Clade Age, Species Richness, And Anolis Lizards


ResearchBlogging.orgDan Rabosky and co-authors have just published an important report on patterns of organismal diversity in PLOS Biology, with one of their main conclusions being that clade age does little to explain species richness.  Luke Harmon has a commentary on this article in the same issue of PLOS Biology, and I’ll refer readers there for a general summary of the work’s implications.  I wanted to give this article a shout-out here at Anole Annals because they used an anole as their icon for squamates in Fig. 3 (see above).

Inspection of their supplemental Table 2 and consultation with the authors, however, reveals that anoles were inadvertently left out of the final analyses due to a book-keeping error involving use of the timetree age for Iguanidae sensu Schulte et al. 2003 but the species richness for Iguanidae sensu Frost & Etheridge 1989. (A quick taxonomic review for the uninitiated: The family diagnosed as Iguanidae by Frost and Etheridge included only a subset of the species previously regarded as members of the much larger family Iguanidae.  Frost and Etheridge assigned Anolis and many of the other genera previously included in Iguanidae to other newly defined families.  They considered this taxonomic revision necessary because they did not recover a monophyletic Iguanidae sensu lato.  Because molecular phylogenetic analyses do tend to recover a monophyletic Iguanidae sensu lato, some subsequent authors, including Schulte et al. 2003, have advocated retention of Iguanidae sensu lato and treatment of Frost & Etheridge’s families as subfamilies [see Daza et al. 2012 for another perspective on this taxonomic debate].)

If we imagine crudely adding a circle to represent Anolis in Rabosky et al.’s figure 3 (assuming an age of ~50 mybp and species richness of ~400 for the genus), its clear that anoles would be among the youngest, yet also most species rich, of all squamate clades, providing further support for Rabosky et al.’s main conclusion that clade age has little role in explaining clade richness.

When alerted of this issue, Rabosky and his co-authors re-ran their analyses including anoles and their relatives (i.e., Polychridae/Polychrotidae of Frost and Etheridge) as well as all of the other Frost and Etheridge families that were overlooked for the same reason (e.g., Tropiduridae, Phyrnosomatidae).  Rabosky sent me a figure that illustrates the position of all these missing clades (in blue), including the clade that includes Anolis (in red) as well as the other squamate clades in the original analysis (in grey).  Because many of these clades stem from series of basal branching events within Iguanidae sensu lato and are relatively similar in age, they rather nicely illustrate the reported absence of a correlation between clade age and species richness.  Not surprisingly, Rabosky et al.’s overall conclusions about clade age and species richness are unchanged by inclusion of these additional datapoints.

At the end of the day, this discussion nicely illustrates how monkeying around with the names of formal Linnean ranks can cause chaos for anyone who is not intimately familiar with a particular name’s complete history.

Rabosky, D. L., G. J. Slater, and M. E. Alfaro (2012). Clade Age and Species Richness Are Decoupled Across the Eukaryotic Tree of Life PLOS Biology DOI: 10.1371/journal.pbio.1001381

World Congress Of Herpetology 7: Anole Color Evolution

Wrapping up our coverage of the World Congress of Herpetology held in Vancouver last week, I have a report on Nick Crawford’s talk on the genetics of colorful pigmentation in Anolis.  Nick began by talking about the basic types of pigments that contribute to anole coloration, which include both pteridines and carotenoids.  Synthesis of pteridines is much better understood, thanks largely to work on zebra fish (reviewed in Braasch et al. 2007).  Nick first showed preliminary evidence from rtPCR analyses suggesting that specific genes along the pteridine synthesis pathway differ in predictable ways among parts of anoles with different coloration (e.g., white venter, green dorsum, pink dewlap).

Crawford went on to note that pteridines may be less important to dewlap coloration than are carotenoids, but that the latter represent a bit of a black box genetically and developmentally.  Crawford then discussed a project in which he uses a bulk segregant approach to ask if regions of the genome associated with color differentiation can be identified by examining genomic sequence data from species with polymorphic coloration.  Crawford was particularly interested in the polymorphic Lesser Antillean Anolis marmoratus.  He obtained sequence data from two phenotypically distinct populations of this species using the Illumina hiSeq platform.  Fortunately this data could be aligned to the A. carolinensis genome, and showed a relatively high degree of synteny with this previously published genome.  Analyses of the new A. marmoratus dataset are still in their early stages, but preliminary analyses recover 1,300 fixed SNPs (only 330 of which appear to be exonic) and suggest the presence of genomic islands of differentiation similar to those reported in many other recently diverged species and incipient species.

Note Added in Press:

One talk we failed to cover at WCH was by Chris Schneider on a similar topic. Here’s the Abstract:

Schneider, Christopher (Boston University); Crawford, Nicholas; McGreevy, TJ; Messana, Nick (Boston University, Canada)

The genetic basis of phenotypic variation and divergence in Anolis marmoratus Continue reading

Evolution 2012: Phylogenetics And Biogeography Of Anole Malarial Parasites

In what should be our final belated post about talks at the Evolution meetings in Ottawa last month, I’d like to share some results from Bryan Falk from Susan Perkins’s Lab American Museum of Natural History.  Bryan has been investigating the diversity of anole malaria parasites (Plasmodium).  Like many other species of vertebrates, anoles have their own strains of malaria (not the same as the ones that effect us humans), and these lizard malaria have been the focus of numerous fascinating research projects over the years (see Schall 1996 for a review).

Bryan’s work investigated phylogenetic relationships among West Indian strains of lizard malaria using sequence data from mitochondrial DNA plus six nuclear loci.  He found that Plasmodium samples on most islands form monophyletic groups, although some clades are found in both Florida and Cuba, suggesting travel between these two regions.  Bryan also reported very low overall genetic diversity, the presence of most genetic variation among (rather than within) populations, and no evidence for purifying selection.  Bryan’s previous work used tree-based delimitation to diagnose previously unrecognized or ambiguous taxa of Plasmodium on Hispaniola, and his new work uses a similar approach across a broader geographic scale.  In the new study, species tree analyses tend to recover island-specific clades and identify 11 potentially unrecognized species within Plasmodium floridense (see Perkins 2000 for more on species delimitation in Plasmodium). Bryan’s time calibration work suggests that intra-island divergences are very young and his demographic analyses suggests that recent divergence and serial bottlenecks may be responsible for low diversity with in populations but high divergence among populations.  It seems like more exciting new results with anole malaria on are on the horizon from Bryan and his collaborators.

Lizard Massacre! Kitty Cam Documents Feline Rampage (And Other Cool Stuff)

The New York Times covered the story, too. http://graphics8.nytimes.com/images/2012/08/08/blogs/cat/cat-blog480.jpg

We reported earlier this month on the talk at the Ecological Society of America where a University of Georgia researcher put kitty cams on housecats to see where they went and what they did. And one finding: they caught a lot of anoles! USA Today ran an article on the front page, and included a video online that has some grisly (ok, not that grisly) footage of this, as well as other cool stuff (encounters with other animals, secret lives of housecats). Check it out!

Amazing Color Differences In Lizard Populations Separated By Little Distance

The guys at Day’s Edge Productions have wrapped up their expedition to Spanish Islands in quest of colorful and highly variable lacertid lizards. They’ve posted their swan song of a video, which reveals extraordinary differences in color in populations literally right next to each other. As always with this team, worth watching.

And while we’re on the topic of great lizard videos by Day’s Edge, here’s a wonderful one on the introduced anoles of Miami and Neil Losin’s doctoral work. Though made more than a year ago, for some reason, it seems to have just made it’s way to Youtube, which is reason enough to pop it up here.

Anole Photo Contest: Reminder, Sept. 30 Deadline

Grand Prize

Just a reminder about this year’s photo contest. Last year we had an Anolis photo contest and produced a 2012 anole calendar. Both were wildly successful. This year, Anole Annals is is combining the two with the 2012 Anole Photo Contest. The grand prize winner will have her/his photo featured on the front cover of the 2013 Anole Annals calendar and will receive an autographed copy of Karen Cusick’s lovely book, Lizards on the Fence. The second place winner will receive a copy of the calendar and have her/his photo featured on the backcover of the calendar. We’ve already got a number of good entries, but the judges feel that there’s still a chance that new entries can rise to the top. So don’t delay–submit today!

This year’s calendar. Put your photo on the cover of next year’s version!

The rules: please submit photos as attachments to anoleannals@gmail.com. To ensure that submissions with large attachments arrive, it’s a good idea to send an accompanying e-mail without any attachments that seeks confirmation of the photos receipt.  Photos must be at least 150 dpi and print to a size of 11 x 17 inches. If you do not have experience resizing and color-correcting your images, the simplest thing to do is to submit the raw image files produced by your digital camera (or, for the luddites, a high quality digital scan of a printed image). If you elect to alter your own images, don’t forget that its always better to resize than to resample. Images with watermarks or other digital alterations that extend beyond color correction, sharpening and other basic editing will not be accepted. We are not going to deal with formal copyright law and ask only your permission to use your image for the calendar and related content on Anole Annals. We, in turn, agree that your images will never be used without attribution and that we will not profit financially from their use (nobody is going to make any money from the sale of these calendars because they’ll be available directly from the vendor).

Please provide a short description of the photo that includes: (1) the species name, (2) the location where the photo was taken, and (3) any other relevant information. Twelve winning photos will be selected by readers of Anole Annals from a set of 28 finalists chosen by the editors of Anole Annals.  The grand prize winning and runner-up photos will be chosen by a panel of anole photography experts. Deadline for submission is September 30, 2012.

This Is Not A Madagascan Day Gecko

What baby wouldn’t love this?

We all know that geckos want to be anoles. But I fear I have unearthed a plot by an unidentified group of gecko-groupies to elevate the lowly gecko in the eyes of the public by forcing innocent anoles to masquerade themselves as (gasp) Madagascan day geckos. It all began several weeks ago, under the guise of a day trip to London to take in a little-known sporting event involving heroic UK demi-gods and demi-goddesses versus some other people (or so the BBC told me). Late in the day, we found ourselves wandering one of our favourite London haunts – the Natural History Museum. The mission: a gift for our soon-to-be-born niece (and where else would you go to find a gift for a newborn other than a natural history museum gift shop?). In the book section, I found a potentially better option: My First Book of Reptiles and Amphibians. It looked perfect – what baby wouldn’t love to be lulled to sleep by a full page close-up of a mouse disappearing down a viper’s throat or tidbits of information like “An adder’s bite is rarely fatal. It can cause mild swelling, and is very painful, but it is unlikely to kill you.” Imagine what herpetological feats said child would achieve later in life!
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Brown Anole Dear Enemies

One of the brown anole males in the McMann and Paterson study. Photo by Stephen McMann.

Anole Annals readers know otherwise, but many people consider lizards to be simpletons, with nary a thought in their head. But that’s mistaken–it’s salamanders that are the truly stupid ones (sorry for the tangential ad hominem). Lizards have more going on upstairs than people realize. Sure, they’re not the sharpest knife in the drawer, but they’re no dummies, either.
ResearchBlogging.org Case in point: lizards are able to recognize and differentiate among other lizards. This conclusion, which has now been demonstrated a number of times, was reinforced by a recent paper by McMann and Paterson in Herpetological Conservation and Biology. They set out to test whether  brown anoles react differently when confronted with a neighbor than when confronted with a lizard that lives farther away and that, presumably, the lizard has not interacted with in the past. This is a test of the phenomenon termed “dear enemy,” the idea that neighbors get to know each other and come to a mutual coexistence in which, when they encounter each other, they go through perfunctory displays, but don’ t get all riled up, because they’ve already been through all of that before. The dear enemy phenomenon has been demonstrated previously in a variety of other lizards. Indeed, these authors have demonstrated it before with brown anoles, but that work was conducted in experimental arenas. This time, the authors wanted to see what happened when the research was conducted in nature, in animals’ own territories. To do this, they presented territorial males with another lizard enclosed within a small cage. Continue reading

World Congress Of Herpetology 7: Year Round Reproduction In A High-Elevation Colombian Anole

We’re just wrapping up a few last posts from last week’s World Congress of Herpetology in Vancouver. In a tour de force, Laura Rubio-Rocha presented two posters, side-by-side, in the first night’s session. We’ve already discussed her doctoral work on geographic variation in adaptation to different climates in A. carolinensis; here I briefly mention her poster on a high elevation Colombian anole that exhibits year-round reproduction in an environment in which there are two rainy seasons. This interesting study was recently published; you can learn more about it in our previous post on that paper.

Find That Sports Illustrated Anole

In a comment on a previous post on anole olympians, Kevin de Queiroz dug into the archives to pull out this vintage Sports Illustrated swimsuit issue photo from 1980, featuring an Anolis cristatellus, as well as some woman in the foreground. Can you find that anole? Incidentally, it’s from the 1980 SI swimsuit issue, which you can access on their website; Christie Brinkley was on the cover and the photos were taken in the British Virgin Islands.

Anole On PBS

BBC host Michael Mosley with a Jamaican anole he captured

Our local PBS station has been airing episodes of the entertaining 2010 BBC series The Story of Science: Power, Proof, and Passion, hosted by medical journalist and doctor Micheal Mosley. The program recounts the history of major advances in science by focusing on the individuals responsible for them.

Episode Three, “How did we get here?”, tracks Evolutionary theory, from the development of geology, through Cuvier’s advances in comparative morphology and on to the field work that kickstarted Darwin and Wallace’s thought processes. In this episode Mosley follows in the footsteps of early collector Hans Sloane. Sloane, as you will recall from a previous post, assembled an expansive collection of Jamaican flora and fauna including anoles.

There is a brief segment where Mosley and his botanist guide construct small nooses and capture an anole, pictured above. I don’t know the Jamaican fauna well, but my guess is that he’s got A. lineatopus. Unfortunately I can’t find any video clips and the only picture available (above) is pretty grainy. If you’ve seen the episode or if you can make out the species from the picture above, let me know if I’m close in the comments.

UPDATE: The anole segment is online! Thanks to Jonathan for sleuthing this out.

Getting Anoles To Lay Eggs – Please Help!

Denizens of the Anole Annals – I need help with my breeding experiment! This summer I am conducting a common garden experiment with Anolis armouri and A. cybotes, two trunk-ground anoles from the Dominican Republic. Things were going pretty well with A. cybotes, but as of late both species have stopped laying. Anolis armouri didn’t lay very much at all in the past month. I have already finessed the dirt moisture in the laying pot and the temperature/humidity conditions are fine. In the interest of getting data, I would like to induce them to lay, perhaps with oxytocin? Does anyone out there have suggestions on what can be used to induce laying? Dosage? Timing? All your advice would be much appreciated!

World Congress Of Herpetology 7: Amber Anoles!

A sampling of the anoles examined by Emma Sherratt

The World Congress called on Emma Sherratt to serve as the closer, presenting the last talk on the last day of the meeting. The choice proved brilliant, as she sent the audience off to the banquet in high spirits with a captivating report on her examination of 30+ specimens of amber-encased anoles. Emma has already wowed us with  the images and videos she produces by micro-CT scanning; needless to say, the audience was amazed. Preliminary analyses suggest that multiple species are present in the sample (only one amber anole has been described in the scientific literature), and several of the types may match present-day ecomorphs. Her abstract: Continue reading

World Congress Of Herpetology 7: Is The Anole Ecomorph Radiation Exceptional?

Travis Ingram reported on a new method he devised to test whether the anole radiations on the Greater Antilles are more similar than might be expected to occur by chance. We all know that each island has experienced its own radiation, producing more or less the same set of ecomorphs. However, some islands have more ecomorphs than others (Jamaica: 4; Cuba, Hispaniola: 6). In addition, there are non-ecomorph species on the larger islands. It is always possible that it is just a coincidence that the same types have evolved on multiple islands. After all, given large enough evolutionary radiations, one would expect the same morphology to evolve by chance on multiple islands. Travis developed a method to test this hypothesis, and found that, indeed, the Greater Antillean radiations are more similar in morphology than would be expected by random evolutionary change. Read all about it in the abstract: Continue reading

World Congress Of Herpetology 7: Reptile Diversity And Distribution In The Highlands Of Western Panama

Sebastian Lotzkat presented a fascinating talk on geographic variation, both morphological and genetic, in Panamanian reptiles, emphasizing the highlands of western Panama. Although he discussed a wide range of species, he spent an appropriately large amount of time focusing on anoles, which if I recall correctly, he termed his favorites. To cut to the chase, he’s found very large amounts of variation in almost every species examined, including in some cases dividing species into several new species. Some of this work has already been chronicled in AA, and another paper will soon be reported on, but apparently there is a lot more yet to come. Read the abstract below the fold. Continue reading

World Congress Of Herpetology 7: Anole Brain Power

Anole brains. For scale, the partial coin is an American penny.

A pair of talks from Duke University took different approaches to examining anole smarts. Recently minted Ph.D. Brian Powell reported on his examination of the brain size and composition of different anole species. Brian reasoned that anoles living in different habitats would evolve differences in brain structure corresponding to the different challenges they faced, and thus that species that use the same habitat should have converged on brain morphology. However, results failed to support this hypothesis and instead indicated that the size of different brain components evolves in concert. More details below.

The three species that have demonstrated behavioral flexibility in the lab. Sure wish I could remember what the third point was

Later in the meeting, Manuel Leal reported on the cognitive flexibility of several anole species. Previous work has shown that A. evermanni is not only adept at solving novel problems, but can reverse previously learned patterns so as to ignore the stimulus that previously was rewarded and instead respond to a stimulus that previously hadn’t been rewarded. Leal has now extended that work to show that two other anoles can do the same. He then went on to test how adept anoles are at telling apart two similar patterns. He found, surprisingly, that they could tell very different patterns apart, but did not seem to be able to distinguish more similar patterns. Leal concluded by wondering whether minor differences in signals are detectable by receivers, which is an underlying assumption of many studies of sexual selection and communication. Manuel’s abstract is below the fold as well, although he went off-script in much of the talk he presented. Continue reading

Puerto Rican Anoles Are Chilling In Florida – New Research By Jason Kolbe And Colleagues

A male Anolis cristatellus dewlaps on a tree in Miami, Florida. Picture reproduced with permission from Kolbe et al. (2012).

Anoles are remarkably adaptable creatures. You can find anoles in hostile environments, such as the tops of mountains in the Dominican Republic, in near-desert environments, and in places with over-winter freezing. Anoles are also a model system for rapid evolution; in response to strong selective pressure, an equally strong evolutionary response occurs within a few generations. It is perhaps unsurprising, then, that anoles are also one of the most invasive reptiles in the World. Although they are endemic to the tropical and subtropical regions of the New World, today anoles can also be found in such remote places as Guam, Hawaii, Taiwan, and Hong Kong.

One of the major questions surrounding anole invasions is how the organisms will respond to the challenges of a new environment. When anoles invade new environments they inevitably encounter new thermal and hydric conditions – how do these anoles adapt to a different environment? Jason Kolbe has spent many years exploring the ecology and genetics of Anolis invasions, and has focused especially on invasions in Florida (1, 2, 3). The Puerto Rican trunk-ground, A. cristatellus, has been found in Key Biscayne and South Miami since the mid-1970s. Ambient temperature is important for A. cristatellus and other anoles have been documented to acclimate to low temperatures. In this study Jason Kolbe and colleagues addressed two questions: (1) To what extent does the thermal environment change from Puerto Rico to Florida? and (2) Is there a phenotypic response in tolerance to cold?

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