Author: Jonathan Losos Page 60 of 129

Professor of Biology and Director of the Living Earth Collaborative at Washington University in Saint Louis. I've spent my entire professional career studying anoles and have discovered that the more I learn about anoles, the more I realize I don't know.

Quest for Anolis roosevelti

This is not Anolis roosevelti. No pictures of that species in life exist. But it probably looked pretty similar to this brown-phase Anolis cuvieri. Photo by Alejandro Sanchez.

Anolis roosevelti, the giant anole of Culebra and Vieques, is famous in anole circles. The only Caribbean species thought to possibly be extinct, the species has not been seen since 1932.

Recently I learned of a report of an expedition to Culebra to track down the wily saurian, written by noted author and mycologist Lawrence Millman. As you’ll see, the expedition was a success, but perhaps not in the way you expect.

A Hunt for the T. rex of Anole Lizards: A Trip to Puerto Rico in Search of a Giant Shrinking Reptile.

Christian Science Monitor, July 12, 2007

“Not too long ago I picked up an old travel book about Puerto Rico and read of a rare giant lizard, Anolis roosevelti, on the island of Culebra.
“Fame will visit anyone who finds this elusive creature,” the author of the book proclaimed. Since Fame had thus far given me a rather wide berth, I hopped a plane to San Juan and then a smaller plane to Culebra.
By the time I arrived on the island, the lizard had shrunk. The book had described it as four feet long, but the local Fish and Wildlife person told me that it was no more than a foot long from snout to vent – hardly competition for a T. rex. Still, A. roosevelti is a T. rex compared with other anoles, which are among the smallest of all lizards.
I also learned that this giant among anoles had not been sighted since 1932. Not officially sighted, that is. But there were anecdotal reports of it being seen in the forested areas on Monte Resaca, Culebra’s highest summit (height: 650 feet), as recently as a few years ago.
So I drove to the base of Monte Resaca and started bushwhacking.
Trusting in serendipity, I expected to see the anole in question basking on every boulder as well as ascending every gumbo-limbo tree. I was so intent on my search that I lost all sense of direction and ended up in someone’s backyard.
A Culebran tending his garden looked up at me in surprise. My usual ploy when I trespass like this is to advance confidently toward the person, shake his hand, and announce in a punctilious English accent: “Dr. Basil Withers of the British Antarctic Survey. Jolly good to meet you, old chap.”
Since this ploy would not work in the subtropics, I said, “Hello, Señor. Seen any big lagartos around here lately?”
“Sí,” the man replied. “All the time.”
“What’s their habitat?” I asked excitedly.
“In my bathroom,” he answered. He invited me in, where I saw the lagartos skittering around on the wall. They were geckos, not anoles, and they weren’t even all that big.
Serendipity had gotten me nowhere, so I got in touch with Beverly Macintyre, who knew the island’s backcountry intimately. She mentioned a particular boulder canyon on Monte Resaca, just the sort of place, she said, where a giant anole might hang out. Then she referred to recent development on Culebra; if it continued at its current breakneck pace, she said, a lot more creatures than A. roosevelti would be either endangered or extinct.
In our search for the lizard, Beverly and I entered not so much the forest primeval as the forest prickly. Ground-hugging cacti jabbed us, mesquite bushes stabbed us, saw-toothed bromeliads slashed at us, and a plant known locally as Fire Man (Tragia volubilis) delivered stings that make the stings of a stinging nettle seem positively genteel.
And to add to it, at one point I was gazing up at what turned out to be a green tree iguana and walked into a barbed wire fence.
We did not see a giant anole. We did not even see one of the small anoles that reputedly were common on the island. But near the end of our trek, we did witness this unusual sight: a man on a horse with reins in one hand and a cellphone in the other.
The next morning, as I took a respite from my search, I began noticing other curious sights. A sign in a shop window in Dewey, the island’s only town, said: “Open Some Days, Closed Others.” A road sign indicated Termina Carretera (End of Road) when, in fact, the road did not end at all.
And in the afternoon, I was sitting on Flamenco Beach when a person in an old-fashioned diving bell emerged from the sea. At the north end of the beach, there was a tank left over from the days when the US Navy used Culebra for war games; in this setting, it had a very surreal quality.
I began to think that I had fetched up on some sort of Caribbean fantasy island – an ideal habitat for, among other things, an incredible shrinking lizard.
Several days later, I still hadn’t found the anole in question. My trip was coming to an end, so I asked Teresa Tallevast, the manager of the Culebra National Wildlife Refuge, if there was any area I might have overlooked. She suggested that I check out the trail that wound down from Monte Resaca to Playa Resaca.
Soon I was hiking on this steep trail. Every once in a while I would stop and peer into the surrounding bush. At one point I thought I saw a finned reptilian tail disappear into a tangle of mesquite, but that could have been my imagination … or another iguana.
At the bottom, the trail meandered through a labyrinth of white mangroves. I looked up at the trees’ gnarled branches and then down at their arching prop roots.
Still no anole.
At last I came out on Playa Resaca, a long, yellow swath of sand where I was the only person in sight. The sun was blisteringly hot, but I didn’t go for a swim. Resaca means undertow in Spanish, and if I had gone swimming, I might have washed ashore on the west coast of Africa or, at the very least, in the Virgin Islands.
Suddenly I saw what appeared to be the tread marks of an 18-wheeler in the sand. I was outraged. But then I realized that the tread marks were actually the flipper imprints of a female leatherback turtle who’d plodded ashore the night before to lay her eggs. Weighing a thousand pounds or more, such creatures are the reptilian equivalent of giant rigs; unlike those rigs, however, leatherbacks are an endangered species. I counted myself extremely fortunate to see even the tracks of one.
And so it was that my quest for a rare reptile on Culebra ended in success.”

Happy New Year!

Photo courtesy Fernando Ayala

Photo courtesy Fernando Ayala

Checkered Anolis maynardi

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This just in from Pat Shipman in the Little Cayman Bureau:

“Today for the first time, we have seen & photographed a checkered A. maynardi here on Little Cayman.  Of all the ones we have seen, green to brown and cold, we’ve never seen one like this before. “

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Reflections on the Joy of Winter Active Anoles

Photo by Janson Jones

Who wouldn’t delight in a passel of festive anoles, frolicking around in mid-December? Janson Jones, a raconteur if there ever was, certainly knows how to live for the moment. Check out his latest saurian musings on Dust Tracks on the Web.

Anolis desechensis: Little Known Anole From The Puerto Rican Bank

 

desechensis island conservation FB

 

Anolis desechensis is a member of the A. cristatellus species complex from Puerto Rico. Found only on the tiny island of Desecheo, very little is known about its natural history. In fact, some might question whether it should be a distinct species, but in the absence of any data, it’s hard to say.

This lovely photo comes from the Facebook page of Island Conservation, a wonderful organization devoted–as its name implies–to the conservation of island biota. I just heard a talk yesterday crediting them for eradicating rats from an island in the Galapagos, paving the way for preservation of a unique giant tortoise race. But that’s another story.

Stephen Jay Gould On Replicated Adaptive Radiation In Anoles

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“Dear Blair, of course you are right, but the scale is all wrong. Predictability of course within a constrained design and clade of close relatives as in your example. My contingency is at the much higher level of designs themselves.”

Blair Hedges recently sent me the image on the left with the following explanation:

“I was preparing a lecture for my evolution class and came across this reply from Steve Gould to me many years ago (Oct 1986), on a post-it note!

I can’t find my original letter to him but I recall it well.   As a grad student, I heard him give a lecture about the Cambrian Explosion where he claimed that evolution operated differently –contingency instead of adaptation or predictability– at the higher level of animal designs.  I told him I disagreed because I was seeing too much predictability in the adaptive radiations on Caribbean islands to believe that it was not happening throughout life at all levels.

Translation of his reply:  “Dear Blair, of course you are right, but the scale is all wrong. Predictability of course within a constrained design and clade of close relatives as in your example.  My contingency is at the much higher level of designs themselves.”

Not sure how you feel about it, but I still don’t agree with his explanation!  500 mya the Cambrian explosion was just an adaptive radiation like anoles.”

Interestingly, this story jibes very closely with a story of my own. In 1998, a number of colleagues and I published a paper in Science reporting a phylogenetic analysis of Caribbean anoles demonstrating convergent evolution of the anole ecomorphs. A reporter for Science contacted me and in the ensuing discussion, I suggested that an interesting person to contact to get an opinion of the paper would be Stephen Jay Gould. I was quite disappointed when her piece appeared and had no quote from Gould. When I subsequently talked to her, I was astounded to learn that she had, indeed, talked to Gould and he had given a reply pretty much exactly the same as on the post-it above. And…she had decided no one would be interested in what S.J. Gould had to say about replicated, convergent adaptive radiation, and so she didn’t include the quote in her article.

Why Aren’t All Crown Anoles Green? The Case of the Polymorphic Canopy Anole, Anolis cuvieri

Brown/Grey phase Anolis cuvieri, just awakened from a nap. Photo by Alejandro Sanchez.

Brown/Grey phase Anolis cuvieri, just awakened from a nap. Photo by Alejandro Sanchez.

Most arboreal anoles are green, and for a good reason: it’s hard to pick out a green lizard amidst green vegetation. Yet, some species are more subdued in their coloration, with browns or grays–e.g., Anolis luteogularis from Cuba or Anolis microtus from Costa Rica.

An interesting twist is provided by Cuvier’s anole, the crown-giant of Puerto Rico, in which a polymorphism exists in which most lizards are green, but some are brown-grey. We were reminded of this situation by Alejandro Sanchez, who sent the photo displayed above with the comment that it had been a long time since he’d seen one of these morphs. Contrast that with his spectacular photo of the more common green morph below.

Green Anolis cuvieri. Photo by Alejandro Sanchez.

Green Anolis cuvieri. Photo by Alejandro Sanchez.

Rivero in his epic Los Anfibios y Reptiles de Puerto Rico notes the polymorphism, but does not provide any explanation or discussion, and I am unaware of any other literature on this subject. Puerto Rican readers out there: what else do we know? Are they definitely different morphs? Someone once whispered in my ear he had seen brown ones turn green, but the only publication of which I’m aware to discuss this phenomenon, Rand and Andrews (1975), says they don’t. But that was based on a very small sample size. Does the gray/brown morph occur throughout the island? Any idea what it’s all about? Any difference in habitat use? As far as I’m aware, the adaptive significance of this polymorphism has never been studied.

The Role Of Genes And Diet In Determining Dewlap Color

 

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Results of mating trials in Ng et al.’s study. Top two rows are within-population crosses; bottom two are between crosses from different populations that differed in dewlap color. Note that in the top, individuals look like their fathers, whether at the bottom, dewlap colors are intermediate between that of the two populations.

Everybody loves a pretty dewlap, and recent years have seen a lot of interest in studying the factors that determine dewlap color, as well as the role dewlap color may play in species recognition, sexual selection and other processes. Many have suggested that the dewlap is a focus of sexual selection; some have even opined that it is an honest signal of something, maybe good genetic quality, maybe the ability to procure lots of color-inducing dietary items. Unfortunately, we know almost nothing about the genetic basis of dewlap color, nor about the effect of environmental variation.

Anolis distichus exhibits more variation in dewlap color and pattern than any other anole, and thus is the perfect choice for such a study. Julienne Ng just completed her doctoral research at U. Rochester on this species, documenting that variation in dewlap color correlates with environment among populations. Now she and colleagues report on laboratory studies to assess the extent to which variation is determined by genes vs. diet.

Why diet? Because reds and oranges are likely determined by carotenoids, which vertebrates cannot synthesize. Thus, it is plausible that the amount of carotenoids ingested by a lizard may correlate with its color. This hypothesis has only been tested once before, in a study on A. sagrei by Steffen, who failed to find evidence for a diet effect on the red-orange dewlap of this species.

This study had two components. First, to study genetics, lizards from two populations–one with an orange dewlap, the other with a plain whitish dewlap–were crossed in the laboratory. Second, lizards were fed lots of carotenoids.

The results: strong evidence for a genetic basis for variation in dewlap color. Purebred individuals looked like their fathers (top two rows in figure above), but crosses were intermediate in color (bottom two). Pretty strong evidence for a genetic basis for the trait. And the effect of diet? Not so much. No difference in color between lizards in the  carotenoid supplementation treatment vs. the control lizards.

The bottom line is that, at least in this species, genes control variation in dewlap color. Combined with Steffen’s study, there are now two negative results for a role of diet. Of course, work on other species is necessary to confirm the generality of these results, as well as additional investigation into the exact genes responsible for dewlap color.

Last Chance to Help the Anole Love Song Get Produced

A message from Monty Harper, the genius behind Anole in Love:

We are down to our last day and a half.

We are 44% funded. We need $5,600 more in pledges to make this CD happen.

That sounds like a lot. But consider…

Kickstarter says the average pledge amount is $70. If each of us – there are 80 backers right now! – if each of us was to bring in just one additional backer today, that could mean $5,600 in additional pledges, which is exactly what we need!

Even if Kickstarter’s average is a bit high for this project, 80 additional backers today would put us within sight of the goal, and would make tomorrow a very exciting day!

So your mission, should you choose to accept it, is to bring in at least one additional backer today.

What tools have you with which to accomplish this Herculean task, you ask?

Facebook, Twitter, Google+, email lists – these are great, but…

A personal email, a text, a phone call, a (gasp) face-to-face conversation! – these are very effective for engaging one person. Who do you know that would really appreciate great kid-friendly science music? A parent, an educator, a librarian, a scientist?

Here are some general talking points –

  • Any pledge of $5 or more gets you an immediate download of 12 science songs
  • The new songs are all written and waiting to be recorded
  • These songs are inspired by conversations with scientists – they are unique in their focus on the scientific process
  • The funding is necessary for hiring musicians and studio time, paying for design and duplication
  • Public libraries are using science as a theme this summer – here is a chance to get some really good material into the hands of people motivated to use it with kids
  • If we don’t reach the funding goal, the CD will be put on hold, and who knows when or if it will ever get made?

Match a song to the person – who do you know that would be excited about one of these song topics?

  • “Vaccination!” – a pro-vaccination anthem!
  • Anole in Love” and “My One and Only Vole” – science themed love songs!
  • “Left Brain” and “This Is Your Brain on Music” – brain science!
  • “Quarks and Electrons” – particle physics, the nature of the universe!
  • “Citizen Scientist” – citizen science is huge right now!
  • “Photosynthesis,” “Green Footprint,” and “Rustbusters” – alternative energy!
  • “Psychology” and “Popular” – psychology!
  • “What Goes On?” – ecology!
  • “Predators, Prey, and the Games They Play” – evolution!
  • “Fizz Boom Read” – a theme song for 2014 summer reading!

Most of these songs are up on YouTube now:

One other tool I can give you is – images to share on social media. You can look for these on my facebook feed, or download and post them yourself:

Just click to get the full-sized image.

A Beatlesque Song about Lizards in Love


You must click on this link and listen to the song (click the red circle in the upper left corner of the page). Then come back here and read the rest.

Anole In Love – The song the Beatles would have written if they were green anoles! This lovely ballad is the work of Monty Harper, who writes: “I write songs that convey what I find awesome about science: the questions, the methods, the passion, dedication, and creativity of the people who do it. My inspiration comes from speaking directly with scientists about their latest research projects.”

This has Top 40 written all over it, all it needs to do is get produced. Help make it happen by going to Monty’s Kickstarter page and making a donation. But, hurry–the deadline is Friday.

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