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  • Writer's pictureAllan Sander

Evolution Revolution

“These guys are utterly fantastic!” I might have been thinking out loud. I don’t really recall. But to witness these two rivaling Cuban Brown Anoles, Anolis sagrei, battle it out reminded me of one of those old Sci-Fi “B” movies I watched as a kid! My entertainment continues until one of these gladiators is dislodged from its platform. The reigning king boldly applauds its efforts with several head bobs. What was intriguing about the anolids living on my in-law’s property here in Jamaica was not only that they were the most prevalent daytime herp, but it was the variety. This small one-acre parcel is a showpiece for what evolutionary biologists call, “adaptive radiation.” (Actually, the entire island constitutes this fact, but it sure is fun to enjoy it first hand in your own backyard!). Here was once a lush forest but it is now filled with exotic fruit and palm trees, bamboo, remnant evergreen deciduous types and a vegetable garden.

These terrestrial and arboreal playgrounds display a unique class of “ecomorph” anolid species. Six have been described based on the specificity of habitat choice: grass-bush, twig, trunk-ground, trunk, trunk-crown, and crown-giant.

Eco…What?! Here is a quick evolutionary rundown. Geographically after an island is born its isolation from a larger land mass allows the introduction of a colonizing species to capitalize on its untouched ecological resources. It has no competition along with the ability to radiate into numerous new species over time. These newfound niches are islands unto themselves where interspecific competition creates behavioral and morphological adaptations. These groups diverge becoming ecological types that cannot interbreed called ecomorphs. “Got it!?” What is even more amazing is that you find the convergence of these entire communities of the same set of ecological specialists (ecomorphs) had also evolved ‘independently’ on the other three Greater Antillean islands: Cuba, Hispaniola, and Puerto Rico!

The more studies undertaken with Caribbean anoles create more questions and new theories. One such view questions if habitat specialization is a result of competition. With that in mind it is evident that habitat preference created adaptations suited for these lizards’ environment. A very cooperative Jamaican giant anole, Anolis garmani, allowed me to observe some of its behavior. Being the largest of the ecomorphs it still showed a comparatively shorter tail and a flatter body. Predator avoidance is more subtle than its ground dwelling counterparts. It uses its sure-footedness due to better developed toe pads, by simply moving to the opposite side of the trunk or branch to which it is residing. Whereas the Cuban brown (Anolis sagrei) and Jamaican gray (Anolis lineatopus) anoles, both trunk-ground species, posses longer legs for jumping and sprinting to chase down food or flee from a predator. The grass and twig ecomorphs are obviously much more slender with longer tails. One can see the physical evolution of the shorter legs of a Jamaican twig anole, Anolis valencienni, a result for gripping its preferred habitat of narrow twigs.

It really is uncanny to have the numbers of these lizards on such a small chunk of land. Practically every ten steps I take I encounter another animal’s territory along with, I assume, some of its brood. Now double or triple that number as you scale up each clump of trees hosting numerous ecomorphs and just imagine the total biomass of these herps!? Anolis is a large genus with over 400 species described with more being added every year. An even more amazing fact is that these current studies of the Greater Antilles anoles claims that 150 species or so of Anolis came from but only two initial colonizing mainland species!

That evening I’m busy photographing the various invertebrates attracted to our porch light when my sister-in-law comes out screaming, “Me can’t sleep in dair!”

“What’s wrong?” I ask. "Aaakk!, Aaaakk!, aaak!" “Dat’s what wrong! Croaking lizard!!”

She’s like most Jamaicans; they have a dreaded fear of Aristelliger praesignis (Jamaican Croaking Lizard) or for that matter, any lizard from the geckonid family. So much folklore revolves around these little guys. One of the most prevalent is just the fear of it biting you,

“It tack yuh!” After capturing it I go to show it to her and she races out of the room. My in-laws think I’m crazy. It is a common nighttime sound in practically every country home as well as out in the bush. It really is an attractive lizard on close inspection with its granular scaled body and multicolored blotches. What is most notable are its bulbous eyes.

“Dem eyes of da devil!”

The sound of droplets of water falling on lush vegetation announces another fog shrouded morning. It was such a delight to amble off into the “bush” as my father-in-law would say, and search for activity. The anole’s body temperature was obviously much cooler at this time so I hoped for getting shots of the deeper brown color phase of these guys, especially Anolis grahami (Jamaican turquoise anole), a trunk-ground ecomorph.

Along fence posts, rock walls, trunks of trees or on a vertical branch one would find a territorial male facing head down, displaying its gular fan or dewlap, each unique to its species and a trademark of this genus. Another characteristic that differentiates anoles from other lizards is their expanded sub digital toe pads with lamellae, much like the geckos. This allows easy transport over smooth surfaces. A quick run-down:

A. lineatopus - white outline with an orange center

A. grahami – deep yellow outline surrounding a deep orange center

A. garmani – all orange

A. opalinus – orange-red

A. valencienni – purple

A. sagrei – yellow outline with a red-orange center

Another characteristic that differentiates anoles from other lizards is their expanded sub digital toe pads with lamellae, much like the geckos. This allows easy transport over smooth surfaces. In a tree just above me, I find a trunk-crown Opal-bellied anole, (Anolis opalensis) clinging vertically in classic anolid fashion.

Inquisitive is an understatement when it comes to my exploratory nature. So here I am scratching through debris to uncover old rusty steel siding to see what it might conceal. “Pay dirt!” Not one but two Jamaican blind snakes, Typhlops jamaicensis.

If this creature didn’t move one would think it was just a piece of discarded wire. Upon close inspection it shows a pair of dots for eyes, basically vestigial, with a smooth scaled body. Adaptations for life underground. I capture one and place it into a plastic jar to take some pictures.

My probing continues with two fleeing geckos and a Jamaican skink, (Spondylurus fulgidus). In my haste to capture it I accidentally break off its tail. This is not uncommon, as it is a means of distraction to the attacker, allowing for a swift escape of the amputee; it will grow back.

Normally I would find a ground snake among this mess but not today. We used to have a trio of dogs that kept the riff raff out but now there is only one. Any mongoose entering the yard would be chased and killed on site. Now only old “Blackie” is our lone protector and because of this I believe these groundsnakes, like this Jamaican Red Groundsnake ( Hypsirhynchus callilaemus), are being wiped out by this introduced predator.

Relaxing along the border of a small patch of trees, a host of Anolis sagrei, like this female,

of various ages vie for prime feeding territory. Nearby a large termite mound captures my curiosity. I jab a limb into its center, twist it slightly and peel off a large chunk. Soldiers immediately set up position to protect against this breaching intruder.

I hope to photograph a feeding frenzy of these anolids. The dominant adult would strike first but often it was busy chasing away other hungry intruders. To my amazement there wasn’t much activity at all. It appeared that only the soft-bodied workers were chosen fare.

They seemed to flee for cover instantly, their ranks replaced with larger bulbous-headed soldiers. Apparently, the termite soldier’s excretion of noxious liquids through its horn-like nozzle was sufficient to ward off these marauding predators.

After enjoying my time on the ground, it seemed like a good idea to take to the trees. Besides, it was apple picking season, so with camera at hand, up I went in search of some tropical delights. These tropical trees are much taller than our temperate variety with a fruit that is more like a pear in shape and texture but has a flavor all its own. Jamaicans call it Titi apple (Syzygium malaccense). It appears that an Opal-bellied anole has claimed an apple for himself with an imposing dewlap display.

Higher up, literally crawling into my viewfinder, was a gorgeous Jamaican crown giant, Anolis grahamii. It’s brilliant, emerald-green upper body was spiked with a row of raised dragon-like scales that ran the length of it back. It blended effortlessly into warm yellow flanks and a creamy white underside. The coup-de-gras came when its contrasting deep orange dewlap was set ablaze with the early morning light!

As a child my innocence and ignorance regarded my first pet “chameleon,” Anolis carolinensis, to be the most awesome thing I ever possessed.It could change colors for crying out loud! Then I read more about lizards and than snakes, frogs, etc. and the intrigue continued to build. The more I read the more in awe I became. Just when I felt I knew all I could about Anolids along come these new findings of ecomorphs and the continued expansion (radiation) of potentially new species. I cannot overemphasize enough for you to maintain that inquisitive, little-kid we all have inside of us; it keeps you young, it keeps you exploring, leading you to new discoveries. Hey, you never know what you might find around the next bend!?

Location: Linstead, Jamaica

Date: February of 2007

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