Another anole bites the dust. Or does it? Over at Chipojolab, Manuel Leal reports the observation of a Puerto Rico racer apparently in the process of ingesting an Anolis krugi. But if you look carefully, the krugi is giving as good as he gets. Or at least doing his darned best. Will it be enough to fend off his demise? Seems unlikely given the size difference, but in lab trials, Leal and Javier Rodríguez-Robles showed that Anolis cristatellus often bites attacking racers on the snout and can hang on for as long as 20 minutes; in 37% of the trials, the lizard actually escaped. Admittedly, cristatellus is bigger and beefier than krugi, but who knows–maybe this guy lived to see another day.
In recent years, concern has arisen about how tropical ectotherms will cope with rising temperatures. For a variety of reasons, tropical species are considered particularly vulnerable, and coarse scale modelling exercises suggest that many populations and species may face extinction in the near future. Some of the most influential studies, such as Sinervo et al.’s mammoth 2010 paper (already cited more than 200 times!), have focused on lizards.
The field of thermal ecological physiology made great advances in the 1970’s and 80’s and a, perhaps the, major player in the work was research on lizards. And amongst this work, studies on Anolis played a particularly prominent role (reviewed in Chapter 10 of Lizards in an Evolutionary Tree). Hence, it is no surprise that a reconsideration of lacertilian prospects, based on detailed understanding of how lizards interact physiologically with their environment, is stemming from in-depth studies on anoles.
Most modelling studies are based on a coarse-grained (1 km2 resolution), remote sensing scale analysis of global temperature variation, with the assumption that relatively little variation in thermal environment occurs within each block. Recent papers focusing on anoles in Puerto Rico (Leal and Gunderson, 2012) and offshore islands in Honduras (Logan et al., 2013) have tested this idea and found it wanting–in open areas and, to a lesser extent, within forests–considerable thermal heterogeneity occurs. Moreover, many anole species thermoregulate behaviorally–i.e., they aren’t passive samplers of the environment, their body temperature a simple reflection of the ambient, but rather they move in and out of sun and shade, and thus can determine their temperature, mediating what is available in the environment. Thus, even if the environment gets warmer, lizards may have the option simply to switch to increased use of the cooler micro-environments, maintaining the same body temperature.
A third point is relevant as well. Physiological performance is generally temperature-dependent, but often a broad plateau exists in which maximal performance varies over a broad range of body temperatures. Hence, populations may be buffered from effects of increased temperatures if the resulting increase in body temperature does not push them off the plateau.
Both studies ask the simple question: if global temperatures go up, will lizards in open and forested habitats experience an increase or a decrease in the quality of the thermal environment, quantified in terms of how readily they are able to achieve their optimal temperature (using sprint speed as a proxy).
The results show interesting similarities and differences. Continue reading
A new journal focused on the natural history of Caribbean fauna and flora has just been announced. As the sample cover to the left illustrates, it might be a great place to publish observations on our favorite critters. The journal has a distinguished board of editors and the webpage states:
The Caribbean Naturalist is a peer-reviewed journal that publishes original articles focused on field research of all aspects of the biology and ecology of terrestrial, freshwater, and marine organisms and the environments of the Caribbean region. The journal offers:
• over 15 years experience of consistently providing timely publication of high-quality peer-reviewed research
• article-by-article online publication for prompt distribution to a global audience
• an efficient and responsive review process
• the expertise to bring to rapid fruition proposals for Special Issues based on a series of invitational articles or conference proceedings
• the capability to accommodate publication of a wide range of supplemental files in association with journal articles
As is the case with Eagle Hill’s other natural history journals, the Caribbean Naturalist is expected to be fully indexed in Elsevier, Thomson Reuters, Proquest, EBSCO, Google Scholar, and other databases.
Check out the details at their website.
Two of the world’s coolest lizards are blue anoles, male A. allisoni from Cuba and both sexes of the fabled blue anole of Gorgona (A. gorgonae). Why the blue? Heck if I know. You can see a male allisoni on a palm from a great distance, so it amazes me that they can survive. Seems clear that they must be trying to advertise their presence. On the other hand, I’m told that A. gorgonae can be very hard to spot when one looks up toward the canopy, where the species hangs out. In this instance, the blue may actual serve for crypsis. Who knows?
Turns out that there are lots of blue animals and the reason for their blueness, as well as the mechanism by which it is produced, is not well known. Kate Umbers has just published a nice review in Journal of Zoology on all things blue, and it’s a worthwhile read, even if she didn’t mention anoles, or even hardly any lizards at all. Among other interesting tidbits, she points out that dichotomizing colors as structural or pigmentary is somewhat misleading, because both pigments and structure can work together to produce blue colors. Also, blue-footed boobies’ feet are bluer when they’re well-fed, and female boobies invest more in their offspring if they have brighter blue feet. Who knows what interesting blue-related aspects of natural history remain to be uncovered in anoles?
Many anoles have blue eyes as well, and this is a trait that seems to pop up repeatedly throughout the clade, though I have no data on this. I wonder what’s up with that.
As a final bonus, here’s a video of a blue knight anole! (and here’s a previous AA post on the same). The video itself isn’t so sharp, but it’s a blue knight anole!
Manuel Leal recently observed this A. stratulus in Puerto Rico licking a leaf high in the forest at El Verde. He describes his observation over at Chipojolab, and suggests that they are not drinking water, and that the behavior is very focused.
Recently in the Bahamas, we observed a female A. sagrei licking a leaf. It hadn’t rained in several days and there wasn’t any dew on the leaves. However, close inspection of the leaf after the leaf left indicated that it was covered with a sticky substance. Perhaps aphid honeydew?
Anole Annals publishes on the WordPress blogging platform and clearly they like us, as they’ve just created a “theme” named Anolis. Maybe it’s time for a blog makeover!
Brother O’Mara has proposed producing a wallet emblazoned with green anoles. It’s on a website, Dynomighty, that appears to be similar to Kickstarter and he’s looking for funding to make the project a go.
A new Dartmouth College study finds human-caused climate change may have little impact on many species of tropical lizards, contradicting a host of recent studies that predict their widespread extinction in a rapidly warming planet.
Most predictions that tropical cold-blooded animals, especially forest lizards, will be hard hit by climate change are based on global-scale measurements of environmental temperatures, which miss much of the fine-scale variation in temperature that individual animals experience on the ground, said the article’s lead author, Michael Logan, a Ph.D. student in ecology and evolutionary biology.
To address this disconnect, the Dartmouth researchers measured environmental temperatures at extremely high resolution and used those measurements to project the effects of climate change on the running abilities of four populations of lizard from the Bay Islands of Honduras. Field tests on the captured lizards, which were released unharmed, were conducted between 2008 and 2012.
Previous studies have suggested that open-habitat tropical lizard species are likely to invade forest habitat and drive forest species to extinction, but the Dartmouth research suggests that the open-habitat populations will not invade forest habitat and may actually benefit from predicted warming for many decades. Conversely, one of the forest species studied should experience reduced activity time as a result of warming, while two others are unlikely to experience a significant decline in performance.
The overall results suggest that global-scale predictions generated using low-resolution temperature data may overestimate the vulnerability of many tropical lizards to climate change.
“Whereas studies conducted to date have made uniformly bleak predictions for the survival of tropical forest lizards around the globe, our data show that four similar species, occurring in the same geographic region, differ markedly in their vulnerabilities to climate warming,” the authors wrote. “Moreover, none appear to be on the brink of extinction. Considering that these populations occur over extremely small geographic ranges, it is possible that many tropical forest lizards, which range over much wider areas, may have even greater opportunity to escape warming.”
Story Source: The above story is reprinted from materials provided by Dartmouth College, via EurekAlert!, a service of AAAS.
We’ve had a lot of discussion of perch height in the green anole, A. carolinensis, and whether or not greens shift their habitat use downward in places where brown anoles, A. sagrei, don’t occur. AA’s man in Georgia, Janson Jones, reported last year that he often found greens very near to the ground, even on water plants. It’s a new year, things are warming up, and the greens are getting active. Janson has vowed to keep a close eye on all things anole this year, and a while back he just posted his first report over on Dust Tracks on the Web. Early reports are that the green anoles are messing with our minds again. Let’s see what happens as the summer progresses.
In a monumental undertaking, Alexander Pyron and colleagues have just produced a molecular phylogeny for 4,161 species of lizards (including snakes), more than 40% of the 9400+ species described to date. The paper, now available online at BMC Evolutionary Biology, is a blockbuster, containing 28 figures, one an overview of the entire phylogeny and the remainder walking through lizard-life one clade at a time.
The analysis is based on sequence data from 12 commonly used and phylogenetically informative molecular markers (seven nuclear genes, five mitochondrial). On average, 12,896 base pairs of sequence data are available per species and, as is necessary in an endeavor such as this, the data set is incomplete, with an average of only 19% of base pair data being available for any given species.
The results are generally very concordant with recent molecular phylogenies, perhaps not surprising given that these data have been used in the most recent studies. The overall picture of lizard phylogeny is little-changed from what we’ve seen in recent molecular phylogenetic publications, but there are a few surprises at lower levels. You’ll have to peruse the paper yourself to check out your favorite group, as there’s way too much in it to go through here.
Of course, what readers of AA really want to know is: what does the phylogeny say about anole relationships? And, in fact, the results are for the most part concordant with previous studies. Perhaps surprising to many readers, the analysis supports the monophyly of the eight clades recognized by Nicholson et al. as separate genera. Well, almost. In contradiction to the paper’s statement, Nicholson et al.’s Anolis is not monophyletic because A. argenteolus is placed as the sister-taxon to the Xiphosurus clade (which contains Chamaeleolis and the ricordii group), rather than occurring with other species placed into the restricted Anolis. This is an odd finding, contradicting both Nicholson et al. and the Alfoldi et al. genome paper analysis, with the implication that the transparent lower eyelids of A. argenteolus and its putative sister taxon A. lucius are not homologous, but I don’t buy it. Other than that, I didn’t find anything too exciting in this phylogeny, though further scrutiny (it’s enormous) may turn up interesting relationships I didn’t notice.
Other than this one exception, however, the Nicholson et al. eight fare well. Nonetheless, the authors of this paper do not follow the Nicholson et al. taxonomic suggestion of subdivision, stating: “since Anolis is monophyletic as previously defined, we retain that definition here…for continuity with the recent literature.”
Probably the most interesting finding concerns the closest relative to anoles, a topic of great uncertainty. This analysis strongly confirms that Polychrus is not the sister group to Anolis; rather, Polychrus appears related to the hoplocercids, which means that it’s dewlap must be convergent with the anole flasher. To whom, then, are anoles related? The answer appears to be the basiliscines (Corytophanidae in more modern parlance), the morphologically diverse and fascinating neotropical group containing not only basilisks, but also Corytophanes and the little-known Laemanctus.
Two last points: first, as noted above, there’s lots of missing data. Clearly, this is not the last word and, in particular, the question of the sister taxon to Anolis cries out for further study. Second, as the authors note, this paper will be of inestimable value in conducting comparative studies spanning the entire lizard radiation. To facilitate such, the authors have made available a Newick file containing the phylogeny (if you don’t know what this means, suffice to say that it’s a very helpful move that will make it easy to use this phylogeny in comparative studies).
Now, let’s get out and sequence the other 5000 species and finish the job!
[Editor’s Update, March 18, 2014]: I was mistaken in saying that the Pyron et al. tree found only one inconsistency with the Nicholson et al. genera. In addition to the exception noted above, Nicholson et al. place christophei in their Chamaelinorops clade, but Pyron et al. find it allying with species that Nicholson et al. put in Xiphosurus.
I’m told that in the old days, all kinds of critters would show up in fruit shipments from tropical regions, but now with pesticides and processing, it’s much rarer. The BBC reports the story of one such recent event:
The reptile, which was about 8ins (20cm) long, was found at Riverford Organic Farms, in Buckfastleigh.
Staff said it was the first lizard they had found since starting to import bananas from the Dominican Republic about a decade ago.
The anolis lizard, which feeds on insects, was sent to Paignton Zoo and is expected to be added to its collection.
Amanda Whittington, from the farm, said the animal had been stored in a container since it was found on Thursday.
She said: “A woman was packing bananas into our fruit boxes and out it popped. It gave her a bit of a shock.
“We then caught it and asked Paignton Zoo what to do.
“It then escaped into the customer services department, but we then managed to catch it again and fed it some crickets.”
‘Certainly a survivor’
She said the bananas took a couple of weeks to transport by boat from the Dominican Republic.
Reptile keeper Rod Keen said: “There are hundreds of species of anolis lizard, which are related to iguanas.
“It is certainly a survivor, as it’s come thousands of miles in various methods of transport and spent time in cool rooms,” a spokesperson added.
The reptile will spend a standard six month period in quarantine at the zoo, and will probably be released into one of the tropical houses.
My recently published paper in Herpetological Conservation and Biology about the effects of human land use on Anolis carolinensis (abstract below) came from an exciting season of field research. The summer of 2010 in Palmetto State Park in Gonzales, Texas was my first field research experience, where I took my first steps of many (little did I know) into the world of Anole biology. I worked under the supervision of Michele Johnson with an awesome lab group: Tara Whittle (our lab technician), Alisa Dill, Michelle Sparks, and Chelsea Stehle. Yes, I was the only male, and yes, that means I did get a tent all to myself. I took so many things from this experience, both scientific and not, that started my future as a field biologist.
We spent our days out in the hot Texas summer heat, catching, measuring, and observing our new friends, the green anoles. Each of us had our own research to work on that focused on various aspects of green anoles, and so we divided up our field time amongst our projects, helping each other collect data. We designated plots throughout the state park so we could compare the anoles in those plots. I studied the ways that human land use, such as clearing land for buildings, or constructing trails through natural habitat, impacts the lizards’ prey and the lizards themselves. While we did not find any clear trends showing that human disturbance impacts insects, which in turn affects the anoles, we were able to show that human-disturbed plots had higher insect biomass. This would seem beneficial to the anoles, who would theoretically have higher body condition (BMIs: SVL divided by mass) because of the greater amount of available food. However, we found that lizards (females in this case) in plots with greater levels of disturbance had lower BMIs.
The non-straightforward results from my study reflect the complexity of the relationship between humans and the environment; our impacts on the world do not always easily appear. I am taking what I have learned from this experience and am continuing to use anoles as a system to study human impacts on the environment at a local scale. This fall, I will attend the University of Rhode Island and study anoles with Jason Kolbe.
ANDREW C. BATTLES, TARA K.WHITTLE, CHELSEA M. STEHLE, AND MICHELE A. JOHNSON
Abstract.—Lizards frequently occur in disturbed habitats, yet the impacts of human activity on lizard biology remain understudied. Here, we examined the effects of land use on the body condition of Green Anole lizards (Anolisvcarolinensis) and the availability of their arthropod prey. Because human activity generally alters abiotic and biotic habitat features, we predicted that areas modified by humans would differ from areas with natural, intact vegetation in arthropod abundance and biomass. In addition, because biological communities in high use areas are often relatively homogenized, we predicted that higher human land use would result in lower prey diversity. Regardless of land use, we also predicted that areas with greater prey availability and diversity would support lizards with higher body condition. We studied anoles in six plots with varying levels of human modification in Palmetto State Park in Gonzales County, Texas. We quantified arthropod abundance, biomass, and diversity in each plot via transects and insect traps. We also determined lizard body condition using mass:length ratios and residuals, fat pad mass, and liver lipid content. We found that, although arthropod abundance did not differ across plots, arthropod biomass was higher in natural than in disturbed plots. Diversity indices showed that the plots varied in their arthropod community diversity, but not in relation to disturbance. Female (but not male) lizard body condition differed across plots, with body condition higher in natural plots than disturbed plots. Together, these results suggest that land use is associated with lizard body condition, but not through a direct relationship with prey availability.
This photo’s bouncing around the internet. It’s clearly Phenacosaurus, but which one? Doesn’t look like the P. heterodermus discussed in recent posts.
Janson Jones recalls the formative role Anolis carolinensis played in his childhood.
Periodically, AA has featured reports on finding three-legged lizards in nature (1,2). And here’s another one, briefly detained on a recent field trip to Abaco. Loss of her hindfoot doesn’t seem to be troubling her too much; heck, she’s even gravid!
Turns out that three-legged lizards pop up all the time. I’ve decided to put together a compilation of the little tricyclers. If you have any information on a three-legged lizard–a photo or more, such as measurements of mass, survival, or sprint performance–I’d love to know about it. Please contact me at firstname.lastname@example.org.
How’s this for a nifty anole decal? A gift from AA contributor and photographer extraordinaire Joe Burgess, the window dressing is the handiwork of Floridian Gary Swenk, who has this to say about himself and his unusual trade: “I am a retired law enforcement officer now doing vinyl graphics from home. I attached a catalog that I use and I also can convert pics, images etc. to vector graphics for making the decals. Black and white or pics with good contrast work best (not all pics, images are able to convert but it is easy for me to test them). I have a lot of different colors available. They can be made in many sizes ( 3″ up to 11″ is a good size). I can customize a graphic with names etc., using numerous fonts. Price is based upon size and single colors would run $2 to $5 for the sizes mentioned plus actual shipping cost which would be minimal. My cell is 904-540-3879.” And his emai is email@example.com.