La Selva Lucky Seven

Anolis carpenteri. Photo from http://ctaudubon.blogspot.com/2011/04/young-researchers-shine-during-costa_05.html

We notched the double anole hat trick in the most unexpected manner last night, as a female of that rarely seen species, A. carpenteri, presented itself sleeping at chest level on an isolated plant in the clearing. With a day yet to go, hope springs eternal that a resplendent green A. biporcatus will make it a lucky seven at La Selva.

News flash—breakfast! Just learned that last night, the team headed for a ditch filled with caimans found an A. biporcatus sleeping on a branch above the trail. Seven anole species in two days!

Seven anole species at one site (eight if we include the unseen A. pentaprion). Certainly, a lot of anole diversity, but not unheard of in any way. In fact, such diversity occurs regularly on the Cuba, Hispaniola, and Puerto. Yet, the anole ensemble here differs greatly from what we would see in a diverse Caribbean community. All species-rich assemblages in the Caribbean are extremely similar, composed primarily of the different ecomorph types. Usually, such a location would have very common trunk-ground and trunk-crown anoles, and then representatives of three or all four of the remaining ecomorph types. The remaining species would either be some of the “unique” habitat specialist types which occur only on one island, such as the rock wall specialist A.bartschi on Cuba or members of the Chamaelolis clade; or they would include multiple members of the same ecomorph type, such as several trunk-ground anoles that use different thermal microhabitats.

By contrast, the La Selva Eight bears little similarity to these assemblages. Only two species parallel the West Indian ecomorphs. Anolis pentaprion is pretty clearly a twig anole in morphology, behavior, and habitat use, and A. biporcatus is somewhat of a hybrid between an extra-large trunk-crown anole and a small and gracile crown-giant (indeed, it is very reminiscent of A. garmani from Jamaica, which itself is the most trunk-crown-like of the West Indian crown giants). Beside those two, however, the similarities are few and far between: there are not species that are similar in any way to grass-bush, trunk-ground or trunk ecomorphs. Conversely, the La Selva species are quite distinctive from anything seen in the West Indies: the spritely A. limifrons, hopping among stems, leaves and trunks near the ground, has no counterpart; the leaf-litter dwelling A. humilis occupies a nearly unused West Indian niche and isn’t particularly similar to A. (Chamaelinorops) barbouri (the only real leaf litter anole in the islands); A. oxylophus is an “aquatic” anole that is morphologically unlike the two West Indian aquatic anoles (which are not like each other, either); A. lemurinus, found on tree trunks from near the ground to high in the canopy, does not closely match any West Indian species; A. carpenteri is a bit of an enigma, its natural history not well known, but its morphology not particularly similar to any West Indian species; and, finally, A. capito, with the remarkable short snout and long spindly legs, living much lower to the ground than any large West Indian anole (and with few parallels in anoledom as a whole), is again unmatched in the islands.

In sum, this mainland community, like all mainland anole communities, is utterly different from those that have evolved repeatedly on the islands. We’ve talked about such differences a bit in the past—the pattern seems well documented, but the cause of this divergence in evolutionary direction is still very much a mystery.

About Jonathan Losos

Professor and Curator of Herpetology at the Museum of Comparative Zoology at Harvard University. I've spent my entire professional career studying anoles and have discovered that the more I learn about anoles, the more I realize I don't know.

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