Author: Graham Reynolds Page 1 of 3

Graham is an Associate Professor of Biology at the University of North Carolina Asheville. His research focuses on Caribbean herpetology- specifically anoles and boas.

In a recent review of old literature for some projects on Cyclura iguanas, I came across some notes from Gosse (1848 ) in which he speculates upon the nature of the lizard dewlap. I think it is fun and fascinating to think about how naturalists approached the idea of deducing what functions these structures might have served! In this narrative about Jamaican lizards, Gosse rather breathlessly describes some exciting correspondence he received from his friend Richard Hill, Esq., of Spanish-Town Jamaica, adjacent to Kingston on the southeast coast:

Hill: “The gular pouch which hangs like the dewlap of a bull beneath its throat can be inflated*. but it is not exactly known under what circumstances, ordinarily, it has recourse to this power of inflation. When filled with air it would give breadth and buoyancy to the body, and if its habits are as aquatic as some accounts make them [those of Iguana proper] to be, it would afford to an herbivorous animal no unimportant aid while swimming and cropping its flowery food.”

Gosse: “*I believe my friend has fallen into a common error here. If I may judge from analogy in the genera Anolis and Dactyloa, the gular pouch in the Iguanidae is extensible but not inflatable, as I hope to show in a future paper on the habits of these genera.”

So, naturalists at the time speculated that the lizard dewlap might be a flotation device! Perhaps a natural explanation for species that readily take to water when they flee, such as Iguana iguana, but potentially applying across lizards with that feature. Gosse has already decided that Anolis dewlaps did not suit this purpose and thus that this seemed less likely for other iguanas as well, but he tees us up for the eventual settling of this issue of inflatable dewlaps.

Gosse continues:

“The notion expressed about the inflation of the gular pouch was the consequence of seeing two very large Iguanas from Cuba, which distended this appendage, and let it collapse again. The skin of these animals hung about them, as if they had been fat, and were, at the time I saw them, emaciated.”

Here Gosse is throwing cold water on this idea again, but you can tell from reading the text relating this correspondence that he must have relished the opportunity to receive such intelligence from the field and then have the opportunity to discuss and evaluate it!

Mr. Hill continues:

“When excited it assumes a menacing attitude, and directs its eye to the object of attack with a peculiarly sinister look. At this time it inflates the throat, erects the crest and dentelations on the back, and opens the mouth, showing the line of those peculiarly-set white teeth, with serrated edges, so excellently made to illustrate the remains of the gigantic fossil Iguanodon. The principle of their construction is so precisely similar, as to leave no doubt of the genuine connection of the extinct with the existing herbivorous lizard. The adaptation of both is for the cropping and cutting of vegetable food.”

Here, just to draw attention to this rather remarkable fact, is an amateur naturalist (although, to be fair, advanced formal training in biology was not available during this time and naturalists were largely self-taught) who in 1847 is pronouncing upon the use of this dewlaps, while also simultaneously acknowledging extinction, evolutionary similarity, and adaptation. We often talk about these latter notions as having crystallized after Charles Darwin and Sir Richard Owen brought ideas regarding natural selection (and adaption) and extinction, respectively, into the mid-19^th Century Victorian intellectual milieu. But Cuvier and others had proposed robust examples of extinction at the turn of the 19^th Century, and millenia of ideas, dating back to Hellenistic Scholars, through the Golden Age of Islamic Scholarship, to the parlors of Renaissance Europe had proposed that some traits proved “favorable.” Further, Iguanodon was discovered in 1822 by Gideon Mantell (not, famously, by Cuvier and Owen). So, such ideas were available to progressively-minded naturalists of the time, and it is refreshing to see such a confirmation in print!

NB: Just to further tempt you to take a dive into this literature, this is also the issue where Sir Richard Owen describes the Moa birds from New Zealand! What epic rainy-day reading! Check out the link to the issue, I recommend it!

With thanks to Ari Miller (WUSTL, Losos Lab) for pointing me toward this reference.

Article:

Gosse, P.H. 1848. On the habits of Cyclura lophoma, an iguaniform lizard. Proceedings of the Zoological Society of London 99–104.

Link: https://archive.org/details/lietuvostsrmoksl48liet/page/n137/mode/2up

Undergraduates among the Anoles: Anolis scriptus in the Turks & Caicos

By Graham Reynolds

On July 14, 2020

In Notes from the Field

The following was written by Keeley Peek and Alyssa Vanerelli, two research students in the Reynolds Lab at The University of North Carolina Asheville. Here they document some experiences with a lesser-known anole species- Anolis scriptus– a species our research group has tried to acquaint AA readers with previously (1,2,3,4).

As aspiring tropical herpetologists, adventures aren’t hard to come by. A combination of traveling to new places and the thrill of encountering new species is a constant excitement. From high in the Blue Ridge Mountains, we heard the soft call of crystal blue waters crashing against a distant shore, and importantly, the scurry of little legs across the sand. It was time for an adventure to the Turks and Caicos Islands.

We touched down in a small plane on the long runway of remote Big Ambergris Cay, one of the last strongholds of the Turks Island Boa (Chilabothrus chrysogaster) and Turks and Caicos Rock Iguana (Cyclura carinata). While these two species seem to rule the island during the night and day, respectively, they are not the only ones that think they own the place. Within a mere moment of tumbling out of the 5-seater plane we spotted our target. The Turks and Caicos Anole (Anolis scriptus scriptus) was soon found to dash under every rock, prickly plant, and structure around. We know surprisingly little about these amazing anoles, which are widely distributed in the southern Lucayan Archipelago. Few focused studies on the natural history of this species have been conducted, and each time our Lab visits this region for our ongoing research on boas and iguanas, we often spot Dr. Reynolds imploring us to find a way to fold in some time for anole study.

Female A. scriptus, hidden among the vegetation.

Although our main efforts were on collaborative boa and iguana research with the San Diego Zoo Institute for Conservation Research, most days we would spend our free time in the afternoons in the hot sunlight trying to catch as many anoles as possible. Without any nooses, nets, or know-how, this was not the easiest task. Around the compound where we stayed, the anoles could be found basking in the sun on the concrete building walls or other human structures, reminding us of work done by Kristin Winchell of Washington University in St. Louis (who gave a seminar at UNC Asheville). They also taunted us from tree branches, just out of our reach. The males on Ambergris Cay stood out with a striking yellow underside, yellow extremities, and an orange-yellow dewlap contrasting remarkably with the beige covered their backs. Females sported a less-colorful look, but have a curious pattern consisting of a light stripe running down their back crossed by thin black bars. We were also able to observe, and sometimes catch, anoles as we worked in the evenings catching boas.

After spotting a beautiful male A. scriptus on what may have been a water heater (we weren’t exactly focused on the structure), we silently stalked towards our scaly tailed friend. After discussing the best angles, timing, and speed we should use to capture this anole, we froze ready to strike. One of us raised a hand for distraction, the other sneaking up in the blind spot to… watch as the anole disappear over the side of the heater. We retreated with a stinging defeat, only to return later as the anole had returned to his basking spot. With a few recalculations and adjustments, we crept in for round two, and emerged victorious.

An amazing feature common among all anoles are their dewlaps which they use to attract females and discourage predators as well as other males. Adorned in vibrant colors, the dewlap is a feature that is easiest to observe when a specimen is in-hand. As newcomers to catching A. scriptus, it was a bit of an adjustment to learn to delicately handle these tiny but surprisingly strong creatures. We received some advice from a seasoned A. scriptus catcher (who doubles as our research advisor), Dr. Graham Reynolds, that the best trick is to let them bite us on the finger and then they will gently extend the dewlap. At first, we believed he was pulling our dewlap, and then we realized he was extremely serious. With a quick game of rock-paper-scissors to determine the anole’s victim, we let the creature’s teeth sink a whole nanometer into our skin and extended its sunrise-colored jewel of a dewlap. We embraced the pain and received the reward of observing one of the anole’s best features. Count us among two of the newest fans of the incredible Anolis scriptus.

Learning a new technique.

p.s. Anolis scriptus is going big-time, having featured in recent publications in Nature and PNAS. We look forward to the time when they are as popular as A. sagrei!

The Reynolds Lab (www.CaribbeanBoas.org) studies the ecology and evolution of reptiles and amphibians in the Caribbean and the southeastern United States. We are an undergraduate research-centric Lab.

Anoles and Drones, a Dispatch from Island Biology 2019

By Graham Reynolds

On August 26, 2019

In New Research

Emma Higgins presenting her work at Island Biology 2019

The third meeting of the nascent Society for Island Biology took place recently in stunning La Reunion in the western Indian Ocean. Conference goers were treated to a wonderful venue at the Université de La Réunion in St. Denis, whose campus looks out down the gentle slope to the open sea. Four hundred attendees from around the world reinforced what we already knew— that island biology as a study attracts a large number of researchers from very diverse fields of study. The conference organizers also are leading the way on making our meetings in remote locations more responsible; using live streaming of the sessions meant that some interested scientists could skip the travel and stay home to watch the sessions. But the real asset was that the organizers calculated the air travel carbon footprint for all attendees, finding that ~30 hectares of forest would need to be planted to offset the carbon emissions. Happily, that is exactly what they did! The conference organizers and hosts, in partnership with communities and other organizations, committed to reforesting exactly that amount in La Réunion and Mauritius.

OK, now on to the anoles! Well, given the remoteness of the meeting location (nearly the antipode of the Caribbean*) perhaps it is not too surprising that few anologists attended. But I am happy to report that Emma Higgins did, and gave an excellent presentation on her work with anoles on the island of Utila, one of the Honduran Bay Islands.

Emma is a 3^rd year PhD student in Adam Algar’s lab at the University of Nottingham, where her thesis is focused on using emerging technology to study lizard thermal biology under changing conditions (think development, climate change, and species introductions). When I say using emerging technology, I mean using #allthetech; Emma uses 3D printing, drones fitted with thermal cameras, Sentinel satellites, and LIDAR to generate her data! Her motivation follows from asking what factors control the abundance, distribution, and microhabitat of anoles on Utila, and whether these variables might be better estimated at extremely fine scales using emerging technology.

A bit of background, there are four species of anoles on Utila, including the endemics A. bicaorum and A. utilensis. An additional native species is A. sericeus, which also occurs elsewhere in the Bay Islands as well as on the mainland. The fourth species is everyone’s favorite— A. sagrei! Utila has experienced a surge of development in the last 10 years, with new roads and development going up faster than conservationists can keep track of. This is a major threat to the island wildlife, which includes an endemic iguana known as The Swamper (Ctenosaura bakeri) which favors the dwindling mangrove forests.

Emma’s work involves collecting data both at anole-level as well as above the canopy. She uses a DJI Phantom 4 drone platform fitted with a near-infrared camera to estimate a normalized difference vegetation index (NDVI, a measure of “greenness”) of the forest canopy across habitats, and found that just NDVI explains 28% of the spatial heterogeneity of lizard operative temperatures (in a mixed-model framework). This suggests that her drone can identify suitable thermal environments for lizards from above the canopy. I should mention that her resolution here is 4cm/pixel! She plans to zoom out to space and test whether similar imagery from the Sentinel 2 satellite will also be useful. Below the canopy, Emma is using LIDAR to simultaneously conduct forest shade modeling (for super fine-scale temporal variation in thermal microhabitat). LIDAR also detects perch availability, as it detects tree trunks very well. Emma also uses 3D printing to produce hundreds of anole models, each fitted with an iButton® temperature recorder and placed on perches in the forest. Each lizard print takes 52 minutes, so Emma ended up taking the printer to her flat to print 24/7 in preparation for her field season!

I should mention that Emma was joined at the conference by two other excellent scientists— lab mate Vanessa Cutts and fellow Utila lizard biologist Daisy Maryon, both of whom won awards for their posters at the conference!

Stay tuned for the announcement for the 2022 Island Biology meeting, to be held on either Mallorca in the Balearic Islands or Wellington, New Zealand. Also stay tuned for Emma’s results; we look forward to hearing more about her work!

Anole Outpost: The Cay Sal Bank, Part III

By Graham Reynolds

On June 28, 2018

In New Research, Notes from the Field

This is the final of a three-part post on our work on the anoles of Cay Sal Bank, Bahamas. In this post, I will visit the Brown Anoles (Anolis sagrei). Like many, many places in the Caribbean, Anolis sagrei occurs across the Cay Sal Bank. This species has the widest range of any Caribbean anole, having colonized a huge range of regions from ancestral origins in Cuba- from the northern Bahamas, throughout the northern Caribbean, all the way to the Atlantic versant of Mesoamerica.

(Mostly) native range of Anolis sagrei.

Our ongoing work on this species has resolved the evolutionary history of A. sagrei across this great range, but one hole that had lingered was the status of the populations on the Cay Sal Bank. Prior to our cruise to the region in 2015, A. sagrei was known from the following islands: Cay Sal Island, the Anguilla Cays (including Cotton Cay), and Elbow Cay (Buckner et al. 2012). Further, these populations were considered to be the subspecies A. sagrei ordinatus, or, the Bahamian Brown Anole (Buden and Schwartz 1968; Buckner et al. 2012). This subspecies was originally described owing to having supraorbital scales in contact and a different dewlap color. We know now that dewlaps are highly variable both among and within populations of brown anoles on the Bahamas banks (e.g., Vanhooydonck et l. 2008). Populations proximal to the Cay Sal Bank- that is- populations on the Bimini islands, have a very distinct dewlap comprised of a light orange background streaked with dark red. Brown anoles on Cay Sal do not share this dewlap color; instead, they have a more classic sagrei pattern of darker red with a light distal border. This is not a smoking gun for considering Cay Sal anoles something other than A. s. ordinatus, of course, given the range of dewlaps we see to the east.

Cay Sal (left), South Bimini (right). Photos by R. Graham Reynolds.

If Cay Sal browns were indeed A. s. ordinatus, that would imply a (likely) westward colonization across the Santaren Channel–not an implausible scenario. During periods of lower sea level, the Cay Sal Bank would have been a big ‘ol target for lizards involuntarily leaving the Great Bahamas Bank. Of course, an alternative would be the reverse: an initial colonization of Cay Sal, followed by dispersal to the east across the Channel. Of relevance, during the course of the work I’m presently describing, we also found a snake: Tropidophis. We determined, using the same molecular phylogenetic techniques, that this snake is most likely T. curtus, and thus a population conspecific with Tropidophis over on the Great Bahamas Bank, evidence for a likely westward colonization.

Map of the Cay Sal Bank, from Reynolds et al. (2018). Note that Cotton Cay is part of the Anguilla Cays.

Of course, Cay Sal browns could also be Cuban in the sense that they might have colonized the bank directly from Cuba across the Nicholas Channel. To parse these alternative origin stories, we collected samples of the species from across the Cay Sal Bank and generated a coalescent gene tree paired with all our sampling from other brown anole populations across the region. We find that Cay Sal A. sagrei are actually much more closely related to western Cuba A. sagrei, rather than Bahamas A. s. ordinatus. Combining this finding with our analysis of A. fairchildi, we find that this particular Anole Outpost was colonized from Western Cuba by at least two species–and likely at different times.

Phylogeny of A. sagrei, showing Cay Sal Bank lineagers in blue (and a Cay Sal specimen in the inset). From Reynolds et al. 2018.

New Records

In addition to these findings, we also documented some novel populations of A. sagrei on the Cay Sal Bank. We added East Doubled Headed Shot Cay, Elephant Rocks, Great Dog Rock to the list of known populations on the bank. What is particularly interesting about these new records is the range of habitat types that they support. Cay Sal Island and the Anguilla Cays are by far the most lush, with lots of vegetation. To the north, the cays become increasingly xeric and barren. East Double Headed Shot Cay is the most vegetated of the northern islands, and has a thick, but low, covering of coastal shrub plant community. Anolis sagrei is not abundant on this island, and we only saw a few dozen during several hours of searching.

East Doubled Headed Shot Cay. Photo by R. Graham Reynolds.

In stark contrast, the Elephant Rocks to the west are tall, jagged, steep, and rocky islets with almost no vegetation at all. We had low expectations as we jumped into the sea from the dingy to start our ascent of these islands at dawn. But, to our surprise, we found some anoles happily living among the rocks. Not at high densities, but here they were, a saxicolous population of A. sagrei.

Elephant Rocks, Cay Sal Bank. Photo by R. Graham Reynolds.

Naturally, Alberto and I would love to follow up on some of this, but Cay Sal is a tough place to work. Maybe someday we’ll get back there, in the meantime, we can reflect on what a special opportunity we had to visit this Anole Outpost.

Sunrise on the Cay Sal Bank. Photo by R. Graham Reynolds.

References

Buckner, S. D., R. Franz, and R. G. Reynolds. 2011. Bahama Islands and Turks & Caicos Islands. In R. Powell and R. W. Henderson, editors. Island Lists of West Indian Amphibians and Reptiles. Bulletin of the Florida Museum of Natural History 51: 85–166.

Buden, D. W., and A. Schwartz. 1968. Reptiles and birds of the Cay Sal Bank, Bahama Islands. Quarterly Journal of the Florida Academy of Sciences 31: 290–320.

Vanhooydonck, B., A. Herrel, J. J. Meyers, and D. J. Irschick. 2009. What determines dewlap diversity in Anolis lizards? An among-island comparison. Journal of Evolutionary Biology 22: 293–305.

Anole Outpost: The Cay Sal Bank, Part II

By Graham Reynolds

On June 24, 2018

In Notes from the Field

Anolis fairchildi from Cay Sal Island, Bahamas. Photo by R. Graham Reynolds.

In a previous post, I introduced some results from our attempts to understand the evolutionary history of anoles on Cay Sal Bank, Bahamas (more results in a future post). We found that the only endemic reptile on the Bank, Anolis fairchildi (the Cay Sal Anole), is a lineage relatively recently derived from western Cuban A. porcatus progenitors. OK, fair enough, but what is this creature we list in our checklists and museum collections with the epithet fairchildi? A comment by James Stroud on a previous post of mine suggested that we visit this species directly here on AA, so off we go!

The anole specimens leading to the description were collected by Paul Bartsch in 1930, a malacologist who spent a week on the bank (Buden 1987). Bartsch found specimens on both Cotton Cay and Cay Sal (more on distribution below). In this manuscript (Barbour and Shreve 1935), Thomas Barbour offers a narrative of an Utowana expedition in 1934 during which time the explorers, including Barbour and J.C. Greenway–another name that lingers after several Latin generic names (e.g. Leiocephalus greenwayi)–sought herpetological novelties. It is worth noting that Barbour and his team secured a “rich booty” of land mollusks (Barbour and Shreve 1935); in other words, they weren’t always just after reptiles and were likely offering tit-for-tat with Paul Bartsh (my opinion). This narrative is followed by his description of some new reptiles, including the Bahamian green anoles A. fairchildi and A. smaragdinus.

Barbour and Shreve gave these Cay Sal individuals the name fairchildi to honor the individual David Fairchild, the prolific botanist whose name also graces the wonderful Fairchild Tropical Botanic Garden (where the recent 7th Anolis Symposium was held!). Let’s pause briefly to consider the man who lends his name to this handsome lizard species. David Fairchild (1869-1954) was a well-known botanical collector, explorer, cultivator, and traveler. Indeed, Pauly (2007) considered him “one of the most important plant explorers in the history of the United States of America.” Like Thomas Barbour of the MCZ, Fairchild was a friend of Allison Armour, and what a great friend for a Caribbean biologist to have. Armour outfitted his 1315-ton steamer Utowana as a research vessel, providing it as a platform for numerous important cruises around the Caribbean and beyond (a “floating palace” according to Fairchild). Wonderful narratives of Barbour (Henderson and Powell 2004) and Fairchild (Francisco-Ortega et al. 2014) aboard the Utowana are definitely worth a read. I particularly love Fig. 2 in the former and consider THAT to have been the good-ol’-days of Caribbean herpetology! As a side note, a name given to Caymanian Anolis conspersus was A. utowanae by Barbour (1932)! You can read more about that interesting story from Steve Poe here or on AA here. Fairchild sailed (well, steamed, really) through the Bahamas at least three times on the Utowana, accumulating a significant amount of botanical knowledge and material. For this reason, and because he was an acquaintance, Barbour named his new anole species after David.

Anolis fairchildi. Photo by Alberto R. Puente-Rolon.

How many people have seen A. fairchildi? Probably not many, and even fewer who appreciated what they were looking at. Cay Sal is a hard place to get to, particularly if one goes via the legal route that necessitates a stopover in Alice Town, Bimini to clear customs (as opposed to running directly, and illegally, from the Florida Keys). Few photos of this species exist, and even fewer narratives of trips in which the species was seen are available.

Anolis fairchildi habitat on Cay Sal Island. Photo by R. Graham Reynolds.

Description

Anolis fairchildi is considered a relatively large green anole, with an SVL of 67–74 mm in males. Barbour and Shreve (1935) suggest it is “allied to” A. smaragdinus and A. porcatus–a natural supposition and borne out in examination–but differing in having “larger dorsal and temporal scales” and also a different coloration. This supposedly diagnostic coloration is a series of white or light blue flecks (comprised of small groups of differently colored scales). James Stroud recently posted a photo of A. carolinensis from Fairchild Tropical Botanic Garden that closely resembles the description of A. fairchildi, a humorous and fitting example of the variation present in the former species. A photo of A. fairchildi in Francisco-Ortega et al. (2014) also shows this coloration. Alberto Puente-Rolon and I did not find such distinct spotting in the specimens we examined from Cay Sal Island in 2015. Thus, it seems likely that A. fairchildi does frequently have light spotting, but that this is not a unique phenotype to Cay Sal.

Distribution

This species is considered endemic to the Cay Sal Bank. Historical records place them on the following islands: Cotton Cay, the eponymous Cay Sal, Elbow Cay, and Double Headed Shot Cays (Buckner et al. 2012). In our cruise to the islands, we did not visit Cotton Cay (=South Anguilla Cay) or North Anguilla Cay, but we did visit the others where the species is thought to occur. We found A. fairchildi on Cay Sal Island only, and observed no individuals on Elbow Cay nor Double-headed Shot Cay.

Map of the Cay Sal Bank, from Reynolds et al. (2018). Note that cotton Cay is part of the Anguilla Cays.

For more, check out our recent publication describing our work on Cay Sal Bank.

A Footnote: how to pronounce this island bank…

Most of us Caribbean ambulators pronounce the word “cay” (=small islands) with a hard k and e sound, like “key.” This apparently is the anglicized version of the Spanish “cayo,” itself possibly cribbed from the Arawak “cairi.” Cay Sal, on the other hand, is frequently pronounced with a hard k and a, as in “cake,” similar to the Spanish. Additional confusion is lent by the historical use of the French word “quay” in the region (originally from the Gaulish “caio”) to refer to docks or gangways present on islands (indeed, small islands would have been dominated by these constructions). An interesting read on all this is González Rodríguez (2016). Any toponomastics buffs have opinions on how Cay Sal should be pronounced?

References

Barbour, T. 1932. On a new Anolis from Western Mexico. Copeia 1932: 11–12.

Barbour, T., and B. Shreve. 1935. Concerning some Bahamian reptiles, with notes on the fauna. Proceedings of the Boston Society of Natural History 5: 347–365.

Buckner, S.D., Franz, R. & Reynolds, R.G. 2012. Bahama Islands and Turks & Caicos Islands. In: Powell, R. & Henderson, R.W. (Eds.), Island Lists of West Indian Amphibians and Reptiles. Florida Museum of Natural History Bulletin, 51, pp. 93–110.

Buden, D.W. 1987. Birds of the Cay Sal Bank and Ragged Islands, Bahamas. Florida Scientist 50: 2133.

Francisco-Ortega, J., et al. 2014. Plant hunting expeditions of David Fairchild to the Bahamas. Botanical Review 80: 164-183

González Rodríguez, A. 2016. El Muelle del Cay of Santander City (Spain) and the Two Big European Maritime Traditions in the Late Middle and Modern Ages. A Lexicological Study of the Words Cay and Muelle. 171-178. Names and Their Environment. Proceedings of the 25th International Congress of Onomastic Sciences, Glasgow, 25-29 August 2014. Vol. 1. Keynote Lectures. Toponomastics I. Carole Hough and Daria Izdebska (eds). University of Glasgow.

Henderson, R.W., and R. Powell. 2004. Thomas Barbour and the Utowana voyages (1929–1934) in the West Indies. Bonner zoologische Beitrage 52: 297–309.

Pauly, P. J. 2007. Fruits and plains. The horticultural transformation of America. Harvard University Press, Cambridge, MA.

Anole Outpost: The Cay Sal Bank, Part I

By Graham Reynolds

On June 20, 2018

In All Posts, New Research, Notes from the Field

What determines species composition on remote Caribbean islands? Geographic proximity to source populations? The vicissitudes of dispersal and colonization? Propagule pressure and prevailing biotic and abiotic environmental conditions? The study of biogeography addresses such questions, and is concerned with understanding the geography of biodiversity- where do species occur and why?

We perhaps often think of species groups accumulating from colonists arriving from the same place, that is, we identify a likely natal source for island colonists. But might species groups be chimeric, in that they contain groups of diasporic species from different natal lands? This is certainly a plausible scenario and could potentially lead to some interesting evolutionary outcomes.

The Cay Sal Bank is a remote island bank, or shallow carbonate platform, on which rests a line of small islands strung out along its margins. This region, as well as our recent expedition, has been mentioned in a previous AA post. Here I am returning to discuss the anoles and the results from our recently published work describing the evolutionary relationships of the terrestrial squamate fauna. Fundamentally, we ask a question that has circulated for the better part of a century: where do the anoles on Cay Sal come from?

Six terrestrial squamates are found on this bank:
Anolis fairchildi (endemic)
Anolis sagrei
Tropidophis curtus
Sphaerodactylus nigropunctatus
Cubophis cantherigerus
Typhlops biminiensis

Dispersal hypotheses for terrestrial squamates found on Cay Sal Bank, from Reynolds et al. 2018

Of these, all but Anolis fairchildi and the recently discovered population of Cubophis were thought to have Bahamian evolutionary affinities. The endemic A. fairchildi has been of particular interest, owing to its status as the product of one of the ex situ speciation events occurring in the green anoles as they dispersed from Cuba (Williams 1969). But a previous AA post (1) reminded us that the origins of Anolis fairchildi had not been resolved- did they come directly from Cuba or are they derived from Bahamian A. smaragdinus (among other alternatives?). Here we tackle this question, using a basic mitochondrial dataset and lots of taxon sampling from previous study of the group (more on A. fairchildi in a future post). We constructed a coalescent gene tree of all “carolinensis-clade” Cuban green anole species, including our samples obtained from Cay Sal Island in 2015. We find unequivocally that A. fairchildi is a recent colonist from western Cuba- nested within the western Anolis porcatus lineage. Thus we see both ancient and recent emigration (divergence) events leading to what we recognize as species in the carolinensis clade of green anoles, setting up a really nice opportunity to examine the accumulation of variation in diasporic populations over different time periods.

Phylogeny of “carolinensis clade” green anoles from Reynolds et al. 2018, with A. fairchildi highlighted in green and shown in the inset photo

Western North Carolina Green Anoles

By Graham Reynolds

On November 11, 2016

In All Posts

Anolis carolinensis basking mid-winter in the Great Smoky Mountains National Park. Note the icicle in the left foreground. Photo by Sandy Echternacht from The Reptiles of Tennessee (UT Press 2013), and used with permission of the photographer and publisher.

Having recently moved to North Carolina, I am naturally inclined to get out and look for anoles. The state encompasses portions of the northern extent of the green anole (Anolis carolinensis) along the eastern seaboard, and a number of researchers are interested in both the evolutionary history of green anoles (Tollis et al. 2012, Campbell-Staton et al. 2012, Tollis and Boissinot 2014; Manthey et al. 2016) as well as, in particular, their ability to adapt to highly season regions (Jaffe et al. 2016). For a subtropical lizard to survive in areas that regularly see snow and ice is potentially an important study in regional adaptation. Indeed, this dramatic photograph below illustrates that anoles and icicles can coexist in both space and time.

This comes from work done by Sandy Echternacht and David Bishop at the University of Tennessee Knoxville. These researchers have shown that the green anoles in the Great Smoky Mountains National Park (yes, they occur there!) exist mostly on south-facing rocky slopes, and that they do not hibernate during the colder months. Instead, they will often bask on the rock faces when the sun shines directly on the rock (even when ambient temperatures are near freezing). During warmer months, the lizards move from overwintering sites into the forest, often along rivers (Bishop and Echternacht 2003, 2004). South of the Park, this species can be found in abundance along the banks of larger rivers.

North Carolina GAP Analysis Project

In North Carolina, green anoles range up the Atlantic coast to Virginia, but have a more jagged latitudinal distribution moving west across the state. Known records (Palmer and Braswell 1995) decline in latitude as one approaches the city of Charlotte from the east, tapering to just barely north of the South Carolina border. Then, some curious incursions and apparently disjunct populations are recorded from west of the I-77 corridor (what generally constitutes Western North Carolina).

Anolis carolinensis from Chimney Rock, NC.

With one season under the belt, so to speak, my Herpetology class at the University of North Carolina Asheville and I have found what we think might be the closest population of green anoles to Asheville, North Carolina. This population occurs in a steep valley near Chimney Rock, North Carolina. Interestingly, they have access to steep south-facing rocky slopes above the valley. I thought I would poll the group and see if anyone has any hot tips on anole populations in the east Tennessee/Western North Carolina region. We are considering making this a Herpetology class project in the future- to map out the anole populations in this part of the state to see if they are in fact disjunct and whether any additional populations can be found. We will keep AA posted.

Anolis maynardi Male-Male Territorial Bout

By Graham Reynolds

On October 4, 2016

In Anole Videos, Natural History Observations, Notes from the Field

This video was filmed and shared by Jen Moss of the Welch Lab at Mississippi State University. She observed the encounter near Preston Bay, Little Cayman, and it’s a great video showing this behavior. Lots of dewlaps, pushups, and potential exposure to predators owing to the use of a non-natural substrate. Thanks Jen!

Anole Surveys on the Cay Sal Bank, Bahamas

By Graham Reynolds

On August 3, 2016

In Notes from the Field

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.

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.