Tyrannosauroids varied widely in size, although there was a general trend towards increasing size over time. Early tyrannosauroids were small animals. One specimen of "Dilong", almost fully grown, measured 1.6 meters (5.3 ft) in length, and a fully-grown "Guanlong" measured 3 meters (10 ft long). Teeth from lower Lower Cretaceous rocks (140 to 136 million years old) of Hyogo, Japan, appear to have come from an approximately long animal, possibly indicating an early size increase in the lineage. An immature "Eotyrannus" was over 4 meters (13 ft) in length, and a subadult "Appalachiosaurus" was estimated at more than 6 meters (20 ft) long, indicating that both genera reached larger sizes. The Late Cretaceous tyrannosaurids ranged from the 9 meter (30 ft) "Albertosaurus" and "Gorgosaurus" to "Tyrannosaurus", which exceeded 12 meters (39 ft) in length and may have weighed more than 6400 kilograms (7 short tons). A 2010 review of the literature concluded that tyrannosaurs were "small- to mid-sized" for their first 80 million years but were "some of the largest terrestrial carnivores to ever live" in their last 20 million years.