The largest group of lizards in Australia belong to the genus Ctenotus. There are nearly 100 species in this genus. They are found throughout much of Australia, but are most diverse in the desert regions and tropical woodlands of Australia's north.
In desert and tropical woodland regions, Ctenotus is usually the largest group of lizards, comprising 10%-25% of the total lizard fauna. In the sand ridges and sand plains of the Great Victoria Desert in Western Australia, 11 species of Ctenotus are known to live in one area which has approximately 40 species of lizard in total.
Lizards of the Ctenotus genus are commonly called 'comb-eared skinks' because of the row of small scales on the anterior edge of their ears. What is most remarkable about these lizards is that there is very little difference in their overall 'body plan' or shape across a huge range of species. In other words, comb-eared skinks are all typical skinks with smooth scales, long limbs each with five digits and long tails which can be up to two and half times the length of the body.
However, comb-eared skinks do vary in size, foraging and sheltering behaviour, and the frequency and times of activity. Their size ranges from 4 to 12 centimetres, not including the tail. Some species forage in open spaces between plants while others forage mainly within, or at the edge of, dense clumps of hummock grass. The active periods of these skinks also varies: some have a unimodal activity pattern in the mid-to-late morning or early afternoon, while others have a distinctly bimodal activity period in both the morning and afternoon.
The subtle differences in 'body plan' and behaviour among comb-eared skinks allows them to coexist in areas without competing too much for the same limited resources.
Words to know:
- GENUS - a group of species with shared characteristics.
- ANTERIOR - towards the head end of the body of an animal.
- UNIMODAL - has an active period once a day
- BIMODAL - has active periods twice a day.