Reconstructing the History of Anole Sex Chromosomes


George Gorman in Dominica

In the 1960s and 70’s evolutionary cytogenetics experienced a remarkable burst of interest and scholarship. Thanks largely to the efforts of George Gorman (at right) and others working at the Museum of Comparative Zoology, anoles played a central role in this research (some historical detail has previously been posted on AA). Among their findings was the occurrence of heteromorphic sex chromosomes, sex chromosomes that are visibly distinguishable from each other under a microscope, in several Anolis species but not others. Furthermore, Gorman and colleagues discovered that those Anolis species with heteromorphic sex chromosomes all had male heterogamety, with some having an XX/XY system while others had an XXXX/XXY system. Chromosomes from nearly 100 Anolis species were examined during this period and about 1/3 of those species had heteromorphic sex chromosomes. Interest in chromosome evolution waned in the 1980’s as DNA sequence data became increasing accessible, but there has been a recent resurgence thanks, in part, to sex chromosomes.

Continue reading Reconstructing the History of Anole Sex Chromosomes

Anole – Gecko Habitat Overlap

Although it may seem paradoxical given their natural history, I often see nocturnal geckos basking during the day. They usually occupy trunks between 1-3m, which is prime trunk-ground and trunk ecomorph territory. In Miami we have two of the former (A. sagrei and A. cristatellus), and one of the latter (A. distichus). Here is a photo fresh from today showing such overlap in habitat use. I have yet to see any interactions between anoles and geckos in Miami, has anyone else observed any here or elsewhere?

Brown anole Anolis sagrei and gecko (Hemidactylus sp., probably mabouia) sharing habitat space_caption

Cuban brown anole (Anolis sagrei – left) and gecko (Hemidactylus sp., most likely H. mabouia – right) sharing habitat space

Of note – this was taken 23rd Feb 2014 in south Miami (FL) at roughly 1:30pm. It’s hot and sunny.

Wet Prairie Anolis carolinensis in Two Parcels in Broward County, Florida: Historical Populations?


Hi Anole Folks,

So life transported me to South Florida to beat Cancer, and looks like I have made good progress, thank you in advance. :-)

As a general naturalist, I get out A LOT, each day- up to three hikes in different habitats.

In my area on the border of Broward and Palm Beach Counties, there are several restored Pine-Lands, some from about 1984- most  cordoned off in a way for even longer due to central farm use, cattle grazing, or logging with left over islands near the wetter areas.

I spent a lot of time in the late 70’s in Coral Gables, Florida-  with a two year stint at the U. of M.  At that time, Anolis carolinensis, while not common, could be found on buildings on Ponce de Leon Blvd. and also areas of Bird Road, LeJeune and others behind the U of M arboretum.  I also would find both A. porcatus and A. chlorocyanus at these locations.  Anolis sagrei was always in great numbers no matter what.

Returning NOW, in 2014- with extensive field searching, failed to find Anolis carolinensis. The typical haunts I’d expect–along homes, in bushes, on trees, and in scrub–failed to yield a single animal.  I put in a lot of effort.  I found A. porcatus, A. equestris, what I think is A. cristatellus, and every morph you can think of of A. sagrei.  I also found Curly Tails living sympatrically with A. sagrei in several pockets.  This I found pretty neat and worthy of some work.

Recently, while hiking a Wet Prairie, along a Cypress Marsh near a domed swamp area, I started to see a very thin green lizard perched atop grass stalks–and very often cattail stalks in the center of the wetland, over standing water.  I could not confirm the species–they were far into the swamp and their flushing distance was ASTOUNDING.   They would see me and DROP clear to the grass below.  One time I saw an individual turn brown in seconds, and disappear, not into tree branches, but into the grass on the ground! I watched this behavior 8-9 times before I knew–I had to hike into the swamp.  So I did.

IMGP0391Eventually I was able to see males and females, of what now I was sure was A. carolinensis hunting and using the grass/cattail stalks for feeding and display.  In the attached image, you will see one on cattail, and this is a typical daily encounter.  I could see five or more in a hike, on the tops of grass stalks near the seed heads.  While bushes and peripheral trees were there, they were not using this substrate. I really was seeing a marshland native Green Anole group.   And to my eyes, this group was rather “gracile” in form.  And they worked the stalks in what seemed to be a new fashion.  I even imagine–since I have not done any morphometrics yet–that their hind legs look longer, tibia/fibula and femur, and toes.  They also have  a posture for most of their time on the stalks that is not something I was used to seeing–legs held way back and tight to the body, as if to reduce their profile.  A thin Green Anole, that can hide on a grass blade :-).   The images here represent two separate anoles from two separate days.

Did the pressures of habitat loss, A. sagrei competition, and A. equestris predatory pressure, isolate this group and/or move them to this grassland habitat over water?  Could this be a recently adapted “ecomorph” which we so timely have read about?

I will be vouchering a male and female for work at the MCZ for others that might be interested.  But in the interim, my favorite interest, watching behavior, will continue.

I know all the BUTS about this- as in- are they even remnants of historical Broward animals at all?  Did they come in with the replanted slash pine and pond cypress?  I’m hoping one day by genetic work, and or even some new Xray work, we might be able to answer some of this.  And of course, in their normal historical lives, they almost certainly used this type of habitat in part.  But what about now?

That there are vigorous groups in these Wet Prairies of Broward attests to the tenacity of the species, and that it is surviving here.  And that  puts a smile on my face!!

If anyone would like additional information for research, and or visit the sites with me, please feel free to contact me at; I’ll be here for at least a few more months.

Would love any ideas, thoughts regarding this as well.  More photos to come as well.

Enjoy the images.


Kenneth E. Barnett


A Peek Inside an Anole

Three different individuals of Anolis cybotes that appear to have small pebbles or debris in their guts.

Three different individuals of Anolis cybotes that appear to have small pebbles or debris in their guts.

While analyzing some xrays of Anolis cybotes for my thesis work, I came across a few specimens that appear to have small dark masses in their guts. The numbers are pretty low – in over 200 xrays, I can only detect these masses in a handful of individuals. My curiosity was piqued. At first glance, they look like they might be gastroliths. Gastroliths, or gizzard stones, are rocks that animals eat to aid in digestion. Basically, the rocks help manually grind the food into smaller bits in a special portion of the digestive track called the gizzard. We know that many archosaurs (crocodilians, dinosaurs [including birds], and pterosaurs) have gizzards. Dinosaur gastroliths are some of my favorite fossils because they are usually polished and quite beautiful. However, unless I’m mistaken, lepidosaurs (squamates and rhynchocephalians) don’t have gizzards and aren’t known to have gut stones. Does anyone have an idea about what this could be? It’s possible that these are just accidental ingestions of small pebbles. Anolis cybotes do often forage near or on the ground, so perhaps it’s not so far-fetched for them to pick up a little rocky debris.

Also, check out this image of a regenerated tail!

Anolis cybotes with a regenerated tail.

Anolis cybotes with a regenerated tail.

Variable Definitions in Community Ecology

Community ecology is a confusing field, confounded by the interchangeable use of many fundamental terms.

Recently, a group of graduate students and I discussed this strange paradigm and thought we would see what people’s own interpretations were.

If you have a spare 5 minutes while drinking your morning coffee, please could you fill out this short (4 question!) poll asking you to give your definition for; ‘community’, ‘assemblage’, ‘guild’ and ‘ensemble’. It will be cool to see how people’s opinions differ!

You can take the survey here!

Many thanks

New Research On Sri Lankan Horned Lizards

Lyriocephalus scutatus. Photograph by Ruchira Somaweera, National Geographic

We at Anole Annals love horned lizards, and so were delighted to read about new research on Sri Lankan hornies, reported on the National Geographic Society’s webpage. Check out the article, which details recent research by Ruchira Somaweera of Sydney University.

Certatophora stoddartii. Photograph by Ruchira Somaweera, National Geographic

Bark Anoles Strutting Their Stuff in Miami

In August of last year, my wife and I made the move from Maryland to Florida so that I could begin my graduate work on signal evolution at the University of Miami. All of my research experience to that point had been centered on avian communication, but it wasn’t long after moving to Miami that my attention was drawn to the massive number of anoles displaying throughout my community. I’ll admit, one year ago my interest in anoles did not go beyond thinking that they were just another cool group of reptiles. However, in the six short months since moving to the area, it will come as no surprise to the Anole Annals community that I am hooked on these fascinating lizards.

This post serves as a friendly hello to everyone here at AA, as well as a quick note of gratitude to all who contribute to making this site such a fun and informative place for all things anole. On that note, I thought it was time I share something myself, and so I’ve included a video I recently recorded of two male bark anoles sizing each other up on a tree near my home. Of course, the video clarity seemed much nicer on my phone, but nonetheless, I hope you all enjoy!

Anole Celebration of Darwin’s Day

Happy Darwin’s day everybody!

Darwin Day

This is the third serial year in which I have remembered Darwin Day in Anole Annals. In the first time, Jonathan Losos made a wise comment in citing the words of Darwin about an anole (read his comment here). That’s why, this year, I have added two pages from ‘The Descent of Man, and Selection in Relation to Sex’ in which Darwin wrote about the sexual selection of Anolis cristatellus and Sitana.


Continue reading Anole Celebration of Darwin’s Day

Anolis Comparative Genomics Underway!

There was a lot of discussion last month about the fabulous anole goings-on at the SICB meetings. However, there were other conferences sporting important anole work over the holidays. One of them was International Plant and Animal Genome XXII, described as “the largest AG-genomics meeting in the world” and held in San Diego in early January. Perhaps not a venue at which you’d expect anole work to be discussed, but there was Poster #720:

Mining the Most Species-Rich Amniote Genus: de novo Sequencing of Three Anole Lizards for Comparative Genomic Analysis #P720

Date: Monday, January 13
10:00 am – 11:30 am


Presenters: Marc Tollis Arizona State UniversityElizabeth D. Hutchins Arizona State UniversityWalter L. Eckalbar Arizona State UniversityMichael R. Crusoe Arizona State UniversityCatherine M. May Arizona State UniversityJessica Stapley Smithsonian Tropical Research InstituteElise Kulik Arizona State UniversityMatt J. Huentelman Translational Genomics Research InstituteRebecca E. Fisher University of ArizonaKenro Kusumi Arizona State University

P720 – Mining the Most Species-Rich Amniote Genus: de novo Sequencing of Three Anole Lizards for Comparative Genomic Analysis

The repeated evolution of morphological adaptations to specific ecological niches makes Anolis lizards a spectacular example of adaptive radiation in vertebrates, and an ideal model for comparative genomics. The complete genome of the green anole (A. carolinensis) has already provided insights to the evolution of genomic and phenotypic variation in vertebrates. A multi-species comparison within the Anolis genus would increase the power of studies seeking to understand the genomic bases of species diversification. We carried out de novo whole genome sequencing and draft assembly of three species, the grass anole (A. auratus), the bridled anole (A. frenatus), and the slender anole (A. apletophallus). Here we report some of our preliminary comparative genomic findings. Analysis of the abundance and diversity of transposable elements within these genomes has revealed repetitive landscapes typical of non-mammalian vertebrates, yet variation between Anolis species is greater than what is observed across most mammals. This may have provided a genomic environment amenable to key adaptations during the Anolis radiation. Using well-defined models such as mouse and chicken, we identified orthologous genes integral to myogenesis and limb development, and are beginning to catalogue interspecific variation in protein-coding genes and cis-regulatory motifs. Functional anatomical and histological studies are being performed to quantify the tail and hindlimb muscle groups of these species compared to A. carolinensis. Our ultimate goal is to identify the divergent alleles associated with ecological speciation, thus bridging the genotype-phenotype gap.

Brown Anoles in Tree Islands

A recent trip to the Everglades with Palm botanist Sara Edelman was meant to provide a welcome break from studying for qualifying exams, and give her the opportunity to further educate me on all things palm (which was previously limited to determining which lizards in Miami appear to live on them).

After spending the morning locating individuals of her study species, the native and state-threatened Paurotis palm (Acoelorrhaphe wrightii), we had received very little wildlife luck (which was the true reason for me volunteering to ‘help’). From past visits, I had found brown anoles (Anolis sagrei) at every car park along the Everglades National Park road down to Flamingo, likely hitch-hiking unwittingly on visitors cars, but to my knowledge they had yet to disperse convincingly out from these. On our second to last survey of the day, to this tree island off the main road just south of Mahogany Hammock, while searching for native green anoles (Anolis carolinensis) which I had yet to see, I heard some rustling in the bushes – lo and behold, sitting there as bold as day signalling straight at me was a male brown anole!

Everglades tree island characterised by Paurotis palm (Acoelorrhaphe wrightii), Saw palmetto (Serenoa repens), Buttonwood (Conocarpus sp.) and Pine (Pinus sp.), and inset brown anole (Anolis sagrei) observed inside

Everglades tree island characterised by Paurotis palm (Acoelorrhaphe wrightii), Saw palmetto (Serenoa repens), Buttonwood (Conocarpus sp.) and Pine (Pinus sp.), with [inset] brown anole (Anolis sagrei) observed inside

Now, observing brown anoles here shouldn’t be a surprise, should it? After all they are already in many surrounding places accessible by car, therefore it was only a matter of time before they spread further afield. However, areas like these in the Everglades may represent one of the last refuges of green anoles from introduced non-native species found everywhere else in south Florida (an idea I mentioned here a few months ago). Tree islands are masses of larger vegetation (unsurprisingly characterised by trees) formed gradually as vegetation clumps in the slow moving Everglades flow. Over time, debris from colonising plants raises the ground level just above surrounding water level, meaning they provide important havens for many wildlife species. During the wet season the dispersal potential for brown anoles would be limited. All of the areas surrounding tree islands are generally inundated, meaning landscape movement through the thin-stemmed sawgrass plains may be easier for more nimble footed green anoles, however somewhat less graceful for browns. This, however, is all hypothetical.

So ruling out human-mediated release or dropping by a clumsy predator, we could assume that this chap arrived there all by himself. This would suggest that brown anoles have no problems in traversing through sawgrass, although temporal factors may be important (i.e. dispersing during the dry season when water levels are low or absent).

The implications for the expansion of this species through the Everglades remain unclear, although their relationship with green anoles leads to a predictable outcome (discussed extensively on AA [1, 2, 3). Just how much effect is a highly fecund, hyper-dense, extremely competitive and resilient insectivore going to have on these small ‘island’ ecosystems?

Display Behaviour in Anolis sagrei: Deterring Predators, Daunting Opponents or Drawing Partners?


Male and female A. sagrei at the famous Soroa, Cuba locality.

Anole displays consist of conspicuous behaviors that are known to be used in multiple contexts, such as exhibiting territory ownership and territory defense, mate attraction and female receptivity, species recognition, and even predator deterrence. As most of you know, the display repertoire typically involves three major signal types: “dewlap extensions” (DE, pulsing of the throat fan or dewlap), “push-ups” (PU, up and down movement of the body and tail), and “head-nods” (HN, up and down movement of the head only). Although the visual display behavior in anoles has been extensively studied, the function of these three major signal types (DE, PU and HN) remains highly equivocal, and especially in the brown anole. Therefore, we decided to set up a behavioral experiment addressing DE, PU and HN signaling rates across diverse contexts, using the brown anole as study species.

Our study differed from previous ones in two main aspects. Whereas most other studies have focused on male signaling only, we looked to the three separate signal types in both male and female lizards. Secondly, our study is the first one to compare display rates across a wide range of contexts using the same individuals over again (repeated-measures design). This design could, however, only work under fully-controlled laboratory testing conditions. The diverse contexts we tested included predator, non-predator and several social interactions (i.e., mirror, male-male, male-female and female-male). For the predator and non-predator interactions, we used a living curly-tailed and equally-sized ocellated spiny-tailed lizard, respectively; the social context involved only conspecific interactions. Rather than examining display structure, we focused on the frequency with which each individual signal type was performed.

What did our results show? We found that brown anoles of both sexes exhibited higher display rates in the presence of conspecifics than when confronted with a predator or non-predator. DE, PU, and HN seem to be of main importance during brown anole social interactions, and thus not in predator deterrence. Whereas the females did not significantly raise display rates in response to a mirror or during intersexual interactions compared to a control situation, males did. The PU signal type only appears to play a major role for brown anole males during aggressive encounters. On the other hand, increased frequencies of all signal types during male-female interactions suggest that DE, PU, and HN are all essential for male courtship.

Staged intersexual interactions in the brown anole

Staged intersexual interactions in the brown anole

Finally, we suggest that intersexual selection is probably a driving force for frequency-related dewlap use in both sexes (we found a very strong, but not significant, trend that females increased their DE frequency only during female-male interactions). In contrast, pronounced intersexual differences were detected for PU and HN rates within a social context. I would like to mention once more that all our behavioral experiments were conducted under controlled laboratory conditions and that caution is needed on the general interpretation of our findings.

To end, I would like to say that we did experience some difficulties in comparing our PU and HN results with results from previous studies on brown anole display behavior, due to an inconsistent terminology found in the literature. Authors have variously used the terms “nod,” “headnod,” “bob,” “headbob” and “pushup” to refer to the stereotyped bobbing display and it is not always clear which movements correspond exactly to which terms (e.g., only head movement, only front legs, whole body movement including/excluding tail). Partan et al. (2011) did a very nice job by discussing several bobbing display terms in her paper, but still we think there is need for a more consistent and defined “bobbing” terminology. In this way, pooling display datasets and comparing display results will become more efficient and accurate, which in turn may lead to better “anole science”!

Driessens, T., Vanhooydonck, B., Van Damme, R. 2014. Deterring predators, daunting opponents or drawing partners? Signaling rates across diverse contexts in the lizard Anolis sagrei. Behav Ecol Sociobiol 68:173–184.

Trunk-ground Anoles Living in High Rises

This weekend I recently saw an adult male Cuban brown anole (Anolis sagrei) perching higher than I have ever observed – roughly 4m high!

Adult male Cuban brown anole (Anolis sagrei) perching uncharacteristically high

Adult male Cuban brown anole (Anolis sagrei) perching uncharacteristically high

So anole aficionados, what dizzying heights have you observed trunk-ground anoles up to?

*My apologies for the poor quality of the zoomed in sections.

Female Display in Anolis cristatellus, and a Call For Your Observations!

In species of Anolis where females have dewlaps, we know very little about exactly how females use their dewlaps. Losos (2009) describes this lamentable situation thus:

“Unfortunately, little is known about how females use their dewlaps, and the little information that is available from three species permits few generalities. Anolis carolinensis females only rarely use their dewlaps in intersexual displays (Jenssen et al., 2000), whereas female A. valencienni use their dewlaps primarily to discourage courting males, including those of other species (Hicks and Trivers, 1983). Both A. carolinensis and A. bahorucoensis females use their dewlaps in intrasexual displays (Orrell and Jenssen, 1998, 2003); in A carolinensis, females use the dewlap more at close range and less at long range in female-female interactions compared to dewlap use in male-male interactions (Jenssen et al., 2000; Orrell and Jenssen, 2003). Unfortunately, without more information on how females use their dewlaps, we will not be able to explain sexual dimorphism and dichromatism in anole dewlaps.”

Since then, Martha Muñoz has added an observation from A. armouribut the numbers are still small.

Attempted forced copulation in Anolis cristatellus

Attempted forced copulation in Anolis cristatellus

In July 2013, I spent ten days observing A. cristatellus in Mayagüez, Puerto Rico, and can add one more species to the list of female anoles that use their dewlaps to dissuade males from mating with them. I was mapping male territories and counting male-male interactions in a park in one of Mayagüez’s fancier neighbourhoods, and came across a male chasing after a female. I sat down to watch the interaction, and was struck by how determined the female seemed to avoid mating with this male. You’ll notice how the male is biting the female much lower down the body than is normal during mating, indicating how the female is trying to get away. Her dewlap is completely extended during this interaction.

The chase went on for several minutes before the female ran to the end of a thin branch and another male showed up to chase the first male away. I proceeded to catch and mark this second male, and later observations revealed him to be the resident territory holder of the tree.

A little later, we caught a male in the tree adjacent to one in which the showdown occurred. In a fantastic stroke of luck that anyone whose work depends on identifying individual animals in the field will appreciate, we were able to determine that this male from the adjacent tree was in fact the first of the two males observed earlier.

How, you ask, did we perform this forensic  wizardry? Observe the second tiny tail of the interloper attempting the forced copulation:IMG_3259


Caught red-handed!

I was showing these photos to Jonathan Losos the other day, and he immediately noted that the observation of a female using her dewlap was pretty rare. Of course, the obvious response was to write a blogpost about it, but then we realised that with Anole Annals‘ daily viewership of up to 1500, we could do more than just write a blogpost–we could do citizen science! So this, ladies and gentlemen, is an invitation to all of you to help build a  dataset. It’s more than the usual request for participation and comments that I end many posts with–it’s a challenge to all of us AA readers to keep an eye and camera out for examples of females using their dewlaps, so that we can together figure out a pretty basic piece of Anolis biology.

We’ve done this sort of citizen science before, quite successfully: here’s Kristin Winchell’s call for data on urban anoles, and here’s the resultant analysis.  And there’s all sorts of exciting natural history questions that would be impractical for individuals to tackle on their own, but that we can solve easily as a team. Let’s make this blog a citizen science hotspot!


Measuring Maximal Performance In Animals: The Cautionary Story From The Calaveras County Frog Jumping Contest

For more than three decades, since the seminal work of Ray Huey, Al Bennett, and Steve Arnold, biologists have measured whole animal performance–how fast they run, how far they jump, how well they can swim–to understand how species are adapted to their environment.  Work on anoles has been a prime example of how we can study differences among individuals and species to understand how natural selection works and why species living in different environments possess different morphologies (several AA posts have discussed this sort of work [e.g., 1, 2, 3]).

But a critical assumption of all of this research is that we can get animals to perform maximally. Otherwise, it’s tough to study what causes variation in maximal capabilities if animals aren’t performing maximally. The catch is: how do you tell if an animal is going all out? Sure, it’s easy to weed out the slackers, but distinguishing a lizard giving it his all from one going at, say, 90% of max…hard to tell.

In an important and entertaining paper, Henry Astley and colleagues provide some sobering information. The short story goes as follows, and you really should watch the video below for more details and some great images: biomechanicians have studied frog jumping for decades to understand how muscles work. Bullfrogs are known not to jump very well. The maximum jump ever recorded in the lab was only 1.3 m, whereas the much smaller Cuban treefrog can bound 1.7 m. The proffered explanation was that bullfrogs live on land and in the water, and so their morphology must be a compromise.

But…the Guinness Book of World Records claims that a bullfrog–Rosie the Ribeter, to be exact–once jumped 2.18 meters at the Calaveras County Fair. That’s  68% farther than any scientist had ever recorded in the lab. Sounds like a bunch of hooey, right? Well, just to debunk this nonsense, a bunch of Brown University biologists headed to sunny California to visit the County Fair, eat some cotton candy, and check out the frogs. And, lo and behold, it’s true–bullfrogs there regularly far exceed the lab record.

The story’s a lot more complicated–it turns out that there are “pro” frog jumpers–and I won’t go into the details; the paper is well worth a read, very entertaining and sobering for lab performance types (abstract here). But the short story is this: it seems that lab studies had massively underestimated how far bullfrogs can jump, calling into question many of the conclusions that had been reached about their physiology. Moreover, records for the maximum jump distance at the fair showed a steady increase for the first 50 years before levelling off for the last 30. This suggests that the people who jump the frogs (and some families have been doing this for generations) have only gradually learned exactly what conditions and behaviors maximally stimulate the frogs. And this suggests that lab scientists, who just guess at what may work best and tinker a little bit, may not have much of a chance of hitting on the right stimuli.

There’s been lots of great press coverage, too–just google “calaveras frog astley” or something like that. But, first, watch the video and go read the paper (I can email you a copy if you can’t access it online).