Photo by Cristian Castro Morales
AA reader Cristian Castro Morales has sent in this photograph of the little known Anolis huilae. He says: Male of Anolis huilae display their dewlap to ward off a possible predator or rival from his perch. This species is reported in Colombia in the departaments of Huila and Tolima.
Photo by James Christensen
Anolis auratus is one of the most widespread mainland anoles, with a range stretching from Costa Rica through much of northern top of South America on both sides of the Andes. It’s biology is surprisingly little known, though it is thought to be a grassland species; that and it’s morphological similarity to grass-inhabiting Caribbean anoles has led some to argue that this species is a member of the grass-bush ecomorph category.
Given it’s wide range in Colombia traversing the Andes, the species is ripe for investigation of geographic variation, and that is just what Martha Calderón-Espinosa and Leidy Alejandra Barragán-Contreras did, examining a large number of museum specimens in the collection of the Instituto de Ciencias Naturales, Universidad Nacional de Colombia. Their work was recently published in Acta Biológica Colombiana. The abstract is appended below, but to make a not-so-long story short, sexual dimorphism exists for several characteristics independent of body size (the sexes don’t vary in size), and these same characters vary geographically. What this means about variation in habitat use of the species across its range remains to be studied.
Abstract
Anolis auratus is a widely distributed species, from Costa Rica in Central America, through northern South America, including Colombia, Venezuela, northern Brazil, Surinam and the Guyanas. In Colombia, its widespread distribution across different life zones suggests that these lizards occupy different environments and exhibit different microhabitat use in different geographic areas. On the other hand, some observations suggest that this species prefers open areas, selecting grasslands over brushy areas, and thus, an alternative hypothesis is that microhabitat use is similar among different populations. In Anolis, body variables related to locomotion (body size and shape) define structural microhabitat use, so two distinct patterns could be expected in this species: conservative or highly variable body size and shape throughout the species distribution. To test these predictions, we characterized geographic variation in morphometric traits of this species in Colombia. Females and males were similar in body size, but exhibited differences in some variables related to body shape. These characteristics also varied among males and females from different regions, suggesting heterogeneous use of structural microhabitat, between sexes and among populations. As an alternative, phylogenetic divergence among populations could also account for the observed differences. Absence of ecological and phylogenetic data limits our ability to identify the underlying causes of this pattern. However, we provide a general framework to explore hypotheses about evolution of body size and shape in this species.
We’ve previously had both a photo and a video of egrets downing not-so-festive brown anoles, and here’s another example from Wild about Spain. Word on the street is that egrets can be major anole predators in some places.
Left: A. apletophallus. Right: Decline in abundance of A. apletophallus on BCI
Monitoring populations over long time scales is one of the most important endeavours in ecology, but maintaining funding over decades is a huge challenge when the tenure of most research grants is only 3 years. The Smithsonian Tropical Research Institute (STRI) has made a concerted effort to address this problem and established long-term monitoring of animals (including an anole), plants and environmental variables on Barro Colorado Island (BCI) and the nearby forests surrounding the Panama Canal. These data provide a rare glimpse into the long-term changes in populations and climate in the tropics.
Recently, we used these data to investigate how population abundance of the anolis lizard Anolis apletophallus has changed over time and whether climate was related to abundance and population growth rate. The study recently published in PLOS ONE identified a decline in lizard abundance over the 40-yr study period. We also observed boom and bust fluctuations in population abundance and found that cycles in population growth rate were related to global weather cycles known as el nino and la nina. Specifically, population growth rate was lower one year after el nino (warmer-drier) events. This decline in abundance and the negative relationship of population growth rate with el nino events is alarming, as el nino events are expected to increase in frequency and severity in the future. Changes in the abundance of this lizard may also have knock-on effects to many other animals in the forest because these lizards are eaten by a range of animals including birds, snakes, other lizards, spiders, ants, bats, monkeys and opossums.
The long-term decline in abundance that we identified is consistent with findings of another long-term study of amphibians and reptiles in Cost Rica by Whitfield et al in 2007. In their study they identified a decline in the leaf litter amphibians and reptiles and suggest this is due to a climate driven reduction in leaf litter. In a more recent follow-up study they provide further evidence of this. Although, we did not measure leaf litter, there is no evidence of a reduction in leaf litter on BCI. The parallel declines that were observed in Panama and Cost Rica are worrying and emphasize the importance of long-term data to help us understand how anole populations are coping with climate change.
Most of the hundreds of researchers that visit STRI’s research station on BCI scarcely notice the anoles. Some are drawn to the monkeys or bats, but most are there to study tropical forest ecology making use of the famous 50ha plot: a forest plot where every free standing tree has been measured every five years since 1980. I can understand how some might overlook the anoles in the forest, they can be extremely well camouflaged, but as readers of AA know, anoles are also highly conspicuous.
Left: Spot the A. apletophallus on the forest floor. Right: Male A. apletophallus displaying
Thankfully, BCI’s anoles have not always been overlooked. The most abundant anole on BCI is Anolis apletophallus (previously limifrons), so abundant that Stan Rand, STRI’s world-renowned herpetologist, described it as the ‘most abundant vertebrate in the forest.’ Thanks in part to Stan’s interest in this little brown anole, the species was the focus of much research on BCI in 70-80s most notably by Robin Andrews. Robin’s research on the ecology, physiology and life history of A. apletophallus remains some of the most detailed knowledge of a mainland anole today. Her work also had a lasting legacy at STRI, and the population monitoring that she began still continues today, some 44 years on.
The annual census, which has been continually funded by STRI, has been able to persist largely because of the efforts of STRI scientists.
Fan-throated lizards (Sitana) are one of the Indian Subcontinent’s most widespread and charismatic lizards, found in many of the region’s drier, scrubbier habitats. Not surprisingly, lizards across this vast range vary dramatically, most strikingly in the size and coloration of the throat-fans for which they’re named. Everyone has long suspected that the lizards in this genus must belong to several different species, and Sitana taxonomy has been long overdue for an upheaval.
Sitana from India. Photographs by Shrikant Ranade, Jahnavi Pai, and Jitendra Katre.
The beginning of the revolution is finally here! Amarasinghe et al. (2015) have just published descriptions of two new species of fan-throated lizards, both from Sri Lanka. The authors also clarify some of the very confusing taxonomic and nomenclatural history of Sitana, paving the way for a comprehensive revision of the whole genus.
As is customary, the species descriptions of Sitana bahiri and S. devakai presented in this paper are based largely on morphological traits, including scale counts and throat-fan size, and I refer you to the paper for the details. The two species also differ in where they’re found, the former restricted to south-eastern Sri Lanka, the latter to the north of the island, separated by the Mahaweli River and surrounding wetter regions. Most interestingly, from my perspective, the authors suggest that S. bahiri and S. devakai differ in the coloration of their throat-fan. Sitana devakai is said to have brighter red coloration as well as a black patch on the throat-fan, whereas S. bahiri is described to have lighter orange coloration and no black patch.
Sitana bahiri and Sitana devakai, two newly described species from Sri Lanka (photos from Amarasinghe et al 2015).
I’m not sure I’m completely convinced of this difference in coloration. Though the differences are apparent in the examples shown above, another photo of S. bahiri shows some black coloration on the throat-fan (Figure 2 in the paper). I’ve also seen variation from bleached orange to deep orange, if not red, coloration within a single population of Sitana in southern India (in what Amarasinghe et al. refer to as Sitana cf. devakai):
Variation in orange coloration on the throat-fan of Sitana from the southern tip of India
The need of the hour for Sitana taxonomy is not only more comprehensive geographic sampling across the whole range of this genus but also close examination of intra-population variation. Moreover, phylogenetic methods for delimiting species and discovering relationships between species will be necessary to understand both morphological evolution and biogeographic patterns in this group. The two species described by Amarasinghe et al. (2015), as well as their clarifications of the descriptions of S. deccanensis and S. ponticeriana, are just the start of an exciting period for Sitana systematics, so stay tuned!
We previously mentioned that the Wild Amelia Nature Festival is featuring the green anole for this year’s shindig in mid-May. Now comes the welcome news that our favorite green graces this year’s t-shirt, a picture of which is shown above thanks to the kind offices of Karen Cusick. A bargain at $15!
Despite the intense study of all things anoles for several decades, some aspects of their natural history are not all that well known. For example, the mating behavior of most species has not been described, and egg-laying behavior has been documented for only a few species.
In the most recent issue of IRCF Amphibians & Reptiles, Alfonso et al. take a small step to remedy this situation by describing these behaviors in the Cuban crown-giant anole, A. smallwoodi. The mating observations are from a year’s fieldwork by the senior author, whereas the observations of egg-laying are from the captive husbandry efforts of second author Veronika Holanova.
I was particularly interested in the description of how gravid females come down to the ground and poke around with their snouts until they find just the right spot, at which point they dig a hole with their snout, lay the egg, and then cover it up by pushing soil over it with their snout and forelegs.
The picture above comes from a post on Jacqui Thurlow-Lippisch’s blog, about an epic battle in Sewall, Florida. Jacqui kindly put me in touch with the photographer, Nina Barcik, who provided some more information:
30 minutes later the snake was gone.
By the way, who prefers the name corn snake to red rat snake?
Here’s another shot:
Nearly two years ago, we reported that Dynomighty, a Kickstarter-like operation, was seeking funding to produce an anole themed wallet. And sure enough, they got enough backers (who wouldn’t want to support development of such a needed product?). So get yours today–only fifteen bills.
And once you do, open them up to buy these anole pillowcases.
Anolis transversalis. Photo by Bejat McCracken.
AA reader Shawn McCracken writes:
While conducting ground-level herpetofauna surveys at the Tiputini Biodiversity Station in Ecuador’s Yasuní Biosphere Reserve, I was lured to the canopy by the cacophony of what had to be undiscovered species coming from the bromeliad, orchid and epiphyte microhabitats. This led me to think how many possible new species may be living in this new frontier? While birding at the canopy towers I saw the Tropical Thornytail Iguana (Uracentron flaviceps) and Banded Tree Anole (Dactyloa [Anolis] transversalis) scurrying about in some of the adjacent trees, amongst other anoles I could not quite identify, there was no doubt I was headed up. Of all the available microhabitat in the canopy, the big tank bromeliads caught my attention the most – little swamps, everywhere at 20+ meters off the ground. Surely there had to be herpetofauna using these as a resource and refuge in the harsh canopy environment.
Aechmea zebrina, the bromeliad species examined by McCracken and Forster.
Before the next field season, I decided I needed to get up into the canopy and collect some bromeliads to have a look inside. After a self-taught crash course in tree climbing, I returned to Tiputini, but quickly realized I didn’t have a long enough rope or the skills to get to those big bromeliads. Packing plenty of rope and a greater confidence in my climbing abilities, I returned for another field season the next year. This time was a success. Along with my assistants, we collected 40 bromeliads representing three species that we sealed in 55-gallon trash bags and carried back to camp. Once we began dismantling the bromeliads, we realized we had hit a treasure trove of invertebrates and herpetofauna. Now several years later and a total of 240 bromeliads collected, we have a pretty good idea of the herpetofauna utilizing canopy tank bromeliads in northwestern part of Yasuní. In this latest publication, we summarize the herpetofauna of one high canopy tank bromeliad species, which includes the gecko Thecadactylus solimoensis and two anoles, Anolis ortonii and A. transversalis.
Some other bromeliad denizens
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