Vegetation-dwellers, group 2

In his book "Biology and Evolution of Australian Lizards", Allen Greer sorted the lizards I study, the genus Ctenophorus, into different groups based on where they live: those that live in burrows, those that live in rock crevices, and those that live in vegetation. Looking at the phylogenetic relatedness of the Ctenophorus dragons, there are two groups of each: two groups of burrowers, two groups of rock-dwellers, and two groups of vegetation-dwellers. I thought it'd be fun to put up pictures and descriptions of all these groups, since I have a large pile of pictures from my fieldwork. These are my posts so far: Rock-dwellers #1, Rock-dwellers #2,  Burrowers #1, Burrowers #2, and Vegetation-dwellers #1.

This last group of Ctenophorus dragons are known as the military dragons. I don't know why, maybe because their patterns are full of stripes. They are also the largest group of Ctenophorus, with seven species. They're all quite small, weighing around 10 grams or less, and are long-legged sprinters. They don't shelter anywhere in particular, so they use a combination of their speed and any available vegetation to hide from predators. During my PhD, I deliberately went after two species, and we came across a third coincidentally while looking for other dragon species.

The two species in this group that I needed for my PhD were the mallee military dragon (Ctenophorus fordi) and the central military dragon (Ctenophorus isolepis). These two lizards are almost the exact same. They are quick, skittish lizards that are always on the flat ground. They never perch on branches, climb trees, or sit on top of bushes as other dragon lizards often do. They do everything - bask, hunt, mate, etc. - on solid ground. They also have a preferred habitat type, spinifex, and are so closely associated with spinifex that we called them the spinifex dragons. Spinifex is a famous type of grass here in Australia, famous mostly because it is basically a clump of outwards-pointing spears. I vividly remember my volunteers trying to catch mallee military dragons by hand; I had horrible visions of them poking their eyes out on the spinifex as they dove for dragons. The dragons use this to their advantage. If they're scared, they dive into a dense spinifex bush, which is basically an impenetrable fortress of spikes!

The immense spikiness of a spinifex plant. Mulga Park Station, Northern Territory, 2012. Photo by Angus Kennedy.

There were a few key differences between the mallee and central military dragons. First, the mallee military dragon was extremely abundant. We broke all records for single-day lizard catching with this species when, on the very last day of my 2012 field season, we caught 32 mallee military dragons between noon and 5 p.m. That is a lot of dragons! On the other hand, central military dragons are only moderately abundant. It took us two days to catch the same number of central military dragons as we caught mallee military dragons in half a day. This is still much more abundant than any other dragon species. That number of dragons would usually take us 4-6 days to catch, and with the rusty dragon it took three weeks!

Central military dragons are also about double the size of mallee military dragons. Mallee military dragons prefer their spinifex to be under the shade of a canopy of mallee trees, whereas central military dragons like their spinifex exposed, with no trees in sight, like in the picture above.

An additional difference is that central military dragons are sexually dimorphic, meaning that the males and females look different, while mallee military dragons are sexually monomorphic, meaning both sexes look the same. In the case of the central military dragon, this means that the male has a heck of a lot more black on him than the female, and has a more complex pattern. Male and female mallee military dragons look almost identical. There is no sexual dimorphism in this species, except for some extra black markings on the underside of the male.

A male central military dragon (Ctenophorus isolepis). Mulga Park Station, Northern Territory, 2012. Photo by Angus Kennedy.

A female central military dragon (Ctenophorus isolepis). Mulga Park Station, Northern Territory, 2012. Photo by Angus Kennedy.

A male mallee military dragon (Ctenophorus fordi). Gluepot Reserve, South Australia, 2011. Photo by Tobias Hayashi.

A female mallee military dragon (Ctenophorus fordi). Gluepot Reserve, South Australia, 2011. Photo by Tobias Hayashi.

While looking for claypan dragons in southwest Western Australia, we came across a few spotted military dragons (Ctenophorus maculatus). This species is very similar to the other two military dragons, but it doesn't live in spinifex. Instead, they seemed to like areas that were open, but with short woody plants all over the place. They also didn't seem to be nearly as common as the other two, but maybe that was just because we weren't looking.

A female spotted military dragon (Ctenophorus maculatus). near Lake Cronin, Western Australia, 2013. Photo by Angus Kennedy.

Those are the three members of this group of vegetation-dwellers we came across during my fieldwork. Of the other four, only one is widespread and well known. The lozenge-marked dragon (Ctenophorus scutulatus) is the largest member of this group and is found over a large area of Western Australia just north of Perth. The other three species, the long-tailed military dragon (Ctenophorus femoralis), the rufus military dragon (Ctenophorus rubens), and McKenzie's dragon (Ctenophorus mckenziei) are all very poorly known critters. They're all restricted to small areas of remote habitat: the former two halfway up the coast of Western Australia, and the latter on the Nullabor plain. McKenzie's dragon also has the unfortunate distinction of being endangered.