Category: Notes from the Field Page 10 of 22

Every now and then we’ve had posts on this blog about non-anole lizards with anole-like dewlaps (e.g. 1, 2). Many agamids have flaps of skin under their throats that begin to resemble a dewlap, but male lizards in the South Asian genera Sitana and Otocryptis have the most “anoline” dewlaps I’ve seen so far. Indeed, some readers were almost fooled by Sitana’s resemblance, in both dewlap and dorsal patterning, to anoles. I spent the summer of 2012 documenting aspects of the display behaviour, morphology, and ecology of Sitana–here are some of my findings

Despite its ubiquity across much of peninsular India and Sri Lanka, Sitana remains relatively unstudied. Individuals across much of the range are classified as a single species, Sitana ponticeriana, despite substantial variation in dewlap morphology. It turns out that there are at least three dewlap variants, which occur, for the most part, in allopatry. Note the gradation in dewlap colouration between the three “morphs.”

Coloured-fanned, intermediate-fanned, and white-fanned male Sitana ponticeriana. Photographs by Shrikant Ranade, Jahnavi Pai, and Jitendra Katre respectively.

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You thought I was kidding about the  Roatan allisoni doing their best grass anole imitation? See how many you find in this photo. There are at least five, but maybe I missed some.

Anolis sagrei nelsoni. Photo by Steve Busack.

Bob Powell raises an important point in a recent comment, concluding “So, at what point does a differentiated isolate cease to be a subspecies and become a species?” In other words, how do we decide whether to recognize a distinctive population as a different species? I’m not talking about the situation where somebody goes out and comprehensively samples a clade and then uses the latest fancy-pants statistical wizardry to decide how to “delimit” taxa into one or multiple species. Rather, I’m going old school, focusing simply on the situation in which one has a population that is distinctive from other populations. Should we recognize that population as a different species? What kind of evidence is sufficient?

The context is the population discussed last week, Anolis sagrei nelsoni, from the remote Swan Islands 90 miles off the coast of Honduras. This isolated population is morphologically distinctive in many ways from other sagrei. It’s larger, has more lamellae on its toes, and, at least in the photograph above, has a very dark dewlap. Very likely, when Randy McCranie is done examining their scalation, he’ll document  other peculiarities. Is this enough to decide to recognize Anolis nelsoni? Certainly, in recent years the same approach has been taken to recognize a number of other Central American anole populations as distinct species.

One problem with this approach is that nelsoni probably lies phylogenetically somewhere within what is currently recognized as A. sagrei (just my guess, but the only phylogeographic study on sagrei to date placed Belize populations in the middle of sagrei). Hence, raising nelsoni to species status would render the rest of sagrei paraphyletic, which bothers some people more than others.

Another option is to name the population (or in this case, retain the population) as a subspecies. I recently semi-seriously suggested to a collaborator that we name two subspecies for populations of a species found on two islands. He just laughed.

The answer, of course, is to conduct a detailed systematic study of the entire A. sagrei clade, using both molecular and morphological data. The problem is that this is a huge undertaking. Even Al Schwartz didn’t tackle variation in sagrei! So, it may be a while before this gets done. What do we do in the meantime? Is it A. sagrei nelsoni or A. nelsoni? Good question, Bob!

Update on Expedition to Swan Islands

While we’re on the topic of A. sagrei nelsoni,

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Albert Schwartz, longtime professor of biology at Miami Dade Community College, was one of the most important figures in anole biology. Schwartz co-authored the authoritative account of West Indian reptiles and amphibians with Robert Henderson, described at least 8 anole species (in addition to many other reptile and amphibian species), authored dozens of reports on anole taxonomy and biogeography (see previous reviews on Anole Annals of his reports on Hispaniolan giant anoles and Hispaniolan trunk anoles for examples of this work), and amassed a collection that would ultimately include over 15,000 anole specimens. Most of Schwartz’s West Indian collection can now be found in the collections of the University of Kansas, including 15,511 anoles. When Schwartz completed his work on the vast collections he had accumulated over decades of intense field sampling, he reached an agreement with KU that would, in 1987, have Bill Duellman and Linda Trueb driving a 38′ U-Haul truck full of over 60,000 reptile and amphibian specimens of  from Florida to Kansas.  In addition to acquiring Schwartz’s preserved material, KU also acquired Schwartz’s original notebooks.

These notebooks are housed in KU Herpetology’s library and I had a chance to check them out during a recent visit. There are more than 40 notebooks in total, and they extend across Schwartz’s career in the West Indies. He kept his fieldnotes primarily in student composition books (some of which actually bear the title “SCHOOLTIME Compositions”). For the most part, Schwartz’s notebooks are simple catalogues of specimens that include a field series number, the species name, and the date and location of the collection. Although he provides color notes on most specimens, he rarely comments on natural history or other aspects of a particular specimen’s biology.

I’d like to get all of these notebooks digitized and transcribed so that the information they contain can be made available to anyone who’s interested.  I’ve been thinking that it might be fun to crowd source the transcription of these notebooks once they’re scanned.  For those who aren’t familiar with crowd-sourced transcription, this process permits large numbers of internet users to transcribe old texts that cannot easily be digitized via optical character recognition.  Today, this approach is widely used by folks interested in transcribing handwritten documents and numerous software applications have been developed to facilitate the process.  It’s already being used to transcribe some historical field notes, including an effort by The San Diego Natural History Museum to transcribe the field notebooks of the herpetologist Lawrence Klauber.

What do you think?  Are there readers of Anole Annals who would be interested in helping transcribe Schwartz’s notebooks?  Does anybody have past experience coordinating such efforts that they’d be willing to share?

Dickerson’s collared lizards. Photo from http://www.herpnation.com/wp-content/uploads/2012/05/Dickersons-Collared-Lizard-Crotaphytus-dickersonae-700×466.jpg

What the heck gives with blue lizards? Collared lizards, geckos, lacertids, teids, anoles—there’s more blue lizards than you can shake a stick at. And they stand out like a sore thumb. How can they possibly survive? And in those species in which only the males are blue, do the lady lizards really have an azure fixation?

Male Anolis allisoni from Atkins Botanical Garden, Cienfuegos, Cuba. Photo by J. Losos.

Male Anolis allisoni from Cuba are famous as the day-glo green lizard with a blue jumper. But their Honduran descendants are much less cerulean—indeed, here on Roatan, they barely have a hint of the cobalt (see below). What’s going on? It would seem that whatever has favored blueness in Cuba is not favoring it here. Do the ladies out here swoon not as much for indigo? Are the predators tougher? Is the environment different? Who knows. And has the population here reached a new, less blue, stable-state, or is it in the process of losing its turquoise entirely, returning to its verdant roots. At this point, we don’t have a good time estimate for how long allisoni has been here—if it’s a recent arrival, it would certainly be a reasonable hypothesis that the blue wash is on its way out entirely.

Male Anolis allisoni from Roatan. Photo by J. Losos

See if you can spot the lizard.

But while we’re on the topic of color craziness, here’s another question: how come green anoles can’t—or don’t—match their background? Color mavens may be offended at my non-analytic assertions, but I insist that green anoles often are conspicuous. On white tree trunks (much less brown or red ones), a green anole stands out a mile away.

How about this one?

Sure, green’s great for camouflage when you’re in the vegetation, but if you could change colors, wouldn’t you do so when on non-green backgrounds. Octopi can do it, why not anoles? Or, at least, why don’t they stay on green surfaces when they don’t want to be detected. Although, truth be told, not all greens are the same, and the bright green of these species often stands out against darker green vegetation (check out the anole in the grass in yesterday’s post, reprinted to the left).

Green lizard in the grass: not so cryptic

Now, some contrarians may claim that they’re actually trying to be conspicuous—Bob Trivers, for one, suggested that the beautiful green A. garmani intentionally perched in conspicuous sites in order to be seen. Maybe that’s so, but most of the time, anoles don’t seem like they’re trying to be seen, especially the females. And, yet, you can’t miss them.

Finally,  of course, I have to acknowledge that it’s possible that I failed to spot one or two green anoles in green vegetation, especially high in trees. So, it may be that green is the color that camouflages them most effectively. Still, they could do better by changing color to match where they’re sitting, or by only sitting where they don’t stand out.