A medium-sized species of frog reaching up to 5 cm in body length. It has a dark brown or dark grey back, with a butterfly-shaped marking between the eyes. The belly is marbled black and white. The pupil is horizontal and the iris is golden brown. The thighs and lower legs have bright red patches. Fingers are moderately webbed and toes are slightly webbed, both without discs. Males have two large protrusions resembling tusks on their lower jaw, and a very large head.
Looks similar to Crinia deserticola, Crinia parinsignifera, Crinia signifera, Crinia tinnula, Uperoleia fusca, Uperoleia laevigata, Uperoleia rugosa, Paracrinia haswelli and Pseudophryne bibronii in its distribution, but the Uperoleia species lack the butterfly-shaped marking between the eyes and the Crinia species and Pseudophryne bibronii lack the bright red patches on the thigh and lower leg. Paracrinia haswelli has additional bright red patches in the armpits that are not present in Adelotus brevis.
The Tusked Frog is found from the mid north coast of NSW to Eungella in mid north QLD along the coast, and extending inland to the ranges.
Eggs are laid as a foamy mass on the surface of permanent ponds, stream pools, water-filled crayfish holes, or cattle tracks. Tadpoles can reach a total length of 3.5 cm and are dark brown in colour, sometimes with a cream-coloured patch on the snout. They often remain at the bottom of water bodies and take around two months to develop into frogs. Breeds during spring and summer.