Keeping and breeding Calumma linotum

Keeping and breeding Calumma linotum

by Alex Laube Haltungsberichte

The keeping and breeding of small chameleons of the genus Calumma has so far, apparently, only found enthusiasts on a rather small scale. So it is all the nicer that a new report on the keeping and especially the successful breeding of Calumma linotum has just been published. Michael Nash from the USA has been keeping the species for over three years and gives a detailed account of his experiences.

He keeps his animals in the terrariums commonly used over here with a completely ventilated lid and either vents in the front bottom or the entire front as ventilation, living plants, and living substrate. T5 tubes with and without UV-B are used for lighting. For food he uses fruit flies (Drosophila spp.) to a good 50%, and otherwise among other things small crickets, house crickets, blowflies, and mantid nymphs.

The best breeding successes are achieved by keeping them individually and putting them together for a few days to mate during the imitation rainy season. To induce mating behaviour, dry and rainy seasons are imitated. The dry season is mainly characterised by a massive night-time drop in temperature to 10°C and less irrigation. During the imitated rainy season, temperatures rise to around 26°C during the day and 18-21°C at night, and there is also increased irrigation during the day.

The females lay 2-3 eggs after an average of 22 to 40 days of gestation. So far, it has been noticed that mated females of the species are capable of fertilisation for an unusually long time, namely up to five clutches. The eggs are first incubated at 16 to 21°C for two to four weeks. This is followed by a diapause of 30 to 45 days at 10 to 15°C. The eggs then lie in daytime conditions. Afterwards, the eggs lie at 22°C during the day and between 16.7 and 19.5°C at night. If the eggs do not show any embryonic and vascular development during shearing after the diapause, it is possible to imitate a second diapause – at the latest, after this, the first egg development should be visible. After 5 to 7 months, active young hatched under these incubation conditions. The author has successfully hatched eleven clutches so far.

All in all, a very readable husbandry report, which hopefully supports other keepers in breeding and long-term conservation of this interesting, small species in the terrarium.

Keeping and breeding Calumma linotum
Michael Nash
Responsible Herpetoculture Journal 7, 2023
keine DOI vorhanden

Species diversification in chameleons

Species diversification in chameleons

by Alex Laube Science

From earlier studies, we know that the first chameleons evolved in the late Cretaceous, about 90 million years ago, on mainland of Africa. Around the border between the Cretaceous and Tertiary periods, about 65 million years ago, different species began to evolve. It is still unclear today which factors contributed to the diversity of species. Two researchers from Swansea University in Wales have now used various computational models of phylogenetics to investigate what might have influenced diversification (the splitting of chameleons into many different species).

First, they studied the diversification of chameleon species in Madagascar. In terms of evolutionary history, there are two points in time when chameleons apparently spread across the sea from mainland Africa to Madagascar. One is about 65 million years in the past, the other 45 million years. You could now think that the climatically extremely different habitats in Madagascar could have driven the evolution of the species very quickly after the spread across the sea. To the surprise of the researchers, however, no evidence of this was found. The species richness of chameleons on Madagascar must therefore come from the fact that chameleons spread there very early and thus simply had much more time to develop into different species than elsewhere.

Furthermore, the researchers investigated whether switching between two ecomorphs – from ground-dwelling stub-tailed chameleons to tree-dwelling chameleons with longer tails – had an impact on species diversity. Rather surprisingly, this did not seem to be the case. The evolution to tree-dwellers with longer tails occurred relatively early on one or two occasions. No evidence could be found that different ecomorphs accelerated diversification. Instead, speciation rates were found to slow down progressively over the last 60 million years. Only a very early dispersal event of the genus Bradypodion in South Africa around 10 million years ago was accompanied by a two- to fourfold diversification rate.

As a third focus of the study, the researchers examined the genus Bradypodion. During the climate change in the Miocene around 10 million years ago, South Africa changed a lot. Forests disappeared, leaving behind isolated forest habitats and, in between, savannahs, some of which are now so-called hot spots of biodiversity. Two of them, the Cape Floristic Region at the southwestern tip of South Africa and Maputuland-Pondoland-Albany on the east coast of South Africa, are home to a particularly large number of Bradypodion species. Each species is limited to a geographically very clearly defined area. The researchers, therefore, suspect that Bradypodion species have actually evolved faster under the influence of habitat change. It should be noted that the diversification rate of the genus Bradypodion is probably rather underestimated, as there are still many hidden species to be assumed.

Diversification dynamics of chameleons (Chamaeleonidae)
Stephen Giles, Kevin Arbuckle
Journal of Zoology, 2022
DOI: 10.1111/jzo.13019