I think as far as anole common names go, Yellow-beard is a top 10 name, just barely, but it’s up there.
The Yellow-beard anole, Anolis gundlachi, is endemic to Puerto Rico which is so overflowing with anoles I think it’s a little bit unfair at this point. With an SVL of about 68 mm in males and 45 mm in females, these medium sized anoles live at high elevations in the forest.
Yellow-beard anoles, following that trunk-ground color scheme, are dark olive to brown with darker striping across their backs and a pale colored ventral side. Their dewlaps aren’t quite yellow but are more of a mustard-brown, and their chins have a touch of pale yellow (Yellow-chinned anole doesn’t sound as good as Yellow-beard though). Males often have tail crests!
Like many of the anoles we know and love, Yellow-beards may eat other anoles and frogs that can fit in its mouth.
Yellow-beard anoles are often parasitized by malaria, and while more research needs to be done on parasite in this anole, there are existing ones noting tail damage in infected anoles and that males are more often infected, and another noting no significant decrease in overall body condition that you can check out.
I think we may have to move #DidYouAnole to Fridays since that seems to be the better for me post recently.
And speaking of this week’s post I remember mentioning that there were other anoles with little rostral appendages and that I hadn’t gotten back to them.
(A shame it took me so long because they really are great anoles)
Anolis phyllorhinus, or the Leaf-nosed anole, is endemic to central Amazonia in Brazil (where I believe they’re called Lagarto papa-vento in Portuguese) but they are an uncommon sighting. They’re a great shade of leaf green, with pale green-white undersides. Like with Anolis proboscis, these anoles’ appendages are also flexible and possibly used to display.
The eponymous leaf nose is only present in the males, with female Leaf-nosed (or Bat) anoles not even having any swelling or prominence of their noses. Female Leaf-nosed anoles also have a greatly reduced white dewlap, while the males have a larger one that is bright red on the front half and blue-green or white toward the neck.
The SVL of a Leaf-nosed anole is about 71-85 mm, excluding the proboscis which itself varies from 20-23 mm in measured specimens.
In a recent study in the Proceedings of the National Academy of Sciences, Bock et al. (2021) conduct a genomic and phenotypic appraisal of adaptive evolution and invasion biology of Anolis sagrei (Wikimedia Commons).
In 2004, Jason Kolbe and colleagues published a now-classic invasion biology study in Nature, mapping out the population genetics of invasive Anolis sagrei populations. Using approximately 1,200 bp of mtDNA sequence data (ND2 and adjacent tRNAs), Kolbe et al. examined the evolutionary origins of the Brown Anole in its journey out of its ancestral area (Cuba), and into a broad invasive range. In several out-of-Cuba dispersal events that formed the collective invasive Brown Anole in Florida, Kolbe et al. (2004) found that invasion had actually increased genetic diversity within these populations, far greater than that observed in the native range. Furthermore, many of the global invasive populations of A. sagrei (e.g., Taiwan, Grenada), sourced from Florida, had maintained comparably high levels of genetic diversity. Hence, the work by Kolbe et al. demonstrated that the repeated introduction of multiple, evolutionarily diverse lineages derived from the native range and subsequently injected into a novel range may be a key force in driving successful invasion.
If we fast-forward five years to 2009, two years prior to the release of the A. carolinensis genome, Chris Schneider publishes a paper in Integrative and Comparative Biology (Schneider 2009) titled “Exploiting genomic resources in studies of speciation and adaptive radiation of lizards in the genus Anolis.” In his paper, Schneider discusses the unique opportunity that lies ahead in understanding evolutionary theory through the lens of Anolis genomic resources. Schneider’s vision—as I perceive it—was one that sought to excite the evolutionary ecology community about the wonderful opportunities ahead that Anolis lizards present in understanding, most broadly, the genetic basis of adaptation.
Now, in 2021, more than 15 years after the study by Kolbe et al., Bock et al. (2021) return for an integrative evolutionary investigation of A. sagrei throughout Florida using a recently generated reference genome and corresponding morphological data. In line with Schneider’s (2009) perspective, Bock et al. (2021) tell a captivating story of adaptation, genome biology, and invasion. Wielding the power of one of the most contiguous and complete squamate genomes assembled to date (more on that another time!), the authors identified a large-effect locus posited to be responsible for adaptive shifts in limb length, which in turn provides insight into how natural selection can modulate hybridization during the course of biological invasion.
New literature alert!
Changes in selection pressure can facilitate hybridization during biological invasion in a Cuban lizard
Bock, Baeckens, Pita-Aquino, Chejanovski, Michaelides, Muralidhar, Lapiedra, Park, Menke, Geneva, Losos, and Kolbe
Abstract
Hybridization is among the evolutionary mechanisms most frequently hypothesized to drive the success of invasive species, in part because hybrids are common in invasive populations. One explanation for this pattern is that biological invasions coincide with a change in selection pressures that limit hybridization in the native range. To investigate this possibility, we studied the introduction of the brown anole (Anolis sagrei) in the southeastern United States. We find that native populations are highly genetically structured. In contrast, all invasive populations show evidence of hybridization among native-range lineages. Temporal sampling in the invasive range spanning 15 y showed that invasive genetic structure has stabilized, indicating that large-scale contemporary gene flow is limited among invasive populations and that hybrid ancestry is maintained. Additionally, our results are consistent with hybrid persistence in invasive populations resulting from changes in natural selection that occurred during invasion. Specifically, we identify a large-effect X chromosome locus associated with variation in limb length, a well-known adaptive trait in anoles, and show that this locus is often under selection in the native range, but rarely so in the invasive range. Moreover, we find that the effect size of alleles at this locus on limb length is much reduced in hybrids among divergent lineages, consistent with epistatic interactions. Thus, in the native range, epistasis manifested in hybrids can strengthen extrinsic postmating isolation. Together, our findings show how a change in natural selection can contribute to an increase in hybridization in invasive populations.
Literature cited:
Kolbe, J. J., Glor, R. E., Schettino, L. R., Lara, A. C., Larson, A., & Losos, J. B. 2004. Genetic variation increases during biological invasion by a Cuban lizard. Nature 431(7005): 177-181.
Schneider, C. J. 2008. Exploiting genomic resources in studies of speciation and adaptive radiation of lizards in the genus Anolis. Integrative and Comparative Biology 48(4): 520-526.
So I’ve been reading a lot of anole papers, aside from the ones I normally read for fun (can’t believe I read papers for fun now), and I found an anole that’s pretty similar to two anoles I’ve looked at before but also still unusual.
Welcome back by the way. Nice to have to you here again.
This week is a third little cave anole, Anolis alvarezdeltoroi, or the Mexican cave anole. Mexican cave anoles live in a similar karst limestone habitat like Anolis bartschi and Anolis lucius and are often found deep inside caves, occasionally sleeping from the roof it. They may also perch from vegetation in or around the caves, particularly as juveniles.
Like the other two anoles, the Mexican cave anole has a similar short body/long hindleg morphology. In a paper redescribing the species, the average SVL of the male anoles they measured was 53.3-74.0 mm, and 49.6-66.5 mm in females.
They seem to rely heavily on the karst habitat with healthy populations being found in areas with diminished forest but intact limestone/cave areas.
Male Mexican cave anoles have dark red dewlaps with white lateral rows of scales, while females have smaller black dewlaps with a similar pattern.
Please read the paper redescribing this anole here! For a while there was only a specimen available of it and not much info, but they worked on it and you should check it out. I wouldn’t have been able to write this if it wasn’t for them.
From April to September of 2017, Jesse Borden was climbing trees and counting lizards around Alachua County.
Sometimes, he could be found in branches on the University of Florida campus or in people’s backyards. Other times, his distinctive red helmet popped in and out of leaves in nearby forests.
The 34-year-old UF student is in his fourth year pursuing a doctoral degree in interdisciplinary ecology, and much of his work has focused on Gainesville’s native green anole lizards and their responses to two threats: development and invasive brown anoles.
He found that in the presence of brown anoles, the green natives moved about 17 times higher in trees, or about 8.3 meters in median perch height, to coexist. But the shift did not allow the lizards to overcome their habitat loss from human development.
These findings were recently published on Oct. 7 in the journal Oecologia.
“The extent to which [green anoles] were shifting was pretty fascinating,” Borden said. “That appears to allow them to coexist with the threat of an invasive species, the brown anole that is competing with it, but it doesn’t make them immune to other effects like urban development. And so it seemed like urbanization was the strongest driver of their decline across the landscape.”
Brown anoles were first introduced to the mainland southeastern U.S. in the early 1900s and were well established by the 1940s, according to the study. In Alachua County, they have been established for decades and appear to thrive in urban environments, Borden said. It is not known exactly how they came to the area, but it could have been via cargo and boats.
To study the green anoles’ response to both development and brown anoles at the same time, he and other helpers surveyed 61 trees and the ground around them for lizards twice each, once per day and once after dark. They then statistically analyzed the data for metrics like abundance, perch height and urbanization.
“It was a lot of fun,” Borden said. “Many thanks to so many kind people who let us use their backyard trees.”
The student said his findings raised many questions and topics for future research, such as how much time the green anoles spend higher in the trees. He is currently working on a project looking at evidence for change in body shape across the urban to natural gradient in lizard species here and change in their temperature tolerance to cold.
For Gainesville residents who miss seeing the little green lizards, Borden said, there are a few things people can do to help bolster their habitat space in the city. Planting native vegetation of varying heights in yard space can benefit the green anoles. Protecting and preserving forest patches and trees also supports them and lots of other wildlife.
“I just hope people are noticing the green anoles,” Borden said. “I find them so beautiful. They’re super cool. They’re a really fun and special part of the southeast U.S. and Florida.”
Contact Borden online via Twitter at @JesseBBorden or Instagram at @borden_ecology_adventures.
green anole basking under UVB, photo credit: r/anoles user, u/BMKMNC
Every so often I notice some of my anoles hanging from the screen lid of their enclosure, directly underneath the UVB light. At first I thought that it was just a fluke, but I have since observed them doing it on multiple occasions. Moreover, this UVB basking behavior has been reported by another green anole owner on the r/anoles subreddit (see pictures below). There must be something that compels them to do this.
I considered that maybe they are UVB basking to compensate for a deficiency. I changed my anoles’ UVB bulbs, but they still sporadically engage in the basking behavior. So, I am looking into other lighting options because I have concerns that the lizards aren’t getting enough UVB light through the screen, or that the lights aren’t strong enough. I do not have a UVB meter to confirm these suspicions. Regardless, my anoles all seem healthy and active.
Although I have not been particularly scientific with my observations, I have noticed that UVB basking is engaged in more frequently by my females and my elderly male anole. Perhaps they require more vitamin D than the average male green anole due to fertility and senescence, respectively. I have not noticed a trend regarding when this behavior occurs; it seems to happen at random. More careful observation is required.
What are your thoughts regarding the cause of UVB basking? Have you witnessed your anoles engaging in this behavior as well?
Green anole basking under UVB, photo credit: r/anoles user, u/BMKMNC
In a new study published in the Proceedings of the National Academy of Sciences, Patton et al. (2021) examine island and mainland radiations of Anolis lizards in an effort to understand what occurs when “adaptive radiations collide.” Discussion of mainland anoles merits featuring one of the oddest mainland species, the Ecuadorian Anolis proboscis (female and male pictured here; credit Santiago Ron [Wikimedia Commons]).
New literature alert!
Upon hearing “anole lizards,” those in the evolution and ecology community familiar with the outstandingdiversity of Anolis lizards may immediately reflect on the replicative adaptive radiations that have occurred in the Greater Antilles, painting a portrait of adaptation, convergence, and ecological character displacement that has served as the basis of research among Caribbean biologists for decades. But, perhaps, what is less generally appreciated is that the vast bulk of Anolis lizard diversity (currently sitting at 436 species, per the ReptileDatabase) actually occurs on mainland Central and South America! Indeed, if we were to zoom out on the Anolis Tree of Life, we could pick out three major clades that represent independent adaptive radiations– one in the Greater and Lesser Antilles, and then two on the Mainland. Hence, as has been appreciated by many Anolis biologists before (most recently, Huie et al. 2021), the multiple radiations of these lizards provides the substrate to examine not only convergence, but, additionally, what happens when these clades come into contact? What happens when adaptive radiations collide?
This question forms the basis (and title) for a recently published study by Patton et al. (2021), who attempt to untangle themes of adaptation, historical biogeography, convergence and divergence in ecology and morphology, and the diversification dynamics of the three major Anolis radiations.
When adaptive radiations collide: Different evolutionary trajectories between and within island and mainland lizard clades
Patton, Harmon, Castañeda, Frank, Donihue, Herrel, and Losos
Abstract:
Oceanic islands are known as test tubes of evolution. Isolated and colonized by relatively few species, islands are home to many of nature’s most renowned radiations from the finches of the Galápagos to the silverswords of the Hawaiian Islands. Despite the evolutionary exuberance of insular life, island occupation has long been thought to be irreversible. In particular, the presumed much tougher competitive and predatory milieu in continental settings prevents colonization, much less evolutionary diversification, from islands back to mainlands. To test these predictions, we examined the ecological and morphological diversity of neotropical Anolis lizards, which originated in South America, colonized and radiated on various islands in the Caribbean, and then returned and diversified on the mainland. We focus in particular on what happens when mainland and island evolutionary radiations collide. We show that extensive continental radiations can result from island ancestors and that the incumbent and invading mainland clades achieve their ecological and morphological disparity in very different ways. Moreover, we show that when a mainland radiation derived from island ancestors comes into contact with an incumbent mainland radiation the ensuing interactions favor the island-derived clade.
Terrestrial animals that venture into the water on a regular basis face a number of challenges not encountered by their strictly terrestrial counterparts. While submerged, they must deal with hydrodynamic drag forces hindering locomotion and with the risk of running out of air. Back on land, the film of water adhering to their body surface may interfere with locomotion and thermoregulation or may increase the risk of bio-fouling. Many semi-aquatic invertebrates (and plants) have developed complex surface microstructures with water-repellent properties to overcome these problems, but equivalent adaptations of the skin have not been reported for vertebrates that encounter similar environmental challenges.
The transition to a semi-aquatic lifestyle has independently occurred multiple times throughout the evolutionary history of Anolis (see Fig. 1A below). In anoles, the skin surface is covered with microscopic hair-like ornaments, and contingent upon its complexity, organization, and length dimensions, these hair-like microstructures may have the potential to generate extreme surface hydrophobicity. Indeed, similar skin surface microstructures have been found in geckos and are shown to be responsible for the highly hydrophobic surface of their skin. The water-resistant properties of anole skin, however, have remained unexamined, but very recent discoveries have provided valuable insight into this matter. Boccia et al. (2021) observed that semi-aquatic Anolis lizards are able to sustain long periods submerged underwater by iteratively expiring and re-inspiring narial air bubbles. As in semi-aquatic insects, a hydrophobic skin is a key requirement for the underwater formation of an air bubble, hence, functional respiration, so a hydrophobic skin in semi-aquatic anoles is implied. However, whether a hydrophobic structured skin surface in anoles has evolved in response to life at the water-land interface is still an open question. Answering this question was the primary goal of our study.
We studied the skin surface morphology of preserved anole specimens using scanning electron microscopy and tested the wettability of the skin surface using contact-angle goniometry (Fig. 1D). We found that the skin surface of semi-aquatic species of Anolis lizards is characterized by a more elaborate microstructural architecture (i.e. longer hair-like structures; Fig 1B,C) and a lower wettability (Fig. 1D,E) relative to closely related terrestrial species. In addition, phylogenetic comparative models revealed repeated independent evolution of enhanced skin hydrophobicity associated with the transition to a semi-aquatic lifestyle, providing evidence of adaptation.
Figure 1 from Baeckens et al. (2021)
We believe our findings bring an additional dimension to the recent biological phenomenon described by Boccia et al. (2021) namely that diving Anolis lizards not only repeatedly and independently evolved a specialized rebreathing behavior with the transitioning to a semi-aquatic lifestyle, but that its evolution presumably also coincided with, or was preceded by, the evolution of a hydrophobic structured skin to successfully do so.
S. Baeckens, M. Temmerman, S. Gorb, C. Neto, M. Whiting & R. Van Damme (2021) Convergent evolution of skin surface microarchitecture and increased skin hydrophobicity in semi-aquatic anole lizards. Journal of Experimental Biology 224(19): jeb242939 (doi: 10.1242/jeb.242939)
This is the everyday experience for residents of a lush neighborhood in Tampa, Florida, that have had a rogue Allison’s anole colony pop up and spread across their houses and yards. Many residents love and cherish the beautiful anoles and have been happy to share them with me. So these pictures are the result of this summer’s visits to the colony. Enjoy these beautiful anoles and the stories that come with them!
Having heard about the location, I sent letters to all the homeowners in the area, requesting permission to study the colony. Many homeowners generously allowed me to wander their properties with gates kindly opened for me.
The male above is one of the alpha males near the epicenter. Around 70-80% of the males observed were on houses, instead of trees and bushes as normally expected from an arboreal anole.
The other alpha male of the epicenter is pictured below in the next three pictures.
His territory includes the lily plants where the first anole was spotted by the homeowner in 2017. This is clearly defined as the epicenter, since the rest of the surrounding homeowners said that they did not see the A. allisoni until a year or two later.
A female, pictured above warily watching me, is less dressed to impress and more to camouflage.
One of the most common ways for invasive anoles to spread is through the plant trade. Bromeliads, lilies, and other thick shrubs are imported from Cuba or other countries in the Caribbean with anole eggs unknowingly hidden in their leaves and trunks. When the plants arrive and are placed in a lush garden, or kept at a nursery, the eggs hatch and the anoles grow and being to reproduce, starting a new non-native population.
Pictured above is one of the many new arrivals to the colony this season. Eggs are laid from April-October and hatch from May-December.
A male, pictured below, whose territory does not include any houses, but a few trees and a fence, displays and then scurries away to hide in his tree.
Before catching sight of me, he was proudly displaying himself.After noticing me he escaped into his tree.
Across the street, two anoles mate while clinging to the side of a house. You can see the drastic sexual dimorphism in this species in this picture, as well as the deep blue coloration that comes out in the males while mating or during territorial disputes.
The anoles seem to prefer properties on the block with houses that have rough stucco walls to cling to, for example the beautiful male below. Houses with smooth exterior siding are shunned by A. allisoni at this colony.
The male below is one of my personal favorites at the colony, a male with almost every color of the rainbow! I only saw him during one visit in July, and in my many visits since then, I have not once seen him. Did he leave to find a new territory? Or was he eaten by a predator? I hope to one day see him again.
Above, another alpha male surveys his territory from a branch, and after catching sight of me, decides to leap away and leave the scene.
Another blue male and a female from his territory, a few feet away.
The colony’s active season is between March and September. Outside of these months, the males have subdued colors, remain brown most of the time, and hide in nooks and crannies of the exterior of the houses.
A young male watches me as I take his picture, above. It was a great experience to find one mid-transition from juvenile to adult and see the colors coming in nicely. Sadly, I have not seen this anole either since then.
A male on the northern outskirts of the colony displays from a tree.
A male with some vivid light blue coloration peeks over the top of a fence to spy on me.
This is an interesting observation. Note the markings on this male clinging upside down to the side of a fence. Was he grabbed by a bird or bitten by a rival male? The rounded imprint close to his legs seems to give away some kind of injury.
This young one is fresh out of a shed!A vivid green female peers at me inquisitively.A juvenile popping its head out from a bush.Usually I was able to spot at least one mating pair on each of my visits.An interesting observation, this adult male with no blue, only green.A common territorial dispute.This male has proclaimed himself King of the Gutter, and basks in his territory.This male is acrobatically clinging upside down to a copper pipe.It was interesting to see the variety in the blue coloration.
Just a year ago, I believed I would have to journey to Cuba to see these exotic creatures. Little did I know I would be spending the following summer with them without leaving home!
I will return to the colony March 2022 to continue my observations. Follow me on iNaturalist as well for more anole content!
If you’re interested in seeing more Florida Allison’s anoles, please visit my Instagram @dailyanole. Don’t forget to watch my video on this colony as well!
Turns out grad school eats up a lot of your time some weeks. Who knew!
So here is a pretty cool Caribbean anole this week. Anolis acutus, the Sharp Anole is endemic to St. Croix. These anoles are tan to olive in colour. Their dewlaps are white with a large yellow-orange blotch closer to the body. Males have an average SVL of 67mm and females, about 49mm.
They are territorial and maintain hierarchies within their habitats. If an individual is removed, they become slightly agitated until the territory is taken over by a new anole or the individual returns (Ruibal & Philibosian, 1974). The adults also tend to be sedentary and have a perch height hierarchy, but exclude juveniles from occupied trees leaving them to find and occupy empty ones or live on the ground (Ruibal & Philibosian, 1974).
St Croix anoles appear to be eurythermal, meaning they have a broad temperature range (McManus & Nellis, 1973).
Photo: Steve Maldonado Silvestrini, iNaturalist
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