What a lovely festive (a.k.a., brown) anole!
For more on the new AMNH exhibit on Cuba, see our previous report.
h/t to Sandra Buckner for notifying us of this magazine cover.
What a lovely festive (a.k.a., brown) anole!
For more on the new AMNH exhibit on Cuba, see our previous report.
h/t to Sandra Buckner for notifying us of this magazine cover.
It’s been a while since we updated this montage…and at least a few months since the last anole cover. Get to work, everyone! And let me know if we’ve missed any.
Peter Uetz of the Reptile Database fame sends the following Valentine’s Day greetings:
If you or your significant other loves anoles, you may want to show her/him this hearty Anolis distichus (Figure 2960, above) on occasion of today’s Valentine’s Day. It clearly shows a heart on it’s head. Some other specimens such as the couple in Figure 3297 (right, from locality 1 in the Google map), also show a heart although it’s not as pronounced. Also note their blunt coloration which doesn’t seem to affect their affection.
Anolis distichus is pretty variable and even within this subspecies, A. d. dominicensis Reinhardt & Lütken 1863, to which all these specimen belong, there is considerable variation. By the way, the guy with the heart (Figure 2960) is from the same locality 3 as two other specimens which do not have a heart (Figures 2948 and 2968) although they display a similar shape on their heads. Figure 3087 shows yet another specimen for comparison, this time from locality 2.
Various authors have described a dozen subspecies from Hispaniola (reviewed in Schwartz 1971, see map 2 from that paper). The northern half of Hispaniola is almost entirely in the hands of A. d. dominicensis, hence the specimens on the photos have been assigned to that subspecies.
Note that Glor & Laport 2012 elevated several Dominican subspecies of A. distichus to full species level, namely A. dominicensis, A. favillarum, A. ignigularis, A. properus, and A. ravitergum. The Reptile Database hasn’t followed this yet because their geographic sampling was limited to relatively few localities and they did not provide any updated diagnoses (but their recommendations have been recorded in the database). Also, there seems to be hybridization among several of these populations.
Thanks to Miguel Landestoy and Luke Mahler who helped with the IDs.
Glor, Richard E.; Robert G. Laport 2012. Are subspecies of Anolis lizards that differ in dewlap color and pattern also genetically distinct? A mitochondrial analysis. Molecular Phylogenetics and Evolution 64 (2): 255-260. http://www.sciencedirect.com/science/article/pii/S1055790310004276
Schwartz, A. 1968. Geographic variation in Anolis distichus Cope (Lacertilia, Iguanidae) in the Bahama Islands and Hispaniola. Bull. Mus. comp. Zool. Harvard 137 (2): 255- 309. http://biodiversitylibrary.org/page/4784182
Schwartz, A. 1971. Anolis distichus. Catalogue of American Amphibians and Reptiles (108)
(used to be available online at ZenScientist, and maybe soon at the SSAR website again).
Anolis distichus in the Reptile Database
(an extended synonymy and distribution section will appear in the next database release)
The database entry also has another 43 references most of which are available online.
Any congress advertising with a horned anole (Anolis proboscis) must be worth attending. Check out the details at the conference website.
A new paper in Zootaxa aims to figure it out, based on the travel journals of its describer, Franz Werner. Here’s the paper’s abstract:
The eminent Austrian zoologist Franz Werner described several new species of amphibians and reptiles from America, including Anolis aequatorialis Werner, 1894 and Hylodes appendiculatus Werner, 1894. Both species were described based on single specimens, with no more specific type localities than “Ecuador” (Werner 1894a,b). After its description, A. aequatorialis remained unreported until Peters (1967) and Fitch et al. (1976) published information on its distribution and natural history. Anolis aequatorialis is currently known to inhabit low montane and cloud forest on the western slopes of the Andes from extreme southern Colombia to central Ecuador, between 1300 and 2300 m elevation (Ayala-Varela & Velasco 2010; Ayala-Varela et al. 2014; Lynch et al. 2014; D.F. Cisneros-Heredia pers. obs.). Likewise, Hylodes appendiculatus (now Pristimantis appendiculatus) remained only known from its type description until Lynch (1971) and Miyata (1980) provided certain localities and information on its natural history. Pristimantis appendiculatus is currently known to occur in low montane, cloud, and high montane forests on the western slopes of the Andes from extreme southern Colombia to northern Ecuador between 1460 and 2800 m elevation (Lynch 1971; Miyata 1980; Lynch & Burrowes 1990; Lynch & Duellman 1997; Frost 2016). To this date, the type localities of both species remain obscure. The purpose of this paper is to restrict the type localities of Hylodes appendiculatus Werner, 1894 and Anolis aequatorialis Werner, 1894 based on analyses of the travel journals of their original collector.
Among their many contributions to evolutionary biology, anoles have historically been at the forefront of research on sexual dimorphism. Much of the recent work in this area focuses on a very general question – how do males and females express different phenotypes despite sharing essentially the same underlying genome?
Not surprisingly, the answer often depends on the type of scientist you ask. An endocrinologist might say that the development of sexual dimorphism requires hormones such as testosterone and estradiol. A quantitative geneticist might reply that it involves the reduction of genetic correlations between the sexes. A molecular geneticist might view the problem as one of regulating the expression of shared genes differently in each sex. Can anoles help us put these different perspectives together into a unified framework for sexual dimorphism?
To address this question, our lab at the University of Virginia teamed up with Christian Cox (Georgia Southern), Joel McGlothlin (Virginia Tech), and Daren Card, Audra Andrew, and Todd Castoe (University of Texas, Arlington). The full details are available in The American Naturalist, but here’s a quick rundown of the highlights:
We conducted a breeding study on a captive colony of Anolis sagrei, a species in which adult males average nearly three times the mass of females. We found that the extent to which males and females share heritable variation for body size starts out high early in life, but declines rapidly as sexual dimorphism emerges during development.
This breakdown of genetic constraint is mirrored by a sharp increase in the sex-biased expression of hundreds of autosomal genes in the liver, particularly those genes that regulate growth, metabolism, and cell proliferation. In other words, although male and female anoles share most of the same genes, each sex tweaks the expression of these genes in different ways as development progresses.
How do they do it? We also show that some of the patterns of male-specific gene expression that emerge later in life can be induced by treating juvenile females with testosterone. Putting these pieces together, we propose that hormones help male and female anoles regulate their shared genes in different ways, which allows them to attain dramatically different body sizes and also helps break down genetic correlations that would otherwise constrain their independent evolution. We hope that our study encourages other Anolis biologists to continue building connections between evolutionary genetics, developmental biology, and endocrinology!
Several years ago, I wrote a series of papers and blog posts about the diversity of anole head shape and its developmental origins. My colleagues and I touched on disparate topics such as whether the head differences among species are similar to post cranial ecomorphology, whether the patterns of cranial modularity are conserved across anoles, and the developmental bases of sexual dimorphism in skull shape.
Since starting my own lab at Loyola University in Chicago last year, I am revisiting these projects on skull evolution. Like in much of science, I have found that my early forays into this area created more questions than answers. Understanding the diversity of skull shape among anoles and other iguanid lizards will be one of the first focal areas of my new lab. We are currently mining museum collections to understand how the variation in anole skulls compares to iguanid lizards more broadly. The ultimate goal, however, is to return to questions about the developmental origins of this variation. Just how many different ways has development been modified to generate all the variation we observe in adult anatomy? We do not yet know.
This is where my attention turns to you. To thoroughly flesh out the developmental origins of anatomical diversity, I must have robust sampling of species across the iguanid phylogeny. I am asking the community to please think of me and my students if you have extra breeding animals, eggs, or hatchlings of any species of anole or another iguanid lizard. I am happy to help offset the cost of the animals or collaborate in a mutually beneficial manner.
One of the most exciting species that have recently had the fortune to work with is Anolis hendersoni. For its body size, this species has one of the longest faces of all anoles. In this case I was contacted by the owner of Backwater Reptiles who had several A. hendersoni adults that we are hoping to get eggs from over the next year at Loyola. The folks at Backwater have been great to discuss “exotic” anoles with as they occasionally receive species like A. woodi, A. cybotes, and Chamaeleolis, all of which could be great additions to my project. This is just one example of how I am trying to broaden the sampling for this project. I ask you, the broader anole community, to help me increase my sampling further. I sincerely thank anyone that has leads for me in advance.
I got up early this morning to put a video camera on one of our A. sagrei eggs that was looking particularly ripe. About two hours later, this little hatchling crawled out. The whole hatching process took about 25 minutes, and I’ve sped up the video by 30x. The video is much more compelling with sound. I personally like “Also Sprach Zarathustra,” though “Ranz des Vaches” by Rossini had some enthusiastic support in lab. If you have other music suggestions, add them to the comments!
Happy birthday, little one!
This video originally appeared in bioGraphic, an online magazine from the California Academy of Sciences that features beautiful and surprising stories about nature and sustainability.
What is bioGraphic, you ask? Here’s what it’s webpage says:
A multimedia magazine powered by the California Academy of Sciences, bioGraphic was created to showcase both the wonder of nature and the most promising approaches to sustaining life on Earth. We hope our stories will spark conversations, shift perspectives, and inspire new ideas, helping not only to shed new light on our planet’s most pressing environmental challenges, but also—ultimately—to solve them.
Through an ever-evolving array of storytelling tools and techniques, we will introduce you to some of the world’s most intriguing creatures and inspiring people. We’ll also transport you to faraway places, enabling you to experience what it’s like to be there and what’s at stake for those involved. Along the way, we’ll take a critical look at the environmental issues that pose the greatest threats to our future—and the most promising ideas for addressing them.
So please come along—and come back often—as we travel the globe in search of stories that inspire both awe and hope for a more sustainable future.
Hello to everybody, I’m an italian naturalist that visited Cuba last December 2016.
I’m mainly a birder, but I like to give a name to all the creatures I meet. So, I’m going to post 20 pictures of lizards photographed in Cuba: for some I have hypotheses about the identification, but I need confirmation. For some others, I’m completely lost!
Can anybody help me??
Sexual dimorphism, or differences in size or appearance between the sexes, was used by Darwin to explain sexual selection in On the Origin of Species. Interestingly, sexually dimorphic traits, like antlers in deer or showy feathers in peacocks, often do not present themselves until the animals are reproductively mature. Juveniles are often sexually monomorphic, or relatively similar in appearance. Few studies have investigated how sexual antagonism, when different sexes have different optimal strategies, of these traits may develop in the wild over the course of the animal’s maturation. So Aaron Reedy from the Bob Cox Lab at the University of Virginia decided to tackle this question with brown anoles (Anolis sagrei) in Florida.
After tracking thousands of lizards for several generations, Aaron found that selection changed throughout an animal’s life. Adult lizards had selection pressure for large males and small females in one year, but reversed the next, which was surprising, but in both cases was still sexual antagonism. For juveniles, on the other hand, larger body sizes were better regardless of sex. This is an example of sexually concordant selection, where both sexes have similar optimal strategies. He also found that there was selection pressure on the dewlap (an important ornament of anoles in courtship displays) to be smaller in one year, but then reversing the next so that males with larger dewlaps had better chances of survival. This year-to-year variation in selection is interesting and hopefully we’ll learn more from this system in the future.
I’ve recently learned that famous nature micro-photographer Piotr Naskrecki observed an aquatic anole catching prey underwater. Here’s what he had to say on his blog, The Smaller Majority:
In a couple of days I am heading off to the Galapagos Islands, where I hope to be able to see the incredible marine iguanas, the world’s only truly marine lizards. Other lizards enter water occasionally, but aquatic lifestyle is quite rare among these reptiles, and few species live and feed under water. But in rainforest streams of Central America there is one little known species of iguana that does just that.I first saw the aquatic iguana (Norops aquaticus) in the southern part of Costa Rica in 1994. These lizards swam and dove in a fast-flowing stream, catching water insects. But when I told a herpetologist friend about it, she refused to believe me.
It took me 13 years to find the aquatic iguana again, and this time I had a camera with me. It was in a different part of Costa Rica (Est. Pitilla in Guanacaste), but the animal and its habitat were the same. I watched it for a couple of hours, following the lizard among slippery boulders, hoping to document its hunting behavior. Eventually I got lucky, but alas, the actual catching of the prey happened underwater, when the iguana cornered a nymph of an aquatic blattodean (a yet undescribed species.) Next time I will definitely try to get a photo of the underwater action.
Update (2 Sept 12): Turns out that the aquatic Norops iguanas that I saw in southern Costa Rica and those from the northern part of the country, shown here, are different species. The animal in the photos is Norops oxylophus, not N. aquaticus. You can read more about the amazing aquatic behavior of N. oxylophus here. (Thanks to Annemare Rijnbeek for pointing me in the right direction regarding the ID of these animals.)
Incidentally, it appears that these lizards are once again being placed in the genus Anolis, where they historically belonged.
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Above: Albert Chung presented on how testosterone influences sexual signals and energetics at the annual Society for Integrative and Comparative Biology meeting in New Orleans, LA.
Many researchers are curious about how sexual signals evolve and if those signals are influenced by an individual’s energetics. Signal expression (such as anole dewlap size or color) and energetics might have the same physiological underpinnings, and signal expression may be limited by energetic state. Albert Chung, a graduate student working with Dr. Christian Cox at Georgia Southern University, along with graduate student, Aaron Reedy, and Dr. Robert Cox at the University of Virginia tested this hypothesis with brown anoles (Anolis sagrei) in the lab and in a wild population in the Bahamas.
The researchers had three different groups in this experiment. In one group, the males were castrated, so they wouldn’t produce natural testosterone. These males were each given a small implant that released synthetic testosterone designed to have the same effects on the body as natural testosterone. In the next group, males went through a procedure to mimic castration, but were effectively left intact, and implanted with an empty implant. These males still produced natural testosterone. In the final group, males were castrated and each one was given an empty implant, so they did not have testosterone in their bodies.
Wild anoles were recaptured after two months. The researchers measured the size and color of the dewlap, how much fat was stored (which provided the researchers with an estimate of energetic state), and body condition. They took the same measurements in the lab population.
There were clear differences between the males that had testosterone (both natural and synthetic) and males that did not have testosterone. Castrated males had smaller dewlaps compared to intact males and testosterone-treated males in both the field and lab populations. Dewlap size of testosterone-treated males was similar to that of intact males in the wild population, but in the lab population, testosterone-treated males had larger dewlaps than intact males.
Castrated males in the wild population had brighter, more saturated dewlap coloration than testosterone-treated males and intact males. In the lab population, dewlap coloration did not differ among the treatments.
In the wild population, castrated males had higher body fat mass than intact males and testosterone-treated males. Wild testosterone-treated males were similar in body fat to intact males. Castrated males in the lab population also had higher body fat mass than intact males and testosterone-treated males.
The researchers also looked to see if either fat mass or body condition were correlated with dewlap size or color within each treatment group. None of these variables were correlated with one another.
Overall, while dewlap expression was not dependent on an individual’s energetic state, both energetics and dewlap expression were directly influenced by a common hormone: testosterone.
Most animal learning studies have been conducted in the lab with the assumption that those findings are representative of behavior in the field. However, assessing behavior in the field increases ecological relevance. In addition, birds and mammals have received much of the attention in cognitive studies. Yet we on Anole Annals know that these lizards can be quite clever.
Levi Storks, a Ph.D. student in Manuel Leal’s lab at Mizzou, set out to address these issues by designing a method for testing behavioral flexibility in brown anoles (Anolis sagrei). Wild lizards in the Bahamas were allowed to feed unrestricted on a maggot placed in the middle of a testing apparatus in order to acclimate lizards to the structure. Storks then used a clear plastic tube to block the direct route to food, requiring lizards to move to either end to gain access. Lizards that successfully completed this task were then tested to see if they could associate unique patterns on the ends of the tube with single openings.
Storks found that a subset of lizards could successfully complete the first detour task, and lizards made fewer errors over the course of solving the detour task. These findings suggest brown anoles can learn and exhibit behavioral flexibility. Stay tuned for more of Levi’s work as he’ll be applying these methods to assess differences in behavioral flexibility between populations that vary in ecology!
The beautiful island of Dominica used to be home to only one anole (Anolis oculatus), but about 20 years ago, the Puerto Rican crested anole (Anolis cristatellus) showed up. Jeanel Georges, a graduate student in Matt Watson’s lab at Midwestern State University in Wichita Falls, Texas who is originally from Dominica, noticed that while A. oculatus occurs in all the ecological zones of the island, A. cristatellus is absent from the cooler, wetter uplands. With an international group of collaborators, Jeanel examined the thermal habitat use, sprint speed, and bite force of both species to determine what may limit the spread of A. cristatellus across the island.
At a lowland site where the two species co-occur, both species had higher body temperatures that the operative temperatures randomly available in the environment. In the much cooler upland site, A. oculatus had much higher body temperatures than the operative models, but these body temperatures were cooler than that species experiences in the lowland site. Jeanel also found that the two species had stronger bite forces and higher sprint speeds in the lowland site than A. oculatus had in the upland site. These data suggest that A. cristatellus and A. oculatus are partitioning the thermal environment of Dominica, and as climate change alters the temperatures available to lizards on the island, the interactions between these two species may change.
This post was written by Brittney Ivanov, research technician in Michele Johnson’s lab at Trinity University.
Austin Hulbert, an undergraduate in Dan Warner’s lab at Auburn University, presented a poster on the behavior of brown anoles (Anolis sagrei) in a novel environment: a few very hot greenhouses in Auburn, Alabama. Brown anoles are an invasive species, most notably in Florida, but some populations have been found farther north in states including Louisiana, Alabama, Mississippi, and Georgia. As ectotherms migrate to higher latitudes, they often have to deal with different thermal environments and must alter their behaviors accordingly. Austin was interested in determining the activity patterns of a population of brown anoles inhabiting a group of greenhouses in Alabama.
During the summer he found that temperatures inside the greenhouses were consistently higher than those outside. Temperatures drastically increased each morning, up to peak temperatures between 11am and 3pm (on average, 45°C inside the greenhouse and 37°C outside). In the evenings, the temperatures again cooled. Austin surveyed the greenhouses and the surrounding areas for anoles during the morning, peak, and evening hours and determined the type of substrate each individual was using (i.e. brick or concrete, ground, metal, or wood). On average, brown anoles were more abundant inside the greenhouses than outside during the morning and peak times. He also found that more of the brown anoles perched on wooden substrate in the morning and evening. During peak hours more lizards perched on the ground. Because temperatures are often cooler closer to the ground, the lizards may be altering their behavior to deal with the extreme heat in the greenhouses during the hottest part of the day. While the visual survey focused on lizards perched in the open areas visible to the surveyor, there may have been individuals hiding under undisturbed objects as a means to keep cool during peak hours. In the future, Austin would like to compare the thermal tolerance of this group of brown anoles to those of populations in Florida to determine if inhabiting these greenhouses has resulted in adaptions to tolerate their more extreme temperatures.
This post was co-written by Maria Jaramillo, an undergraduate in Michele Johnson’s lab at Trinity University.
A mother’s experience during gravidity may alter her offspring’s development, particularly through altering hormone levels in the yolk of her eggs. Stress hormones such as corticosterone (CORT) alter various aspects of offspring phenotype following in ovo exposure, and physical exercise elevates CORT in many vertebrates. In the work he presented at SICB, Jerry Husak and colleagues used exercise and food restriction to manipulate female Anolis carolinensis CORT, and to then determine whether the increased CORT was transferred to the females’ egg yolks.
Jerry assigned females to one of four treatments with different combinations of exercise and food restriction: 1) no exercise, regular diet; 2) no exercise, restricted diet; 3) exercise, regular diet; and 4) exercise, restricted diet. He found that maternal exercise increased maternal CORT (as expected), but surprisingly did not result in higher CORT in the eggs. Further, diet restriction did not affect maternal CORT, but moms with restricted diets laid eggs with reduced CORT.
This study suggests that anole mothers may manipulate the environments of their eggs in ways we don’t yet understand – the mechanisms by which CORT is transferred to eggs is an area ripe for future study!
Every year since 2013, the Division of Ecology and Evolution (DEE) hosts the Huey Award Symposium at the annual SICB meeting. The Huey award is given for the best student presentation in DEE, in honor of Ray Huey, professor emeritus at the University of Washington. Ray’s career featured a lot of key research on anoles, and so there is often good representation by anole biologists at the Huey award. At this year’s symposium, Ariel Kahrl, a graduate student in Bob Cox’s lab at the University of Virginia, presented her research on pre- and postcopulatory selection in Anolis lizards.
We know that male competition for mates occurs both before copulation (mating success) and after copulation (sperm competition). Her research focuses on investigating the evolutionary connection between these two phases of competition. She found that larger males have smaller relative testis size, indicating a tradeoff between pre- and postcopulatory success, as larger males will have better success gaining access to females, but less sperm available for mating.
When she looked at testis and sperm morphology in greater detail, a few interesting patterns emerged. First, she found that testis size evolves faster than body size, consistent with other studies showing that reproductive organs evolve faster than other body traits. She also found that the midpiece section evolved faster than the head and the tail of the sperm. Importantly, the midpiece section of the sperm was strongly associated with male condition and sperm swimming speed, whereas the head and tail of the sperm were not associated with male condition or sperm swimming performance. She further hypothesized that sperm count may be a more important target of selection than sperm morphology.