In this day of online publication of papers, the significance of the actual appearance of a journal’s latest issue, with an article right there, in ink on paper, has greatly lessened. Nonetheless, I, for one, still consider that moment to be the official publication of a paper. And in that vein, the anole genome paper officially appeared in this week’s issue of Nature. It’s freely downloadable here.
Author: Jonathan Losos Page 113 of 130
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.
Even Neil Losin’s cellphone photos turn out spectacular!
Dewlap variation in Anolis distichus in Hispaniola. The photos at the bottom show the change in dewlap color along the two transects in the recent study by Ng and Glor.
Despite all of the research on anole evolution conducted in the last 40 years, one important question still eludes us: how does speciation in anoles occur? This, of course, is of fundamental importance, because the great species richness of these lizards implies that speciation has run rampant in this group. So, we’d like to know why.
We don’t know much about speciation in anoles, but we do know a little. First, it is thought that the dewlap plays an important role. Sympatric anole species almost never have identical dewlaps, and experimental and observational evidence suggests that anoles use their dewlaps for species-recognition. Hence, understanding anole speciation may, to a significant extent, reduce to understanding the factors that cause populations to evolve differences in their dewlaps.
A different perspective on anole speciation relates to the classic question of whether allopatry is necessary or whether, as suggested by many recent studies, natural selection driving differentiation—whether in allopatry or not—is a more important stimulus to genetic differentiation. Recent work in the Lesser Antilles by Thorpe and colleagues has argued that environmental differences are the primary drivers of genetic differentiation within anoles, a result also suggested by Leal and Fleishman’s studies on A. cristatellus in Puerto Rico.
In this light, perhaps the most enigmatic anole is Anolis distichus of Hispaniola.
Not content with kicking butt in Florida, Anolis sagrei has recently been reported from the Caribbean coast of Costa Rica. Photo by Melissa Losos.
Anole Annals has previously reported on the ongoing interactions between A. cristatellus and A. sagrei in Miami (for example, here and cool video here), as well as the invasion of Costa Rica by A. cristatellus. Now the plot has thickened.
In a 2009 paper in Zootaxa, Savage and Bolaños reported that A. sagrei had been collected in the vicinity of Limon, the same region in which A. cristatellus also has been introduced. Jay Savage has kindly provided further information that A. sagrei is not only common in some parts of central Limon, where A. cristatellus is also known to be common, but it is also reported to be common at a Shell gas station in the nearby town of Moin, a town in which, again, A. cristatellus is common. It will be interesting to see how rapidly A. sagrei spreads in Costa Rica, and how the two species interact. One interesting twist: in Miami, it is A. cristatellus that has invaded in the presence of an already well-established A. sagrei; in Costa Rica, the table is turned. There’s a great research project waiting to be done here!
From this site: http://www.drsfostersmith.com/pic/article.cfm?aid=2791 (note: you have to go to the site for the answers; the link below is part of the image pasted into this post and is not active)
Anolis nebulosus displaying. From Jenssen (1970)
In a recent post, Rich Glor–he of little faith–claimed that the multi-splendored Sitana ponticeriana outdoes all of Anolis kind by unfurling its spectacular dewlap while standing on its hindlegs. However, Joe Macedonia set the record straight in a comment, pointing out that just such behavior was reported for A. nebulosus by Jenssen. Anyone else seen anything like this?
Puerto Rican anole photographer extraordinaire, Father Alejandro Sanchez (you must see his webpage here) describes these photos of a female A. cuvieri: “In a karstic forest in north-western Puerto Rico, a female Puerto Rican giant anole (Anolis cuvieri) patrols its territory in search of prey. When doing so, members of this species usually move in a very deliberate way, reminiscent of chameleons to the point of moving their eyes independently as they scan the vegetation for food or danger. Anolis cuvieri is usually very tame, and this individual hardly paid any attention to my movements or the camera’s flash. After I finished shooting, the lizard allowed me to stroke its tail for a few moments before jumping out of reach.” He also noted that “I saw a couple of A. cristatellus make themselves scarce as this female A. cuvieri approched.”
For example, we’re proud to be the first “related link” on this post.
In many species of anoles, females vary in their back patterning, some gaudily adorned with saddles, diamonds, or crosses, others sporting simple lines and speckles, some sad lasses with no markings at all. Although such female pattern polymorphism has long been noted and its adaptive significance studied (for example, here), no one has compiled a list of which species exhibit it and which don’t, much less examined patterns of FPP evolution.
Until now. In a very nice paper, Paemelaere et al. have surveyed the literature and recorded the presence or absence of of FPP in 179 anole species. They find a wide variety of interesting findings. First, there is phylogenetic signal: closely-related species tend to be similar in the presence or absence of FPP. Nonetheless, second, FPP has evolved and been lost many times—overall, at least 28 evolutionary transitions, with more gains than losses. The ancestral condition, incidentally, appears to be an absence of FPP. Third, there is great biogeographical heterogeneity (see figure above). FPP is far-and-away most common among mainland anoles, and is also reasonably common in the Lesser Antilles, but much less common in the Greater Antilles. Within the mainland anoles, it is particularly members of the Norops club that have FPP; much less among dactyloids. However, Norops also occurs on Cuba and Jamaica, and there they don’t exhibit much FPP.
One additional interesting pattern not remarked upon by Paemelaere is that among Greater Antillean species, FPP occurs primarily in trunk-ground anoles, having evolved at least three times independently on different islands (in three members of the sagrei clade on Cuba; A. cristatellus on Puerto Rico; and three members of the cybotes clade on Hispaniola).