Parasaurolophus walkeri

Parasaurolophus walkeri was a large lambeosaurine hadrosaur from the Campanian Dinosaur Park Formation of Alberta. Its crest contained elongated nasal passages that looped from the nostrils to the tip of the crest and back into the skull. The crest probably combined visual display with sound resonance, although no fossil can reveal an exact call. Almost everything diagnostic about this species rests on ROM 768, a skull and partial skeleton that remains one of the most recognisable dinosaur fossils in the Royal Ontario Museum.

Its fossils occur between approximately 77 and 76 million years ago. Values shown here are approximate and reflect the current curated seed dataset.

ROM 768 preserves the complete skull and much of the trunk and limbs, but most of the tail and the hind limbs below the knees are missing. The long crest is built mainly from the premaxillae and nasals and carries paired air passages through most of its length. A broad, toothless beak cropped plants, while tightly packed dental batteries continually replaced worn teeth. The forelimbs could support the body during ordinary walking and feeding, while the more powerful hind limbs also permitted bipedal movement.

• Long, backward-projecting tubular cranial crest
• Paired nasal passages looping through the crest
• Broad keratin-covered beak for cropping vegetation
• Dental batteries with hundreds of replacement teeth
• Robust forelimbs with hoof-like weight-bearing fingers
• Powerful hind limbs permitting facultative bipedal movement
• Deep tail that balanced the trunk and powered locomotion

A University of Toronto field party found ROM 768 near Sand Creek along Alberta's Red Deer River in 1920. William Arthur Parks described the animal in 1922, choosing Parasaurolophus—'near Saurolophus' or 'near-crested lizard'—for its resemblance to the shorter-crested Saurolophus. The species name walkeri honours Sir Byron Edmund Walker, a major supporter and chair of the Royal Ontario Museum's board. Later study showed that the type skeleton records several healed injuries, including damaged ribs and unusual vertebral bone growth.

Discovery credit: University of Toronto field party.

Naming authors: William Arthur Parks.

P. walkeri lived on warm, humid coastal lowlands crossed by rivers and floodplains west of the Western Interior Seaway. The Dinosaur Park Formation supported conifers, flowering plants, ferns and dense waterside vegetation. Corythosaurus, Lambeosaurus, ceratopsids, ankylosaurs and predators such as Gorgosaurus and Daspletosaurus occupied the same broad ecosystem, although not every species occurred at exactly the same place and time.

Parasaurolophus used its beak and dental batteries to crop and process fibrous plants. Computer and physical models show that the crest could resonate at low frequencies in adults, and a juvenile specimen of the genus indicates that resonance changed as the crest grew. This supports an acoustic signalling role alongside visual display, but it does not reproduce the animal's actual voice. Hadrosaurs sometimes formed groups, yet the rarity of P. walkeri provides no direct basis for assigning it a particular herd structure. Healed damage in ROM 768 shows that this individual survived substantial trauma.

• The celebrated ROM skeleton is the actual holotype, not merely a cast, but it lacks most of the tail and the lower hind limbs.
• ROM 768 preserves healed rib fractures, a dental lesion and abnormal bone growth around parts of the back and pelvis.
• A falling tree has been proposed as one possible cause of some injuries, but it is a scenario rather than a fact recorded by the fossil.
• The crest was once imagined as a snorkel; its closed tip and internal anatomy rule out that popular idea.
• Juvenile Parasaurolophus had a much smaller crest, and modelling predicts that its resonant frequencies became lower as it matured.

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1. 01
   The Paleobiology Database

   Open source
2. 02
   Parasaurolophus walkeri, a new genus and species of crested trachodont dinosaur

   William Arthur Parks · University of Toronto Studies, Geological Series 13 · 1922

   Open source
3. 03
   Acoustic analyses of potential vocalization in lambeosaurine dinosaurs

   David B. Weishampel · Paleobiology · 1981

   Open source
4. 04
   Ontogeny in the tube-crested dinosaur Parasaurolophus (Hadrosauridae) and heterochrony in hadrosaurids

   Andrew A. Farke, Derek J. Chok, Annisa Herrero and 2 coauthors · PeerJ · 2013

   Open source
5. 05
   Description and etiology of paleopathological lesions in the type specimen of Parasaurolophus walkeri, with proposed reconstructions of the nuchal ligament

   Filippo Bertozzo, Fabio Manucci, Matthew Dempsey and 4 coauthors · Journal of Anatomy · 2021

   Open source
6. 06
   Dinos and Friends: Royal Ontario Museum family guide

   Royal Ontario Museum · 2026

   Open source