Anole Annals

We’ve had a week now to let the proposed reclassification of Anolis sink it, so it’s time to start discussing it. A revolutionary new view of the scientific review process suggests that in the future, all papers will be published open access online (as this one is–thanks Nicholson et al.), the journal in which it appears (if any) will not matter, and peer review and evaluation will be conducted post-publication on internet discussion sites. Realistic? Who knows, but why not give it a try?

The paper by Nicholson et al. is undoubtedly the most important paper on anoles to be published in the last several years. Not only does it propose to split Anolis into eight genera, but it also presents provocative findings about the ecological evolution of anoles (including throwing out the ecomorph concept), anole biogeography, and the dating of evolutionary events in anole history.

Anole Annals’ goal is to be the meeting place for discussion of all things Anolis, so let’s take this post-publication review and commentary idea out for a spin. Anole Annals invites members of the anole community to post their thoughts on any aspect of the Nicholson et al. paper. We hope to get a conversation going on the merits of splitting the genus, as well as the other issues raised in the paper. In fact, this has already begun, as evidenced by the comments by Mssrs. Crother, Hillis and Duellman, among others.

To get the ball rolling, here’s a short précis of the paper:

1. Phylogenetic analysis based on previously published data of all sorts (genetic, morphological, karyological), with a smidgeon of new molecular data, reveals a phylogeny with eight strongly supported clades in a Bayesian analysis. These clades are recognized as distinct genera.

2. The ecomorph concept does not apply to mainland anoles because species similar in habitat use are not similar in morphology. Hence the term “ecomode” is coined for species similar in habitat use. Phylogenetic analysis of ecomode evolution on the phylogeny suggests that the crown-giant ecomode is ancestral for Anolis. The ecomorph concept is argued to not work for Greater Antillean anoles and should be discarded.

3. Biogeography is reconstructed on the phylogeny. Using the phylogeny, the authors argue that the eight clades differentiated about the time that the proto-antillean islands were passing between what is now North and South America. The Norops clade differentiated on several of these blocks (both island and mainland), explaining why Norops is nested within Caribbean non-Norops taxa without requiring the island-to-mainland colonization of Norops proposed by a number of previous papers.

4. Molecular clock dating reveals that anoles are surprisingly ancient, originating in South America approximately 130 million years ago.

Nicholson, K. E., B. I. Crother, C. Guyer, J. M. Savage (2012). It is time for a new classification of anoles (Squamata: Dactyloidae) Zootaxa, 3477, 1-108

An interesting paper in 2009 showed us that jumping without a tail can be a disaster for green anoles. In that paper, the authors found that the bodies of tailless individuals often underwent extensive posterior rotations in the air, resulting in very awkward landings. Moreover, tail regeneration can take months to complete, which implies that losing stability in the air may not be a short term situation. So we wondered: can green anoles quickly improve in-air stability, or do they just have to wait until they have their tails back again? To address this question, we tested in a recent study whether tailless green anoles can improve in-air stability in five week’s time and whether gaining more jumping experience facilitates the improvement.

We found that there was extensive variation in how much an individual could improve within five week’s time. By the end of our study period, some individuals showed no sign of improvement,

httpv://youtu.be/aTfui2FlC9Q

whereas others did improve their in-air stability as time went by.

httpv://youtu.be/5s86p8KMWTE

Interestingly, the acquisition of more jumping experience did not seem to matter. Lizards with more jumping experience on average did not do better than those without. It appeared that the motor coordination capacity of an individual might be the most relevant factor for locomotor recovery in tailless green anoles. Our finding suggested that the cost of tail loss might be very different among individuals in natural populations. It would be very interesting to perform a manipulative field study to see whether individuals that are unable to improve in-air stability alter their habitat use and movement patterns to a greater extent to avoid jumping.

CHI-YUN KUO, GARY B. GILLIS and DUNCAN J. IRSCHICK (2012). Take this broken tail and learn to jump: the ability to recover from reduced in-air stability in tailless green anole lizards [Anolis carolinensis (Squamata: Dactyloidae)] Biological Journal of the Linnean Society DOI: 10.1111/j.1095-8312.2012.01958.x

Here on the Anole Annals we like to talk food. Although anoles are predominantly insectivorous creatures, we have documented some of their stranger eating habits on this blog. For example, through recent research we have learned that they are more frugivorous than previously thought. They also include other vertebrates into their diets, such as frogs. Chamaeleolis anoles, we have learned, have specialized molars to aid in crunching mollusks.

Sadly, however, anoles are often also on the receiving side of predation. Anoles are important prey items for many different animals. Sometimes, even plants get their fill on anoles.

In her recently published undergraduate thesis, Dr. Yudisleidy López Ricardo from the University of La Habana, Cuba discusses the diet of the barn owl (Tyto alba furcata) in several localities in Villa Clara and Ciego de Ávila. Dr. López Ricardo examined nearly 300 owl pellets (regurgitated bits that contain food remains) and found 69 different prey types. As expected, small mammals such as the house mouse and black rat were common prey items. A novel finding of this study, however, is that large species of anoles, namely A. equestris, A. porcatus, and even Chamaeleolis sp. lizards were found in the owl pellets. Smaller anoles, including A. jubar, A. sagrei, and A. lucius were also found in the diets of the barn owl. The authors also found that a different herp, the Cuban tree frog, Osteopilus septentrionalis, was not uncommonly found in owl pellets, but this species is nocturnal.

The finding that anoles are a small, but important, component of this species’ diet is quite interesting in light of the fact that Tyto alba, like most owls, is nocturnal. The main question for me is how they are finding and catching anoles. Owls rely heavily on sensitive hearing to locate moving prey at even great distances. But anoles are predominantly diurnal creatures, and are typically asleep and quite still by nightfall. Owls also have great vision and may be spotting anoles during crepuscular hours. Or are they opportunistically feeding on anoles? Perhaps a different predator scares an anole out of its sleeping site and owls are snatching up fleeing anoles.

Any thoughts from the Anolis community on this interesting finding?

Squares are A. gaigei; circles are A. tropidogaster; triangles are locations of members of the species complex for which specimens were not examined and thus determination to species has not yet been accomplished.

Gunther Köhler’s at it again! This time with a merry band of colleagues he’s split Anolis tropidogaster, a little brownjob of an anole widespread in southern Central America and Colombia, into two species, A. tropidogaster in Colombia and eastern Panama and A. gaigei sandwiching it in western panama and the Santa Clara Mountains of Colombia.

Like a number of recently differentiated mainland anoles, the species differ markedly in the shape of their hemipenes. However, in contrast to some other cases, they also differ in dewlap color and a number of scale characters. Further, a limited genetic analysis suggests that the two forms may be substantially differentiated genetically.

The title of the paper says it all: “It is time for a new classification of anoles (Squamata: Dactyloidae).” No doubt, AA contributors will have something to say about this before long, but comments–or posts–are welcome now. The paper–by Nicholson, Crother, Guyer, and Savage–is a 108 page monograph in Zootaxa (text runs to page 69). Anolis is proposed to be split into the following genera: Dactyloa, Deiroptyx, Xiphosurus, Chamaelinorops, Audantia, Anolis, Ctenonotus, and Norops. In addition to presenting a phylogeny and a new classification, the paper also has sections on biogeography, dating, ancestor reconstruction and–most intriguingly–“Evolution of ecomodes in the family Dactyloidae.” Stay tuned!