A male Ngome Dwarf Chameleon Bradypodion ngomeense from the Ngome Forest in KwaZulu-Natal.
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In the forests and kloofs of South Africa, there be miniature dragons. A slow, careful, forward gait with feet clasping thin twigs, and eyes scanning in two different directions, a small, drab little reptile suddenly freezes, its eyes now focused intently forward. The mouth opens slightly and within a split second, a long projectile tongue shoots out, ensnaring a fly on the moist bulbous tip and instantly retracts back into the mouth. 

The first species to be described from South Africa was the Cape Dwarf Chameleon, described by Daudin in 1802. In 1943, renowned South African herpetologist and former director of the Transvaal Museum, Dr Vivian F. FitzSimons, included 10 taxa in his monograph The Lizards of South Africa under the genus Microsaura. In 1976, a KwaZulu-Natal-based herpetologist, Lynn Raw, resurrected the genus Bradypodion and described three new species. 55 years later, herpetologist William R. Branch of the Port Elizabeth Museum included 15 described species in his 1998 Field Guide to the Snake and other Reptiles of southern Africa. Currently, there are 17 described species with at least five more awaiting formal scientific description. The Ngome Dwarf Chameleon was only described in 2009, the Umlalazi Dwarf Chameleon in 2008 and the Swartberg Dwarf Chameleon in 2006. 

In 2004 Krystal Tolley and colleagues published the first phylogenetic study on South African dwarf chameleons using two gene sequences – 16S ribosomal RNA and ND2. This gave a clearer picture of the evolutionary relationships between dwarf chameleons indicating the presence of probable cryptic species within the genus. This study contributed towards the three newly described species mentioned above. 

Several chameleon species, notably some of the Madagascan species, exhibit spectacular and vivid colour displays, particularly males during courtship. These colours may be bright red, turquoise green, electric blue and bright yellow. Research undertaken by Jérémie Teyssier and colleagues from the University of Geneva demonstrated how Madagascan panther chameleons can shift colour through active tuning of a triangular lattice of guanine nanocrystals within the superficial layer of dermal iridophores. A deeper cluster of iridophores with larger crystals reflect a substantial amount of sunlight. Within dwarf chameleons, those that live in dense forest appear to exhibit much brighter and vivid colour patterning and may have similar mechanisms at work. Those that live in more open savanna, karoo or fynbos biomes are drab with browns and greys. Melanophores in the skin produce the dark pigment. The green colourations is caused by chromatophores and the yellows by xanthophore pigments. 

Many chameleon species, including dwarf chameleons, have pale or white lateral lines. These have been shown to serve some form of predator avoidance. When a threat is detected, the chameleon will angle its body in such a way that the lateral lines cause a disruption of the body form confusing the predator. In many chameleons, but not dwarf chameleons, they have a white ventral (belly) stripe which they angle towards the perceived threat. This stripe may disrupt the outline of the chameleon’s body, making it harder to detect, but the results in these studies were not conclusive, and more research is required. 

A recent exciting discovery is that some chameleons can produce fluorescence which illuminates under the ultra-violet spectrum and is produced from bone just underneath a superficial layer of skin. This has been discovered in several chameleon lineages including the dwarf chameleons. This aids chameleons living in shaded forests in mate and conspecific recognition. Research has demonstrated that fluorescence emits strongly in the spectrum of around 430 nm (nanometers) in a blue colour which contrasts vividly against the green and brown background of forest habitats.   

Research by Devi Stuart-Fox and colleagues demonstrated the ultraviolet spectrum is used in visual display for conspecifics to detect one another against the dark forest environment whilst at the same time remaining cryptically concealed from potential predators. 

Dwarf chameleons are viviparous giving birth to live young. This is an unusual method of reproduction in chameleons as most lineages (genera) lay eggs, the only other exception being certain members of the Trioceros genus from east and central Africa. These live-bearing chameleons are however found at high altitudes, sometimes above the frost line, so viviparity is advantageous in that the females can thermoregulate efficiently while the embryos develop. As with South African dwarf chameleons, they tend to be smaller than their egg-laying counterparts. Bradypodion is thought to have radiated around 14 million years ago during a very cool period. Forest refugia was believed to offer a stable climate, but dwarf chameleons would have had to resort to viviparity in order to successfully reproduce.  

Dwarf chameleons are a highly threatened family of reptiles. Under the latest IUCN Red List threat classification, there are currently three species listed as Endangered. These include the Umlalazi Dwarf Chameleon, the Pondo Dwarf Chameleon and the Midlands Dwarf Chameleon.

As tempting as it may be to snatch a dwarf chameleon for your garden, these beautiful lizards should never be translocated. There are currently several introduced populations of dwarf chameleons in various parts of South Africa, including Eastern Cape Dwarf Chameleons in Johannesburg! By all means, encourage chameleons to naturally colonise your garden from surrounding areas by planting indigenous vegetation and avoiding the use of herbicides and pesticides. 

Article and photos by: Warren Schmid


Warren holds a Master of Science degree in Ecological Sciences awarded by the University of KwaZulu-Natal, South Africa. He has three decades of experience in ecology, conservation science, invasion biology and herpetology. He has worked as a journalist, magazine editor, and lecturer, and has presented talks, seminars, and lectures.

References:

  • da Silva, J. M. & Tolley, K. A. 2017. Diversification through ecological opportunity in dwarf chameleons. Journal of Biogeography doi:10.1111/jbi.12966.  
  • Hughes, D. F. & Blackburn, D. G. 2019. Evolutionary origins of viviparity in Chamaeleonidae. Journal of Zoological Systematics & Evolutionary Research (2020) 58: 284-302. https://doi.org/10.1111/jzs.12328
  • Prötzel, D., Heß, M., Scherz, M. D., Schwager, van’t Padje, A. & Glaw, F. 2018. Widespread bone-based fluorescence in chameleons. Scientific Reports (2018) 8:698 doi:10.1038/s41598-017-19070-7 
  • Resetarits, W. J. & Raxworthy, C. J. 2016. Hidden in plain sight: how ventral line markings in chameleons may enhance camouflage. The American Naturalist 187 (2): 262-273. 
  • Teyssier, J., Saenko, S. V., van der Marel, D. & Milinkovitch, M. C. 2015. Photonic crystals cause active colour change in chameleons. Nature Communications 6:6368 doi:10.1038/ncomms7368 
  • Tolley, K. A., Tilbury, C. R., Branch, W. R. & Matthee, C. A. 2004. Phylogenetics of the southern African dwarf chameleons, Bradypodion (Squamata: Chamaeleonidae). Molecular Phylogenetics and Evolution 30 (2004): 354-365. 
  • Tolley, K. A., Hopkins, K. P. & da Silva, J. M. 2019. Genetic structure associated with habitat diversification supports the independent evolution of ectomorphs in Bradypodion pumilum. African Journal of Herpetology https://doi.org/10.1080/21564574.2019.1646324

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