Centrosaurus

Chapter • Meet the dinosaur

Overview

Centrosaurus apertus was a solidly built, four-legged plant-eater some five to six metres long, with body-mass estimates usually falling between about 1.5 and just under 3 tonnes. Its most obvious feature was a single large nose horn that in adults often curved forward or backward, paired with small, blunt brow horns. The neck frill was comparatively short but broad, edged with small pointed processes and pierced by two large openings. Two heavy hooks curled forward from the back margin of the frill and over those openings – a signature feature that separates Centrosaurus at a glance from relatives such as Styracosaurus. The animal walked on pillar-like hind limbs and slightly shorter forelimbs, carrying its tail clear of the ground. Most Centrosaurus material comes from enormous bonebeds in which hundreds or thousands of individuals lie jumbled together. This is the strongest evidence that the animals lived in large herds, at least seasonally, and that whole groups could die at once in floods. The bonebeds mix juveniles, subadults and fully grown animals, suggesting herds of several age classes. Horn shape changed dramatically during growth, and most researchers interpret the horns and frill primarily as signals for species recognition and dominance display rather than as pure weapons – though healed injuries on some skulls show that individuals did sometimes clash head to head. Centrosaurus fed on low-growing vegetation. A powerful beak cropped branches and foliage, and behind it sat dental batteries of hundreds of tightly packed teeth that worked like a continuously self-sharpening pair of shears. Jaw motion was mainly vertical and slicing rather than grinding. The diet probably included ferns, cycads, conifers and the flowering plants that were spreading across North America in the Late Cretaceous. The species was described in 1904 by the Canadian palaeontologist Lawrence Lambe, based on material from the Red Deer River in Alberta. The name means roughly "pointed lizard", referring to the small spikes along the frill margin rather than to the nose horn. For decades Centrosaurus was tangled up with the poorly defined genus Monoclonius, but better skulls and the great bonebeds of Dinosaur Provincial Park have since made Centrosaurus apertus one of the best-known horned dinosaurs in the world.

Chapter • Where it lived

Habitat

Centrosaurus lived roughly 76.5–75.5 million years ago, during the Campanian stage of the Late Cretaceous, on the low coastal plain west of the Western Interior Seaway. The setting was a warm, humid mosaic of floodplains, meandering rivers, wetlands and forests of conifers, ferns and early flowering plants. Almost all specimens come from the Dinosaur Park Formation of Alberta, Canada, especially Dinosaur Provincial Park and the vast bonebed near Hilda.

Chapter • Wild behavior

Behavior & Ecology

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Chapter • Scientific place

Taxonomy