Monolophosaurus

Chapter • Meet the dinosaur

Overview

Monolophosaurus was a medium-sized predatory dinosaur, roughly five to six metres long and weighing somewhere between 350 and 750 kilograms, with an often-cited figure of about 475 kilograms. Its trademark is the single tall crest running along the midline of the snout, from the tip of the muzzle back towards the eyes. The crest is built from the nasal and premaxillary bones and is hollow inside, connected to the air passages of the skull, so it was a lightweight structure rather than a solid weapon. The rest of the animal was a fairly typical early tetanuran: powerful hind limbs, a stiffened tail held horizontally as a counterbalance, short but muscular arms with three clawed fingers, and jaws lined with recurved, serrated blade-like teeth. No skin or feather impressions are known for Monolophosaurus, so its body covering is genuinely unknown; filamentous feathers cannot be ruled out in early tetanurans, but there is no direct evidence for them in this species.

Chapter • Where it lived

Habitat

Monolophosaurus lived in the Middle to early Late Jurassic, roughly 166 to 161 million years ago. Every known fossil comes from the Shishugou Formation of the Junggar Basin in Xinjiang, China. That landscape was a river-crossed floodplain with lakes, wetlands and stands of conifers, ginkgoes and ferns, under a climate with pronounced wet and dry seasons. It shared the environment with long-necked sauropods, the small horned dinosaur Yinlong, the crested tyrannosauroid Guanlong and several other theropods.

Chapter • Wild behavior

Behavior & Ecology

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Chapter • Scientific place

Taxonomy