were too thin to be used for defense against predators, although the thicker, solid frills of Triceratops might have evolved to protect their necks. The frills of Centrosaurus were most likely used "for species recognition and/or other forms of visual display". Paleopathology A specimen of Centrosaurus apertus recovered from Dinosaur Provincial Park in 1989 was discovered to have crippling osteosarcoma in its right fibula. Examination of the cancerous lesions in the bone suggest the cancer had reached an aggressive stage. The cancer would have resulted in a severe limp that would have made the ceratopsian more vulnerable to predation. However, the fact that it was part of a herd allowed the Centrosaurus to survive much longer than would be expected for an animal infected with such severe disease. The individual itself is believed to have died from drowning in the flash flood that created the Centrosaurus bone bed where it was found. The specimen remains one of the few dinosaur specimens found with severe cancer. Paleobiogeography Thomas M. Lehman has observed that Centrosaurus fossils haven't been found outside of southern Alberta even though they are among the most abundant Judithian dinosaurs in the region. Large herbivores like the ceratopsians living in North America during the Late Cretaceous had "remarkably small geographic ranges" despite their large body size and high mobility. This restricted distribution strongly contrasts with modern mammalian faunas whose large herbivores' ranges "typical[ly] ... span much of a continent." See also Timeline of ceratopsian research References External links Centrosaurus at The Dinosaur Picture Database Centrosaurus, from the Dinosaur Encyclopaedia at Univ. of Illinois at Urbana-Champaign Centrosaurines Campanian genus first appearances Campanian genus extinctions Late Cretaceous dinosaurs of North America Dinosaur Park fauna Paleontology in Alberta Fossil taxa described in 1904 Taxa named by Lawrence Lambe Ornithischian genera Campanian life