Author: Thomas Sanger Page 5 of 6

Thom Sanger is an Assistant Professor at Loyola University in Chicago. His lab specializes on understanding the developmental bases of Anolis lizard diversity.

Pure Amazement

As anole specialists we sometimes overlook how exciting our animals can be to other biologists and the general public. After returning to campus with a male Anolis equestris yesterday the people on my floor were amazed by this animal (granted they work on fruit flies). Photos were taken and shared with friends. While we would likely default to using cut and dry adjectives to describe most lizards, I think that the quote below demonstrates well the emotions that a non-scientist feels when observing a giant green lizard.

“OMFG! Is it just me or is that a freaking gorgeous animal? Look underneath it’s feet, the rubber part of the toes! aww. I cant get over it’s chin..Why do Lizards have that elongated loose neck…what is it called and is it used for digesting food? Your camera takes great photos. squishy and i wanna kissy.  🙂
Ok I’ll stop”

Thanks to Didem Sarikaya for passing this along. Didem’s photo is below.

New AA Challenge: How many species in a single photo?

Several community challenges have emerged on Anole Annals in recent years such as the popular “Spot the anole” series (here, here, and here for example). Today I raise a new challenge to anole enthusiasts worldwide. I challenge you to post a single photo of anoles in the wild with the greatest species diversity. Integrity counts: photos and lizards should not be manipulated. The lizards should have naturally come into close proximity on their own volition.

To start this out I will set the bar to beat at three species. I took this photo last weekend at the University of Miami arboretum. The three species, from left to right, are A. distichus, A. carolinensis, and A. sagrei. I expect that three should be relatively easy to beat so lets see what you’ve got!

Lizards in a Bottle

Anole Annals posts are constantly pushing the technological limits of herpetological research, from exciting new uses for vacuum cleaners to new caging systems (here and here) to novel methods of visualizing the anole skeleton (here and here). Thanks to Kim Orrell (Shenandoah University) I learned of a new technique of shipping small anoles that may hold promise for the future.

 

 

 

 

 

 

 

A common challenge I often face is finding best way to ship small anoles, often hatchlings or juveniles, to collaborating labs. While hatchlings are often hardier than they look, they do require some extra protection from getting bumped around so I don’t like using bags. Most Tupperware containers are simply too big and can, at times, be difficult to get the small lizards in and out of. The  package I received today used an ingenious method of packing small lizards in recycled plastic water bottles. Each bottle was loosely packed with paper towels with one or two lizards added. The bottles have a relatively small foot print and little space between bottles when packed tight. Each bottle cap had two small holes drilled for air exchange. Removing the lizards was surprisingly easy. I simply pulled each paper towel out using forceps and gently tapped each bottle until the lizard slid out the hole, usually in two to three taps. While working with these bottles today I could not help but to also think that I was on the verge of the next great Sobe ad!

Meeting Summary: Anolis Evo-devo and Genomics

The Anolis Gene Nomenclature Committee (AGNC) recently held an open discussion regarding our ongoing efforts to develop Anolis as a model system for integrative biology* and genomics at SICB 2012 in Charlestown, SC. To facilitate further discussion from the community I wanted to post a summary of this meeting here. If anyone would like to add to this discussion or propose additional objectives or concerns please leave your comments below. This is an exciting and fast-paced time for Anolis biologists and discussions such as this are necessary to continue the productive development of this genus for research in a post-genomic era.

Ongoing efforts

The AGNC was formed to efficiently develop resources that will be useful to the Anolis research community. We opened the meeting with short presentations about our ongoing resource development efforts. Carlos Infante (UGA) described work from the Menke Lab to develop cell culture protocols that will be used to test transgenic constructs directly in anole tissues rather than distantly related model systems such as the mouse or chicken. He noted that they recently had promising results testing the piggyBac transposon system in cultured anole fibroblasts. Building on her poster presentation Jeanne Wilson-Rawls (ASU) described her experiences isolating and culturing satellite cells – small stem cells found in mature muscles – and her ongoing collaboration with Kenro Kusumi (ASU) studying the mechanisms of tail regeneration in A. carolinensis. Dr. Kusumi described a relatively new project aimed at obtaining genome and transcriptome sequences for A. apletophallus from Panama as part of a collaboration with the Smithsonian Tropical Research Institute (also see this abstract from E. Hutchins). Dr. Kusumi also reminded the audience of their recent release of additional transcriptome data for mid-stage A. carolinensis embryos (available through NCBI).

One of the AGNC objectives is to aid in the dissemination of laboratory protocols, genomic data, and to create a pipeline for integrating data from multiple populations and species (see below). Several web-based resources are now being created along these lines. Tonia Hsieh and Rob Kulathinal (Temple Univ.) concluded this introduction by describing their efforts to develop Lizardbase, a web portal for geographic and genomic data mining. While still in its development phase the portal promises to become a useful tool for the anole research community and its public outreach efforts as data is added. To build this database Drs. Hsieh and Kulathinal are soliciting geo-tagged data for this portal and are in the process of adding a searchable database of contributors.

Looking forward – Goals for 2012

Anolis (Embryos) Snag Another Cover!

Many editors have recently come to acknowledge that an anole on a book or journal cover generates much enthusiasm from the community (here, here, here, here, here, here and here– I hope that I didn’t miss any). The trend continues in the February issue of Proceedings of the Royal Society. In this issue Sanger et al. describe the developmental bases of limb length convergence among trunk-ground and trunk-crown habitat specialists (previously described on Anole Annals). It should be noted that the only thing that can  possibly trump the beauty and eloquence of an anole in its native environment are developmental series of anole embryos (see here for further proof)

Ahead by a Nose: Variation in Anole Head Shape

Anole morphology holds an important place in the recent history of evolutionary biology. For example, comparisons of morphology, behavior, and ecology among Anolis species led E. E. Williams to conceptualize ecomorphology (discussed here). The repeated Caribbean anole radiations are also of great importance for studies of convergence, parallelism, and constraint (e.g., here and here). Surprisingly, however, the vast majority of anole research has focused on postcranial characters; comparatively few studies have surveyed variation in head shape and its functional and ecological significance. While strong correlations between relative limb length and microhabitat have been the subject of much research, one cannot overlook the fact that variation in head shape may also have important ecological and evolutionary significance for this genus.

Even a brief visual survey of the MCZ skeletal collection reveals an array of variation in anole head shape: from the robust skull of A. cybotes to the slender skull of A. dolichocephalus to the ornate skulls of Chamaeleolis (Here is a real challenge: Can anyone name the species in the picture?). Harmon et al. (2005) used three-dimensional geometric morphometrics for 21 anole species and concluded that anole heads primarily vary in relative length and depth. To further investigate which skeletal elements contribute to this variation and how many times anoles have independently converged on similar head shapes Sanger et al. recently analyzed skull shape variation among males of 106 Caribbean species (yes, Sanger, that’s me).

International Congress on Vertebrate Morphology 2013 – Call for Symposia

The International Congress on Vertebrate Morphology will be convening in Barcelona, Spain July 8–12, 2013. I have found past meetings extremely enjoyable with many exciting talks. How many from the anole community are considering attending?

The call for symposia for ICVM 10 was recently announced and the deadline for proposed symposia is April 15. With the growing number of labs studying anole development is it time to consider organizing an anole evo-devo symposium? What about a “reptilian” evo-devo symposium that brings together biologists working on other squamate, crocodilian, and turtle species? Perhaps its too soon or maybe another meeting? While mulling these ideas over I would appreciate hearing thoughts from others in the community. Please leave your comments below or email me directly.

Anole Food Preference Experiment

As Jonathan describes in Lizards in an Evolutionary Tree (Chapter 8 ) data on anole food preferences are sparse. However, this is a critical element of anole biology that needs to be more thoroughly explored if we are going to understand the diversity of skull shapes (the topic of a future post), nutrition, or energetics in anoles. The question is simple in principle but difficult in practice: do species preferentially eat certain insects? If so, has head shape adapted for the preferential capture or mastication of insects of a particular size or hardness? Do lizards that eat insects of lower “quality” eat more often or move less often? Perhaps anoles will eat what ever bug it happens to encounter and skull diversity is the result of other selection pressures. At this time we do not yet know. Interestingly, however, preliminary evidence suggests that the primary food source of many anoles are just ants, which while quite abundant are not very nutritious. Ants can account for up to 80% of the stomach contents of A. distichus for example.

The embedded video gave me an idea for a great experiment that can be done in a controlled setting.  Simply run various bugs across the screen of an iPad and see if different species preferentially target particular sizes or shapes. If anyone would like to donate an iPad to this cause of utmost importance I would be happy to perform the experiments.

SICB 2012: Open Discussion on Anolis Evo-devo and Genomic Resources

December 27, 2011
UPDATE: There has been a room change for this meeting. It will now be held in the Wando Room which is in the lobby level of the Embassy Suites hotel.

SICB 2012 is only three weeks away and a large number of biologists interested in Anolis evo-devo and genomics are expected to attend the Charlestown Meeting. Twenty-six presentations of anole research are scheduled, many with aspects of genomics, comparative development, physiology, or molecular evolution as one of their primary components (see my previous post here). To facilitate discussion among researchers from these disparate disciplines we are organizing an open discussion on the resources currently available to this young, but rapidly growing community. For example, beyond the A. carolinensis genome what sequencing efforts are underway? Because we do not yet have transgenic technologies, what cell-based resources are being generated that can be used to test molecular hypotheses in vitro? As the community builds its experimental and comparative infrastructure discussions such as this will be necessary to avoid costly duplication of efforts and to determine the needs of the community at large.

Not All Embryos are Created Equal

The pages of Anole Annals were recently graced with beautiful photos of Anolis embryos (here), their allure attracting attention from far and wide (here). Unfortunately, development doesn’t always go according to plan. While slight perturbations to development can create fodder for natural selection, more extreme phenotypic mutations can create not-so-hopeful monsters (a play on R. Goldschmidt’s theory of hopeful monsters which predicts that relatively large homeotic mutations can contribute to evolutionary saltations). Several years ago I dissected this embryo of A. sagrei. Count the body parts.What do you see?

This is likely one of the most extreme mutant Anolis embryos I have collected. I regularly find dead embryos that appear normal morphologically and died for unknown causes. But this is the other extreme. This embryo clearly possesses a well-developed, seemingly normal head, limbs, and tail. It is even beginning to develop scales on the limbs and body. Without dissection I cannot be precisely sure about the nature of this mutation, but one can readily discern that there is no well-defined body axis, the head, tail, limbs all emerge from a nondescript central mass of tissue. Perhaps more interesting  in this light, there also appears to be an axis duplication. Eight limbs, two tails, and two sets of hemipenes are visible, but only one head (note, only one eye is visible but both are present). Can’t see everything? Check out the labeled photos below.

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