New distribution data on Chamaeleo zeylanicus

New distribution data on Chamaeleo zeylanicus

by Alex Negro Verbreitung Science

A biologist from India has published findings of the Indian Chameleon (Chamaeleo zeylanicus) that narrow down the distribution of the species more precisely. The Aravalli Mountains are located about 150 km west of the Indian capital New Delhi in northwest India. It runs for 670 km in a south-westerly direction, passing through three different states: Haryana, Rajasthan, and Gujarat. Until now, the Indian chameleon was thought to occur in the south and centre of Rajasthan, but was not common in the north, east, or west. So far, no findings had been documented from Haryana at all.

The biologist describes six observations of the Indian Chameleon between 2015 and 2022, during which Chamaeleo zeylanicus was seen four times in the Sariska Tiger Reserve and once each at Manesar and Damdama lakes, at altitudes between 223 and 476 m asl. The former is in northern Rajasthan, the two lakes not far from it in southern Haryana. The forest of the site in the Sariska Tiger Reserve is dominated by Indian lungwort (Adhatoda vasica), prairie mugwort (Parthenium integrifolium) and mesquite tree (Prosopis juliflora). The chameleons found in Haryana were found on roadsides with carira (Capparis decidua) and mesquite trees.

New distributional records of Asian Chameleons (Chamaeleo zeylanicus Laurenti 1768), from the Northern Aravali Hill range, India
Debaprasad Sengupta
Reptiles & Amphibians 30 (1), 2023: pp. 1-2
DOI: 10.17161/randa.v30i1.18614

The Indian Chameleon in Jhalawar (India)

The Indian Chameleon in Jhalawar (India)

by Alex Negro Science

Three scientists from India have recently published a survey of reptile and amphibian occurrences. The Jhalawar study area is located at the southernmost tip of the state of Rajasthan in northwest India. It is located on the edge of the Malwa Plateau, a volcanic highland. The area lies well to the southwest of the Ganges River, which is generally considered the distribution limit of the Indian Chameleon (Chamaeleo zeylanicus). The climate is divided into a long summer season and a shorter winter, which lasts from October to February. During the summer, temperatures above 45°C are common, while in winter temperatures can drop to as low as 1°C.

The three researchers were on site for about six hours each for 70 days. To search for reptiles and amphibians, they rummaged through loose soil as well as the foliage layer and visually searched for animals in parallel. 45 different species of reptiles and amphibians were found. Chamaeleo zeylanicus was documented for the first time in Rajasthan.

Herpeto-faunal diversity study: Analysis and critical observations from south-eastern Rajasthan, India
Yadav Vijay Kumar, Nama Krishnendra Singh, Sudhindran Rimal
Indian Journal of Ecology 49 (5), 2022: pp. 1581-1587
DOI: 10.55362/IJE/2022/3700

Chamaeleo gracilis in Taï National Park (Côte d’Ivoire)

Chamaeleo gracilis in Taï National Park (Côte d’Ivoire)

by Alex Negro Science

Little is known about chameleons in the Republic of Côte d’Ivoire. Ivorian biologists have now confirmed the presence of various reptile species in one of the country’s national parks. For the first time, they have found Chamaeleo gracilis in Taï National Park, which matches its known range in West Africa.

Taï National Park is located in the southwest of Côte d’Ivoire in western Africa. The climate changes four times a year. From March to June there is a rainy season, in August it is dry, followed by a second rainy season in September and October and a second dry season from November to March. 40 areas, each 50 x 50 m in size, were surveyed. Of these, 18 were in primary forest (rainforest), seven in secondary vegetation with more shrubby growth, five in coffee or cocoa plantations, five in rubber tree plantations and five in rice fields. On each of 40 days, three researchers were in the demarcated areas for more than eight hours and visually scanned the surroundings for reptiles.

Chamaeleo gracilis was the only reptile observed exclusively in the rainforest. As is often the case with chameleons, a female was discovered laying eggs on the ground. The species was not found in secondary vegetation or agricultural landscapes.

First record of seven species of lizards in Taï National Park (South West, Côte d’Ivoire)
Kouadio Atta Léonard, Assemian N’guessan Emmanuel, Goly N’guessan Simplice, Keita Gaoussou, Tiédoué Manouhin Roland
International Journal of Zoological and Entomological Letters 2022, 2(2): 36-41
DOI: not available

Factors in the geographical dispersal of chameleons

Factors in the geographical dispersal of chameleons

by Alex Negro Science

For a long time, people have been trying to find out how and why chameleons have spread across the African continent, to islands and as far as Europe and Asia. French scientists, in collaboration with international colleagues, have now used phylogenetics and various computational models to investigate how the factors of body size, coastal habitat and extreme lifestyles may have affected the distribution of different chameleon species. The study examined 181 species divided into nine main biogeographical regions: North Africa and Arabia, Central Africa, Southeast Africa, Southwest Africa, India, Socotra, Madagascar, Comoros and Seychelles.

Chameleon species that occurred more than 10 km from the sea historically spread significantly less than the 74 coastal chameleon species. A similar phenomenon is known from skinks and crocodiles. Dispersal probably took place mainly along the coasts, mostly on the same continent and only rarely across the water to other continents or islands.

The size of the different chameleons also seems to have influenced their dispersal throughout history: Large chameleons spread further and more frequently than small chameleons. This could be related to the fact that larger chameleons have a lower metabolic rate – so they need less energy overall relative to smaller competitors. In addition, larger chameleons lay clutches with significantly more eggs, which simply gives them an advantage in numbers.

A somewhat unexpected result came from the study of different life cycles. One would initially assume that short life cycles are associated with faster dispersal. In fact, the calculations showed that especially chameleon species with extreme life cycles spread further. Thus, those that reproduced particularly slowly or particularly quickly were historically more successful among chameleons than the species “in the middle”. In this regard, the authors consider whether particularly slow life cycles with late sexual maturity and long gestation might be more successful on the same continent, while faster reproductive strategies with large clutches are more favourable for dispersal across the sea to islands and other continents. In line with this, Furcifer polleni and Furcifer cephalolepis in Comoros and Chamaeleo zeylanicus in India, all three examples of aquatic dispersal, have a very fast life cycle.

The 34 chameleon species with the combination of living close to the coast, large size and extreme life cycle had a 98% higher dispersal rate than species without these characteristics.  All in all, this is certainly a very theoretical study, but it nevertheless provides exciting insights into the historical distribution and dispersal of chameleons.

Chameleon biogeographic dispersal is associated with extreme life history strategies
Sarah-Sophie Weil, Laurie Gallien, Sébastien Lavergne, Luca Börger, Gabriel W. Hassler, Michaël P.J. Nicolaï & William L. Allen
Ecography
DOI: 10.1111/ecog.06323