Author: Pierre Legreneur

In his beautiful monograph on anoles of Guadeloupe (A. marmoratus ssp), Lazell (1964, 1972) showed the existence of a large variability of phenotypes and described six subspecies of Grande-Terre and Basse-Terre , i.e. A. m. inornatus, A. m. speciosus, A. m. setosus, A. m. girafus, A. m. alliaceus and A. m. marmoratus (see my previous post “The anoles of Guadeloupe“). However, as Lazell indicated Lazell in 1964, “there exists between two distinct populations occupying different geographic areas a zone in which “intergrade” individuals assure continuous gene flow betweens the two extremes.” In other words, the classical subspecies could be considered as extremes that would be relatively few relative to the entire population of Guadeloupe anoles.

Within the framework of a project funded by the National Park of Guadeloupe and the University of Lyon (France) and in collaboration with the DEAL of Guadeloupe, we have identified this year the population of anoles on Basse-Terre and Grande-Terre. 120 stations distributed over the entire territory were studied. 687 anoles were characterized and 260 genetic samples were taken. This study demonstrated the existence of extreme variability of phenotypes between stations and within each station, with a minority representation of the subspecies classically described in the literature. This variability is represented by the poster below. This result leads us therefore to question the relevance of currently distinguished A. marmoratus subspecies as well as on the work of the field experimenter. What should be the selection criterion to select an individual on a station? Should it be random regardless of the phenotype, or should we select the one that is closest to the referenced phenotype, although this phenotype is a minority within the population?

Anole predation in Guadeloupe

By Pierre Legreneur

On February 19, 2013

In Natural History Observations

Currently in Guadeloupe to investigate in collaboration with the National Park the distribution of sub-species of anoles with a colleague of the University of Toulouse (France), we saw an extraordinary scene of predation of a female anole (Anolis marmoratus speciosus) by Scolopendra gigantea. In Guadeloupe, the predation pressure is essentially due by cats, dogs, blackbirds and thrushes. At our knowledge, the scolopendre have never been reported before …

The Anoles Of Guadeloupe

By Pierre Legreneur

On April 7, 2012

In Natural History Observations, Notes from the Field

Guadeloupe is composed of two islands whose shape is that of a butterfly and that were joined together in 1806 by the wooden Union Bridge and then the Gabarre Bridge in 1929:

Situated to the west, Basse-Terre has an area of 848 km2. This is a volcanic mountain whose summit is the Soufriere, located at 1467m altitude. It is covered with a dense rainforest with many rivers and waterfalls.
Situated to the east, Grande-Terre has an area of 586 km2. The substrate is limestone and consists of a plain bordered by a mangrove forest in the southwest, an irregular succession of hills called “les Grands Fonds” in the center and an arid plateau of rocky coasts in the north.

The species of endemic Anolis of Guadeloupe is called Anolis marmoratus, with reference to the orange marbling on the head of the specimens described by Dumeril and Bibron in 1837. In fact, Anolis marmoratus is a species which has 6 subspecies of Guadeloupe and six others on the islands around (La Désirade, Petite Terre, Marie Galante, Les Saintes, Les ilets Pigeons, Les Ilets Kahouanne, les Ilets Fajous).

Regarding Anolis marmoratus of Guadeloupe, the subspecies are:

Anolis marmoratus marmoratus

Anolis marmoratus marmoratus, which Lazell in 1962, noted as “the most beautiful anole he never saw.” It lives around Capesterre, at the southeast of Basse-terre. Adult male are apple-green, shading to blue on the tail and yellow-green on the limbs. The head, the neck and the orbital area are marbled with orange, the throat fan orange-yellow with yellow scales. Preliminary work we have conducted suggests that it could be classified as a trunk-ground ecomorph.

Anolis marmoratus girafus

Anolis marmoratus girafus that lives along the west coast of Basse-Terre in the driest area of this island.

Why Study Locomotion And In Particular The Leaping Ability Of Anoles?: Comparing The Jumping Mechanics of Humans, Lemurs, And Anoles

By Pierre Legreneur

On April 6, 2012

In New Research

httpv://www.youtube.com/watch?v=r33UMVk1o5s&feature=email

As a scientist in life sciences, I have always tried to highlight the existence of laws. It seems to me that all science should be predictive. Once we are interested in locomotion, the first idea that comes to mind is the following: are there any laws of locomotion that transcend forms, species? Is it possible to predict locomotion of any species to the knowledge of environmental constraints it faces (Legreneur et al., 2012)?

I am not a herpetologist. Over 15 years I have worked on humans, and especially high-level athletes and the elderly. I demonstrated in humans that the trajectory of any point controlled by the central nervous system was still as linear as possible. This point is either the fingertip during a pointing or grasping task, or the body center of mass during locomotion, e.g. during the takeoff phase of a jump. Since most joints move in rotation, and that the controlled point displaces through a linear path, it is necessary to dephase the rotating joints to transform the rotation kinematic energy into linear energy. Finally, for transmiting force from the body to the substrate, for example from the hip to the ground during the jump, the joints move in a proximal-to-distal manner, i.e. the extension of the hip precedes the ones of the knee and the ankle.

To demonstrate that these laws observed in humans were applicable to all terrestrial tetrapods, I am interested in two phylogenetically very distant arboreal jumpers, i.e. a prosimian, Microcebus murinus, and a squamate, Anolis sp. I reproduced with these two species the same experiments that I conducted on humans, i.e. leap up to maximum and submaximal heights. Thus I demonstrate that the coordination observed during take-off in maximal leaping were identical in humans, Microcebus and Anolis (Legreneur et al., 2010; Legreneur et al., 2011; Legreneur et al., 2012).

Full Morphometric Database For Anolis sagrei And Anolis Carolinensis

By Pierre Legreneur

On March 31, 2012

In New Research

Most studies that describe anole locomotion are based on the analysis of kinematic and dynamic data. One of the challenges in biomechanics is to deduce from these data the interarticular forces and moments produced during locomotion. Indeed, evaluation of these dynamic data can inform us about the force production and absorption mechanisms that are crucial in movements for which the musculoskeletal system is in high demand, e.g. running, jumping or landing. These movements are essential in the fitness of individuals in arboreal environment during predator avoidance or prey attack and need to develop very high force levels by the musculoskeletal system, and especially by the hindlimbs during takeoff and forelimbs during landing.

To evaluate these dynamic constraints, the most usual procedure is to use a mathematical method called “inverse dynamics.” It consists in deducing the interarticular forces and moments for the knowledge of the ground reaction force, the linear and angular accelerations of the different segments, and their morphometric characteristics. However, there was no morphometric database to date in anoles.

That’s why we conducted a study to characterize the centers of gravity, moments of inertia, masses and lengths of major segments in Anolis carolinensis and Anolis sagrei (Legreneur et al., 2012). To do this,