The Indian Chameleon in Solapur (India)

The Indian Chameleon in Solapur (India)

by Alex Laube Verbreitung Science

It has long been known that the Indian chameleon occurs in Maharashtra. A recently published survey study has even found evidence of it in an area near Solapur that is covered only with grass and bushes.

The area studied is a 15 km² area of semi-arid grassland around a site earmarked for an airport at an altitude of 450 to 500 metres. The nearest village is Boramani, a small town just outside the city of Solapur in the state of Maharashtra in western India. For one year, about half of the grassland was surveyed four times a month for the presence of reptiles. Squares of 50 metres x 50 metres were laid out, each at least 300 metres apart. Each observation period consisted of five hours and only observations with the naked eye.

During the study period, 888 individuals of 14 different reptile species were recorded. Of these, more than 300 were Sitana laticeps, a fan-throated lizard. Among the species found were two Chamaeleo zeylanicus. The activity of the lizards increased from March, stabilised during the monsoon season in June-July and then declined again from August.

The authors argue in favour of protecting the grassland area due to the existing biodiversity. This should prevent the construction of the airport and thus the disappearance of the habitat.

Ecology of lizards in an ecologically significant semi-arid grassland patch near Solapur, Maharashtra, India
Mahindrakar Yogesh Y., Waghmare Akshay M., Hippargi Rajshekhar V.
International Journal of Zoological Investigations 9 (2) 2023, pp. 210-223
DOI: 10.33745/ijzi.2023.v09i02.022

Comparative anatomy of the forearms of different chameleons

Comparative anatomy of the forearms of different chameleons

by Alex Laube Tiermedizin Science

The anatomy of chameleons seems to be strongly adapted to their way of life. Tree-dwellers differ in many aspects from ground-dwellers. Several studies at the University of South Dakota this year have already looked at various anatomical aspects of chameleons. A new study is dedicated to the hands and arms.

For the investigation, the arms and hands of a total of 12 chameleons were isolated from existing microcomputer tomography scans and displayed in 3D. These were measured to about 30 different lengths and widths using software. Scans of the species Bradypodion damaranum, Bradypodion occidentale, Calumma hilleniusi, Calumma crypticum, Chamaeleo namaquensis, Chamaeleo zeylanicus, Furcifer balteatus, Furcifer campani, Rhampholeon spinosus, Rhampholeon temporalis, Trioceros goetzei goetzei and Trioceros werneri were evaluated. When selecting the species, care was taken to select one strictly tree-inhabiting chameleon and one more ground-inhabiting chameleon per genus.

The evaluation revealed that tree-dwelling chameleons show few differences in forelimb anatomy compared to ground-dwelling chameleons. Tree-dwelling species showed a majority of separated metacarpal bones 1-3, while ground-dwelling species showed fused metacarpal bones. Interestingly, this study differs from earlier studies by other authors, which yielded different results. The relatively small number of animals studied may be related to this. Larger studies could be helpful here.

Ecological and evolutionary drivers of chameleon forelimb variation
Ellie M. Schley
Honors Thesis 302 der Universität von South Dakota, 2023
DOI: gibt es nicht

Comparison of pelvic girdles in chameleons

Comparison of pelvic girdles in chameleons

by Alex Laube 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

 

New distribution data on Chamaeleo zeylanicus

New distribution data on Chamaeleo zeylanicus

by Alex Laube 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 Laube 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

Factors in the geographical dispersal of chameleons

Factors in the geographical dispersal of chameleons

by Alex Laube 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