The annual meeting of the Society for Molecular Biology and Evolution meetings start this weekend in San Juan, PR and there are a number of talks and posters to appeal to the squamatophile.
There are three presentations from AA contributors (Marc Tollis and Tony Gamble) using anole genomic data, as well as posters and talks on phylogeography of Puerto Rican Sphaerodactylus, and genome-scale studies of Sceloporus, skinks, and snakes. You can see the full list after the jump.
Doc Frog (a.k.a. Cesar Barrio Amorós) has the most amazing balcony anywhere. Previously, we posted photos of Anolis biporcatus mating and A. charlesmyersi being beautiful, taken from that overlook. Now the good doctor reports photographs of anoles taken not from his balcony, but on his balcony. Specifically, two male A. limifrons in a tense encounter.
We’ve had posts in the past of other anoles sticking their tongues out in male-male encounters (e.g., A. fuscoauratus, A. stratulus). I wonder how widespread it is in the anole kingdom. I am unaware of any review of this topic, but the first place to start would be Schwenk and Mayer’s paper, “Tongue display in anoles and its evolutionary basis,” published in Anolis Newsletter IV.
Who else can report tongue use in anole displays?
Convergent evolution is Anolis Lizards’ middle name, and so it is with great interest that we read two brand-spanking new papers on convergent evolution. The first is by Arbuckle et al. out of the University of Liverpool. Published in Methods in Ecology and Evolution, the paper describes a new method for quantifying the strength of convergent evolution. You’ll have to read the paper for the details, but the gist of the method is that convergence is greatest either when species are greatly different phenotypically from other species or when the convergent species are distantly related phylogenetically.
And the focal taxon used to demonstrate the method with empirical data? Why, none other than Greater Antillean ecomorphs. The paper found that in “In Anolis lizard data set, perhaps the most notable finding is that ecomorphs differ in the strength of their convergence—grass-bush and trunk-ground anoles stand out as having particularly strong convergence compared to others. Furthermore, some traits are more strongly convergent within some ecomorphs but not others. Therefore, patterns of convergence in particular traits are ecomorph specific.” Specifically, “analyses found the strongest convergence in limb length occurred in grass-bush anoles compared to the other ecomorphs, consistent with Losos’ (1990b, 2009) finding of relationships between limb length and jumping and sprinting (perhaps particularly important for grass-bush anoles). The strong convergence of lamellae number detected in trunkground anoles suggests that there is a notable degree of adaptation in this trait.”
The abstract of the paper is appended at the bottom of this post.
Meanwhile, in a non-anole example, Collar and colleagues, in a paper in the American Naturalist, looked at convergent evolution in snail-eating moray eels. The authors found that the durophagous eels evolved in generally the same direction morphologically relative to their non-snailivorous relatives, but that there was substantial variation among the shell-crackers, actually more variation than seen among their relatives.
The authors explain this “imperfect convergence” in this way: “we show that following 10 transitions to durophagy (eating hard-shelled prey) in moray eels (Muraenidae), cranial morphology repeatedly evolved toward a novel region of morphological space indicative of enhanced feeding performance on hard prey. Disparity among the resulting 15 durophagous species, however, is greater than disparity among ancestors that fed on large evasive prey, contradicting the pattern expected under convergence. This elevated disparity is a consequence of lineage specific responses to durophagy, in which independent transitions vary in the suites of traits exhibiting the largest changes. Our results reveal a pattern of imperfect convergence, which suggests shared selection may actually promote diversification because lineages often differ in their phenotypic responses to similar selective demands.”
Such imperfect convergence is not unknown among anoles. For example, Langerhans et al. showed that despite the convergence among the ecomorphs, there were also island-specific effects that produced variation among members of an ecomorph. Moreover, a larger scale example is the comparison of mainland and Greater Antillean anoles. Is the lack of convergence due to environmental differences, or is it an example of species evolving different adaptations to living in the same environment?
Exciting times for those of us interested in convergent evolution!
The abstract of the Arbuckle et al. paper:
And it’s a looker!
The species, described recently in Amphibian & Reptile Conservation by Fernando Ayala-Varela and colleagues, comes from the western slope of the Andes in Ecuador. In appearance, it’s most similar to A. gemmosus, which occurs to the north. Detailed examination shows it to be most phenotypically similar to that species and A. otongae, and DNA analysis indicates that A. gemmosus is its sister taxon.
Check out the paper, which has lots of lovely photos not only of the new species, but of some of the species with which it is sympatric.
Sleeping Sitana
If you’re in the field looking for lizards, knowing where they sleep can be tremendously useful. Anyone who’s tried catching an anole at night knows how much easier this can be than catching it during the day. When I began working with Sitana, therefore, I was keen to locate where these lizards slept. Being primarily terrestrial, it made sense that they would sleep under rocks, in cracks in the ground, or buried beneath grass, bushes, or leaf litter. I had some indirect evidence for the utilization of these locations as sleeping sites–I had seen lizards emerging from and retreating to these locations early in the morning and late in the evening, respectively.
However, I did not expect that fan-throated lizards would sleep completely in the open on the ground. Yet that is precisely what my colleague Divyaraj Shah recently observed. You can see the lizard’s head pointing downwards, resting on the ground below–he does not seem disturbed at this point.
Is it common for terrestrial lizards to sleep in open, unsheltered spots?
Keratins are the structural proteins of skin, hair, nails, feathers, and scales. There are 54 described keratins in humans, a subset of which has also been found in the green anole genome. Distinct combinations of keratins in skin appendages are what give these tissues their unique properties such as flexibility, rigidity, or cornification (i.e., the process of forming an epithelial barrier). Lizards have a number of specialized scale types, likely due to the distinct distribution of keratins in those scales. Dating back at least a decade, Lorenzo Alibardi and colleagues have been making great progress describing the keratin gene family in lizards and describing the distribution of these proteins across the body. Alibardi has recently added to this long series with a description of keratin localization in the lamellae of Anolis carolinensis. Because I am not an expert in keratin biology I will let the Abstract give you the details:
ABSTRACT Knowledge of beta-protein (beta-keratin) sequences in Anolis carolinensis facilitates the localization of specific sites in the skin of this lizard. The epidermal distribution of two new beta-proteins (betakeratins), HgGC8 and HgG13, has been analyzed by Western blotting, light and ultrastructural immunocytochemistry. HgGC8 includes 16 kDa members of the glycine-cysteine medium-rich subfamily and is mainly expressed in the beta-layer of adhesive setae but not in the setae. HgGC8 is absent in other epidermal layers of the setae and is weakly expressed in the beta-layer of other scales. HgG13 comprises members of 17-kDa glycine-rich proteins and is absent in the setae, diffusely distributed in the beta layer of digital scales and barely present in the beta-layer of other scales. It appears that the specialized glycine-cysteine medium rich beta-proteins such as HgGC8 in the beta-layer, and of HgGC10 and HgGC3 in both alpha- and beta layers, are key proteins in the formation of the flexible epidermal layers involved in the function of these modified scales in adaptation to contact and adhesion on surfaces.
Fig. 10 from Alibardi 2014
Courtesy Nirvana Reptiles
I may have given the Evolution 2014 logo an Anolis upgrade.
It’s that time of year again! The annual Evolution meeting is upon us. In just under a month, scientists from around the world will converge on Raleigh, North Carolina to learn about new and emerging trends in evolutionary biology. As with the Society for Integrative and Comparative Biology meetings, anoles have had a strong presence at Evolution. It appears that this year will be no different. A quick search for talks including the terms “anole” or “Anolis” yielded seven presentations, and so this meeting should be quite fruitful for those of us interested in what’s new and exciting in Anolis. You can view the list of scheduled presentations here – simply put Anolis into the keyword search at the bottom and all seven presentations will be displayed. Or just look below. As in previous years, we’ll be blogging live from the conference, so stay tuned.
As a senior in college I wanted to study courtship behaviors, and the brown anole (Anolis sagrei) piqued my interest. In going through the literature, I noticed that some studies reported finding evidence for the presence of female choice in brown anoles and others reported that female choice didn’t occur in the species. So I decided to see if females exhibited a preference for males based on two different characteristics: male physiology and male territory quality, each of which would provide females with different benefits. I expected that females would choose males based on territory quality, because females usually mate with the males whose territories overlap theirs in the wild.
I tested for female preference in two different choice experiments using anoles that I ordered and had sent to my college, Colby College, in Maine. I was given access to a small storage closet (which I cleaned out) in the basement of Colby’s biology building in which I kept my crickets and anoles. To test for differences between males with different physiological traits, I tested male endurance by placing them on a treadmill and running them until they couldn’t run any longer. This was perhaps one of the most stressful parts of the experiment for me, since the lizards really didn’t like being put on the treadmill, so during this part of the experiment I got to chase many lizards around the room.
A brown anole running on a lizard treadmill
I then paired similarly-sized males with very different running times to see if females spent more time with one male over the other. For the preference tests, the males were tethered to posts in a mate choice box originally constructed for zebrafinches, and the females were able to run freely through the box.
In the territory tests, rather than pairing males with different endurance scores, I randomly placed males on the side of the box with many plants and twigs, or on the side without. In both tests, I recorded the amount of time females spent on either side as well as the behaviors of the males and females (I watched many hours of video to score behaviors).
Mate choice arena for the territory quality experiment
My results were somewhat surprising; I found that in both experiments the more active male was the most preferred one. This was contrary to my prediction, especially since our measure of activity included all male behaviors, not just courtship behaviors. This is not surprising in the broader scheme of mate choice, since active mates are often preferred, and it’s interesting to see how anoles fit into the bigger picture of mate choice and sexual selection in general. This study is now published, so check it out if you’re interested in the details! Please feel free to contact me if you have any questions or would like a copy of the pdf.
Northeast India is a rather unexplored place even though it boasts huge biodiversity, mostly due to the numerous rivers and mountains that dot the landscape and form formidable barriers to dispersal. A majority of the taxa found in this region still await valid descriptions. I have been working on amphibians in the state of Arunachal Pradesh (one of the seven states that form the ‘Northeast’) during my undergraduate years and during my field work, I came across some very striking gular color morphs of the genus Japalura. The genus Japalura consists of 26 species which range from Northeast India in the west to Japan and Taiwan in the east, north to Shaanxi province in northern China and south to northern Vietnam. Of these, four species have been so far reported from Northeast India.
From the photographs taken in the field, Ulrich Manthey identified all of them as belonging Japalura andersoniana. If all of them are the same species, the variation in the gular coloration indeed comes across as striking. There was a note in Sauria (Bhosale et al 2013) that listed various morphs, but no speculations on what could be the possible causes. I have seen these lizards in Eaglenest Wildlife Sanctuary (EWS) and Talley Valley Wildlife Sanctuary (TVWS). The published note has color morphs from another place – Kamlung Wildlife Sanctuary (refer to the map for relative locations of the two places within Arunachal Pradesh)
The locations of Eaglenest Wildlife Sanctuary, Talley Valley Wildlife Sanctuary and Kamlung Wildlife Sanctuary
The observations for each specimen with the corresponding number from #01- #05 is summarised from my field notes. Note: All the animals were encountered opportunistically; there was no dedicated sampling effort toward lizards whatsoever. Elevation recorded from a Casio altimeter watch.
The different color morphs of Japalura species – The field notes are listed corresponding to #01-#05
#01 – EWS, June 2012, Adult, It is the most commonly occurring color morph in EWS. I have also seen juveniles with similar throat colors, Seen in the elevation range 1100m – 1600m asl.
#02 – EWS, May 2012, Adult, encountered at an elevation of around 1800m asl. I haven’t come across a second individual resembling this throat coloration.
#03 – EWS, June 2012, Juvenile, encountered at around 1990m asl; I have never encountered an adult with such coloration.
#04 – Juvenile, throat not very well developed, could possibly be a female, encountered at an elevation around 1350m asl where I have encountered larger individuals with no throat color.
#05 – Juvenile, however, an expedition the previous year by a different group found an adult with similar throat color, the only color morph seen in Talley Valley.
Even if they are the same species, it is quite possible that the different throat color morphs are divergent populations breeding in isolation, especially because apart from #01, the other color morphs have been reported from only particular localities. It is also important to survey more of the Northeast to see if the unexplored areas are home to novel throat color morphs. Speculations with just a few records would be rather vague.
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