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.
That’s one beat up looking old dude, but apparently he’s still got it. Or does he? She seems to have one foot out the door.
We’ve been following the backyard anole antics reported in Daffodil’s Photo Blog for some time now, and Easter provided a heartwarming photo-story of an old guy who can still find some love. And this old guy seems like he’s seen some better days.
The saga continues. Last December, the Reptile Database, the online listing of all recognized reptile species, issued an update in which anoles were split into the eight genera proposed by Nicholson et al. Now, in the subsequent update released yesterday, they’ve done an about-face and changed all anoles back to Anolis. Here’s what they have to say:
“Anolis. After serious contemplation (and consultation with several experts) we changed the names of anoles back to Anolis. For some reasons see Poe et al. (2013) Zootaxa 3626 (2): 295–299.”
Interestingly, the very next item was this:
“Teiidae. The names of many teiids have changed following the suggestions of Harvey et al. (2012) Zootaxa 3459: 1–156. However, we are already getting complaints that this may not be tenable…”
So, seems like these issues may not necessarily be unique to anoles. The Reptile Database is a great resource for the herpetological community, but I don’t envy it the task of trying to decide when to change names and when not to. Moreover, since it has become so widely used, its decisions probably have an outsized impact on whether people adopt proposed changes or not.
In any case, for any readers who need to get up to speed, the Poe et al. paper referred to above was discussed several weeks ago, and the entire discussion thread on the proposed taxonomy of Nicholson et al. is probably best found by searching with the term “Nicholson” in the search bar to the right.
AA reader Ava writes: “Ironic that on Easter, I found myself on an egg hunt and found a green anole egg that I suspected had just been laid. She would have laid it last night. I put it in a cricket keeper (covered big holes), included the very soil the egg had been laid in and placed the keeper back in the main terrarium in the area where I had found it.
I read, afterward, that the position of the egg should not be disturbed. I fear I may have shifted it around in transfer. Have I blown it? Can one tell which end is up?
I live in Florida where the ‘takeover’ of the brown Bahamian anoles has been increasingly apparent. The ‘greenies’ as we call them have taken to the trees, but seem fewer every year. The browns are so aggressive. My hope is to ‘repopulate’ a certain mango tree where we used to see them. Pointless? Anyone?
I previously mentioned this book, but through the kindness of author Karin Mesa, I can report on the contents of Oliver the Overachiever. This fine children’s book details the lifestyle of non-conforming independent thinking Oliver, who from the day of his hatching, insisted on doing things his way. Needless to say, the conservatives were against change, worrying–correctly–about the threats posed by housecats. But Oliver persevered and eventually triumphs, bringing great joy to the anole masses.
This is a fine message to send to young readers. The drawings are full of whimsy and the book is the recipient of the Mom’s Choice Awards in the category “Children’s Picture Books (Suitable For Ages Birth To 9)” and Preferred Choice Award of the Creative Toy Awards 2011. Apparently, this may be the first of many in the Oliver series and, who knows, maybe they’ll span a movie. You can learn more about Karin’s artistic diversity at her website.
Collecting data in Mosquito Lagoon. Yoel Stuart manning the helm, with Todd Campbell and Casey Gilman.
Moments ago, AA stalwart Yoel Stuart successfully defended his Ph.D. dissertation, entitled Character Displacement and Community Assembly in Anolis Lizards. The four chapters include work on species turnover in island and mainland anoles and eleutherodactylid frogs, which was published last year in Proceedings of the Royal Society of London; a review of the evidence for character displacement, just out in Trends in Ecology and Evolution; and a study on rapid evolution of character displacement, which has been discussed previously in these pages.
Let the celebrating begin! Actually, it already has.
Yoel now moves on to his postdoctoral work in Dan Bolnick‘s lab at the University of Texas in Austin, where he will be studying evolutionary divergence in the Canadian aquatic anole, Gasterosteus aculeatus. Congratulations and good luck, Yoel!
Anolis ventrimaculatus. Photo by Diego Garcés
Morphological differences between the sexes and among populations have been studied extensively in Caribbean anoles, but—like so many other aspects of biology—not so much in mainland species. Studies in the islands suggest that differences, both sexual and geographic, often represent adaptation to different conditions, either the sexes partitioning niches or populations adapting to different circumstances.
Martha Calderon and colleagues have just published a paper in Revista de Biología Tropical on variation in the Colombian anole A. ventrimaculatus. Examing museum specimens from seven populations, they find consistent size dimorphism (males larger) and substantial dimorphism in body proportions. The extent of these dimorphisms, however, varies among sites.
Unfortunately, at this time little is known about the habitat use and general ecology of this species, much less about differences among populations, so evaluation of the potential adaptive significance of this variation awaits further fieldwork.
The paper’s abstract:
Variation in body characteristics related to lizard locomotion has been poorly studied at the intraspecific level in Anolis species. Local adaptation due to habitat heterogeneity has been reported in some island species. However, studies of mainland species are particularly scarce and suggest different patterns: high variability among highland lizards and poorly differentiated populations in one Amazonian species. We characterized interpopulation variation of body size and shape in the highland Andean Anolis ventrimaculatus, an endemic species from Western Colombia. A total of 15 morphometric variables were measured in specimens from the reptile collection of the Instituto de Ciencias Naturales, Universidad Nacional, Colombia. The study included individuals from seven different highland localities. We found size and shape sexual dimorphism, both of which varied among localities. Patterns of variation in body proportions among populations were different in both males and females, suggesting that either sexual or natural selective factors are different in each locality and between sexes. Since this species exhibits a fragmented distribution in highlands, genetic divergence may also be a causal factor of the observed variation. Ecological, behavioral, additional morphological as well as phylogenetic data, may help to understand the evolutionary processes behind the geographic patterns found in this species. Rev. Biol. Trop. 61 (1): 255-262. Epub 2013 March 01.
Not effective at a great distance
Think about when you want to communicate with someone, but first you have to get their attention. Let’s start with verbal communication. If Fred is across the room, you probably holler out “Hey Fred” a lot louder than if he’s sitting next to you. Now, suppose you’re the non-verbal sort. If Fred’s a long distance away, you’re going to have to wave your hand wildly, maybe even jump up and down, to get his attention. But if he’s nearby, a little wave, even a discreet hand gesture, will suffice. Why we don’t whisper or make slight movements to attract the attention of those far away is pretty obvious–the target won’t hear or see you. But why not yell loudly or gesture emphatically even when the target is nearby (ok, we all know some annoying people who do this, but mostly people don’t)?
Signal modulation is an area of great interest in the field of animal communication, and Steinberg and Leal have just published a fascinating study on the Puerto Rican A. gundlachi in Animal Behaviour (pdf). The key to understanding signal modulation is to investigate how signal detectability changes as a function of distance. Building on prior work by Fleishman on A. sagrei, Steinberg and Leal conducted lab studies in which they move a black disk against white paper to determine how much movement is needed to attract the lizard’s attention. Fortunately, this can be easily done with lizards because they have something called the visual grasp reflex–when something gets their attention, they shift their eye to gaze right at it. Easy to determine in the lab. So, by moving the disk up-and-down different amounts and varying the distance of the lizard, the authors were able to determine the degree of amplitude of movement in the visual field most detectable by the lizards (see figure on right). Notably, there is not only a minimum visual angle, but also a maximal one, above which response declines (and then increases again; for reasons discussed in the paper, Steinberg and Leal focus on the maximal peak in the 0.25-0.75 degree range).
Of course, because the movement is expressed as an angle relative to the visual field, then as the distance to the target receiver increases, larger amplitude movements would be necessary to be detected. Moreover, looked at the other way, because there may be a degree of movement too great to maximally stimulate a response, the amplitude would be expected to decrease at shorter distances.
Anolis pogus. Photo from Wildlife of St. Martin.
The resemblance is uncanny
The diminutive A. pogus of St. Martin is sometimes referred to as the bearded anole. Since anoles lack hair, facial or otherwise, one might wonder where the name comes from. In fact, Mark Yokoyama explains on his Wildlife of St. Martin site, the name is a misnomer, a misguided translation of the specific epithet pogus. Rather than being derived from the Greek pogos, the name is a reference to the cartoon character Pogo the possum! Who else would be behind this than AA faithful Skip Lazell? Anyone have any other favorite anole scientific names?
Anolis heterodermus. Photo by J. Losos.
Although many generic names have been proposed for species within the anole clade, traditionally only three other than Anolis were widely used: Chamaeleolis, Chamaelinorops and Phenacosaurus. Each of these clades—which at one time were thought to represent early, pre-Anolis derivations from the anoline line—are morphologically distinctive. The former two, Chamaeleolis and Chamaelinorops, need no introduction—they are oddball species that at first pass might not even be recognized as anoles, and that have received a modicum of scientific study. The third clade, Phenacosaurus, by contrast, has been mostly ignored. This is surprising, because at least some species are quite notable morphologically, with head casques, heterogeneous scalation, wild colors, and an all-over prehistoric appearance. Moreover, they live at remarkably high altitudes, at least by anole standards, and have a passing resemblance—some species more than others—to Caribbean twig anoles. Nonetheless, there is almost no literature on the natural history or evolution of these anoles.
Ken Miyata’s 1983 Journal of Herpetology paper is the one exception. In it, he describes the habitat use of A. heterodermus in areas near Bogotá, Colombia. His description paints the species as one that uses narrow perches on bushes and other vegetation, and that is especially plentiful in blackberry bushes. Combined with its short legs, heterogeneous body and head scalation and elongate and compressed body, reminiscent of twig anoles like A. valencienni, one might entertain the possibility that it is in functional terms a mainland twig anole.
A year and a half ago, we reported in AA on our studies of another phenacosaur, the much smaller A. orcesi from Ecuador. Our studies conclusively demonstrated that it is in all respects like a twig anole—behaviorally, it moves extremely slow; ecologically, it is found almost entirely on narrow surfaces; and morphologically, it is a Caribbean twig anole doppelgänger. But in one respect, A. orcesi was a disappointment—it looks just like any old anole, without the wildly prehistoric aspect for which the larger phenacosaurs are renowned. For this reason, it was time to examine another phenac, and what better choice could there be than A. heterodermus, the subject of Miyata’s study, supposedly common near Bogotá, and appropriately wild in appearance?
And so Rosario Castañeda, Anthony Herrel and I converged on Bogotá in late February for just this purpose, joined by Rafael Moreno, a graduate student at Universidad Nacional de Colombia, who has just completed his masters degree research on this species, with one fine paper out and more in the works. Our plan was simple: go to appropriate spots on the outskirts of Bogotá, locate lizards in the vegetation, watch them and record habitat use and behavior, then capture them and bring them back to the field lab to measure sprinting and biting capabilities and to examine their stomach contents.
Tess Driessens, but that’s no lizard
Channel 27 in Grand Cayman has just aired a report on the doctoral work of Tess Driessens (co-winner of the 2012 Anole Photo contest!) and Simon Baeckens (actually, from their webpages, this seems like Tess’s project). They’re studying the diversity of dewlap color in Anolis sagrei by looking at brown anoles throughout their range.
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