Anole Annals

Arboreality in tuatara. Who knew?

A few months back, AA noted the publication of Tuatara: Biology and conservation of a venerable survivor, written by Alison Cree and published by Canterbury University Press (available for purchase here). The Journal of the Royal Society of New Zealand asked me to review the book, and here’s what I said in the most recent issue (photos from the book, but not in the review):

Oh, tuatara, why do we love you so?

In 2003 I had the thrill of a lifetime, getting to stay for five days on Stephens Island, where toots (as I was told they are called by a mischievous Australian) were so abundant that you had to be careful where you stepped. When I retell the tale of living amid the rhynchocephalians, my listeners swoon with envy. Never have I met someone not visibly impressed that I have actually held one in my hand.

But what is it about Sphenodon punctatus  that inspires such emotions? Let’ s face it: the spiny back (the literal translation of the Māori word tuatara ) is not the prettiest of animals. And at face value, it doesn’ t seem extraordinary; it looks, to those not in the know, rather like a dowdy lizard, a smaller and duller iguana.

The famous third eye of the tuatara. Pictures of this are very hard to find .

A so-called ‘third eye’, unusual chewing mechanism and lack of intromittent organ—the tuatara certainly has its fascinating idiosyncrasies. But its trademark feature, its real claim to fame, is its antiquity. Or, to be more precise, the antiquity of its lineage, for the tuatara is the sole surviving member of the Rhynchocephalia, a group of reptiles that evolved about 250 million years ago. It flourished mightily in the Triassic, then petered out, all but disappearing along with the dinosaurs at the end of the Cretaceous. All, that is, but for the tuatara, the last member of the sister group of lizards and snakes, somehow, for some reason, hanging on only in New Zealand.

This history has led the tuatara to be dubbed a ‘living fossil’. But if there’ s one message Alison Cree wants readers to take away from her fabulous new book, Tuatara: biology and conservation of a venerable survivor, it is that the tuatara has been miscast. Far from being a survivor from the ‘Age of Dinosaurs’, an old, ill-adapted species that has managed to persist, unchanged, in its antipodean hideaway, the tuatara is a model of evolutionary adaptation, a thoroughly modern species well adapted to its current conditions, or at least to the conditions it experienced up to the arrival of humans, rats, cats and dogs.

The postcard legend reads: “This was the first and only living animal for countless ages on the face of the earth.”

Indeed, misinformation is pervasive. Cree reports that 73% of first-year university students in New Zealand think that the tuatara is more closely related to dinosaurs than to lizards, no doubt a consequence of its ‘living fossil’ appellation. And even professional herpetologists (well, at least this one) will be surprised to learn that the tuatara’ s fossil record extends not to the Cretaceous, but only to the late Pleistocene (although Cree notes that a recent palaeontological find may extend the record back into the Miocene). Things were worse a century ago. George Boulenger, curator at the British Museum and perhaps the leading herpetologist of the early twentieth century, called the tuatara the ‘oldest existing reptilian type’; Otago University Museum curator William Benham described the tuatara as ‘the most ancient reptile on earth’, ancestral to crocodiles and turtles. None other than the famed palaeontologist George Gaylord Simpson referred to toots as ‘immortals… one of the most remarkable examples of evolutionary stagnation’ with essentially no evolution in 140 million years. Unfortunately, this view also pervaded the popular press, which often portrayed the tuatara as an outmoded relic of a time long past, a species no longer able to cut it in the modern world. Tuatara  will put an end to these misconceptions.

Indeed, this book is everything you’ d expect from Cree, one of the world’ s foremost experts on tuatara biology.

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Here’s a new, working link for this video, and here’s what we said about it a year and a half ago:

We’ve been privileged to see a number of great videos of Cuban anoles recently [1,2], and here’s another, an hour-long documentary on Cuban wildlife in Spanish entitled “Cuba. La Isla Salvaje del Caribe.” It goes without saying that the anoles steal the show. There’s an excellent 2.5 minutes of anole footage beginning at the 38:46 mark, highlighted by lovely shots of a male A. allisoni and video of Chamaeleolis (also homolechis, sagrei or a close relative, a pale-dewlapped grass anole, porcatus and lucius). In addition, just before this, there’s a nice depiction of how Cuba was split into three islands when sea-levels were higher.

Oh, and here’s the video in English:

Surely among the most extraordinary anoles are the six (or so) species in the genus Chamaeleolis. They’re sometimes called false chamaeleons, and for good reason–at a distance, you might mistake one for a chameleon. Not much is known about their natural history, but in a paper more than a decade ago, Manuel Leal and I showed that they behave in many respects just like chameleons, mostly in terms of their slow, jerky movements. They’re also renowned for their snail-munching ways, and we’ve had some great posts on that in the past.

Recently, the Anoland Facebook page posted a video of a C. guamuhaya eating a blueberry (above). Great stuff. I went to Youtube and found that the cinematographer, Torsten Kunsch, posted another video of possibly the same animal slowly dewlapping (below). In turn, this led me to consult Youtube for other Chamaeleolis videos. There are a bunch, though not a huge number, all seeming to be of captive animals. If I recall correctly, a documentary on Cuban wildlife that we screened a while back has some footage of wild individuals. More is needed!

This photo comes to us from Greg Braun, who found this exceptionally patterned juvenile anole during a recent visit to the Turks and Caicos Islands. It looks to me like a striking Anolis scriptus scriptus. I have previously reported on Southern Bahamas Anoles  (1,2,3) and always enjoy seeing pictures of this remarkable species. Enjoy!

Juvenile Anolis s. scriptus from the Turks and Caicos islands. Photo by Greg Braun.

The first Anole Annals post, as Anthony Geneva reminded us a few days ago on AA’s fifth anniversary, consisted of a few anole-related haikus. One of them was:

Dewlap and Toepad.
Adaptive Radiation.
Key Innovations?

Key innovations are traits that are thought to enable lineages to diversify greatly, as these traits are adaptations that remove constraints and allow lineages access to new niches and adaptive zones. In anoles, the dewlap is considered a key innovation as it provides greater potential for diversity in signaling traits important for mate and species recognition, thereby increasing the rate of speciation across  Anolis.*

The toepad is also thought to be a key innovation. Toepads allow anoles to climb on smooth surfaces. By climbing, anole species can partition the habitat not just in horizontal space, but vertical space as well. Thus, toepads have opened the arboreal niche to anoles, thereby playing a likely role in Anolis community assembly during adaptive radiation.

Several lines of evidence support the toepad’s role as an adaptation to arboreality. (1) Large toepads do tend to be found on those anole species that live higher in the canopy; (2) larger toepads impart better clinging ability; and (3) a recent study showed that populations of A. carolinensis that shifted to higher perches rapidly evolved larger toepads.

However, anoles also have claws.

As anyone who has ever had a cat jump onto their head knows, claws are also useful for climbing. Claws can interact with surfaces by interlocking with surface irregularities, or through friction, and the morphology of the claw determines in part how useful it is for climbing. Very few studies have been conducted on the Anolis claw, however, so we don’t have a good sense for whether and how anoles use the claw during climbing. We also don’t know how the claw  might co-evolve with the  toepad, if it does. Thus, the role of the claw in anole evolution, and its relation to arboreality, remains unknown.

To that end, Crandell et al. investigate the claw (and toepad) in a new paper just out in Zoology. They find that the toepad doesn’t tell the whole story of Anolis climbing. Perhaps, the claw also determines which Anolis have to stay on the ground and which can go into the trees. Read on…

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I recently found this adult male Cuban brown anole (Anolis sagrei) in Miami, FL.

He isn’t in particularly good shape by the looks of it! Can anyone shed any light on what might have happened?

Adult male Cuban brown anole (Anolis sagrei) caught in Fairchild Tropical Botanical Gardens, Miami FL

This is from Chris Pratt’s Facebook page (screenshot above). You’ll have to click on the link to see the cool footage.

In two recent papers, philosopher of science Jim Griesemer of U.C. Davis discusses how David Wake’s salamander-based research played a key role in the unfolding of evolutionary developmental biology and the advance of evolutionary biology.

Griesemer’s theme is that in contradiction to much of what we are taught about how science is conducted, organism-based research programs are fundamentally important by providing a means of crossing disciplinary boundaries and linking different fields. He illustrates this thesis by discussing Wake’s career-long focus on plethodontid salamanders.

One paper, published last year in Studies in History and Philosophy of Biological and Biomedical Sciences, is a general treatment of the role of organism-based research programs in evolutionary biology, whereas the other explicitly discusses the role Wake’s program played in the development of evo-devo–this paper just appeared as a chapter in a new book on the famous Dahlem conference on evo-devo in 1981 (both papers may be accessed by visiting Griesemer’s webpage, scrolling down and clicking on the appropriate paper’s link).

I think one point in particular captured the essence of the papers. Quoting Wake from a 1982 paper: “it will be increasingly important for morphologists to work as developmental biologists, biomechanical engineers, mathematical biologists, molecular biologists, and even population and community ecologists. Not for a moment do I advocate departing from morphology to these areas. Rather, I believe that instead of making morphology relevant to these areas, it is morphologists who must take the lead in making neighboring disciplines relevant to morphology.’’

The papers make fascinating reading and I highly recommend checking both out. I’ll paste the abstract and part of the conclusion of the 2013 paper below.

But before doing so, I need to address one point. Some Anole Annals readers may wonder why we are using our precious pages to report on papers by a salamander biologist. There are two answers. The first, of course, is that following the lead of Ernest Williams, many anole biologists take a similar, organism-based approach to studying diverse evolutionary questions. Indeed, Wake’s work has been an inspiration to many of us in the field, from anole evolutionists to anole developmental biologists to anole natural historians.

But if that’s not enough, consider that Wake was co-author on the description of a remarkable new genus of Central American salamander named Nyctanolis and pictured below. The biology of this endangered species (N. pernix, the only species in the genus) is little known and we can only speculate to which ecomorph it belongs. Moreover, the species description was published in the festschrift honoring Ernest Williams. Clearly, David Wake is an honorary anolologist and we suggest that there is nothing left to know about salamanders and thus he should start working on anoles.

Nyctanolis pernix. Photo by Tim Herman

Abstract of Griesemer. 2013. Integration of approaches in David Wake’s model-taxon research platform for evolutionary morphology

What gets integrated in integrative scientific practices has been a topic of much discussion. Traditional views focus on theories and explanations, with ideas of reduction and unification dominating the conversation. More recent ideas focus on disciplines, fields, or specialties; models, mechanisms, or methods; phenomena, problems. How integration works looks different on each of these views since the objects of integration are ontologically and epistemically various: statements, boundary conditions, practices, protocols, methods, variables, parameters, domains, laboratories, and questions all have their own structures, functions and logics. I focus on one particular kind of scientific practice, integration of ‘‘approaches’’ in the context of a research system operating on a special kind of ‘‘platform.’’ Rather than trace a network of interactions among people, practices, and theoretical entities to be integrated, in this essay I focus on the work of a single investigator, David Wake. I describe Wake’s practice of integrative evolutionary biology and how his integration of approaches among biological specialties worked in tandem with his development of the salamanders as a model taxon, which he used as a platform to solve, re-work and update problems that would not have been solved so well by non-integrative approaches. The larger goal of the project to which this paper contributes is a counter-narrative to the story of 20th century life sciences as the rise and march of the model organisms and decline of natural history.

Part of Concluding Section:

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Well, not quite, but thanks to Twitter, AA has learned of two new anole films. The first is about Anolis roquet from Martinique and illustrates the tremendous geographic variation of this species. But…it’s in French. Can anyone help us out and tell us what it’s all about? (Editor’s note: additional films have been added; go to the “playlist” in the upper left and choose number 6).

And let’s not overlook the lovely, multichromatic Anolis grahami. In the following Youtube clip, we see one of these wondrous beasts being colorful and running in Bermuda, where it was introduced a century ago.

An iguana at the Fairchild Botanical Garden. Photo by Diana Robinson.

AA contributor James Stroud thinks it might. In an informative recent article in the Garden’s magazine, The Tropical Garden (go to page 28), James discusses the species, which range from the glorious red-headed agama to six–count ’em, six!–introduced anoles, along with the native green. Of course, introduces species are not a good thing, but at least they’re quality species! You can also read more about them in a recent AA post by James.

Red-headed agama at Fairchild. Photo by James Stroud.