Anole Annals

The ability for some lizards to adhere to smooth surfaces has attracted considerable attention from scientists, engineers, and the public for quite some time. Anoles can exhibit considerable amounts of adhesion, although they lack the fancy specializations that most pad-bearing geckos have, such as the upward curling of the digit tips (to detach the adhesive system) before the foot is lifted from the surface. This might be related to the higher adhesive forces exhibited by geckos in comparison to anoles. Unlike anoles, the gecko adhesive system has appeared and disappeared several times. The simplification of the system appears linked to the transition from a climbing to terrestrial lifestyle. However, it has been unclear how this innovation might arise and how the early stages might appear.

The evolution of digit form in Gonatodes

That’s where the genus Gonatodes comes into play. Gonatodes is a reasonably diverse (27 species are currently recognized) and ancestrally padless clade of mostly diurnal sphaerodactylines that is sister to Lepidoblepharis. After examining the microscopic anatomy of a number of species from the genus Gonatodes, it was clear that one species (G. humeralis) was a bit different. Upon investigation of the subdigital micro-ornamentation, we found that the spinules in the vicinity of the digital inflection are longer than in other species of Gonatodes and are expressed as branched, spatulate-tipped setae on the free distal margin of these scales. In other words, it looked like this species of gecko was showing signs of incipient adhesion without actually having any toepads. Now that the morphological differences were identified, we wanted to know how/if this translates into functional and ecological differences.

The origin of frictional adhesion in geckos

In collaboration with Anthony Russell and Tony Gamble, We sought to understand how this incipient adhesive system works in nature, whether G. humeralis can generate adhesive force, and what it permits these lizards to do on smooth surfaces in the lab. I traveled to French Guiana with Clint Collins, a Ph.D. student in my lab, in order to collect G. humeralis and examine its adhesive force. After that, Anthony Russell and I traveled to Trinidad & Tobago to collect a number of other species, in addition to G. humeralis, to see how they used their habitat and whether G. humeralis could out-perform the other species in the lab. To our surprise, G. humeralis was found on smooth bamboo stalks, whereas other species lived on the ground or on rough tree trunks. In the lab, G. humeralis could exhibit considerable adhesive force (for its size), exceeding that of skinks, but falling short of anoles and other pad-bearing geckos. That’s quite impressive for a gecko that lacks all of the bells and whistles of a typical pad-bearing gecko! Importantly, no other species of Gonatodes that we collected could generate any measurable force, agreeing with our previous morphological analyses! Now to the locomotor tests. Pad-bearing geckos are renowned for their ability to ascend vertical smooth surfaces, so we decided to test the ability of different species to climb different inclined smooth acrylic surfaces. A closely related species, G. vittatus, was unable to ascend any incline greater than 40 degrees. However, G. humeralis could climb up a vertical surface, as shown above.

 

 

What does all of this mean?

Although major transformations in vertebrate evolution are common, and often very complex, their origins are often elusive. We offer a glimpse into the early development of the complex adhesive system of geckos. However, the setae of G. humeralis are effective without all of the muscle, tendon, and vascular modifications that are often associated with gecko adhesion. Much like the anoles, the relatively simple setae of G. humeralis provide a dramatic advantage in areas of the habitat typified by leaves or other smooth surfaces (e.g., bamboo stalks). As noted in our paper, our discovery of a functionally intermediate form in the transition to frictional adhesion in a lineage of geckos highlights a statement by Ernst Mayr back in 1960: “Perhaps most astonishing is the relative slightness of reconstruction that seems to be necessary for successful adaptation to rather drastic shifts of adaptive zones.” The relatively simple morphological modification in G. humeralis has permitted a dramatic shift in biomechanics and likely habitat use.

The paper:

Higham, T.E., Gamble, T. and A.P. Russell. 2016. On the origin of frictional adhesion in geckos: small morphological changes lead to a major biomechanical transition in the genus Gonatodes. Biological Journal of the Linnean Society. Doi: 10.1111/bij.12897.

For the past few years the authorities of Chiayi County, southwestern Taiwan, have paid bounties to citizens for brown anoles they collect. Every year the bounty per lizard has decreased and yet they spend their budget and the brown anole persists. This year is the same – a lower bounty – but with a slight difference; the green iguana is now also on the list. In theory, it would be ideal if the invasive lizards can be exterminated, but in reality, I am convinced, they will fail. The brown anole exists in southwestern and eastern Taiwan, and simply targeting them in one location will simply retard their dispersal to new localities (and even with the bounty in place, their distribution is extending). We recently published the results of a study in which we compared brown anole specimens from southern and eastern Taiwan, and we found that there are some variations, most likely due to adaptations to the local habitats (no surprise there!). What this means is that in Taiwan, if brown anoles can reach (either by natural dispersal or with the help of people) open disturbed habitats, with structures that can be used as perches, they will most likely adapt and establish new populations.

And then I wonder why is the brown anole singled out for extermination. Eutropis multifasciata, a relatively large invasive skink, also exists in Chiayi County. Due to its size, it has greater abilities than the brown anole to compete with and prey upon native lizards and arthropods, and yet, they are not on the list. People regard Hemidactylus frenatus, a very common gecko species in urban areas in central and southern Taiwan, as a native species, not realizing that it too is an invasive species.

My honest opinion is they have to accept that just like Hemidactylus frenatus, Anolis sagrei will spread in Taiwan and become a common sight in areas disturbed by humans. They will become (and in many ways already are) part of local ecosystems as competitors, predators and prey. Conservation efforts should thus rather be directed at the re-establishment and conservation of large areas of secondary forests in disturbed lowland areas of Taiwan. This would not only contribute to the conservation of native forest species, but such areas will also function as reservoirs for species like Japalura swinhonis that can compete with Anolis sagrei, as well as being barriers for its spread. People should also be encouraged to be more tolerant towards snakes, in particular non-venomous species such as Lycodon (Dinodon) rufozonatum rufozonatum, Lycodon ruhstrati ruhstrati, and Sibynophis chinensis chinensis, which can prey upon brown anoles. And, finally, an important part in the conservation efforts of native urban wildlife is to develop a better appreciation among the general public of native birds and lizards in urban gardens and parks, and to reduce the impact on these animals by their pets, especially domestic cats (Felis catus), which may prey on them.

 

Just for interest sake, here is a current list of exotic invasive lizards in Taiwan:

Anolis sagrei

Eutropis multifasciata

Hemidactylus frenatus

Iguana iguana

Lepidactylus lugubris

Physignathus cocincinus

It’s not clear whether Rick Shine would know an Anolis lizard if one hit him on the head, but there can be no doubt that he is a great scientist and herpetologist. Anole Annals is delighted to learn that tonight in Parliament House in Canberra, Australian Prime Minister Malcolm Turnbull will present Rick with the 2016 Prime Minister’s Prize for Science. Previous winners have been biomedical researchers, cell biologists and astronomers, among others. Read all about it here. Congratulations, Rick!

Wendy Lee photographed a Graham’s anole eating another anole, probably an A. lineatopus. The event went down on November 25, 2013 in Runaway Bay, Jamaica, where Wendy runs a wildlife rescue facility, the Seven Oaks Sanctuary for Wildlife. We’ve discussed anoles eating other anoles several times in these pages, most recently with regard to A. sabanus. 

 

Greetings AA readers! It’s that time of year again – leaves are changing, the air is getting brisk, and it’s time for the Anole Photo Contest!

As in previous contests, the Anole Annals team is calling for submissions of your best anole photographs for our 2017 calendar.

The editors of Anole Annals will choose a set of 30-40 finalists. Twelve winning photos will then be selected by readers of Anole Annals and a panel of anole photography experts. The grand prize winning and runner-up will have his/her photo featured on the front cover of the 2016 Anole Annals calendar, second place winner will have his/her photo featured on the back cover, and they’ll both win a free calendar! (Last year we had so many submissions we had to make two calendars; check them out here and here).

The rules: submit your photos (as many as you’d like) as email attachments to anoleannalsphotos@gmail.com (note the change in email address from last year). To make sure that your submissions arrive, please send an accompanying email without any attachments to confirm that we’ve received them. Photos must be at least 150 dpi and print to a size of 11 x 17 inches. If you are unsure how to resize your images, the simplest thing to do is to submit the raw image files produced by your digital camera (or if you must, a high quality scan of a printed image).  If you elect to alter your own images, don’t forget that it’s always better to resize than to resample. Images with watermarks or other digital alterations that extend beyond color correction, sharpening and other basic editing will not be accepted. We are not going to deal with formal copyright law and ask only your permission to use your image for the calendar and related content on Anole Annals (more specifically, by submitting your photos, you are agreeing to allow us to use them in the calendar). We, in turn, agree that your images will never be used without attribution and that we will not profit financially from their use (nobody is going to make any money from the sale of these calendars because they’ll be available directly from the vendor).

Please provide a short description of the photo that includes: (1) the species name, (2) the location where the photo was taken, and (3) any other relevant information. Be sure to include your full name in your email as well. Deadline for submission is November 4, 2016.

Good luck, and we look forward to seeing your submissions!

 

Last week, Miguel Landestoy provided the details on the discovery of Anolis landestoyi, the new species from the Dominican Republic. The paper was published recently in The American Naturalist. Here’s what the press had to say:

The Canadian Broadcast Corporation:

A Caribbean lizard that remained undiscovered for many years despite its large size and distinctive looks has been identified as a new species.

The lizard, an anole that looks like a chameleon and has a similar talent for camouflage, lives in the canopy of a rare type of forest in the western Dominican Republic. Adults have a body length of up to 13.5 centimetres and a tail up to 18 centimetres long, making them unusually large for an anole. The new species is described as a “giant chameleon-like lizard” in a study published in the journal The American Naturalist.

• 3 new fish species found in Hawaii marine conservation area

The lizard was first spotted in 2007 by Dominican naturalist Miguel Landestoy while he was studying endangered birds called bay-breasted cuckoos.

‘There’s nothing else like that in and around the island.’– Luke Mahler, University of Toronto

“He noticed that these birds were agitated and seemed to be attacking something,” recalled Luke Mahler, a University of Toronto biologist and the lead author of the new study.

When Landestoy got closer, he saw a lizard and snapped a picture of it.

Convinced it was a new species, he showed the photo to Mahler, a lizard researcher who was working in the Dominican Republic at the time. But the photo was so grainy that Mahler couldn’t tell much other than it was an anole. He suggested that Landestoy try to capture a specimen.

Several years later, Landestoy spotted the lizard again and took some better photos.

“As soon as he sent the pictures,” Mahler recalled, “I was like, ‘What the expletive is that? … There’s nothing else like that in and around the island.”

He added that the Caribbean has been very well explored, so that typically, any new species found there are so similar to existing species that they can only be distinguished with DNA testing.

The new lizard was a big anole, with stubby limbs, a short tail, and green-grey and light brown scales that help it blend in among the moss-covered branches of the semi-dry tropical forest where it lives.

“It’s super camouflaged, basically. It looks just like the bark,” said Mahler, who thinks that’s why it’s never been spotted before. “It’ll sit there and hug a branch and very slowly move one limb at a time.”

The lizard is similar to related anoles found in Cuba called chamaeleolisor chamaeleonides because they’re also chameleon-like.

Different islands, similar adaptations

That’s intriguing because biologists have always expected to find a lizard similar to chamaeleonides on Hispaniola, the island shared by Haiti and the Dominican Republic. Islands in the Caribbean tend to have similar environments and tend to evolve species with similar adaptations, even if they are not closely related.

Mahler says more analysis needs to be done to figure out if the new lizard is similar to the chamaeleonides lizards because it’s closely related or because it evolved similar adaptations over time.

The new lizard has been named Anolis landestoyi after its discoverer.

Sadly, even though the new species was so recently discovered, it may not be around for much longer.

“We think that they’re probably quite endangered,” Mahler said.

That’s because it lives in a unique type of forest halfway up a mountain slope close to the border with Haiti. Although the forest is in a reserve called Lomo Charco Azul that’s officially protected, it’s threatened by illegal logging for agriculture, livestock grazing, and firewood.

The researchers are requesting that the new lizard be officially listed as critically endangered. They hope the new discovery will help draw attention to the threats to its habitat and lead to better protection.

Science Newsline:

We tend to think the contours of biodiversity are well known, especially in extensively studied areas. However, this is not necessarily the case and sometimes strikingly new species are discovered even in well-trod areas. A case in point is the country of the Dominican Republic, which has been thoroughly studied by biologists for more than 40 years, particularly by herpetologists who have exhaustively catalogued the reptiles and amphibians there for several decades.

Read More

My first encounter with the new Hispaniolan giant anole species was in December 2005, when leading a birdwatching tour west of Puerto Escondido, Sierra de Bahoruco, for a group from Scotland. Early one morning, just before dawn, we stopped at what was to become the type locality of the new lizard species and stayed for several minutes searching for some night birds (nightjars, poorwills and potoos) which are most active during crepuscular time windows. It became light, though still without sun. While standing next to the forest edge, the crawling of one of these giant lizards caught my eye. It was moving from a lower tree branch (presumably its roosting perch) towards the trunk and the treetop. It quickly moved out of view, disappearing within seconds. There were no chances for photography or capture.

One and a half years later, in May 2007, I was conducting a nest search for the endangered endemic Bay-breasted Cuckoo at the same locality. Starting at around 9 am, I hiked the trail that goes north in the bottom of the canyon, and nearly one hour later, I spotted two of these fairly large forest birds, foraging in the well wooded area. Closely and silently following the pair, I hid in a stalking manner behind vegetation and logs, occasionally getting my small binoculars out from my shirt pocket to see in detail behavioral events (feeding and mating were observed). This forest is pretty lush during the rainy season, and mosquitoes were everywhere, covering all exposed areas of one’s body. Somewhere between 11 and noon, on a sunny day, the pair seemed to have had enough activity and their stomachs may have been full (with all the cicadas around, that wouldn’t have been too hard). The birds were resting, not high in the trees, and away from sun. One of them was closer to me, well in view, and this same bird took off from its branch once, striking and trying to pull something off of a branch… It happened so fast that I could only pay attention to the bird. But my curiosity was piqued: there should be something on that branch… Binoculars out again, with cautious moves, I examined the branch. A slow scan revealed an extremely well camouflaged lizard, head facing down, that was also getting away from the sunny tree canopy. At first glance it resembled one of these large, big-headed anoles (wait, this looks like one of those barahonae-ricordii giants), but it was distinctly and unusually ashy and pale in coloration. I stared at the anole for some time, and when the birds were gone, it started moving lower down slowly. It came as close as 2 meters from ground, the right moment to attempt capture. Fortunately I had a bit of more luck than the birds had, and I captured the animal. Briefly studying the animal in hand, I noted the large dewlap and odd pattern, and took a few photos, but the lizard was faster than it looked! In a matter of seconds it quickly ran along the branch and then up the trunk and escaped!

One year later, I met some great friends and professionals. Rich Glor was visiting with some students, as was Luke Mahler and some of his (Losos) lab mates and field assistants. I showed them a photo of the animal from my laptop, that only depicted the front part of the animal (head and anterior half). They had a very tight and ambitious schedule to complete during that visit, and unfortunately they weren’t able to visit that fairly distant locality.

The following year I was taking a workshop on natural history and scientific illustration given by the acclaimed Cuban naturalist and artist Nils Navarro, and while choosing some photos for an illustration, one from the strange anole came in view. Nils, who knows the Cuban fauna very well, immediately noted its similarity with Cuban Chamaeleolis-clade anoles. To his chagrin, I told him I hadn’t secured a specimen yet, but that I would try.

No more news from the odd looking anole, until March 2010, when I had the opportunity to re-visit the locality on my own, and dedicated some time to search for the beast. After three hours of night herping, scanning many epiphytes, tree branches, twigs, vines, leaves and trunks, I found one individual, very close from the 2005 encounter! This individual was captured and photographed. The more detailed images of the new individual revealed more unique characters, strongly pointing out the argument that was in fact a new species, and its resemblance in many aspects to the Cuban Chamaeleolis-clade was already obvious. Those photos were sent to the authors, which prompted a visit by Luke.

Nearly a week later, on April 1st, Luke was already sitting at the ministry office when we first spoke by phone that day. To Luke’s unfortunate coincidence with the current date’s event, I told Luke that I did not believe that he could take a plane so fast to the DR… “Wait, what? Luke, don’t tell me you actually came all the way down here man!” Luke responded: Yes man, I told you I would.” Me: “But I couldn’t believe you were so decided, and so responsive to those photos. Luke, honestly, those were actually taken in Cuba during my last visit to the land of Chamaeleolis.” Luke: “Are you serious man? Don’t tell me that now, Jesus!”… When I was convinced he had enough torturing, I came clean and told him it was a just a joke: “Happy April’s Fools Day amigo!” Luke was still skeptical, since he wasn’t sure I was still playing the prank, nor I was just revealing that I was in fact playing a prank to him. Bad (or actually good, indeed) timing, I guess.

Luke came not only to see the specimen I had in captivity, but also to personally visit the locality and get to know the habitat and the species in the field. After several hours of traveling, we arrived just before evening, right after a light rain shower. We began our search once Luke took some habitat photos at the day’s last light. It may have taken nearly two hours to find the first one, a male that I spotted at about 1.5 m of height, head down. Luke secured a female some minutes after, and there they were, a pair of adults!

Finally, after some years of hard field and lab work, the species came out of the anonymity, even though it must still be hiding deep into the dense viney and undergrowth transitional vegetation of the well wooded canyon (or more technically proper, “polje”), where the spanish moss and other epiphytes hang paradoxically within the cacti and hardwood forest surrounded by the big blocks of limestone that characterize this yet remote mountain chain. Threats are not too far from this rarity: in spite of this area being protected (Reserva Biológica Loma Charco Azul), due its proximity to the Haitian border, there is intense slash and burning agriculture in the hills west, and wood charcoal is produced in large amounts and taken to Haiti where it is the basic fuel for cooking. Is the species confined to the bottom valley of this canyon? All current knowledge point it out as very possible, which would mean that the species has a very small and highly vulnerable range.