The tusked frog (Adelotus brevis) is a species of ground-dwelling frog native to eastern Australia from Eungella National Park, Queensland south to Ourimbah, New South Wales. It is the only species in the genus Adelotus - adelotus meaning "unseen" and brevis meaning "short". Description The tusked frog is a unique frog within Australia, as it is the only species where the female is smaller than male. Males can reach a maximum length of about , while females reach . The common name of "tusked frog" derives from the small protrusions on the lower jaw, similar in position to tusks, which can reach about in length in males (only visible when the mouth is open). The pair of bony tusks are modified teeth that protrude from the middle of the lower jaw and fit into special grooves on the upper jaw when the mouth is closed. They are slightly curved and sharply pointed, and are present in both males and females, although they are larger in males. Males have been observed 'locking jaws' with each other, in a similar way to male deer locking antlers in the struggle to exert dominance over each other. Male tusked frogs have a disproportionally large-sized head, compared to the body, and females have a smaller proportioned sized head than males. The males have been known to fight, biting each other under the head, and around the neck. This behaviour has presumably led to the sexual dimorphism of larger heads, body size and tusks to increase success of fights (Katsirakos & Shine 1997). The dorsal surface of the frog is normally brown, but can be olive to black, with low ridges, warts and irregular darker markings. There is usually a butterfly shaped marking between the eyes. The [ventral] surface of this species is more striking - being marbled black and white with flashes of red on the groin and hind legs. Males and females have different belly patterns. Fingers and toes are cylindrical and are not webbed. Ecology and behaviour A. brevis is associated with dams, ditches, flooded grassland and creeks in rainforest, wet sclerophyll forest and woodland. It is known from coastal and highland areas, however it has suffered declines in many highland areas, particularly the New England Tablelands of New South Wales. Males create hidden nest sites in leaf litter and vegetation in streams and the edges of dams. This species has a call