Tag Archives: anole

Subfossil Record Reveals Human Impacts on a Lesser Antillean Endemic Anole

Figure 2: Landmarks (black point circled in white) and sliding landmarks (black points) used in the geometric morphometric analysis.

Figure 1. Landmarks (black point circled in white) and sliding landmarks (black points) used in the geometric morphometric analysis.

The knowledge of the past squamate fauna of the Guadeloupe islands (French Lesser Antilles) dramatically increased these last years in the framework of two European paleontological research programs. New archaeological and paleontological excavations (about which I previously talked) have been conducted and led to the discovery of thousands of squamate remains allowing to complete the pioneering works conducted by G. K. Pregill in the 90’s (Pregill et al., 1994). Results obtained on iguanas (Bochaton et al., 2016b), galliwasps (Bochaton et al., 2016a), ameivas (Bochaton et al., 2017a) and other taxa (Bailon et al., 2015; Bochaton et al., 2015; Boudadi-Maligne et al., 2016) point to high extirpation and extinction rates, mainly taking place during the last centuries after the European colonization of the archipelago and probably in relation to introduction of exogenous competitors and predators, as well as the practice of intensive agriculture.

In the middle of all of these extinctions, anoles, which are still very common in Guadeloupe, appeared to be kind of indestructible and were apparently not impacted at all by recent anthropogenic disturbances. However, the study of a huge assemblage of anole remains from Marie-Galante Island dated from Late Pleistocene to the 14th century reveals that this first impression was far from true.

Nearly 30,000 anole remains coming from several deposits were investigated using a combination of morphological and morphometric approaches. Size estimations (see Bochaton, 2016; Bochaton and Kemp, 2017) indicate that whatever the stratigraphic layer they come from, fully mature individuals range in three groups of Snout-Vent Length (SVL) size (Figure 2).

Figure 2.  SVL reconstructed on the basis of fully mature humeri (N = 66) with the results of a mixture analysis indicating a trimodal distribution. MTMS1, minimal theoretical maximal size obtained from the smallest fully mature humerus; MTMS 2, minimal theoretical maximal size obtained from the largest immature humerus; MTMS 3, minimal theoretical maximal size obtained from the smallest mature humerus included in the intermediately sized group.

Figure 2. SVL reconstructed on the basis of fully mature humeri (N = 66) with the results of a mixture analysis indicating a trimodal distribution. MTMS1, minimal theoretical maximal size obtained from the smallest fully mature humerus; MTMS 2, minimal theoretical maximal size obtained from the largest immature humerus; MTMS 3, minimal theoretical maximal size obtained from the smallest mature humerus included in the intermediately sized group.

These SVLs partly match those of the females (max 75mm SVL) and males (max 120 mm SVL) of the modern solitary Marie-Galante anole (Anolis ferreus). However, a third group of fossil specimens of very large size reaching 150mm SVL also occurred in the deposits and has no modern counterpart on the island. Still, morphological analysis indicates that these large specimens were also A. ferreus. A geometric morphometric analysis (Figure 1, above) was also conducted on dentaries of Marie-Galant fossils and included in a modern sample of Lesser Antillean anoles.
Figure 3. Two first axes of the PCA conducted on shape data collected for fossil and modern A. ferreus dentaries showing a diminution of morphological variability between fossil and modern anoles.

Figure 3. Two first axes of the PCA conducted on shape data collected for fossil and modern A. ferreus dentaries showing a diminution of morphological variability between fossil and modern anoles.

This analysis reveals a strong heterogeneity of the morphology of the dentary mostly depending of their size (allometry). The three fossil size groups are however closer to modern A. ferreus than to any other modern taxa and are linked by a common allometric relationship between their size and shape which differs from modern A. ferreus. The morphological variability of the fossil dentaries is also higher than that of modern A. ferreus (Figure 3).

These results indicate that all fossils are likely to correspond to A. ferreus. However, fossil representatives are more morphologically variable in terms of size, shape, and allometry than modern A. ferreus.The morphology of fossil A. ferreus remained stable during more than 30,000 years before an abrupt change that occurred during the last centuries. There is, however, a void of fossil data during the modern period which precludes linking this reduction of morphological variability between fossil and modern A. ferreus to a distinct event. Yet, this phenomenon is contemporaneous to the numerous extinction events documented on Marie-Galante and is thus very likely to be also related to the anthropization of the island.

This study also provides a strong argument again the hypothesis of the past occurrence of a second anole species smaller than modern A. ferreus on Marie-Galante and used to explain the large size reached nowadays by this insular solitary anole.

More details can be found in the publication of this work:

Bochaton, C., S. Bailon, A. Herrel, S. Grouard, I. Ineich, A. Tresset, and R. Cornette. 2017b. Human impacts reduce morphological diversity in an insular species of lizard. Proc. R. Soc. B 284:20170921.

References

Bailon, S., C. Bochaton, and A. Lenoble. 2015. New data on Pleistocene and Holocene herpetofauna of Marie-Galante (Blanchard Cave, Guadeloupe Islands, French West Indies): Insular faunal turnover and human impact. Quaternary Science Reviews 128:127–137.

Bochaton, C. 2016. Describing archaeological Iguana Laurenti, 1768 (Squamata: Iguanidae) populations: size and skeletal maturity. International Journal of Osteoarchaeology 26:716–724.

Bochaton, C., and M. E. Kemp. 2017. Reconstructing the body sizes of Quaternary lizards using Pholidoscelis Fitzinger, 1843 and Anolis Daudin, 1802 as case studies. Journal of Vertebrate Paleontology 37:e1239626.

Bochaton, C., R. Boistel, F. Cassagrande, S. Grouard, and S. Bailon. 2016a. A fossil Diploglossus (Squamata, Anguidae) lizard from Basse-Terre and Grande-Terre islands (Guadeloupe, French West-Indies). Scientific Report 28475:1–12.

Bochaton, C., S. Grouard, R. Cornette, I. Ineich, A. Tresset, and S. Bailon. 2015. Fossil and subfossil herpetofauna from Cadet 2 Cave (Marie-Galante, Guadeloupe Islands, F. W. I.): Evolution of an insular herpetofauna since the Late Pleistocene. Comptes Rendus Palévol 14:101–110.

Bochaton, C., S. Bailon, I. Ineich, M. Breuil, A. Tresset, and S. Grouard. 2016b. From a thriving past to an uncertain future: Zooarchaeological evidence of two millennia of human impact on a large emblematic lizard (Iguana delicatissima) on the Guadeloupe Islands (French West Indies). Quaternary Science Reviews 150:172–183.

Bochaton, C., R. Boistel, S. Grouard, I. Ineich, A. Tresset, and S. Bailon. 2017a. Evolution, diversity and interactions with past human populations of recently extinct Pholidoscelis lizards (Squamata: Teiidae) from the Guadeloupe Islands (French West-Indies). Historical Biology.

Boudadi-Maligne, M., S. Bailon, C. Bochaton, F. Cassagrande, S. Grouard, N. Serrand, and A. Lenoble. 2016. Evidence for historical human-induced extinctions of vertebrate species on La Désirade (French West Indies). Quaternary Research 85:54–65.

Pregill, G. K., D. W. Steadman, and D. R. Watters. 1994. Late Quaternary vertebrate faunas of the Lesser Antilles: historical components of Caribbean biogeography. Bulletin of Carnegie Museum of Natural History 30:1–51.

Bark Anole Battle Scars in Miami, FL

As it starts to heat up here in Miami, anole interactions are at the highest while males try to stake their claim for the most attractive territories in town. Earlier during an afternoon stroll around South Miami I came across this bark anole (Anolis distichus) that looks like it’s had a pretty rough time recently!

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I assume this injury to his nape is probably from another lizard, likely another male A. distichus, incurred during a territorial dispute, and not a predation attempt. Either way, it looks like it didn’t dent his confidence too much!

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How Many Lamellae Are on this Toepad?

One of the age old questions in anole morphology is at what point do you stop counting lamellae on the toepad?

Without giving any more information on various techniques or methods, I thought it would be interesting to ask the AA community their personal opinions. Below I have attached a flatbed scan of a toepad. Could people please fill out the corresponding poll below, and I will present the results in a follow up post!

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Lamellae numbered 1-51 on the 4th digit of an Anolis lizard hindfoot

Finding the “Rare” Anolis duellmani

Like many quests to find rare herps, this is a story of courage, persistence, and strength. Just kidding; it was a piece of cake.

Anolis duellmani was described by Fitch and Henderson (1973) based on four specimens from the southern slope of the Volcán San Martín Tuxtla, Veracruz, Mexico. Even though the phylogenetic position of A. duellmani is uncertain, no additional morphological variation had been described for the species. As part of a major effort led by Dr. Adrián Nieto-Montes de Oca and Dr. Steven Poe to untangle the systematics of Mesoamerican anoles, Israel Solano-Zavaleta, Levi N. Gray, and I went to Los Tuxtlas to search for the elusive species.

Continue reading Finding the “Rare” Anolis duellmani

Anoles have it tough in south Florida!

A common concept in ecology is that predators have a strong influence on the behaviour of prey species. Anolis lizards have been used as a classic model system to investigate the effect of predator presence on the behavioural response of prey species. On small experimental islands in the Bahamas the manipulated introduction of curly-tailed lizards (Leiocephalus carinatus), a large terrestrial anole-predator, has resulted in brown anoles (Anolis sagrei) shifting higher up in the vegetation, presumably in an understandable effort to avoid being eaten (1, 2, 3). However, predator-prey interactions such as these which may shape community structure are often difficult to observe.

Here in Miami FL we have a rich and diverse, although largely non-native, lizard community. There are two species of “crown-giant” anoles, the Cuban knight anole (A. equestris) and the Jamaican giant anole (A. garmani), that could be potential predators of smaller anoles in the canopy of trees and upper half of tree trunks (although see Giery et al. 2013 for an empirical analysis that suggests this may not be the case). Additionally, there are several large, terrestrial lizards present which may be filling a similar role to curly-tails in the Bahamas.

Potential lizard predators in south Florida:

– *Red-headed agama (Agama agama)
– *Cuban knight anole (Anolis equestris)
– Jamaican giant anole (Anolis garmani)
– *Brown basilisk (Basiliscus vittatus)
– Spiny tailed iguana (Ctenosaura similis)
– Curly-tail lizard (Leiocephalus carinatus)
– Giant day gecko (Phelsuma grandis)
– Black and white tegu (Tupinambis merianae)

*Present at Fairchild Tropical Botanical Gardens

Earlier this afternoon, while taking a break from my office at Fairchild Tropical Botanical Gardens (a hot spot for any anologist visiting Miami; 1, 2, 3, 4) in a typical graduate student effort to put off work that I should be doing instead, fellow lab member Evan Rehm and I noticed some scuffling in a nearby bush. At around 2.5m, and admittedly on relatively precarious branches by this stage, sat an adult female African red-headed agama (A. agama) around 30cm from an adamantly motionless adult male Cuban brown anole (A. sagrei)! As we moved towards the bush the agama was quick to ungraciously thump itself to the floor, while the brown anole remained still. On closer inspection, it soon became apparent why both lizards were so high.

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Adult male Cuban brown anole (A. sagrei) found ~2.5m high in Miami FL, supposedly following a predation attempt from an African red-headed agama (A. agama) – JStroud

The significance of tail loss/damage in a population is still debated. The classical view argues that high proportions of tail damage indicates high predation pressure, therefore prey populations are under high predation stress (1). Alternatively, high proportions of tail damage could indicate low predator efficiency, which would suggest prey populations are experiencing low predation stress (1, 2). But the debate doesn’t stop there! Having already lost a tail, a lizard may experience either a resulting increase or decrease in predation depending on the predator species and its associated foraging tactic (1).

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The extent of tail damage is clearer in this photo. The lizard had autotomised the lower half of it’s tail however a secondary half-completed break is also evident – JStroud

African red-headed agamas (A. agama) are similar morphologically to curly-tailed lizards (L. carinatus), although are taxonomically distinct (Agamidae and Leiocephalidae, respectively). Predation of anoles by agamas in Miami has not previously been officially recorded, and the impact of these large predators remains unclear. Unlike in the Bahamas, there are multiple predators in the same geographic vicinity that anoles need to be aware of. For example, at Fairchild, brown anoles (A. sagrei) could be eaten from below by agamas, eaten at intermediate levels by basilisks and eaten from above by knight anoles!

South Florida is a tough place to be an anole!

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Adult male African red-headed agama (A. agama) at Fairchild Tropical Botanical Gardens, Miami FL. The population of agamas is localised to the botanical gardens; the source remains unclear but is likely an introduction from the pet trade – JStroud

Help Identify Anole Seen in Barichara, Colombia

photo 1During a recent trip to the interior of Colombia (March 2013), we spotted this large striking anole. It was located just outside the town of Barichara, on the ancient Camino Real trail to Guane. Average elevation of this area is approximately 4,200 feet. Can anyone help identify this species and gender?

photo 2As it was early in morning, the anole had just begun to bask in the morning sun. It had probably not thoroughly warmed its body yet, and made for an easy capture! We examined, photographed, and released unharmed. -Marc Kramer, DVM (Miami, FL)

 

Anole At My Door

I have extensively photographed Anole in an urban environment because they are so readily available here in south Florida literally outside my door and frequently indoors too. Despite the lamentations of displacement of the native Anolis carolinensis, they are frequently observed in my immediate area. I will present a few photos showing confrontations between the variety of West Indian Anole and the native green. Knight anole is also present, mostly juvenile as I do not observe fully grown specimens either because of adult movement to other areas or the wide variety of predators, mostly large birds. More about geckoes, basilisks and iguana will be posted in related forums.