Author: Jonathan Losos Page 90 of 133

Variation in the hand morphology of lizards. The drawings to the right of each foot indicate the arrangement of the tendons. Note that in B (anoles and Polychrus) and C (geckos), the tendons are independent, whereas in the others, they fused into tendenous plates in the palm of the hand.

In a paper in Acta Zoologica, Tulli et al. examine the tendons of the hands of a variety of lizards, including a dozen anole species. Their hypothesis is that differences in tendon struct should reflect ecological adaptation: in arboreal species, the tendons running to each finger (digit) should be independent, allowing great flexibility, whereas in more terrestrial lizards, the tendons should be fused, presumably providing great stability during locomotion at the cost of less agility.

The data show great variation in tendon morphology, with much of the variation falling out along phylogenetic lines. Form B in the figure above corresponds to all anoles and Polychrus. The data provide a suggestion that the authors’ hypothesis is correct, but statistical analyses incorporating phylogenetic information–affected by the similarity of closely-related species–fail to confirm the result.

Marıa J. Tulli, Anthony Herrel, Bieke Vanhooydonck and Virginia Abdala (2012). Is phylogeny driving tendon length in lizards? Acta Zoologica, 93, 319-329 DOI: 10.1111/j.1463-6395.2011.00505.x

Brown anole eating a curly tail lizard. Photo by Joseph Wasilewski.

We’ve had a number of posts concerning predation by curly tail lizards on brown anoles, in the Bahamas, Florida, Cuba and elsewhere. Now comes a report from near Miami that the brownies aren’t just sitting back and taking it. Rather, they’re rounding up vigilante posses to track down and consume baby curlies, hitting the predator’s population where it’s vulnerable. Ok, perhaps that’s a stretch, but in a recent note in Herpetological Review, Krysko and Wasilewski publish the first report of Anolis sagrei preying on Leiocephalus carinatus, revealing that the ecological interactions between the two species are more complicated than previously thought: we already knew that curlies prey on brown anoles and that the two species also compete for some of the same insect prey (making this an example of the phenomenon of intra-guild predation),  but this study raises the possibility that the interaction–and its likely ecological and evolutionary consequences–could be substantially more complicated. One might think that because of the massive size advantage of the curly-tails, the effects must mostly be one-way; however, the massive population size differential between the two species means that brown anoles, in theory, could greatly affect curly tail populations as well. Although the effects of curly tails on brown anoles have been studied, the opposite experiment has not been done. Of course, previous work on tiny Bahamian islands indicates that curly tails substantially reduce brown anole populations, but maybe dynamics are different in larger and more complicated ecosystems. Personally, I wouldn’t bet on it, but who knows?