is grey to green, sometimes brown, and resembles lichen. The females have yellow-orange dewlaps with black spots, while males have white, unpatterned dewlaps.
The limbs of this anole are short and it has been found sleeping on twigs and ferns from 2 to 8m off the ground.
Because this anole was recently found and described, there’s not a lot of information about it. Yet!
Journal of Natural History, 2017. doi:10.1080/00222933.2017.1391343
Here’s a bit of lizard joy for you today! HUGE shoutout and credit to The Amphibians and Reptiles of Mindo by Arteaga et al. because I can’t find any natural history info about this anole anywhere but in this book. If you can get it, you should! Because of current events they can’t do their normal herping tours (Tropical Herping) and could use the support. Their photography is amazing and you can get calendars, posters and pocket field guides!
Anolis gracilipes, the Charm Anole, certainly is a charming little anole.
It’s been classified as a twig ecomorph, a group of small anoles whose bodies are adapted for narrow surfaces like, you guessed it, twigs. This little lizard can get up to 172-181 mm for males and 169-191 mm for females.
This anole has a brown colouring on its back, with triangular markings and green on its throat, down to its chest.
Sorry I missed last week but I’m here to make it up to you with another impressively coloured anole.
This week is Anolis gemmosus, the Gem Anole.
The Gem anole is another Ecuadorean anole where they are common in the cloud forests.
Female gem anoles have no dewlap, are mainly green in colour and typically have a tan stripe or chevron pattern down their back.
Photo by Andreas Kay
Males typically have spotting all over or in the form of stripes down their tails and bodies and their dewlaps are large starting with blue closer to their necks, shifting to green then yellow-green. They also have white stripes across the dewlap. The largest recorded Gem anole was 66mm (SVL) and they may be quite long-lived.
Their pattern makes them very cryptic and difficult to spot, and since they prefer to perch in foliage, it helps them as ambush predators.
Gem anoles don’t bask intentionally (Arteaga et al, 2013). How does that work?? Well they just happen to get filtered sunlight where they choose to hangout and wait for their prey. They don’t look for perches in direct sunlight to bask. They do appear to pick perches to sleep in however, that get exposed to sunlight when the sun rises so they can quickly reach activity temperatures.
Ecuador’s most wanted! This lizard was thought to be extinct for nearly fifty years, and still after its “rediscovery” in 2005, it remains hard to locate.
Most records of Horned Anole are in disturbed areas, including near roads vegetation, botanical gardens and bamboo trees.
It took me more than two years of constant visits to Mindo, a cloud forest-town in the Western Ecuadorian Foothills, to meet with the Horned Anole (Anolis proboscis)! I always felt it was a mythological reptile, not only for Ecuadorian herps but throughout the world. Has anyone seen a lizard with a long appendix on the tip of his nose, a wide color throughout the body, prehensile tail and even spines on the back? It is difficult not to speak mystically when we refer to Horned Anole.
For over 50 years it was listed as “Possibly extinct,” until 2005, when a group of Ecuadorian scientists “rediscovered” it. But it was not until two years ago when the global and local Anole experts, led by Jonathan Losos, Steven Poe and Fernando Ayala, started several expeditions to investigate everything about its morphology, phylogeny and natural history.
Its tail is prehensile and is possibly used to embrace the branches when it sleeps.
The Horned Anole is a diurnal and slow-moving lizard that usually is found perched between 4-8 meters above the ground. Although most records are in vegetation on roadsides, highways and near open areas can be very difficult to find due to their excellent camouflage that blends perfectly with twigs full of mosses, lichens and epiphytes, perfectly rhyming its colorful skin.
But what use their proboscis? Sexual selection and defense of territory are the first hypotheses that leap to the mind. Science will tell us soon! But even that, we are left to enjoy its beauty and unparalleled mystique.
Definitely its silhouette is unmistakable. His sharp proboscis distinguishes it from all Ecuadorian lizards.
It can be difficult to find. Not only because they are commonly perched on high branches, but also for their camouflage, forming an ideal combination with branches and colorful leaves.
It is slow-moving and spends most of its time 450–800 cm from ground and feeds on a variety of arboreal arthropods.
Anolis proboscis sleeps on horizontal twigs and leaves (juveniles seem to prefer lower perches).
