Author: Jonathan Losos Page 92 of 133

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.

We’ve had a lot of great discussion about Nicholson’s et al.’s proposal to split Anolis into eight genera. To date, most of the commenters have been against the proposal; I’d like to explain why I agree with this majority view.

Anole Annals summarized the arguments for splitting Anolis several days ago. Nicholson et al. argue that the failure to divide Anolis in the past has inhibited evolutionary and systematic research:

“Systematic progress in this regard has been delayed by an extremely conservative taxonomic approach to recognizing the diversity within the group and its extraordinarily ancient historical roots.” (p.4)

“The current practice (following Poe, 2004) of treating all dactyloids as comprising a single genus underemphasizes the evolutionary diversity within the family (as currently recognized) and obfuscates major biological differences among clades. In addition, simply because of the large size of the family (nearly 400 valid species), the single genus concept can be a hindrance to scientific communication regarding evolutionary events and directions of future research.” (p.13)

These quotes suggest that research on anoles is being held back by treating the entire clade as a single genus, but where is the evidence for these claims? No examples are provided. Quite the contrary, research on anoles has flourished over the last several decades, making it a well-known group for the study of many diverse evolutionary phenomena, and much of this work has explicitly incorporated phylogenetic information. Indeed, anole evolution, considered in a phylogenetic context, has become a commonly cited textbook example of adaptive radiation, and work on anoles has become so broad and deep that one commenter at last year’s Evolution meetings noted that “I didn’t go to the Evolution meetings for three years…When I “returned” in 2011 in Norman, it was like everybody had switched to working on anoles and sticklebacks!” The Dobzhansky Prize winners at the last two Evolution meetings have conducted phylogenetically-based research on anoles, and anole workers have nabbed the Fisher Prize and four Young Investigators Prizes at the meetings in that time span. Anole research is going gang-busters, and it is hard to see how retaining the name Anolis for the entire clade has had any sort of detrimental effect. (see also comments by Eric Schaad on why taxonomic names are no longer important for conducting phylogenetically-based evolutionary studies and by Yoel Stuart on why splitting evolutionarily-interesting clades may actually impede research).

I disagree with the proposal to split Anolis into eight genera for two reasons. First, it is not possible for the Linnean classification system to fully represent phylogenetic relationships—splitting genera simply changes the information conveyed, gaining some bits of information and losing others (for more discussion on this point, see the recent post by Luke Mahler and ensuing commentary). Second, splitting Anolis will be extremely disruptive for scientific researchers and the public.

Day Geckos Eating Cheerios

By Jonathan Losos

On September 30, 2012

In Natural History Observations

httpv://www.youtube.com/watch?v=gPti2cm2ypw&feature=player_embedded

Those darn faux anole day geckos are out-cuting our boys again. The title of this post is self-explanatory, but the link to anoles isn’t completely tenuous–the gene that encodes for taste receptors that are sensitive to sweet things isn’t posssessed by all animals (e.g., cats lack it), but it has been found in the anole genome and, Matthew Cobb guesses based on this video, in geckos as well.

Color-Changing, Water-Cruising Anoles

By Jonathan Losos

On September 30, 2012

In Natural History Observations

Check ’em out on dust tracks on the web. Who says green anoles perch high up when in areas where brown anoles don’t occur (check out this recent post and especially the comments to find someone who says they do, at least in North Carolina).

Anolis Carolinensis Named “Invasive Species Of The Week”

By Jonathan Losos

On September 29, 2012

In Anoles and Anolologists in the News

The Invasive Species Specialist Group, a Species Survival Commission (SSC) of the International Union for the Conservation of Nature and Natural Resources (IUCN), recently gave the weekly top honor to our favorite greenie. We love ’em here in the U.S., but as we’ve documented many times, they can be a problem elsewhere. A pdf of the picture above is available at the ISSG site.

Dietary Data For Anolis Capito In Costa Rica

By Jonathan Losos

On September 29, 2012

In Natural History Observations

AA contributor Dave Steinberg is in Costa Rica filming anoles. He’s posted his first report over on Chipojolab, featuring information on the diet of a juvenile A. capito he caught, with a surprising twist.

How Often Do Anoles Lose Their Tails In Intraspecific Fights?

By Jonathan Losos

On September 28, 2012

In Natural History Observations

Male A. pogus fighting. Photo from http://www.lesfruitsdemer.org/wp-content/gallery/anolis-pogus-battle-03-01-2010/DSC_7573.jpg

Recently, our lab group was discussing what can be inferred from calculating tail loss rates in anole populations. It was pointed out that tail loss doesn’t necessarily result from predators and that, in fact, males may bite off the tails of other males in fights, and the victor or vanquished may even eat the tail. Someone pointed out that the older literature certainly pointed this out with examples*, but we haven’t seen much of this in more recent literature. So, we then asked, has anyone ever actually seen a tail lost in a fight? No one had. I then got online to look for photos. I could find plenty of males fighting, usually locking jaws or sometimes biting the body or a limb, but I found no photos of an anole biting another’s tail, much less biting off a tail. So, I ask you, fair AA reader, have you ever seen this? Can you provide a photo?

*By earlier literature, we were thinking 1960’s and 1970’s, but here’s a quote from the 1870’s, referring to A. cristatellus. Can you name the author? “During the spring and early part of the summer, two adult males rarely meet without a contest. On first seeing one another, they nod their heads up and down three or four times, and at the same time expanding the frill or pouch beneath the throat; their eyes glisten with rage, and after waving their tails from side to side for a few seconds, as if to gather energy, they dart at each other furiously, rolling over and over, and holding firmly with their teeth. The conflict generally ends in one of the combatants losing his tail, which is often devoured by the victor.”

Green Anoles Are A Gardener’s Best Friend

By Jonathan Losos

On September 27, 2012

In All Posts

That’s right, it says so right here!

No surprise to us at AA, but greenies apparently provide yeoman service as garden pest control. And the wonderful folks at www.getmypestout. com provide all kinds of good advice about how to foster a healthy anole population in your garden. Good on ’em!

High Flyin’ North Carolina Anoles

By Jonathan Losos

On September 23, 2012

In Natural History Observations

This NC green anole is on the ground, but mostly they apparently are up in the trees. Photo from http://www.wildherps.com/images/herps/standard/08041129PD_green_anole.jpg

We’ve had a lot of talk here on AA about how green anoles can be found low to the ground in places where A. sagrei has not invaded. But Manuel Leal says that’s not so in sagrei-less North Carolina, where all the ones he saw in the woods were high in the trees. What gives?

Anolis Electrum: The Amber Anole From Mexico

By Jonathan Losos

On September 22, 2012

In Classics from the Literature

A recent photograph by Emma Sherratt. Amber tends to darken over time, which explains the deep orange color.

We’ve had previous posts on fossil anoles in amber. Emma Sherratt is currently studying them and has examined some three dozen specimens. All of these are from the Dominican Republic. Except the first one ever discovered, a Mexican piece described by Skip Lazell in 1965. Anolis electrum, as it was named, has had a pretty quiet scientific life. Now middle aged, the species has not been the subject of any subsequent research in the 47 years of its existence. But now it’s in the spotlight, as its phylogenetic position and dating may be pivotal for the recent calculation by Nicholson et al. that anoles originated more than 100 million years ago. In this post, I summarize what is known about A. electrum (examine the short original paper for yourself!). No doubt, we’ll be hearing more soon about the relevance of this species–specifically its phylogenetic placement and age–for dating anole diversification.

As you can see for yourself in the photo above, there are actually two pieces, a front half of a lizard and a back half a lizard. Since they were found together (or at least made it to the Paleontology Museum at UC-Berkeley together) and are matching in size, it seems like too much of a coincidence for them not to come from the same animal. Various aspects of the animal’s scalation are discernible, including some nicely visible toepads. Lazell stated that all that was left was skin, or the impression of skin, the bones having been eaten away, but Emma’s cat scanning has shown that this is not quite correct (see below).

Based on the specimen, what can be said about its phylogenetic placement? All anoles in Mexico today are from the Norops clade. Unfortunately, the primary character for identifying Norops is the shape of the caudal vertebrae, which cannot be discerned in this tailless specimen. Lazell compared the scalation of this specimen (a 26 mm juvenile) to various species, and found that the scalation was unlike most species. He concluded that electrum was most similar in scalation to A. fuscoauratus, A. maculiventris, and A. chloris, and among species found in Mexico, to A. limifrons (full quotations at the bottom of this post).

What should we make of all of this? It’s important to remember that this paper was published in 1965, prior to the description of many extant anole species and a year before Willi Hennig’s classic introduction to cladistic analysis was translated into English. This is a purely phenetic comparison of the amber baby lizard to known species, clearly non-phylogenetic and utilizing characters that now are recognized to generally have little higher level systematic utility in anoles. And the conclusion is that it is either a Norops clade anole (fuscoauratus, limifrons or maculiventris) or a Dactyloa species (chloris).

The other question one might have is: how old is this fossil? Dating amber is notoriously difficult. Solórzano Kraemer reviewed all of the data on Mexican amber bearing deposits in the 2010 volume Biodiversity of Fossils in Amber from the Major World Deposits and concluded: “In summary, it can be said that Mexican amber can be correlated with Dominican amber, with an age of approximately 15-20 million-years-old.” In other words, Mexican and Dominican amber anoles were contemporaneous.

Did anyone notice anything odd on the fossil of the lizard posterior (B, above)?

2012 Anole Photo Contest: Last Chance To Enter

By Jonathan Losos

On September 22, 2012

In All Posts

We’ve already received a lot of great entries, but there’s room for more! We’re reprinting the announcement below. Deadline is September 30, so submit today!

Last year we had an Anolis phot o contest and produced a 2012 anole calendar. Both were wildly successful. Today, Anole Annals is pleased to announce it is combining both. We herewith announce the 2012 Anole Photo Contest. The goal of the contest is to identify 12 winning photos. 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.

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.