Author: Jonathan Losos Page 46 of 133

Anolis transversalis. Photo by Bejat McCracken.

AA reader Shawn McCracken writes:

While conducting ground-level herpetofauna surveys at the Tiputini Biodiversity Station in Ecuador’s Yasuní Biosphere Reserve, I was lured to the canopy by the cacophony of what had to be undiscovered species coming from the bromeliad, orchid and epiphyte microhabitats. This led me to think how many possible new species may be living in this new frontier? While birding at the canopy towers I saw the Tropical Thornytail Iguana (Uracentron flaviceps) and Banded Tree Anole (Dactyloa [Anolis] transversalis) scurrying about in some of the adjacent trees, amongst other anoles I could not quite identify, there was no doubt I was headed up. Of all the available microhabitat in the canopy, the big tank bromeliads caught my attention the most – little swamps, everywhere at 20+ meters off the ground. Surely there had to be herpetofauna using these as a resource and refuge in the harsh canopy environment.

Aechmea zebrina, the bromeliad species examined by McCracken and Forster.

Before the next field season, I decided I needed to get up into the canopy and collect some bromeliads to have a look inside. After a self-taught crash course in tree climbing, I returned to Tiputini, but quickly realized I didn’t have a long enough rope or the skills to get to those big bromeliads. Packing plenty of rope and a greater confidence in my climbing abilities, I returned for another field season the next year. This time was a success. Along with my assistants, we collected 40 bromeliads representing three species that we sealed in 55-gallon trash bags and carried back to camp. Once we began dismantling the bromeliads, we realized we had hit a treasure trove of invertebrates and herpetofauna. Now several years later and a total of 240 bromeliads collected, we have a pretty good idea of the herpetofauna utilizing canopy tank bromeliads in northwestern part of Yasuní. In this latest publication, we summarize the herpetofauna of one high canopy tank bromeliad species, which includes the gecko Thecadactylus solimoensis and two anoles, Anolis ortonii and A. transversalis.

Some other bromeliad denizens

We’ve heard a lot about Gunther Köhler in the last few days. What you might not know is that when he’s not busy snatching sleeping lizards off of leaves in the highlands of Mesoamerica or counting scales in his Frankfurt laboratory, he plays guitar in a flaggstaff, a country band. The band is about to release its latest CD, Stomping Grounds, and one single, Chiriqui Stream, is appropriate for our pages. You can download the MP3 and then sing along:

Chiriqui Stream

1. When the nights grow late and the fires die down

When the fog and mist start boiling around

At camp site down by the Chiriqui stream

Where we search for creatures nobody’s seen

2. The thrill of the night hike blows you away

As we move on, magic’s underway

We poke through the forest with its pines and oaks

With the sound of the woods, the creeks and slopes

Chorus: Living my dream at the Chiriqui stream

Finding my fortune in this unreal scheme

With a family of creatures nobody’s seen

Right down at the Chiriqui stream

3. On the fog shrouded slopes and rugged peaks

A world of its own with its lovely creeks

Its unforeseen bugs and mystical sounds

No doubt we’re here on unknown grounds

Photo by Benny Diaz

AA stalwart Liam Revell was forwarded the photo above on Facebook and decided to look into it. Here’s what he reports:

This impressive photo showing a Puerto Rican crested anole (Anolis cristatellus) being attacked by a Puerto Rican racer (Borikenophis portoricensis) was recently posted to the Facebook group ‘Biodiversidad de Puerto Rico’ by a photographer Benny Diaz. He has kindly allowed us to re-post his photo here and also supplied the following description of the predation event he witnessed transpiring in the Puerto Rican state forest Bosque Estatal Guajataca (translated from Spanish):

“I first saw this anole and tried to take a photo of it after noticing that it was marked with two different colored spots of paint on its back. As I slowly approached it, the animal suddenly reacted with a jump and just at that moment a Puerto Rican racer (Borikenophis portoricensis) appeared out of nowhere and captured the anole in midair!”

Although the predation event is remarkable in itself (and the photo capturing it terrific), perhaps even more notable is the fact that the lizard appears to have been marked by an investigator conducting research on anoles! After some (social media-aided) investigation of the matter, led by Puerto Rican USFW biologist and avid photographer J.P. Zegarra, this scientist revealed herself to be University of Puerto Rico Ph.D. candidate, and friend of Anole Annals, Luisa Otero. Luisa is studying anoles in Puerto Rico as part of a multi-institutional collaborative NSF project to investigate the vulnerability of tropical ectotherms to global climate change. More can be learned about this project, and Luisa’s research, from the project website.

Luisa recounts the following about this particular lizard:

“Yes, we took the Tb (Editor’s note: body temperature) of the poor lizard in the picture a few weeks ago in Guajataca. Prof. Hertz was here and we were taking body temperatures and operative temperatures from models. It was the last trip of the ‘ vulnerability of tropical ectotherms’ project!! I usually use paint to mark the lizards so we don’t re-sample them the same day. This poor guy was sampled two days in a row…. (that’s why it has two colors)… and a few weeks later was eaten by this Alsophis (Ed. recently renamed Borikenophis)… very sad.”

Some years ago, Manuel Leal and Javier Rodríguez-Robles conducted a study in which they investigated what happened when a Puerto Rican racer confronted a crested anole. I summarized the study in Lizards in an Evolutionary Tree:

“In laboratory trials, Leal and Rodríguez-Robles (1995) showed that the snake, (which can attain a length of more than 1m), attacked anoles much less often  when the lizard displayed. Moreover, they demonstrated that when attacked, the lizards fought back, often biting the snake on the snout for as long as 20 minutes and managing to escape in 37% of the encounters (Leal and Rodríguez-Robles, 1995)—remarkable given the size discrepancy of the snake and the lizard.”

Diaz’s observations confirm that this behavior is not a laboratory artifact–crested anoles will chomp down and hang on for all their worth. But, just as in the majority of the lab trials, the valiant defense was for nought. After a few minutes, Diaz reports, the lizard

appeared to be immobilized (probably the result of the rear-fanged snakes venom) and the snake began to work the lizard around, little by little, until it was able to swallow it head first.

After the lizard let go of its grip, the snake slowly moved its grip up the lizard’s body. Photo by Benny Diaz.

The time between the first photo (above) and the last one (below), in which the lizard is well on its way to digestion, was eight minutes.

Photo by Benny Diaz

It’s also worth mentioning the follow-up study Leal conducted. Again from Lizards: “

In field trials, Leal (1999) found that the extent of display behavior toward a snake model correlated with the endurance capacity of the lizard (as determined in subsequent laboratory trials); the greater the endurance capacity of the lizard, the more it displayed to an approaching snake model. Anole displays to predators may be an example of a pursuit deterrent signal (reviewed in Caro, 2005). By signaling their endurance capability, anoles may be indicating their ability to fight back, escape, and potentially even injure a snake (Leal, 1999).”

In the most recent issue of IRCF Reptiles & Amphibians, Powell and Watkins provide an eyewitness account of an adult male Anolis sabanus killing a juvenile, presumably en route to eating it (which occurred off stage). The paper also provides a listing of other documented cases of Caribbean anole cannibalism, of which A. sabanus becomes the 19th species known to eat its own.

Editor’s Note: The IRCF webpage appears to be down. You can access the paper here.

Husak Lab member Erik Sathe putting a lizard through its paces. Photo by Jerry Husak

AA contributor Jerry Husak has just published a great paper in The Journal of Experimental Biology on the effect of training (=practice) on the sprinting and endurance capabilities of green anoles. The Inkfish blog on Discover magazine’s website has written a brilliant description of the study:

Athletes don’t normally need to be chased down the track to get their training mileage in. But a green anole lizard is not a normal athlete.

Scientists wanted to know whether it’s possible to train a lizard at all. Human athletes and other mammals perform better with consistent exercise, but is this universal? Can a reptile increase its stamina? What about its sprint speed? So the scientists became lizard athletic trainers, which really means lizard harassers. Results were mixed.

The green anole lizard, or Carolina anole (Anolis carolinensis), is a common laboratory species. Basic rules of its biology—for example, how it responds to exercise—ought to apply to other vertebrates, such as humans. In the past, scientists have successfully used exercise to increase endurance in frogs, birds, alligators and crocodiles. But the same efforts with lizards have been inconclusive.

Jerry Husak, a biologist at the University of St. Thomas in Minnesota, studies lizards with the help of undergraduate researchers. He and his students decided to try creating “Olympic lizards.” They would train their subjects for two kinds of athletic ability, neither of which was totally foreign to the reptiles. Some lizards would become endurance athletes; this long-distance locomotion would mimic the slow patrolling and foraging anoles do in nature. And other lizards would become sprinters; in nature, they use bursts of speed to escape predators.

Thirty lizards were divided into sprinters, distance runners, and a control group. The sprinting track was a dowel two meters long and five centimeters wide, propped at a 45-degree angle. The researchers chased the lizards up the dowel and used infrared beams to measure their fastest speed. Sprinters “trained” three days a week for eight weeks. Gradually, the researchers increased the training intensity by making the lizards do more runs per day.

Meanwhile, the distance runners did their training on a treadmill. The researchers set the treadmill to a low speed and gently prodded the lizards with a paintbrush to keep them moving. These athletes had to stay on the treadmill for 30 minutes at a time, or until they were exhausted. (How do you know anoles are exhausted? “When we flip them over onto their backs and they can no longer flip themselves back onto their feet,” Husak explains. Glad he’s not my trainer.) These lizards, too, exercised three times a week for eight weeks, while the steepness of the treadmill gradually increased.

At the end of the training regimen, the researchers tested all their lizards a final time. The distance runners had clearly improved. On a fast treadmill, the endurance-trained lizards could run for almost three times as long as they had initially. Blood samples showed that their hematocrit levels—a measure of red blood cells, which carry oxygen—had also increased. And dissecting the limbs of dead lizards revealed that their muscle fibers had grown, just as they do in exercising mammals.

The sprinting lizards were a little more disappointing. In their final trials, they didn’t run any faster than they had before training. But their muscle fibers had also grown. Husak suspects that these athletes had actually improved—they just didn’t feel like performing.

“I definitely think the sprint-trained ones increased their sprinting abilities,” Husak says. But after the lizards had spent so much time being handled by humans, he says, “We just couldn’t motivate (i.e., scare) them enough…to run as fast as they could.”

There’s not likely to be a lizard Olympics anytime soon. Creating athletic anoles isn’t the only goal of Husak’s research, though. He’s ultimately interested in the tradeoffs that come with being a good athlete. Animals that spend more energy on reproduction, for example, may have to sacrifice life expectancy or immunity. Do the same tradeoffs happen when animals spend their resources to build beefy muscles?

Husak has gotten closer to answering that question by showing that lizards can be trained. Now he just has to figure out how to scare them into performing their best—because even if the biology of exercise is the same across vertebrates, the power of a “Just Do It” poster isn’t.

The post doesn’t say much, but it’s nice for this lovely anole to get the attention it deserves!

If you search for photos of A. lividus online, there aren’t all that many. Several more nice ones have appeared previously on AA, such as this one:

Photo by Jim Hewlett

and here’s one from Calphoto:

If you want to read more on this not-well-studied species from an island recently ravaged by volcanoes, AA is the place [1,2].

Photo by Dick Bartlett.

Dick Bartlett found this lizard a week ago, deep in the rainforest along the Rio Mazon, Dpto Loredo, Peru. He says “The blue irises initially indicated transversalis but the more I’ve thought about it, the more unsure I have become.” Anyone able to identify it?

Phelsuma guimbeaui from Mauritius.

Despite the brilliant colors, the natrual history of day geckos (Phelsuma) is little known. The most recent issue of Herpetological Conservation and Biology includes a very nice study on the habitat use of two Mauritian species, showing that they are most abundant in native forest and pointing out that, thanks to their pollinating services, they are keystone species. An interesting point is that even though day geckos are essentially Old World anole doppelgängers, in their habitat use they differ in rarely leaving the trunks of trees. One of the authors is legendary ornithological conservationist Carl Jones, almost single-handedly responsible for preventing the extinction of several Mauritian bird species.

Here’s the abstract:

Many fragile ecosystems across the globe are islands with high numbers of endemic species. Most tropical islands have been subject to significant landscape alteration since human colonisation, with a consequent loss of both habitat and those specialist species unable to adapt or disperse in the face of rapid change. Day geckos (genus Phelsuma) are thought to be keystone species in their habitats and are, in part, responsible for pollination of several endangered endemic plant species. However, little is known about key drivers of habitat use which may have conservation implications for the genus. We assessed the habitat use of two species of Phelsuma (Phelsuma ornata and Phelsuma guimbeaui) in Mauritius. Both species showed a strong affinity with tree trunks, specific tree architecture and are both restricted to native forest. Tree hollows or cavities are also important for both species and are a rarely documented microhabitat for arboreal reptiles. Both P. ornata and P. guimbeaui avoid areas of high disturbance. Our data suggest that active conservation of Phelsuma requires not only the protection and restoration of native forest, but also implementation of forestry practices designed to ensure the presence of suitable trees.

We’ve had a number of previous posts on orange-colored brown anoles, but here’s a nice blog post that discusses them a bit further, with a bonus photo of a yellowish green anole. Christina Chappell, the majordomo of serenityspell.com, reports that the lizard was seen in the northern part of the Everglades. And, no, in case you’re wondering, the photo was not altered in any way.

The Faculty of Arts and Sciences at Harvard University has a quaint but lovely tradition of reading a “memorial minute” to honor deceased members of the faculty. I recently came across the minute concerning Ernest Williams, which was presented in 2009 and published in the Harvard Gazette.

At a Meeting of the Faculty of Arts and Sciences on May 19, 2009, the following Minute was placed upon the records.

Ernest Williams was a man of many contrasts. Biology at Harvard in the third quarter of the last century was full of outsized personalities—titans in the field with strong opinions and no reservations about expressing them. In such company, Williams appeared a wallflower, seemingly wishing to be anywhere but in the midst of their arguments. Yet, one-on-one, Williams had an incisive wit and a dry sarcasm—discussions with him were always stimulating and provocative as he never missed a chance to challenge one’s thinking, sometimes quite pointedly.

To some, Williams’s work came across as old-fashioned. His subject, systematics — the study of the evolutionary relationships of species—is among the oldest in science, and his papers — florid and opinionated and, above all, long—recalled an approach to scholarship no longer in vogue. Yet much of his work was boldly innovative; some papers are still widely cited, and in several cases his work was well ahead of its time, presaging approaches to the study of evolutionary biology that were not to catch on for several decades.

Ernest Edward Williams was born January 7, 1914, in Easton, Pennsylvania, the only child of middle-aged parents. Like many boys, particularly of that time, he grew up loving nature and spent many hours capturing salamanders and other creatures. After attending Lafayette College, Williams joined the Army, serving in Europe during World War II. Upon his return, Williams entered graduate school at Columbia University, where he was the last graduate student of the great anatomist William King Gregory.

Williams’s doctoral thesis focused on the structure of the neck vertebrae of turtles and how variation among species reflects their evolutionary heritage. The work demonstrated the combination of careful attention to detail with the ability to interpret results in the broader context that was to characterize Williams’s career. More than fifty years later the work is still foundational in understanding the evolution of turtle diversity.

In 1950, after completing his degree, Williams moved to Harvard, where he initially served as a laboratory coordinator for the anatomy course of the legendary paleontologist Alfred Sherwood Romer, then subsequently was appointed as an assistant professor and made coordinator of a General Education course on evolution. The Museum of Comparative Zoology’s Curator of Herpetology, Arthur Loveridge, retired in 1957, and Williams was appointed to take his place.  In 1970 Williams rose to the rank of professor and in 1972 became Alexander Agassiz Professor of Zoology.

Williams initially focused on continuing his work on turtle systematics, leading to a series of publications including a still-important treatise published with Loveridge in 1957. Williams soon realized, however, that the museum’s collections were inadequate for the detailed analysis he conceived, which required large samples from many populations. This recognition that the museum’s herpetological collections were wide in scope, but lacking in depth, led Williams in two directions. First, it compelled him to work greatly to expand the Herpetology Department’s holdings, ultimately leading to a quadrupling of the department’s collections (to more than 300,000 specimens) by the time he retired as curator in 1980, making the Museum of Comparative Zoology (MCZ) one of the greatest herpetological repositories in the world. Second, it led Williams’s attention to focus on lizards in the genus Anolis, a very species-rich group from the Caribbean and Central and South America. A previous curator of herpetology and director of the MCZ, Thomas Barbour, had extensively collected anoles in the Caribbean; Williams, whose focus was much more evolutionarily-oriented than most systematists of the day, recognized that this group could be a model for studying large-scale evolutionary and biogeographical phenomena.

And, indeed, they were, and still are.

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