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As you have heard before on Anole Annals, the Lizards On The Loose project involves middle school students conducting anole surveys in their back yards, school grounds, and local parks throughout South Florida. You can read more about the background and early results of this project in an earlier AA post which summarizes my talk at the Ecological Society of America’s (ESA) 2016 annual meeting.

Well, now we have updated results! Chris Thawley, a postdoc in Jason Kolbe’s lab and new member of the Lizards On The Loose team, has produced this video which explains what we have learned from the new data collected by students during their 2016-17 surveys. One species that we are particularly interested in is the Puerto Rican crested anole (Anolis cristatellus), whose distribution in Miami has been closely monitored since their introduction in the 1970s (see Kolbe et al. 2016 for a review of this species’ range dynamics in Miami). To our amazement, middle school students identified populations of crested anoles that were brand new to us! Watch below for more information:

By Andres Marmol and Ignacio Moore

A new study by Diego R. Quirola and collaborators about the enigmatic Ecuadorian proboscis anole has been published a few weeks back. In this study, the authors report new ontogenic and social behaviour data regarding males of this amazing lizard and its most noticeable character: the proboscis. But before going into the data, lets draw a short background.

Of all the Ecuadorian reptiles, Anolis proboscis is arguably the most remarkable. Originally described by Peters and Orcés in 1956, this elusive species was not seen for almost 50 years and was believed to be extinct, until 2005 when a group of ornithologists spotted and photographed a male (see Almendáriz and Vogt, 2007; see this previous post for a discussion of this history). Since then, a number of researchers have been interested in this lizard. However, a major question remained unclear regarding the species’ most notable character: how do males use the fleshy rostral appendage in social interactions?

Ernest E. Williams (1979) gave the first reliable hypothesis around this question in his taxonomic analysis of the proboscis anoles (of which there are two additional species; see more details in Williams, 1979). Based on collected male specimens, he proposed that the proboscis was the result of sexual selection. Two main questions required an answer to support William’s hypothesis: (1) do females also have the proboscis (Females were unknown at that time)?; and (2) how is the proboscis used by these lizards (No data on the natural history of the species had been described particularly regarding social interactions).

The first part of the riddle was solved in 2010 when the females were discovered confirming that the proboscis was only observed in males (see Yánez-Muñoz et al., 2010 for a proper description). Documenting the behaviour of the species in nature, however, was a greater challenge —as anyone that has attempt to study animal behavior knows— due to both the cryptic coloration of the species and its elusive nature. Two more years went by before the first insights about the natural history of the species were known — Losos et al. (2012) described the habitat use, diet, and activity patterns, whereas Poe et al. (2012) reported anecdotal observations of intra- and intersexual social behavior of the species and some uses of the proboscis. Despite these advances, more detailed observations of the species’ social behavior were needed. And more importantly, the use of the proboscis remained undescribed.

This point is where the new publication becomes relevant. By using a semi-natural environment where males and females were placed, the authors were able to record social interactions for the first time in this species. In particular, the study describes the agonistic behaviour between males, including the displays and the proboscis function during the encounter. The study provides a complete description of the courtship and mating behavior, reporting for the first time a female display during male-female interactions. As a bonus, the research reports the ontogeny of the rostral appendage.

Among the highlights of the paper include the description of four different displays that the males appear to use. Most interesting is the behaviour termed “proboscis flourishing”: a display composed of stereotyped lateral movements of the head that appear to be a way to present the rostral appendage to the female counterpart. The authors discuss the possibility that females can be assessing males by using this display as it was only observed during male-female encounters and before chasing—another new report of the reproductive behaviour of the species—occur (Video 1, Supplementary material).

Journal of Natural History, 2017. doi:10.1080/00222933.2017.1332790

In addition, the paper reports the first captive-born A. proboscis along with a long-awaited answer: males are born with a tiny appendage (see a previous entry or check Hepu’s footage). But most of all, in terms of use of the rostral appendage, this study confirms with several independent observations that the proboscis is actively lifted before any bite attempt and is not, under any circumstance, used as a weapon against other males— as previously discussed by Poe et al. (2012) and Losos et al. (2012). In contrast, the authors suggest that the movement of the proboscis could be performed to facilitate feeding behaviors or even other behaviors related to courtship as the proboscis was lifted when males stimulate the female’s nape (similar to what is described in other anoles).

In the last ten years, knowledge about this enigmatic anole has increased substantially thanks to the contribution of studies like Quirola et al. In particular, is clear that the rostral appendage has no direct use in physical combat. However, there is still a long way to go before we understand why and how this exaggerated trait evolved. Other variables regarding proboscis morphology, such as size or straightness, could be possible characters that may be honest indicators of quality and/or may confer an advantage against other males during agonistic behaviors. One thing is sure: we have only scratched the surface of the mystery of the evolution of the proboscis and this fascinating lizard.

Useful References:

ALMENDÁRIZ, A. C. & VOGT, C. 2007. Anolis proboscis (SAURIA: POLYCHROTIDAE), UNA LAGARTIJA RARA PERO NO EXTINTA. Politécnica, 27, 157-9.
LOSOS, J. B., WOOLLEY, M. L., MAHLER, D. L., TORRES-CARVAJAL, O., CRANDELL, K. E., SCHAAD, E. W., NARVÁEZ, A. E., AYALA-VARELA, F. & HERREL, A. 2012. Notes on the Natural History of the Little-Known Ecuadorian Horned Anole, Anolis proboscis. Breviora, 1-17.
POE, S., AYALA, F., LATELLA, I. M., KENNEDY, T. L., CHRISTENSEN, J. A., GRAY, L. N., BLEA, N. J., ARMIJO, B. M. & SCHAAD, E. W. 2012. Morphology, Phylogeny, and Behavior of Anolis proboscis. Breviora, 1-11.
WILLIAMS, E. E. 1979. South American Anoles: The Species Groups. 2. The Proboscis Anoles (Anolis laevis Group). Breviora, 449, 1-19.
YÁNEZ-MUÑOZ, M., URGILÉS, M. A., ALTAMIRANO, M. B. & CÁCERES, S. S. R. 2010. Redrescripción de Anolis proboscis: Peters & Orcés (Reptilia: Polychrotidae), con el descubrimiento de las hembras de la especiey comentarios sobre su distribución y taxonomía. Avances en Ciencias e Ingeniería, 2, 1-14.

The latest work on genetic differentiation and species status within the Anolis distichus group has just been published by MacGuigan, Geneva and Glor in Ecology and Evolution. In line with previous work from the Glor lab, the study finds evidence for seven distinct evolutionary lineages worthy of recognition as species, and further finds that variation in dewlap color in some cases does not correlate with geographic isolation. Finally, geographic isolation seems to play a key role in genetic divergence.

Here’s the abstract, followed by a few comments:

Abstract

Delimiting young species is one of the great challenges of systematic biology, particularly when the species in question exhibit little morphological divergence. Anolis distichus, a trunk anole with more than a dozen subspecies that are defined primarily by dewlap color, may actually represent several independent evolutionary lineages. To test this, we utilized amplified fragment length polymorphisms (AFLP) genome scans and genetic clustering analyses in conjunction with a coalescent-based species delimitation method. We examined a geographically widespread set of samples and two heavily sampled hybrid zones. We find that genetic divergence is associated with a major biogeographic barrier, the Hispaniolan paleo-island boundary, but not with dewlap color. Additionally, we find support for hypotheses regarding colonization of two Hispaniolan satellite islands and the Bahamas from mainland Hispaniola. Our results show that A. distichus is composed of seven distinct evolutionary lineages still experiencing a limited degree of gene flow. We suggest that A. distichus merits taxonomic revision, but that dewlap color cannot be relied upon as the primary diagnostic character.

The authors suggest that there are at least seven species within the distichus complex, but they suggest that it is premature to recognize them officially at this time. Nonetheless, Poe et al. in their recent Systematic Biology paper (hey! who’s going to write a post on this one?) recognize at least some of these taxa as distinct species.

Finally, I do have one tiny bone to pick. The authors state:

“Together these results suggest that dewlap color is not by itself a reliable diagnostic trait in the A. distichus complex, and perhaps in anoles more broadly.”

I take umbrage with the final statement, “and perhaps in anoles more broadly.” The distichus complex has always been recognized as the major exception to the idea that dewlap color variation relates to reproductive isolation. Consequently, demonstrating what has been suggested—with some evidence—for 40 years doesn’t necessarily argue against the role of the dewlap in reproductive isolation more generally. Now, you may quibble with the data underlying this general proposition, and it certainly is worthy of further study, but the results of this study confirm what was already recognized as an exception to this general rule..

With summer just around the corner (any day now, Boston!) that can only mean one thing – the annual ASN/SSE/SSB sponsored Evolution meeting is almost here! This year the anole community is attending in full force with 2 posters, 11 regular talks, and 2 symposium talks.

We regularly cover this meeting here at Anole Annals, and once again we are asking for YOU to help us out. If you will be attending Evolution and are interested in writing a short blog post about one or more of the talks or posters, send me an email (kristin.winchell001@umb.edu) or comment below. I will give you all the information you need to get started and a little help on how to write a blog post for us if you haven’t done so before. We always appreciate the extra help and fresh perspectives.

For those of you not attending the meeting (or maybe still debating attending), here’s the current list of anole talks in the schedule.  Are you particularly excited about a talk at Evolution this year? Did we miss a talk that should be on our list? Let us know in the comments!

Bill Rainey observed this lizard on a restored portion of one temple at Altun Ha, an ancient Mayan city in modern-day Belize, in an area shaded by trees. Anyone know what it is?

The following is taken from the Society for the Study of Amphibian and Reptile’s website:

Catalogue of American Amphibians and Reptiles

The Catalogue consists of accounts of taxa prepared by specialists, including synonymy, description, diagnosis, phylogenetic relationships, published descriptions, illustrations, distribution map, and comprehensive list of literature for each taxon. Over 900 accounts have been published since the initiation of the series in 1963. The series covers amphibians and reptiles of the entire Western Hemisphere. Previously, accounts were published as loose-leaf separates; beginning in 2013 accounts are published as on-line PDFs.  All accounts are open access and are available for free download at the University of Texas Library Repository.

Just this week, one of the latest catalogue entries is for the little known Anolis ruibali of Cuba, written by Robert Powell, Javier Torres, and Nils Navarro Pacheco.

Poor Anolis, snack box of the jungle. Seems that just about anything will eat an anole. So, it’s not surprise to learn that the teid lizard Kentropyx calcarata joins the lizard of anole consumers. So report Franzini et al. in a recent report in Herpetology Notes. Anolis fuscoauratus was the unfortunate victim, the crime discovered by examination of stomach contents.

Consider two lizard species that differ in limb length, with one species having relatively longer legs than others. During development, how does this difference arise? Do the limbs start at the same length when they first appear in the embryo, but grow at a greater rate in the longer-legged species? Or is the initial limb bud longer in the embryo of the longer-legged species, and then the rate of growth the same in the two species, preserving the initial difference?

Thom Sanger’s elegant work showed that the latter answer is correct for Anolis: the limb buds of long-legged species start out longer and then grow in parallel with those of shorter-legged species.

But does this finding also hold when comparing across a broader range of lizards? Robin Andrews and Sable Skewes decided to find out, comparing embryos of a chameleon, two geckos, and the brown anole.

The answer: the same pattern as within anoles! And it applies to tail length (but not head length) as well as limbs.

My good friend Trace Hardin, a professional entomologist but also avid herper and snake breeder, just sent me these photos below. Here’s what he had to say about the encounter on Instagram:

hardinherpetologica: Interesting observation while walking through the woods. Found this #BoxTurtle eating a dead #GreenAnole. I’m assuming it was a scavenged find but the entire body was gone by the time I came upon the scene. #Neature

Has anyone else observed box turtles (or any other chelonian [I guess now testudine?]) interacting with anoles?

Thanks to the work of Roger Thorpe and colleagues, Lesser Antillean anoles are renowned as an example of adaptive geographic variation. On many islands in the Lesser Antilles, populations in wet areas, where vegetation is lush, are green in color, whereas those in more xeric areas tend to be a drab gray, often with markings on their back. This pattern is repeated on many different islands, the convergent geographic variation thus making a strong case for the adaptive basis of anole coloration.

See Pavitra Muralidhar’s previous post for more information on geographic variation in Lesser Antillean anoles.

In a new paper in PLoS One, Thorpe takes this work a step further, asking whether we can use the parallel patterns seen across Lesser Antillean islands to predict the coloration of an anole species on another island. The focal species is Anolis bonairensis, which occupies the extraordinarily dry island of Bonaire (see our previous posts on this species).

The prediction: A. bonairensis should be grayer and drabber than populations of anoles that occur at the driest sites on Lesser Antillean answers.

The answer: yes! Just as predicted, Anolis bonairensis is one drab lizard. Score one for evolutionary predictability!

Anolis bonairensis is represented by the red circles. The x-axis goes from aridity on the left to the most mesic on the right. As you can see, A. bonairensis‘s color and patterning is well-predicted by variation in other species.