Anole Annals

Anole March Madness: Final 4!

On April 5, 2016

Anole MM16

Our (fictional) anole tournament is nearing its end. The two semi-final matches concluded leaving only two anoles remaining. Who will be the ultimate champion, an island anole or a mainland anole?

Here’s the recap of the Final Four:

Anolis aquaticus (photo by John Sullivan)

Anolis frenatus (photo by Tobias Eisenberg)

Winner match 25 (Anolis aquaticus) versus winner match 26 (Anolis frenatus)
In the rainforests of Columbia, Anolis aquaticus has ventured slightly out of his native range. Skittish from his previous streamside encounter with the giant Anolis insignis, he warily watches the canopy despite coming out on top in his last battle against Anolis limifrons. He is no stranger to Anolis frenatus, whose range extends north into Costa Rica, yet he fails to recognize the danger he is in as he climbs a tree towards a swarm of tasty insects. Out on a branch 10m up A. aquaticus gorges himself on the abundant food that tasted so much better than the streamside meals he was used to. Out of the corner of his eye, he sees the imposing form of Anolis frenatus move. More than twice his size, A. frenatus is a sight to behold. Anolis aquaticus quickly surveys his escape options. Seeing a stream below he rationalizes that he can escape if need be. He continues to gorge himself. Anolis frenatus is taken aback at the impertinence of this newcomer. He makes his way towards the branch upon which A. aquaticus is perched. Not willing to abandon his smorgasbord, A. aquaticus boldly stands his ground. He turns to face A. frenatus and begins to dewlap; perhaps this is a friendly giant that will want to avoid conflict. Anolis frenatus stops to size up this intruder and quickly determines that this tiny anole poses no threat to him. Anolis frenatus does not even bother to dewlap back. He continues on his path towards Anolis aquaticus, who stubbornly continues to dewlap and push-up in his cloud of tasty morsels. Anolis frenatus lunges at A. aquaticus, who instinctively turns and leaps without looking towards the stream. Anolis aquaticus sails through the air and lands safely in the water, or so he thinks. As he climbs onto a boulder, a fish-eating spider (Trechalea spp.) with a body size of nearly 17cm seizes the opportunity and leaps onto the unsuspecting and soggy anole. The spider makes quick work of the aquatic anole. Anolis frenatus watched from his high perch with a mouthful of delectable insects which he incidentally gobbled when he leapt at A. aquaticus with mouth agape. Anolis frenatus revels in his glory as he watches his competitor meet his end below. ***Anolis frenatus wins***

Anolis equestris (photo Wikipedia)

Anolis bimaculatus (Photo by Statia Wildlife, Flickr)

Winner match 27 (Anolis equestris) versus winner match 28 (Anolis bimaculatus)
A hurricane of unprecedented proportions has just ripped through the Caribbean. The Cuban Knight Anole, Anolis equestris, and the Panther Anole, Anolis bimaculatus, both find themselves washed up on an unfamiliar low-lying island. The waves periodically break over the island, washing away the debris on the ground. Both lizards quickly find a perch and scramble to escape an incoming wave. As the reach safety atop their scrubby perches, they catchy sight of each other. Clearly this island refuge has room for only one of them. Two lizards enter, one lizard leaves on this subsiding volcanic dome. They lock eyes and begin to dewlap. Nearly evenly matched it’s not clear who will claim this island as his new home. Anolis equestris extends his dewlap first. He unleashes a flurry of push-ups and rapid flashes of his cream colored dewlap. The slightly smaller Anolis bimaculatus has no choice but to stand his ground. He strains to extend his orange-yellow dewlap as far as he can. Unfortunately, his species has a disproportionately small dewlap for their size, and this A. bimaculatus is average sized at best. Anolis equestris, completely and utterly unimpressed, leaps from bush to bush with waves breaking over the rocky ground below him as he heads towards A. bimaculatus. Anolis bimaculatus makes an offensive move and lunges at A. equestris, who has by now reached the neighboring bush. Anolis bimaculatus lands a calculated blow on the abdomen of A. equestris. Despite the searing pain in his kidney, A. equestris reaches around and snatches A. bimaculatus in his forceful jaws. In one quick motion, A. equestris flings the slightly smaller A. bimaculatus over his shoulder and off the perch. Anolis bimaculatus hits the rocky ground and begins to sprint toward the nearest bush. At this moment a large wave crashes over him and carries him off the low-lying island. Anolis bimaculatus scrambles onto a floating log, but is immediately caught in the outgoing rip and is carried far into open water within moments. Anolis equestris watches A. bimaculatus ride the waves out of his life and weathers the remainder of the storm safely on his elevated perch, alone. ***Anolis equestris wins***

Which brings us to our dramatic conclusion: Anolis frenatus, representing the mainland, versus Anolis equestris, representing the islands!

Anole March Madness: Elite 8 reduced to Final 4!

By Kristin Winchell

On April 4, 2016

In All Posts

Anole MM16

The third round of our (fictional) anole tournament is now complete. We started with 32, and now there are 4.

Here’s what you missed in the Elite 8 round: Anolis aquaticus proves he’s in it to win it when he battles Anolis limifrons; Anolis proboscis wonders what his proboscis is good for as he battles the giant Anolis frenatus; Anolis equestris shows Anolis porcus who the king of the jungle is; and the big-cat-lizards Anolis marmoratus (AKA Leopard Anole) and Anolis bimaculatus (AKA Panther Anole) face off.

Spring Break Herp Style

By Nick Herrmann

On April 4, 2016

In Natural History Observations

“This is not a Spring Break trip to Costa Rica, it is a herpetology class trip to Costa Rica that happens to be over Spring Break.” So said Jonathan Losos to a room full of eager students, many of whom had chosen to take Herpetology in part because of the adventure that awaited them. As first year Ph.D. students in the Losos lab, we were as excited as anyone for the opportunity to see some of Costa Rica’s rich biological diversity. Plus the well-publicized stereotype of how young people spend Spring Break has never really appealed to us. We’d rather be in the nighttime forest with a headlamp.

The lichen anole, A. pentaprion

The trip started with a day and a half at Veragua Rainforest. We saw tons of frogs and a handful of snakes, but anoles were hard to come by except for a few individuals along shallow, slow-moving streams (A. humilis, A. limifrons, and A. oxylophus). One of our most exciting finds of the trip was along one of these streams – an A. pentaprion hugging a narrow stem at eye level. It was shocking to see this lizard so close to the ground as it is often found high in the canopy and has even been observed gliding between perches. While many mainland anoles don’t fall clearly into the classic ecomorph categories, this lizard, with its small legs, long body and head, and slow but sneaky evasive behavior, is very reminiscent of West Indian twig anoles (and he’s got a gorgeous dewlap too! see photo at end of post).

From Veragua we moved to La Selva Biological Station where we spent five action-packed days exploring the forest and documenting the herpetofauna.

Anoles of Culebra

By Audra Barrios

On April 3, 2016

In All Posts

I am very interested in IDing the following anoles I saw on the island of Culebra, which is 17 miles east of Puerto Rico. I thought I would be able to find a guide to anoles of this area online, but IDing them turned out to be harder than I thought. Thank you for your time!
1) First one was found in the parking lot of Flamenco.

2) Also found near Flamenco.

3) Found in town. Bright yellow dewlap.

4) Found in town.

5) Found in town.

6) Found in town. Dewlap was dark orange with yellow near the throat.

Anole March Madness: Sweet 16 Round Complete!

By Kristin Winchell

On April 2, 2016

In All Posts

Anole MM16

Our (fictional) tournament of anoles is well underway as we complete the Sweet 16 round! The competition was tough and a few favorites fell from glory (sorry!). We’ve been repeatedly asked how the competitions are being decided. We are not rolling dice or using random outcome generators. For each match, we (K. Winchell, M. Muñoz, and P. Muralidhar) are reading up on the biology of the species involved and we debate what would happen if they were to meet each other and try to highlight some facts about each. In cases where we might be biased we step aside and let the others decide. If it were up to me of course, Anolis cristatellus would be in the final! (Really, they’re scrappy and mean little guys!)

And now the results!

How Different Do Two Different Colors Look? Ask an Anole

By Leo Fleishman

On April 2, 2016

In New Research

In trying to understand the evolution of visual signal diversity we are often faced with problem of asking which of two possible signals is most visible against a particular natural background. Alternatively we may want to know how easily different signals (for example signals of sympatric species) can be told apart.

When animals use colorful signals to communicate with conspecifics, selection will tend to favor colors that are highly visible against the natural background and colors that can easily and unambiguously be distinguished from signals utilized by other similar-looking species. Thus, in order to understand the evolutionary pressures on signal properties, we often want to know how distinct two different colors appear to an animal viewer. Perception of color by most animals differs from human perception because of differences in visual-system anatomy and physiology. How, then, can we quantify the difference in appearance of colors to an animal viewer?

A useful approach is to quantify the perceived difference between color stimuli as a distance in the animal’s “perceptual color space.” This refers to some measure of the difference in sensory stimulation elicited by different colors. At present most studies of visual ecology and communication use one of two methods to measure perceptual color space distance between pairs of colors. The first involves determining the relative stimulation of the different classes of cone photoreceptors by each color stimulus in units of relative photon capture, plotting colors in n-dimensional space (where n is the number of photoreceptor classes), and then measuring a simple Euclidian distance between the points. The second approach involves estimating the noise within each photoreceptor channel, determining the detection threshold – defined as the just-noticeable difference, or JND, between the two colors – determined by photoreceptor noise, and then estimating the distance between two colors in units of multiples of this threshold, or in units of JNDs. The photoreceptor noise method has been shown to be effective for estimating color discrimination thresholds, but the idea that differences between supra-threshold colors can be measured in multiples of the JND is more controversial. Each of these methods has some theoretical support, and each has advantages and disadvantages in terms of assumptions required and the information needed to do the calculations. However, empirical tests of which method works best are lacking, and there is not much agreement on the best way to measure perceived differences between colors that are well beyond the threshold for discrimination.

What we need here is a model system – and that usually means anoles! Anoles have an excellent, well-understood color vision system. Moreover a method has been developed that uses visual attention as an assay of signal visibility. Fleishman et al. (2016) used this method to quantify the visibility of different colors viewed against a gray background by Anolis sagrei. They then used these behavioral results to test the accuracy of the two different popular methods of measuring distance in visual color space. In these experiments anoles viewed a checkerboard of gray squares in their visual periphery (Fig. 1). One square was then abruptly shifted to some other color. The distance in color space from the initial gray to the newly appearing color was determined using the two different metrics described above. The probability of a gaze shift towards the novel colored stimulus was quantified, and colors throughout the anoline color space were tested. The probability of detection was then plotted against the different measures of perceptual color distance.

anole_annal_fig1

Figure 1. (a) Lizard sits on the perch in a small cage. The experiment waits until its gaze is directed straight outward towards the video camera (t1). At t2 a small colored stimulus square is presented in the middle of the checkerboard visual field. The camera records whether or not the lizard notices the newly introduced color-square and shifts its gaze towards it. See the video above. The video at the top of the page illustrates the appearance of the stimulus to a lizard and shows a positive response.

Which method best predicted the results? It turns out both methods gave excellent predictions of the behavioral data! In this case anoles are the peacemakers. Basically, the information available to the color vision system is how much difference there is in the photon capture by different cone classes exposed to different colors. These two different ways of quantifying this change turn out to give rather similar predictions, and both sets of predictions accurately predict detection probability. Thus the anoles give a firm go ahead for both methods of modeling distance in color space. The ability to easily model distances between colors in anoline perceptual color space should greatly facilitate studies of the evolution of dewlap color diversity because we can easily figure out which color is most visible under each set of natural habitat light conditions.

Now we just have to figure out why Anolis dewlaps come in so many different colors!

Is There a Crisis in Anolis Taxonomy?

By Julian Velasco

On March 31, 2016

In All Posts

A few days ago, I had a very interesting discussion in twitter with some colleagues (see here [1] and here [2]) about whether there is a decline and crisis of new taxonomists in amphibians and reptiles. I wonder if this situation might be the case fir Anolis lizards, or whether Anolis has its own tendency in species description. So, I decided to take the bull by the horns and I went to the Uetz Reptilia Database to see the numbers.

First, it seems that there is not an increase in species description for anoles across time. In early years, it was a bunch of new descriptions as also recently (Fig 1).

However, if you check how many anole taxonomists have described species, an interesting pattern emerges. Very few people have described almost all of anole diversity (Table 1). Only 15 anologists have described all currently known species (400 according to the Uetz database), and more interesting is the fact that only five of them are still alive! (Gunther Köhler, Orlando Garrido, James McCraine, Steven Poe and Larry Wilson; Table 1).

Table 1. Ranking of anole taxonomists by number of species described.

Then, to establish if new authors (new anole taxonomists) are emerging in recent times, I made an accumulation curve of authors across years of description (Fig. 2). I considered only the senior author (Fig. 2, top) and all authors involved in the description (Fig. 2, bottom). From these figures, it is possible to see, apparently, that very few new authors are emerging as anole taxonomist specialists.

Accumulation of authors by year. Only senior author (top), all authors involved in the description (bottom)

This suggests, at least to me, that something is happening in anole taxonomy. As we discussed in twitter, this scarcity in taxonomists in recent times could be due to several factors: lack of interest in describing new forms, lack of funding resources, lack of access to comparative material (i.e., herpetological collections), lack of writing skills to generate scientific papers, or lack of adequate taxonomic training. In any case, I feel that anole taxonomy would be in crisis if new people, mostly from Latin America, are not interested in describing and revising new species in each country. But, why are very few people seem to be interested in describing new valid species nowadays? Is it perhaps that taxonomy is a discipline with little interest in academia? Does doing so serve to get a job? Is it not worth publishing papers in taxonomy or even describing new forms?

Although today there are a bunch of journals oriented to taxonomy and many online resources to access to primary literature (Sci-Hub [3], BHL[4], etc.), it seems that very few people are interested to tackle these problems in our iconic lizards.

I would like to see your opinions on this

References

[1] https://twitter.com/CrawfordAJ/status/713398834005561344

[2] https://twitter.com/CrawfordAJ/status/713459231983280130

[3] https://en.wikipedia.org/wiki/Sci-Hub

[4] http://www.biodiversitylibrary.org

City Slickers: Performance and Substrate Properties in Urban Anoles

By Kristin Winchell

On March 29, 2016

In New Research

Anolis cristatellus on a smooth, vertical substrate in Puerto Rico (photo by K. Winchell)

In urban areas, the number of natural substrates (e.g. trees) is reduced. In their place are novel manmade substrates (e.g. walls, metal gates). These surfaces undoubtedly have different properties relevant to anole locomotion: they are smoother, harder, and (in the case of walls) much broader and flatter compared to natural surfaces in a forest. In urban areas lizards still use these substrates at high frequency, but do they do so effectively? Kolbe and co-authors began to dive into this complex topic in their recent publication, “City slickers: poor performance does not deter Anolis lizards from using artificial substrates in human-modified habitats” (Kolbe et al. 2015).

The relationship between habitat use, morphology, and performance for anoles has been extensively studied in natural environments (reviewed in Losos 2009). Urban environments add new dimensions to this area of research. Resource distribution and abundances differ drastically compared to natural areas. For example, the distribution of available perches and what they are made of in urban habitats is very different from a forest. Moreover, the properties of these resources differ drastically as well: urban substrates are smoother, broader, and have different thermal properties, to start. Understanding these differences in habitat use and how they influence performance and, ultimately, adaptive responses in anoles is the topic of ongoing collaborative research that I (K. Winchell) and the Kolbe lab have been conducting.

Anole March Madness: Round 1 Complete!

By Kristin Winchell

On March 27, 2016

In All Posts

Anole MM16

If you’ve been following along with our “Anole March Madness” tournament and you didn’t catch the updates on Twitter, you’re in luck. Here are the recaps of the second half of the Round of 32.

And of course, we remind our readers that these battles are fictional and are meant to highlight ecology, distribution, and traits of some well-known and not-so-well-known anoles. All battles are written by myself (K. Winchell), Martha Muñoz, and Pavitra Muralidhar using “complex algorithms” to determine the ultimate champion.

The next round (Sweet 16) kicks off on Twitter March 28 at 8pm. Follow along live and tag your comments #AnoleMM2016! Also next week we will be highlighting the “state of the knowledge” about the anoles featured in our tournament. Any guesses (no cheating) which species has the most citations and which has the least? We’ll give you the run-down of what we know and don’t know about who.

And here’s the recap of the second half of the Round of 32!

Download Skip Lazell’s 1972 Monograph on the Anoles of the Lesser Antilles

By Jonathan Losos

On March 26, 2016

In All Posts

From Skip Lazell’s 1972 monograph

Like many other biodiversity journals, the contents of the Bulletin of the Museum of Comparative Zoology are available on the Biodiversity Heritage Library. However, the BHL can be somewhat cumbersome to deal with, if not downright counterintuitive. Just today, I downloaded Lazell’s spectacular, classic monograph on the Lesser Antillean anoles, full of detailed descriptions, lovely illustrations (as above) and incisive commentary. Every digital library should have a copy, and so here’s your chance to get one easily, by clicking on this link. But note: the link apparently is only good for 30 days (and someone had to try it twice to get it to work, so be persistent). Also note: it’s a big file, so be patient as it downloads.

Enjoy! And after you look it over, write a nice comment for Skip, AA‘s all-time leading commenter, to read.