These stills are of an anole fight we saw yesterday along the Rio Bani. This fight happened on a rock between two male Anolis distichus ravitergum. On the left, the two males are facing off. In the middle, one male is charging and biting the other. On the right, the two are tumbling down the boulder. Shea Lambert recorded the video and plans to post a version with slow-motion and music sometime soon; it should be epic.
In the Dominican Republic, there are few anole hunting localities more famous than the Recodo Road, a road running along the Rio Bani just west of Bani (you can get some background on this locality from several previous blog posts 1, 2, 3). Anthony Geneva, Shea Lambert, and I arrived here on Sunday to continue our studies of speciation in the distichus species group. One feature of this road familiar to anyone who’s visited are the river crossings that are necessitated by the absence of bridges. With a 4×4, these crossings are a piece of cake when the water is low, but completely impossible when the water is high. After a recent tropical storm, both of the two required crossings are on the verge of uncrossability. We made it through the first one (see photos above), but have decided to hold off on attempting the second until the river settles a bit more. Note the beautiful Kapok (Ceiba) tree at the first crossing, which is one of the oldest and most beautiful native trees in the region (it’s also from a genus with rather remarkable transatlantic dispersal capabilities [Dick et al. 2007]). More soon on the lizards we’re seeing so far!
Phylogenetic tree from Castañeda & de Queiroz's concatenated dataset (left), instability of relationships among five major clades resulting from analyses of mtDNA (top center) and nDNA (bottom center), Anolis (Phenacosaurus) heterderma from Juan Salvador Mendoza's Flickr (http://www.flickr.com/photos/ecoterror/page6/) (top right), and geographic distributions for major clades identified by Castañeda and de Queiroz (bottom right).
A few days ago, I discussed a paper that proposes assignment of anoles to a new family called Dactyloidae. Today, I want to call attention to another new paper about anole systematics and taxonomy that involves a clade beginning with ‘dactyl’: the Dactyloa clade of Anolis. The Dactyloa clade includes around 80 species of anoles found across southern Central America, northern South America, and the southern Lesser Antilles. Although most anole biologist believe that its best to continue recognizing the species in this clade as members of a unified Anolis, the Dactyloa clade does seem to represent one of the few genera proposed by Guyer and Savage that is largely monophyletic (albeit with the addition of species previously assigned to Phenacosaurus).
In a paper published in Molecular Phylogenetic and Evolution, Castañeda and de Queiroz generate new phylogenetic trees for this group based on DNA sequence data from three loci (two mitochondrial and one nuclear) sampled across 40 of 82 previously recognized species, two new species, and 12 outgroup taxa. Castañeda and de Queiroz’s analyses of concatenated and individual gene datasets using GARLI and MrBayes recover support for five well-supported and geographically cohesive clades within Dactyloa. Three of these clades closely match groups defined based on previously morphological and biogeographic analyses: Phenacosaurus, the roquet series, and the latifrons series. Two of the clades identified by Castañeda and de Queiroz were not diagnosed by previous morphological analyses, but do make sense biogeographically: one of these clades occurs across the eastern cordillera of the Colombian Andes and the Venezuelan Andes (the “eastern” clade of Dactyloa) and the second can be found across the western and central cordilleras of the Colombian Andes, the western slope of the Equadorian Andies and the Pacific lowlands of Panama, Colombia, and Ecuador (the “western” clade of Dactyloa). The monophyly of two clades previously identified by morphological analyses – the aequatorialis and punctatus series – is strongly rejected by the new molecular data, reaffirming problems that have long plagued taxonomic studies of mainland anoles based on morphological data. Relationships among the five well-supported and geographically-cohesive clades identified by Castañeda and de Queiroz are poorly supported and unstable among analyses, seemingly due to short basal branches. Although their results clearly indicate the need for taxonomic revision of Dactyloa, Castañeda and de Queiroz reasonably suggest that any such revisions should await more comprehensive species-level sampling is available.
Watch Miguel Landestoy kiss Anolis darlingtoni! (at 1:39 on the video)
A time calibrated tree from Townsend et al. and photographs of Polychrus (from http://reptile-database.reptarium.cz/species.php?genus=Polychrus&species=gutturosus), Anolis, and Basiliscus (from http://scienceblogs.com/tetrapodzoology/2009/01/something_new_about_basilisks.php)..
For decades, anole have been assigned to Polychrotidae, a family or subfamily of Iguania whose core members have always included Anolis and Polychrus. In spite of the morphological similarities shared by these genera, molecular studies conducted over the past decade have consistently recovered a non-monophyletic Polychrotidae and have never recovered strong support for a sister relationship between Polychrus and Anolis. In recent Bayesian and maximum likelihood analyses of 29 loci sampled from 47 iguanians and 29 outgroup taxa, Townsend et al. (2011) drive the final nail in the coffin of the notion that Anolis and Polychrus are closely related and form a clade that should continue to be recognized as Polychrotidae. The sister-group relationship between Anolis and Polychrus is completely absent from the posterior distribution of trees generated from Townsend et al.’s 29-locus concatenated dataset and this relationship appears in only one or two of their 29 single-gene trees. As a result, Townsend et al. limit Polycrhotidae to Polychrus and resurrect the family name Dactyloidae for Anolis. Although they acknowledge that Dactyloidae is a less intuitive name for this clade than Anolidae, the latter is junior synonym of the former, having been coined by Cope (1864) some 20 years after Fitzinger (1843) recognized Dactyloidae. Students of squamate phylogenetic systematics should definitely check this paper out, Townsend et al.’s results concerning Polychrotidae are only one of their many interesting insights.
Image of Anolis darlingtoni from http://www.philly.com/philly/blogs/evolution/A-Long-Lost-Lizard-is-Found-in-Haiti.html
Last week, Blair Hedges led a team of scientists, journalists and naturalists on a helicopter tour of some of the most remote forested habitats remaining on Haiti’s Tiburon Peninsula. For anole enthusiasts, this expedition’s most remarkable find was the rediscovery of Anolis darlingtoni, an enigmatic species that hasn’t been seen since 1984. As reported by Faye Flam at Philly.com, expedition member Miguel Landestoy spotted a single animal sleeping around 2m up in a tree fern. This seems to have been the only darlingtoni recovered by the expedition, but full trip details are still filtering in.
Even with this rediscovery, Anolis darlingtoni remains the rarest anole on Hispaniola, and the one that is the most immediate danger of extinction. Luke Mahler and I went to a great deal of trouble to search for A. darlingtoni in remnant forests at the western end of the Tiburon Peninsula a few years ago and came up empty, so I know that finding this species is no easy feat. My congratulations to Blair, Miguel, and the rest of the team!
Over the years, many talks on anole dewlaps have featured an image from Nicholson et al.’s 2007 paper from PLoS One on anole dewlap evolution (I saw this image at least once at JMIH this year). Now that its been almost five years since this image was published, I think its time we came up with a new collage of anole dewlaps. Which dewlaps should we include? Who’s got dewlap photos to share for the effort? If you’ve got some nice photos to share for the collage please post them here at Anole Annals and I’ll put them all together to generate our anole community dewlap collage! See the guidelines for posting for instructions on how to post images as part of a comment. (For my part, I’ve accumulated lots of photos from the Greater Antilles, but have almost nothing from the mainland or the Lesser Antilles.)
Table from Portik et al.'s Conservation Genetics paper reporting new primer pairs for amplification of nuclear loci (left side) and a phylogeny generated using some of these loci from Stanley et al.s' 2011 MPE paper on cordylids (right panel).
A new study by Portik et al. used the anole genome to develop more than 100 new primer pairs for the amplification of nuclear-encoded DNA from squamates, some of which have already proven useful for inferring relationships within and among species. Portik et al.’s carefully thought out strategy for marker development – which focused on rapidly evolving protein-coding loci – ensures that their loci will be particularly useful for phylogenetic analyses. First, Portik et al. focused on intronless protein-coding genes, with the goal of limiting length variation and simplifying alignment. Second, recognizing low variability relative to non-coding regions as a potential limitation of protein-coding loci, Portik et al. focused exclusively on developing markers from loci that are more variable than the first third of RAG-1 (one of the most useful and widely-used of the nuclear genes used previous phylogenetic studies of squamates). This strategy yielded 104 genes and led to development of primers for 170 gene fragments ranging from 407-2,492 bp. Portik et al. conducted limited PCR testing on 70 of these loci and found varying degrees of success across five squamate families, including Scincidae, Varanidae, Agamidae, Cordylidae, and Gekkonidae. More importantly, some of the loci have already proven useful for phylogenetic studies of skinks (Portik et al. 2010 , Portik et al. 2011), cordylids (Stanley et al. 2011) and iguanids (anole genome paper, which is currently in press at Nature).
While high throughput sequencing technology will eventually render PCR primers and Sanger sequencing nothing more than curiosities from a previous generation, this time is at least a few years away. In the meantime, Portik et al. have given the herpetological community some very useful new tools to play with.
A figure illustrating dewlap color variation in the distichus species group from Anthony Geneva's award winning poster.
Two posters on anole evolution presented at JMIH last weekend were honored with SSAR poster awards. Anthony Geneva, a PhD student at the University of Rochester took home the prize in the Evolution, Genetics, & Systematics category for his poster on “A Multi-locus Molecular Phylogeny of Distichoid Anoles.” Mingna Zhuang, an undergraduate researcher at UC Berkeley, won in the Ecology, Natural History, Distribution, & Behavior category for her poster on “Comparative Gliding Performance of Anolis carolinensis and Anolis sagrei.” Although not on anoles, it also bears noting that Daniel Scantlebury’s study of adaptive radiation in Sphaerodactylus – which has been inspired partly by work on Anolis – won the SSAR’s Henri Seibert Award for best student talk on Evolution/Systematics. Congrats to Anthony, Mingna, and Dan!
The Sunday night poster session at JMIH 2011 had a few more anole offerings. Melissa Moody from Iowa State reported on a laboratory experiment on the developmental and fitness consequences of varying Anolis sagrei egg incubation temperature and humidity. Anolis sagrei eggs seem relatively robust to the variation experienced during this experiment. Paul Cupp of Eastern Kentucky University asked whether ground skinks (Scincella lateralis) and green anoles (Anolis carolinensis) could detect chemical deposits from the Eastern Milk Snakes (Lampropeltis triangulum); he found evidence that the skinks could detect these deposits while the anoles could not. Finally, Mingna Zhuang discussed comparative gliding performance of Anolis carolinensis and Anolis sagrei. She found that A. carolinensis is a considerably better glider, perhaps due to the fact that it has a flatter gliding posture than A. sagrei.
Powered by WordPress & Theme by Anders Norén
