Guanlong

Chapter • Meet the dinosaur

Overview

Guanlong wucaii was a small, lightly built two-legged predator about three to three and a half metres long from snout to tail tip, weighing roughly 60 to 125 kilograms. Its most striking feature was a thin, crescent-shaped crest running along the top of the snout and back over the skull. The crest was built from paper-thin sheets of bone around air-filled chambers, far too fragile to serve as a weapon. Unlike its later relatives, Guanlong had long arms with three clawed fingers and a long, narrow skull filled with small, blade-like serrated teeth. Because close relatives such as Dilong and Yutyrannus are preserved with simple hair-like feather filaments, most researchers reconstruct Guanlong with a covering of downy protofeathers. The skeleton suggests an agile, quick animal. Long hind limbs and a stiffened, counterbalancing tail point to bursts of speed after prey, and the grasping hands were probably far more important in hunting than the tiny arms of later tyrannosaurs. The crest was almost certainly a display structure used for signalling to other members of its own species — in courtship, in sorting out rank, or simply in recognition. The younger of the two known specimens has a much smaller crest than the older one, hinting that the structure grew as the animal matured. Guanlong was a carnivore that most likely targeted smaller prey: juvenile plant-eating dinosaurs, small ceratopsians such as Yinlong, lizards, early mammals, and probably any fresh carcass it could find. Its narrow, recurved teeth were built for slicing flesh rather than for the bone-crushing bites of the much later Tyrannosaurus rex. The species was described in 2006 by a Chinese–American team led by Xu Xing, based on two skeletons from the Shishugou Formation of the Junggar Basin in Xinjiang, northwestern China. The name means roughly "crowned dragon" in Chinese, while wucaii refers to the five colours of the striped badlands where the fossils were found. The discovery was important because it showed that the tyrannosaur lineage had already evolved highly distinctive features in the Late Jurassic, long before the group produced giants.

Chapter • Where it lived

Habitat

Guanlong lived in the Late Jurassic, during the Oxfordian stage roughly 161–156 million years ago, in what is now the Junggar Basin of Xinjiang, northwestern China. Its fossils come from the Shishugou Formation at the Wucaiwan locality, a landscape of river floodplains, meandering channels and forests of conifers, ginkgoes and ferns under a seasonally variable climate. Parts of the formation preserve deep pits of volcanic mud in which dinosaurs became mired; both known Guanlong specimens were found stacked in one such trap. Its neighbours included the early ceratopsian Yinlong, the toothless ceratosaur Limusaurus and large sauropods of the mamenchisaurid group.

Chapter • Wild behavior

Behavior & Ecology

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Chapter • Scientific place

Taxonomy