Chameleons in Bobaomby (Madagascar)

Chameleons in Bobaomby (Madagascar)

by Alex Negro Verbreitung Science

The Bobaomby complex is located at the northernmost tip of Madagascar, north and west of the largest coastal town in the north, Antsiranana (Diego Suarez in French). It consists of dry forest at sea level up to a maximum of 200 metres above sea level as well as extensive savannahs on karst rock and various rock formations. The area has not been protected to date.

Scientists from Madagascar conducted reptile counts in the Bobaomby complex in 2018. The counts were carried out in February and March, i.e. during the rainy season. Five different locations were analysed: Beantely, Antsisikala and Ambanililabe as examples of varying degrees of degraded dry forest, Anjiabe for its intact dry forest and Ampombofofo with relatively intact forest. To find animals, the visual survey was used on 25 days during the day and at night in selected transects, sometimes specifically in suitable habitats such as leaf axils or under dead tree trunks, and pitfall traps along erected fences were also used.

A total of 42 reptile species have been recorded. All of them, except one gecko species, originally only occur on Madagascar, while two other gecko species are now also found on neighbouring islands. There is a small novelty among the chameleons: the leaf chameleon Brookesia ebenaui was recorded for the first time in Bobaomby, more precisely in Beantely. Brookesia stumpffi and Furcifer petteri were found in Beantely, Anjiabe and Ampombofofo. Furcifer pardalis and Furcifer oustaleti occurred as expected throughout the whole Bobaomby complex.

The authors suggest that the Bobaomby complex – especially the three forests where most of the reptiles were found – should be protected to preserve the local herpetofauna.

Overview of reptile diversity from Bobaomby complex, northern tip of Madagascar
Randriamialisoa, Raphali R. Andriantsimanarilafy, Alain J. Rakotondrina, Josué A. Rakotoarisoa, Nasaina T. Ranaivoson, Jeanneney Rabearivony, Achille P. Raselimanana
Animals 13: 3396, 2023
DOI:  10.3390/ani13213396

Photo: Furcifer petteri, male, in the north of Madagascar, photographed by Alex Laube

Chameleons in the Montagne des Français (Madagascar)

Chameleons in the Montagne des Français (Madagascar)

by Alex Negro Verbreitung Science

The Montagne des Français is a limestone massif with dry forest in northern Madagascar. It reaches up to 425 m above sea level and is within sight of the largest coastal town in the north, Antsiranana (French Diego Suarez). It has been a protected area since 2007. Scientists from Madagascar and the USA conducted counts of reptiles and amphibians in the Montagne des Français in 2014 and 2020.

Counts were made in January and May, i.e. during and at the end of the rainy season. In 2014, the focus was on the region around Andavakoera, while in 2020 it was on Sahabedara, Ampitiliantsambo, and Andavakoera. In order to find animals, the search was conducted during the day and at night along predefined paths, partly in suitable habitats, and partly in pitfall pits.

A total of 20 amphibian and 50 reptile species were recorded. Four new amphibians and one reptile were found for the first time in the Montagne des Français. The snake Langaha pseudoalluaudi was discovered again for the first time since 2007. Among the chameleons, there were minor new discoveries. Brookesia stumpffi could only be found in 2014, but no longer in 2020 – however, due to the relatively wide distribution of the species, this should not be a problem for the entire population. Brookesia tristis, one of the smallest chameleons in the world, was also only seen in 2014. Here, the body size, which makes it very difficult to find, and the time of year (May is relatively late for this species) could play a role. Brookesia ebenaui was detected in Andavakoera in 2014 and in Sahabedara in 2020. The two tree dwellers Furcifer oustaleti and Furcifer pardalis were found in both years in Andavakoera and Ampitiliantsambo. Furcifer petteri, on the other hand, was present at all the sites surveyed in both years.

Amphibians and reptiles of the “Montagne des Français”: Update of the distribution and regional endemicity
Herizo Oninjatovo Radonirina, Bernard Randriamahatantsoa, Rabibisoa Harinelina Christian Nirhy, Christopher J. Raxworthy
Preprint
DOI: 10.20944/preprints202306.1499.v1

Photo: Furcifer petteri on Madagascar, photographed by A. Laube

Comparison of pelvic girdles in chameleons

Comparison of pelvic girdles in chameleons

by Alex Negro Science

The anatomy of chameleons is strongly adapted to their way of life. Tree-dwellers differ in many aspects from ground-dwellers. The pelvic girdle has been little studied anatomically in chameleons so far – a publication from the USA now deals with it in more detail.

For the study, the pelvic girdles of 22 chameleons were isolated from existing microcomputer tomography scans and displayed in 3D. These were measured to 16 different lengths and angles using software. Archaius tigris, Bradypodion damaranum, Calumma gallus, Calumma parsonii parsonii, Chamaeleo zeylanicus, Furcifer balteatus, Kinyongia matschiei, Kinyongia tavetana, Nadzikambia mlanjense and Trioceros quadricornis gracilior were assigned to tree dwellers. Brookesia brygooi, Chamaeleo namaquensis, Palleon nasus nasus, Rhampholeon temporalis and Rieppeleon brachyurus were attributed to ground-dwelling species. The species Bradypodion occidentale, Brookesia ebenaui, Chamaeleo anchietae, Furcifer campani, Rhampholeon spinosus, Rieppeleon kerstenii kerstenii and Trioceros goetzei goetzei were classified as semiarboreal. Mainly males were examined.

As expected, the evaluation showed that tree-dwelling chameleons had narrower, shorter girdles than ground-dwelling ones. The narrower pelvic girdle makes it easier to hide behind branches and flatten the body to the maximum. It also ensures that the body’s centre of gravity is closer to the branch and thus increases stability when climbing. Ground-dwelling chameleons, on the other hand, had larger and wider pelvic girdles. These allow them to step more quickly and provide greater stability when walking on ground surfaces.

How phylogeny and arboreality affect pelvic girdle anatomy of chameleons
Dakota J. John
Honors Thesis 299, University of South Dakota, 2023
DOI: none