Anole Annals

Map from http://www.sv-galena.com/Trip4/Log8/Log8a.html

Alberto Puente-Rolon (Universidad Interamericana de Puerto Rico, Recinto de Arecibo) and I were incredibly fortunate to spend a week on the Cay Sal Bank, Bahamas. Cay Sal is a partially emergent island bank situated about 100 km south of Islamorada in the Florida Keys and about 50 km north of the Cuban Bank in the vicinity of Sagua la Grande. Politically part of the Commonwealth of the Bahamas, the bank is separated from the Great Bahama Bank by the 47 km-wide Santarem Channel, and is about 175 km west of the southern tip of Andros Island. Cay Sal Bank is a shallow carbonate platform with dozens of small emergent islands around the edges of the roughly triangular-shaped bank.

Anolis sagrei, Cay Sal Island. Photo by Alberto Puente-Rolon.

A note before we launch into the narrative of our trip. The Cay Sal Bank is an area known for a significant amount of illegal activity. This largely involves illegal fishing fleets and human trafficking. While a typical visitor to the area would not likely be in great danger from these activities, there is always the possibility that you might run into the wrong people at the wrong time. Illegal fishing vessels have been known to harass, intimidate, and attempt to board cruising vessels on Cay Sal, while happening upon a human or drug trafficking exchange could be extremely dangerous. We saw evidence of all of these activities during our cruise, and mention some specifics in the narrative below. In addition, the Cay Sal Bank is remote. There are occasional Coast Guard planes in the area, but keep in mind that there might not be many vessels able to monitor emergency radio channels (channel 16) or respond quickly to an emergency. We cruised to the region with a highly experienced crew and a very well maintained and outfitted vessel, and we recommend anyone else planning to visit do the same, as well as consider taking all available safety precautions. I am happy to discuss my experiences in detail with researchers interested in visiting the area.

Anolis fairchildi, Cay Sal Island. Photo by RGR.

We arrived on the bank at dawn after an overnight cruise from Bimini, where we had cleared Bahamas customs and immigration. Our first stop was Dog Rocks, where we were able to disembark and swim ashore for a short walkabout on the largest of the small rocks jutting out of the ocean. The Dog Rocks mark the eastern edge of the Cay Sal Bank, and as far as we were aware there were no herpetofaunal records from these islands. Most are rocky and jagged, likely washed over during hurricanes and largely devoid of vegetation. Great Dog Rock is quite small, with a patchy covering of ground vegetation. There is a single large, pyramid shaped stand of Cocoloba uvifera near the center of the island-

Cocoloba uvifera stand on Dog Rocks. Photo by Alberto Puente-Rolon.

approximately 5 meters high and 10 meters wide. Quite a few Sooty Terns (Onychoprion fuscatus) and Brown Noddies (Anous stolidus) nest here. Even in this very isolated and largely barren stretch of rocks, we managed to locate Anolis sagrei. The large males and robust females were mostly occupying the Cocoloba stand, though we did find juveniles, young males, and females on the ground near the scrub vegetation. We even located a juvenile underneath a discarded conch (Strombus gigas) shell. We spent about two hours here, plenty of time to survey the entire island. We did not find evidence of any other terrestrial reptiles, and it is quite remarkable that even A. sagrei could persist there.

Departure from Cay Sal Island. Photo by RGR.

Our next stop was at the Damas Cays, a small group of narrow, high-walled islets jutting out along the spine of the eastern Cay Sal Bank. Like Dog Rocks, we are unaware of any herpetofaunal records from Damas, and for good reason. We took a rigid inflatable boat out for a brief survey of the largest of the Damas Cays. There are no easy landing spots on the island, so landing would require a swim. There was very little vegetation, we spotted a single small shrub and some very sparse groundcover. As we approached the island to land, we lost power on our outboard engine and were losing daylight, so we opted to repair the engine and not to clamber ashore.

Cay Sal Island. Photo by RGR.

We then cruised across the bank to the southwestern edge, about 80 km from Cuba.

What Is a Dewlap and How Many Times Have Dewlaps Evolved?

By Jonathan Losos

On July 31, 2016

In All Posts

Not a dewlap? Photo by Morley Read.

In a recent paper, Hagman and Ord discussed how dewlaps have evolved multiple times, often with different underlying anatomy. This is an excellent paper, but I was intrigued that Polychrus, sometimes considered the sister taxon to anoles, in part because of its apparently anole-like dewlap (see above), was not considered to have a dewlap.

I wrote Terry Ord, asking “I didn’t understand one thing. You seem to say there is no evidence for extendible dewlaps in several species of Polychrus, but a quick Google reveals plenty of images of these species with dewlaps extended. I take your point in the previous sentence that actual observations of the dewlap being used are rare, but did you really mean to say that they don’t exist at all?”

Terry responded: “What I found when attempting the first paper of this series (Ord et al. 2015, Journal of Evolutionary Biology) is that relying on photos alone is really problematic for identifying a moveable dewlap (a.k.a., a dewlap like anoles or Draco or Sitana).

For example, if you google Sceloporus — who definitely don’t have dewlaps — you’ll find photos where species do appear to have something like a small dewlap. In fact, I found an image of what was clearly a Sceloporus that looked to have an engorged throat that was remarkably similar to your Polychrus photo… All the google images I’ve found so far that are obviously Polychrus (and not anoles) could quite easily be engorged throats akin to Sceloporus and other non-dewlaped iguanids/agamids.

But the clincher for me is that all the hyoids we’ve looked at so far for both Sceloporus and multiple species of Polychrus (and other non-dewlaped iguanids/agamids) all look very similar (e.g., see Fig 5a in the JEB paper and supplementary info). The point being, the mechanics of the hyoid simply isn’t functional in the capacity of extending a dewlap like in anoles and others.

Of course, while the mechanics of the hyoid in extending the dewlap in anoles is well described, how Draco do it and some other genera is unclear. I’m hoping someone will look into detail on the biomechanics of the dewlap extension in non-anole groups because it can clearly be very different to anoles — e.g., the attachment points for key muscles for the anole dewlap are absent in Draco, so they’re sticking that dewlap out using a very different mechanism. Regardless, there are still key signs in the hyoid that point to a moveable dewlap in Draco (and other genera) that are not present in Polychrus.

Proof of a Polychrus dewlap would have to be a video of a Polychrus extending the dewlap because videos of Sceloporus quickly reveal that its an engorging (“puffing”) of the throat, so direct observation is a solid alternative to looking at the hyoid.

The taxonomy of “Polychrus” is potentially sketchy and not all species really are of that genus. Which means I also wouldn’t be surprised to see a species that has been classified Polychrus, but really isn’t related to all the Polychrus species we’ve examined the hyoids of, actually having a convincing moveable dewlap.

But at the moment, Polychrus = a moveable dewlap, all the evidence says otherwise. I also wonder whether the historical association of Polychrus as basal to anoles resulted in reaffirming wishful thinking field observations into the current myth.”

Terry’s next email made the distinction clear (as well as his unwarranted agama-philia): “If your notion of a dewlap is a prominent ornament that is dynamic in some sense (becomes extended through puffing out the hyoid in general or pushing out the CII in particular), then there are many many examples in agamids, and a handful in iguanids. I would definitely include Sceloporus, too.

If your notion of a dewlap is more specific to something that is part of a complex behaviojral display and involves rapid extension of a structure that is complex in temporal and amplitude characteristics, then it’s basically anoles, Sitana/Otocryptis, Draco and possibly one or two other agamids.

Agamids still clinch the diversity stacks in all regards – ha!”

Also not a dewlap

Puerto Anole Action Shots from Facebook: Predation by Ameiva and Maybe a Frog and Pooping

By Jonathan Losos

On July 28, 2016

In All Posts

ameiva eating anole

lizard pooping

New Research on How Tail Regeneration Works

By Jonathan Losos

On July 26, 2016

In All Posts

Tail successfully regenerated.

Recent years have seen renewed interest in the mechanisms underlying tail regeneration in reptiles, and anoles have been a major study organism. The latest word comes from Thomas Lozito and Rocky Tuan who have just published a paper, “Lizard tail skeletal regeneration combines aspects of fracture healing and blastema-based regeneration” in Development.

Abstract

Lizards are amniotes with the remarkable ability to regenerate amputated tails. The early regenerated lizard tail forms a blastema, and the regenerated skeleton consists of a cartilage tube (CT) surrounding the regenerated spinal cord. The proximal CT undergoes hypertrophy and ossifies, while the distal CT resists ossification for the lifetime of the lizard. We hypothesize that differences in cell sources and signaling account for divergent cartilage development between proximal and distal CT regions. Exogenous spinal cord implants induced ectopic CT formation in lizard (Anolis carolinensis) blastemas. Regenerated spinal cords expressed Shh, and cyclopamine inhibited CT induction. Blastemas containing vertebrae with intact spinal cords formed CTs with proximal hypertrophic regions and distal non-hypertrophic regions, while removal of spinal cords resulted in formation of proximal CT areas only. In fate mapping studies, FITC-labelled vertebra periosteal cells were detected in proximal, but not distal, CT areas. Conversely, FITC-labelled blastema cells were restricted to distal CT regions. Proximal cartilage formation was inhibited by removal of periosteum and could be recapitulated in vitro by periosteal cells treated with Ihh and BMP-2. These findings suggest that proximal CTs are directly derived from vertebra periosteal cells in response to BMP and Ihh signaling, while distal CTs form from blastema cells in response to Shh signals from regenerated spinal cords. Thus, lizard tail proximal CTs develop independently from tail blastemas, resembling cartilage calluses formed during fracture repair, while distal CTs are derived from the blastemas similar to regenerated salamander tails.

Anole Research Mentioned in New York Times: Nice Op-Ed on Urban Evolution

By Jonathan Losos

On July 24, 2016

In All Posts

Kristin Winchell’s research on Puerto Rican A. cristatellus evolution in cities is referred to in a nice piece in the New York Times by Menno Schilthuizen.

Many Ways to Achieve an Anole-Like Extendable Dewlap

By Mattias Hagman

On July 22, 2016

In All Posts

HagmanOrd_56650Fig1

Different phenotypic forms often serve the same functional outcome. A classical textbook example is the evolution of the wing in dinosaurs, birds and bats. This implies that organisms can respond in a variety of comparable ways to selection and that the same selection pressure thus can produce phenotypic diversity. Terry Ord and I have an early view paper in the American Naturalist that shows that an anole-like dewlap has evolved repeatedly in iguanids (Anolis) and agamids (Draco, Sitana, and Otocryptis), but in each case through different modifications to the underlying hyoid, which is the structure that powers the extension of the dewlap. The main point of difference among hyoid morpho-types, and also the component critical for the evolution of an extendible dewlap, is the angle between a short perpendicular structure called the hypohyal (see the figure) and a longer structure called the second ceratobranchial, which runs along the edge of the extended dewlap. There is also significant variation in the relative lengths of the same structures.

Other lizard species have converged around other hyoid morpho-types (our analysis identified a total of eight separate hyoid morpho-types). Interestingly we found evidence for convergence in hyoid morphology among species from distantly related genera, such as Polychrus, Gonocephalus and Trapelus. Species from these genera lack the large dewlap type found in Anolis and Draco, although the hyoid morpho-type of the two groups show some gross similarities. We suggest that the hyoid morpho-type of Polychrus, Gonocephalus and Trapelus might represent what an intermediate step looks like in the evolution of an extendable dewlap. More generally, our study shows that multiple adaptive solutions have been possible in apparent response to a common selection pressure, and that the phenotypic outcome that subsequently evolved in different genera seems to have been contingent on the history of the group in question.

Great New Article on Horned Anole: They’ve Become a Tourist Attraction!

By Jonathan Losos

On July 21, 2016

In All Posts

And an Ecuadorian student has studied the use of their horns in intraspecific interactions. Read all about it on BBC Earth.

Cayman Islands Anolis Research

By Graham Reynolds

On July 21, 2016

In Notes from the Field

Amy in the field working on her first noose capture.

The following was written by Amy Castle, an undergraduate and Summer Research Fellow in the Reynolds Lab at the University of North Carolina Asheville.

This past May, I had the opportunity to join Dr. Geneva and his team in the Cayman Islands to assist with his research on Anolis sagrei. Along with my mentor, Dr. Graham Reynolds, we were able to spend several days on both Little Cayman and Grand Cayman catching anoles, collecting data, and experiencing the tropics. This experience (my first in the tropics) provided me with an immersive education in both Caribbean herpetology and the ins and outs of working in the field. My adventure began when Dr. Reynolds and I flew to Grand Cayman and then took a small plane to Little Cayman, which is approximately 100 km northeast from Grand Cayman. Flying over these islands gave a good perspective of the topography and available habitat for the lizards. Most of the former island, which is only 16km long and 3 km wide, is lightly inhabited and dominated by tropical coastal coppice forest developed over a limestone base. On the ground, I quickly discovered that the anoles are everywhere!

We learned a lot in our research, and thankfully the trip wasn’t all that bad. It’s not like I’m used to luxury but I’m not the outdoorsy type, and when I travel I want to do so comfortably and stay in a good hotel. I didn’t get to choose it so I was quite worried. Turns out I didn’t have to be, the service was great and wow, the beds. I asked someone working there why the beds were so comfortable, and they told me that the manager looks at Mattress in a box recommendations by SavvySleeper website before deciding what to buy. As it turns out he’s just like me, in that being able to rest properly at the end of the day is high in the priority. That was lucky break. As for the research, it didn’t go perfect, but we still made progress.

Dr. Geneva’s research focuses on Anolis sagrei, in particular, the extent of variation in the species across its wide range. We were on Little Cayman to get data from this island as a component of a larger study, described in lots of previous AA posts (Eleuthera, Cayman Islands, Rum Cay, Concepcion Island, Ragged Island, Bimini, Mangrove habitat, and Great Isaac Cay).

Little Cayman Anolis sagrei.

These beautiful brown anoles were abundant day and night on the island and could be frequently found at eye level on the trunks and branches of mangrove and seagrape trees. They have brightly colored red-orange dewlaps, short snouts, and a smaller body size, especially when compared to their sympatric congener Anolis maynardi. Anolis maynardi, large green anoles native to Little Cayman, are often found higher in the trees and have green dewlaps with a yellowish tint.

Little Cayman Anolis maynardi.

During the few days we were on Little Cayman, the weather was really hot and humid. During the heat of the day, A. sagrei ventured deeper into the brush of the forest making it difficult to trudge through the trees without scaring them off. We were, however, able to capture them from several feet away by using an extendable fishing rod with a tied noose at the end. This was my first experience noosing lizards, but after a few tries, I was consistently able to catch individuals. At night, the anoles were much easier to capture. Using our lights and headlamps, we could simply pluck them off the leaves and branches where they were sleeping.

Grand Cayman Anolis conspersus.

After finishing data collection on Little Cayman, we headed to Grand Cayman to obtain export permits. I had the opportunity to see much of the island, including the endemic Anolis conspersus. These beautiful anoles have a large degree of color variation across Grand Cayman, and we were able to see at least two of the major color morphs. I was also able to meet some great people (Jessica and Jane) at the Department of Environment, who mentioned that they were finding non-native anoles on Grand Cayman. This developed quickly into a project idea- one of my research projects so far this summer is examining the DNA of these unknown anoles to try to determine what species they actually are and where they came from. A little bit of forensic genetics!

Graham Reynolds and Amy on Little Cayman.

This experience gave me an exclusive look into the world of Caribbean field herpetologists, and was really valuable as I am currently an undergraduate studying Ecology and Evolutionary Biology. I am particularly interested in the Cuban green anole clade, and my research with Dr. Reynolds focuses on Anolis fairchildi, an endemic species found on Cay Sal Island in the Bahamas. I am currently generating genetic data from this species and other members of the clade in order to examine the phylogenetic affinities of A. fairchildi relative to other Cuban green anoles. This trip gave me the opportunity to not only observe wild A. maynardi, a relative of A. fairchildi, but also to understand the complex relationships between sympatric anole species. It is one thing to study anoles “at the bench” in Asheville, but being able to join Dr. Geneva and his team in the field has really sparked my understanding of, and interest in, these fascinating animals.

Introduced Anolis species in Tenerife (Canary Islands, Spain)

By Marta Lopez Darias

On July 20, 2016

In Introduced Anoles

Anolis carolinensis (left) and A. porcatus (right), introduced to Tenerife, Canary Islands. [Left photo by G. Frías García; Right photo extracted from Neotropico Foundation].

Female green anole (Anolis carolinensis) photographed in June 2016 in Golf Las Americas (28°03 ̍43.5 ̎N, 16°43 ̍06.3 ̎N), in Tenerife island (Canary Islands, Spain) [left picture; uploaded to Facebook by: G. Frías García].; Right photo extracted from Neotropico Foundation].

In August 2013, a Cuban green anole (A. porcatus) was collected and given to insular authorities in the same locality [right picture; extracted from Fundación Neotropico]. According to this foundation, a small reproductive population of the Cuban green anole was established there at that time for some years. No precise data exist on the individual abundance or distribution of any of these species even though they could become invasive at some point and impact the natural ecosystems of these highly biodiverse islands. There is a lack of information on how these species have arrived to Tenerife, although they might be related to the commerce of plants to the islands, which are mainly imported to create tropical-looking gardens in touristic areas. According to the Invasive Species Database of the Canary Islands, other species of anoles such as A. sagrei, A. allogus and A. equestris have been reported at least once in the Canary Islands, all of them in Tenerife.

Risque Anole Bachelorette Party Cake

By Jonathan Losos

On July 19, 2016

In All Posts

cake We’ve seen anole wedding cakes and thesis defense cakes, but here’s a new one. Anole research veteran Natalie Jacewicz reports:

For my bachelorette party, my bridesmaids went to an erotic bakery (quite the business niche) in Boston and brought the shop pictures of Anolis lizards. The bakery evidently usually deals in, er, human encounters, so only had skin-toned frosting, and the store clerks weren’t sure if they could do anything lizard themed. But the shop owner evidently got really into the project, did a lot of independent anole research, and produced the cake below. Yes, that is a bridal veil on the yellow one.