As Skip Lazell showed nearly a half century ago, Anolis roquet on Martinique is extraordinarily variable in color across its range. This variation has been the subject of much recent work by Roger Thorpe’s lab.
In a recent paper in Herpetological Review, Anderson et al. report on finding an unusual color variant during their recent fieldwork on Martinique.
Bermuda only has one native lizard, a skink. However, during the first half of the 20th century, three anole species were introduced. The first, the beautiful Anolis grahami from Jamaica, quickly spread over most of the archipelago, as David Wingate reported in 1965. However, Wingate noted that the subsequent two species, A. leachi from Antigua and A. extremus from Barbados achieved only more localized distributions.
Thirty-one years later, I published a follow-up survey. By that time, A. grahami had conquered the entire entire and A. leachi had greatly increased its range, but A. extremus was still limited to a far corner on the west end of Bermuda.
Joe Macedonia and colleagues have now returned for a 20-year follow-up, now 51 years after Wingate’s paper. In a paper just published in Herpetological Review, hey find that A. leachi is now also found throughout the Bermudian archipelago. Curiously, however, A. extremus has not advanced at all, with still a very small distribution in the west (see map below). The explanation doesn’t seem to be habitat availability, because there is no obvious difference between where A. extremus occurs and where it doesn’t. Macedonia et al. conclude, as I did, that it is competition from the very similar A. grahami that is preventing A. extremus from expanding its range.
Macedonia et al. also provide a wealth of information on the habitat use of all three species. And there’s a kicker–A. sagrei has recently been introduced to Bermuda. Will it expand its range and, if so, how quickly. Notably, A. sagrei is considerably more terrestrial than the other anoles on Bermuda, so the opportunity seems to exist.
We’ve had previous posts on the penchant of anoles to hitch a ride on a windshield, but this one’s the topper.
The truth must be told.
Previous work by Anthony Russell has demonstrated that geckos have a sophisticated vascular system and connective tissues that allows the toepad of geckos to be molded to the surface with great precision, enhancing the contact between the setal hairs on the pad and the surface. It had been speculated that a similar system existed in anoles, but no one had looked carefully. Now, Russell has, and he reports in Acta Zoologica that previous statements were mistaken: anoles lack what most pad-bearing geckos have. Here’s what the abstract says:
Adhesive toe pads of geckos house modified components of vascular and/or connective tissues that promote conformity of the setal fields with the locomotor substratum. Similar modifications have been claimed for the digits of Anolis, but evidence for them is not compelling. Angiographic and histological investigations of Anolis failed to identify any evidence of either an intralamellar vascular reticular network or a central sinus. Instead, their vascularity more closely resembles that of lizards in general than that of pad-bearing geckos. The loose connective tissue of the toe pads likely contributes to their general pliability and flexibility, promoting localized compliance with the substratum. Through the shedding cycle, the lamellae change shape as the replacing setae elongate. The outer epidermal generation lacunar cells on the inner lamellar faces simultaneously hypertrophy, providing for compatibility between overlapping lamellae, enabling reciprocity between them. This contributes to continuing compliance of the setal fields with the substratum. Overall, digital structure and attachment and release kinematics of the toe pads of Anolis are very similar to those of geckos exhibiting an incipient adhesive mechanism. Both lack major anatomical specializations for promoting conformity of the setae with the locomotor substratum beyond those of the seta-bearing portions of the epidermis.
In q previous post, Hispanioland showed us a picture of the fake dead behavior by Anolis distichus. This year I breed my pair of Anolis sagrei and I have several offspring.
I can see that this behavior is rather common among the offspring, and I partially filmed it in the following video. I didn’t see the same behavior in my other anoles species. Maybe only for trunk-ground species?
In which species have you seen this behavior ?
In this case, the offspring begins to stiffen, twists and falls to the ground. Then, he opens his mouth and stops breathing. The limbs are tense as a dead person. When the young are put back to safety (some seconds later), the individual “awakes.”
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Karen Cusick, proprietor of Daffodil’s Photo Blog, watched this green anole turn from green to brown. Or mostly brown. I’ve seen this sometimes myself. Anyone know what’s going on here? Seen it in other green anoles?
Thank you to all who sent in photos for our contest; we received a total of 101 submissions! We’ve tallied the results and consulted our panel of experts, and are ready to announce the winners for Anoles 2017. The grand prize winner is the photo above, Anolis equestris potior, taken by Jesús Reina Carvajal. The second place winner is below, Anolis aquaticus, taken by Lindsey Swierk. Congratulations!
The rest of the winners can be seen in the 2017 calendar here! Click the link to order your calendar, just in time for the holidays. Congratulations to all the winners, and thank you again to everyone who participated!
Happy holidays! Can’t wait to see the submissions next year!
A newborn anole arrives in November. Photo by Karen Cusick
Who says global warming is such a bad thing? Ok, it is, but at least there are some benefits, especially if you’re a brown anole in Florida. Read all about it in Daffodil’s Photo Blog.
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