Tenuibranchiurus is a genus of diminutive freshwater crayfish that live in the Australian state of Queensland. Only one species has been described, the swamp crayfish, T. glypticus. T. glypticus is reportedly the smallest species of crayfish in the world. It is distinguished from other crayfish by its small size, adults being only around 25 millimetres (1.0 in) long, and its claws which open vertically rather than horizontally or obliquely.