Anole Annals

Jessica Alfoldi of the Broad Institute writes:

“Matthew Breen from NCSU has a copy of the Anolis BAC library used in the sequencing and anchoring of the reference Anolis genome:CHORI-318: Green Anole Lizard . He unfortunately no longer has room for it, and will have to throw it out very soon unless someone else can give it a new home. If you would like to have a copy of this BAC library, please email me back as soon as possible.

Thank you,

Jessica”

Lourdes Rodriguez Schettino speaking at the 2009 Anolis symposium

Symposia on anole biology have been held three times in the last 25 years. First, in 1989 as part of the ASIH meetings in San Francisco, then in 1999 in conjunction with the herpetology meetings at Penn State, and most recently as a stand-alone meeting at the Museum of Comparative Zoology at Harvard in 2009. These meetings have been a great success–the MCZ meeting was attended by more than 125 people (take a photographic trip down Memory Lane).

The time has come to think about the next Anolis Symposium. The meeting organizers have settled on 2016 in Miami. We’re considering a number of great venues there, so it should be a fun, anole-filled event, easily accessible for anole researchers from all over.

The question is: when should the symposium be held? In January, right after the holidays? February, in the heart of winter? August, right after the Ecological Society of America meeting in Fort Lauderdale? October, like the last meeting?

We’re going to try to pick the date that works best for most potential attendees, so please comment below and let us know which dates are good or bad, and why.

Anolis sagrei in the Bahamas. Photo by Christian Cox from the Washington Post

In these times of rapidly changing climates, a major question is whether species will be able to survive. Essentially, they have two options: either shift their geographic ranges to stay within their ancestral niches, or adapt to new circumstances. Or, of course, go extinct. In recent years, evolutionary biologists have come to realize that evolutionary change can occur very rapidly when selective pressures are strong. The question is whether it can occur rapidly enough to accommodate quickly changing environments.

A recent study suggested that many tropical lizards are imperiled by a warming world. This study suggested that lizard populations would not be able to adapt rapidly to warmer conditions, but the analysis wasn’t very detailed.

First author Mike Logan hard at work at the field site. Photo reprinted from the Washington Post

In a study that is the first of its kind, Mike Logan and colleagues at Dartmouth have investigated the selective forces that may impinge on lizards as the world warms. The study was conducted on the old workhouse, the brown anole, Anolis sagrei. In essence, what the researchers did was calculate the extent to which sprinting capability was affected by temperature in two populations, one in an area in the Bahamas currently occupied by the anoles, and another in a population transplanted to a warmer era that served as a surrogate for conditions that will be experienced under global warming.

The study was gargantuan in its scope. Each lizard was put through its paces a number of times at each of a number of temperatures. From these data, the researchers could establish the temperature at which each lizard ran fastest and the breadth of temperatures at which they ran reasonably fast (compared to their maximum), which is termed performance breadth. They then marked the animals and returned them to their habitats. They then returned three months later to recapture the lizards to see which had survived and which hadn’t, allowing them to see whether their sprint capability measures were acted upon by natural selection.

It turns out that a fair amount of variation exists in the lizards in terms of both optimal temperature and performance breadth. In the natural habitat in Georgetown, Great Exuma, Bahamas, there was no evidence of selection operating on any of their measures.

The transplant experiment was conducted a year later on the Bahamian island of Eleuthera, which is not all that far from Great Exuma. In this case, the thermal characteristics of the habitat from which lizards were taken were very similar to the study site on Abaco. However, the more open, exposed area into which the lizards were transplanted was several degrees warmer, and also more variable in temperature.

Lizards in the transplanted population experienced body temperatures 1.5 C higher than those in the reference population. When the researchers recaptured the lizards on Eleuthera, they found strong evidence for natural selection, and in the direction expected: lizards that performed better at higher temperatures survived better than those with lower performance optima, and those with a broader thermal range survived better than those more narrowly adapted. In other words, there was strong selection for adaptation to warmer conditions.

The big question is whether populations can adapt to such strong selection pressures. The authors didn’t measure the heritability of the traits—that is, the extent to which adults with higher temperature optima produce offspring with similarly high optima, and such heritability is crucial to predicting evolutionary response. Nonetheless, if these traits have levels of heritability equivalent to that of other thermal performance traits in other species, the authors argue, then the brown anole may well be able to adapt evolutionarily to the warming predicted to occur in the next century.

This paper received a lot of attention in the press and blogosphere. For example, nice articles appeared in the Washington Post and on Scientific American‘s website.

Understanding dispersal—the extent to which organisms move from their place of birth—is of obvious importance in understanding many aspects of the natural history of a species, such as how related individuals are in a population or how genetically distinct one population is from another. Despite the intensive study on Anolis, however, very little is known about their dispersal. This is particularly surprising for species like the green and brown anoles, which are so common in so many places. Now, in a very nice experimental study in Behavioral Ecology, Calsbeek and colleagues have shed light on dispersal in the brown anole in the Bahamas.

Basically, the study went like this: the authors collected a bunch of gravid females from a variety of sites on a single, small island in the Bahamas. They got the lizards to lay eggs in the lab and hatched them out, then released them within three weeks of hatching back on their mom’s island. Each lizard was individually marked. The researchers then returned the following spring to find which animals had survived and how far they had moved. Then, they returned again in the fall to see how these survivors fared over the following summer and whether subsequent survival in this second period varied as a function of the distance they had dispersed in the first period.

There are a lot of interesting specific details and I encourage you to read the paper, but the broader story is this:

1. Males dispersed substantially further than females

2. Surviving males grew faster than surviving females

3. Survival of the lizards was low

4. Among females that survived the first period, those that had dispersed shorter distances survived better in the second period

Surprisingly little is known about the extent of anole dispersal, and so this paper is an important advance. As far as I’m aware, dispersal of only two other anoles have been studied. Here’s a summary from Lizards in an Evolutionary Tree:

“Little is known about the dispersal of anoles. One study of A. limifrons found that most lizards dispersed very little and that the home ranges of many individuals moved little from the juvenile to adult age. The maximum dispersal distance, measured as distance from the center of the juvenile home range to the center of the adult home range, based on 148 individuals, was 45 meters. Both the mean and extremes were greater for males than for females (Andrews and Rand, 1983). Anolis limifrons is a small and short-lived mainland species; it is always possible that larger, longer-lived species may disperse further.

The only other data come from Anolis aeneus, which moves as much as 150 meters or more after hatching to occupy open clearings (Stamps, 1983b, 1990). Ultimately, the lizards move back into shadier areas when they reach subadult size, although it is not known whether they return to the vicinity of their hatching site.

A number of arboreal species are known to disperse across open ground between trees (Trivers, 1976; Hicks and Trivers, 1983; Losos and Spiller, 2005).

I awoke to a placid summer day in Cambridge, Massachusetts, on 3 August of 2013. My hosts at the aptly named Friendly Inn had prepared a sumptuous breakfast, which I had again slept through before embarking on my then-daily walk to the Museum of Comparative Zoology. As I strolled on, my concerns vacillated between the upcoming Catalina Wine Mixer and the validity of the lizard name Anolis utowanae, an enigmatic name associated with a single specimen ostensibly from Mazatlan, Mexico. Perhaps distracted by the excitement of the coming social season portended by the Mixer, I wandered a bit longer than usual and entered a quaint shop of letters on Massachusetts Avenue. The shop had on display a historical map featuring the population growth of the Pacific shipping ports shortly after the completion of the Panama Canal in 1914. As I gazed on that map, I experienced an epiphany regarding A. utowanae. What if Thomas Barbour, the describer of this problematic species, had in fact collected the specimen earlier, on the other side of the canal in the West Indies? My jubilance at this realization was such that I could not help but engage the curious shopkeep.

“Sir, with this display, do you realize what you’ve done?” I asked, gesturing towards the map.

The shopkeep stared at me, wide-eyed in bated anticipation.

“You have helped solve one of the great mysteries of Mexican anole taxonomy, ” I told him.

His pride was palpable as I exited the shop and proceeded hurriedly to the Museum to test my hypothesis.

The above narrative is largely but not completely true. It is a fact that I was in Cambridge in August 2013, I did walk to the MCZ every day, and I often thought about the Catalina Wine Mixer during my morning walk. But the important part—the part that might make this story a passable introduction to a scientific paper 80 years ago—is patently false. There was no epiphany about A. utowanae. Rather, my suspicion of the status of this name had been growing ever since I’d gotten serious about Mexican anoles. The time at MCZ just gave me the material to write a paper establishing this species as a junior synonym (Poe 2014; available now for free on the Breviora website!).

Figure 1. Thomas Barbour. He would hide his disgust if he weren’t so disappointed in you. (Photo: Marine Biological Laboratory, Woods Hole, Massachusetts)

Some readers of Anole Annals are likely aware of the story of Anolis utowanae. The species was described in 1932 with type locality near Mazatlan, Mexico. In the ensuing years, no additional specimens were procured despite the accessibility of the type locality and a lot of interest in Sinaloan herps. Thomas Barbour (Figure 1), of MCZ and anole fame and one of the kings of the Rich White Guy on a Yacht period of herpetological exploration, began the Anolis utowanae species description with a detailed story of the collection of the type specimen. Here it is:

On a day last spring, April 10, 1931, while driving with Mrs. Barbour and my daughter, Mary, to a finca some miles north of Mazatlan, we stopped in a dusty lane to let a herd of calves pass by. The herd was followed by a barefooted Indian who trudged wearily behind them through the deep dust. He carried in his hand a long lashed whip and from time to time he snapped it viciously and in so doing killed the lizards on rocks or fence posts by his way with most extraordinary skill. We watched him some time quite fascinated. I asked him what on earth he was pocketing these lizards for. He looked at me with surprise and then added, “I am taking them home to feed my cats.” I bought what he had for a few cents. It was obvious that he felt quite certain that he had been dealing with a person of unsound mind as he walked on looking at the coins, for it surely had never occurred to him that such small game had a cash value. Among these lizards one, I feel quite certain, is unknown.

                    —-Barbour (1932), description of Anolis utowanae

Thomas Barbour’s story of the discovery of A. utowanae shares some qualities with my epiphany story. His treatment is at least partially untrue and, more particularly, I am convinced that the important part of Barbour’s story—that he obtained a new species of lizard on an April day in 1931 in Mazatlan—is false. But I am getting ahead of myself.

I was at MCZ in August of 2013 to collect additional data on some projects in my lab that require information on every species of Anolis. Thus, I was addressing important questions like “how many toe lamellae does Anolis granuliceps have?” (answer: about 15) and “how many scales are across the snout at the second canthals in the parvauritus version of Anolis biporcatus? (answer: 11.5). In the context of this work, we must make a decision on every species of Anolis: Valid or Not? These decisions go beyond simple literature searches; we really are trying to predict what species are likely to end up valid in the foreseeable future. For example, we are not going to include Anolis ibague Williams 1975 in our key to Anolis, because we have visited the type locality of ibague (Ibague, Tolima, Colombia) and found several individuals of the supersimilar and earlier-described species Anolis sulcifrons, some displaying the purportedly unusual headscales of the type specimen (a juvenile female) of A. ibague (sorry, Ernest). We could include A. ibague in our analyses—virtually any list of Anolis species would include this name—but if there are no traits to distinguish ibague and sulcifrons, and we are fairly certain ibague is a junior synonym of sulcifrons…would such an approach really be scientifically responsible?

I mention the example of Anolis ibague because A. utowanae was a similar case, but with a more concrete answer. When I was at MCZ in 2013, we were finishing an electronic key to all Mexican Anolis and we needed to know whether the name utowanae is valid. Some recent work (Kohler, 2012; Nieto et al. 2013) had cleared up several other Mexican anole names, but A. utowanae remained an enigma. With the MCZ type specimen (MCZ 31035) in front of me, I gave myself two nights to figure this out.

The key ingredients to elucidating the status of Anolis utowanae were 1) the wonderful MCZ anole collection (Figure 2); 2) the nearly equally wonderful MCZ herpetology library, including texts by Barbour; 3) the excellent paper by Henderson and Powell (2004); 4) my electronic (Lucid) key to Anolis; 5) my lab’s inability to find A. utowanae during a stop near Mazatlan in 2011 (not the safest place to be walking around at night looking for anoles); and 6) later, the diary of Thomas Barbour’s daughter Mary (Leaves from my Diary, 1932). Oh, and the kindness and hospitality of Joe Martinez, Tsuyoshi Takahashi and Jonathan Woodward (Messrs. Losos and Rosado usually are equally tolerant hosts, but they were absent during this particular visit).

Figure 2. As most Anole Annals readers know, MCZ has a fantastic anole collection. Here are some of the specimens I examined during my visit.

Put these elements together and you get my paper published this month in Breviora. I will spare you the time of reading the paper and summarize: Thomas Barbour apparently collected the Anolis utowanae specimen during his stop on Grand Cayman during the earlier part of a family voyage from Miami to Baja Mexico via the Panama Canal on a yacht called the Utowana. That is, Anolis utowanae = A. conspersus (Figure 3), and the skepticism of workers like Stuart, McDiarmid, and Lieb regarding the status of this name is validated. The lizard-whipping incident described in the paper probably actually occurred, but evidently involved a different lizard than the A. utowanae specimen. At some point Barbour mistakenly attributed a Grand Cayman anole to Mexico. Specifically, he associated an Anolis conspersus with the event where he and daughter Mary met a local cattle farmer in Mazatlan. How did this switch happen?

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