Anole Annals

Screenshot from https://www.instagram.com/reel/DCnjCxhJmVS/

Read about Steve Nielsen, the artist, here.

Distribution of sampling localities for individuals included in our breeding experiment. A Male slender anole dewlaps come in two morphs: solid and bicolor (photographs taken by John David Curlis). B Sampling localities in the Canal Zone of central Panama and associated morph frequencies of males in those populations (circle size corresponds to relative sample size from each site). The frequency of solid morph individuals generally declined from the Pacific to the Caribbean versant of Panama. C Sampling localities for individuals included in our Poolseq experiment. All these individuals were collected along a central trail that bisects Soberanía National Park, near the town of Gamboa.

Color us intrigued! In the world of Anolis lizards, the dewlap—a colorful throat fan used for communication—is one of the most iconic features. It’s been flaunted, flashed, and filmed in countless studies of behavior and adaptive radiation. But for all the attention it gets, we still know surprisingly little about how this flashy ornament is inherited at the genetic level.

Enter the slender anole (Anolis apletophallus), a small but charismatic lizard that ups the dewlap drama with a striking polymorphism. Males come in two distinct throat flavors: the “solid” morph, sporting a fully orange dewlap, and the “bicolor” morph, featuring a mostly white dewlap with a splash of orange at the base. What’s behind this variation?

To find out, we set up 99 crosses (yes, 99!) using individuals from populations that were either monomorphic (fixed for one morph) or polymorphic (home to both morphs). The results? A classic Mendelian plot twist. The dewlap polymorphism in this species is likely controlled by a single autosomal locus, with the solid orange morph dominant over the bicolor version. Simpler than we expected—but the story doesn’t end there.

Pooled sequencing revealed a strong candidate locus (single-minded 1, SIM1) that may underly the slender anole dewlap polymorphism. A Manhattan plot illustrating genomic differentiation between the dewlap morphs using pairwise FST values, and B Fisher exact tests. The red lines in B and C represent the Bonferroni correction (p value= 8.9), with points above the line indicating significantly differentiated SNPs across the slender anole genome. C One locus on scaffold 3, the transcription factor SIM1, contained a peak of many highly differentiated SNPs between morphs. The vertical green bars in the inset represent exons and the arrow represents the direction of genome annotation. D Nucleotide diversity (π) of SIM1 for the bicolor (green) and solid (brown) dewlap morphs. Note that nucleotide diversity was often higher in the dominant solid morph. E SNP panel showing segregating alleles in all significant SNPs (n = 175) in the candidate region of SIM1 for each morph plotted as a heatmap. We denote ref/ref in green representing that solid morph individuals were fixed for one allele and alt/alt in purple indicates that bicolor individuals were fixed for an alternative allele. Ref/alt in blue represents more than two alleles segregating at that position for either the solid or bicolor population. F Male slender anole dewlaps come in two morphs: solid and bicolor.

We also dove into the genome using pooled sequencing (Pool-seq) to search for regions associated with the trait. Our outlier analysis spotlighted a single genomic region with a strong signal—and within it, a prime suspect emerged: single-minded 1 (SIM1), a transcription factor with a flair for phenotypic control. Could this be the mastermind behind dewlap color in slender anoles?

The plot thickens, and we’re excited to keep unraveling the genetic threads behind one of the most iconic signals in lizard evolution. Stay tuned!

Link to the paper just published in Heredity.

Photograph by April Brown

Anole Annals has featured a series of posts on three-legged lizards over the years (e.g., here and here). Now we need help. Some time around 2017, April Brown contributed a photo of a brown anole missing both of its forelegs. The photo was taken in Winter Park, FL. We’d like to contact April, but can’t locate her. Can anyone solve the mystery?

A clip of a much longer video:

Two anoles, the ubiquitous Jamaican (Graham’s, Anolis grahami), which adorns every wall in Bermuda, and the seldom seen Barbados (A. extremus), just an occasional shadow in the shade, somehow finding themselves on the desirable territory of my bedroom window. They never came to blows, but the latter was definitely the winner, the Jamaican eventually retreating with his tail between his legs (metaphorically) after 8 minutes of posturing.

For more on the introduced anoles of Bermuda, see previous AA posts (here and here).

Photo by Wendy Frith

I live in Bermuda.

Many years ago, my daughter and I witnessed a large male Graham’s anole devour a small female, same species. We were horrified as we had watched these particular individuals so often we’d named them…the male was Pat Rafter as he spent much of his time up by the porch ceiling light catching bugs there; the victim was Porsche, because she was always on the porch wall railing. 

One day, I heard a scream from the porch…not from the lizard, but from my daughter: “Pat is eating Porsche!” and I arrived in time to see him sitting in her favorite spot with her back-half still protruding from his mouth. After the final gulp, he sat basking in the sun for a long time, then waddled off leaving an extra-long turd behind. My daughter and I went over and addressed it, with many apologies. We hadn’t known he was not just merely blue (and turquoise and purple) but was a reptilian Bluebeard…in fact, even worse: a Cannibal Bluebeard!

On the other side of the house there was a male I named Brown (because a friend of mine had a brown dog he’d named Purple). I taught him to accept food from my finger, and to come to the bathroom window when I whistled Bach’s Brandenburg Concerto #3 in G. He’s the one pictured at the top and bottom of this post.

Drawing by Wendy Frith.

Anolis winstoni from https://commons.wikimedia.org/wiki/File:Anolis_oculatus_at_Coulibistrie-b01.jpg

Peter Mudde writes:

I am chairman  of Lacerta, the Dutch Herpetological society. I also am a regular contributor to the magazine Lacerta. Lacerta  recently made an “Anolis special.” We are preparing a printed English version and we have an internal discussion about the matter below. 

In 1962 the late Skip Lazell, a regular contributor to Anole Annals described Anolis oculatus winstoni, stating: “This subspecies is named for Charles A. Winston, Manager of Woodford Hill Estate, and his family.” In recent years, the epithet “winstoni” has been changed to “winstonorum” as that would be he proper grammatical form if the subspecies was indeed named after Winston and his family (Michels and Bauer, 2004). This was critisized by Dubois (2007).

Now I am not familiar with the latest in zoological taxonomy, but I was under the impression that a name once given could not be corrected afterwards. That’s why the American alligator still misses a character in it’s scientific name.

Indeed, the combination Anolis occulatus winstonorum has emerged several times, mainly in non-scientific literature. Now my question is: how do those working with anole taxonomy refer to this subspecies?  Your verdicts please.