Parasaurolophus
The name Parasaurolophus means “like crested lizard”, derived from Saurolophus (“crested lizard”), as the scientist who first described it believed it looked similar. However, we now know that the two are not closely related.
Physical Characteristics
Parasaurolophus likely spent much of its time walking on all four legs but was capable of moving on just its two hind legs, especially when running or reaching for taller vegetation. This was a sizable dinosaur, growing up to 9 m in length and weighing around 5 tonnes (5,000 kg).
The body of Parasaurolophus was robust and bulky, with relatively short, strong forelimbs and a stiff tail that likely aided in balance and quick movement. Skin impressions reveal that its body was covered in uniform, pebble-like scales, suggesting it had a tough, protective hide.
The Crest
The skull of Parasaurolophus, including its crest, measured around 1.5 - 2 m long. The crest itself was hollow, with internal tubes running from the nostrils through to the end of the crest and looping back into the skull. These structures varied between species - P. tubicen, for instance, had a more intricate tube arrangement with tubes coming together and diverging, compared to the simpler structure seen in P. walkeri.
The function of the crest remains a topic of debate. It may have been used to produce sounds by blowing air through the tubes, served as a visual signal for display or communication, or helped with thermoregulation. Crest variation even within the same species suggests it may have been a sexually dimorphic trait, meaning that it differed between males and females. It also may have changed with age.
However, whether the dinosaur actually used the crest this way remains uncertain.
Species and Crest Differences
- P. walkeri (the type species, found in Canada) had a long, smoothly curved crest.
- P. tubicen (the largest species, from New Mexico) had a longer, straighter crest with a more complex internal structure.
- P. cyrtocristatus (also from New Mexico) was the smallest of the three, with a shorter, strongly curved crest.
Diet and Teeth
As with other hadrosaurs, the teeth of Parasaurolophus were arranged into dental batteries - dense rows of closely-packed teeth which form a large surface for grinding plant material. These teeth were continuously replaced as they were worn down, meaning Parasaurolophus had hundreds of teeth, but only some of these were in use at any one time. Its diet consisted of leaves, twigs, and pine needles.Fossil Locations and Habitat
Fossils have been found in what is now western North America, including Canada and the United States. During the Late Cretaceous, this area was part of an island continent called Laramidia, which featured vast floodplains and a warm, humid climate. There is some debate about potential Parasaurolophus specimens found in Asia - some researchers argue they may belong to a different genus called Charonosaurus.As with many dinosaurs, the fossil record for Parasaurolophus is incomplete. The first skeleton discovered lacked the tail and parts of the hind legs. Although a few additional specimens have been found since, Parasaurolophus fossils remain rare compared to those of other hadrosaurs.
Individual Species Environments
Parasaurolophus walkeri lived in the Dinosaur Park Formation of Alberta - a lush landscape of rivers, floodplains, and swamps near a shallow inland sea. The climate was warm, frost-free, and seasonal, with towering conifer forests and lush ferns. This species shared its habitat with famous dinosaurs like horned Centrosaurus, armored Euoplocephalus, and predatory Gorgosaurus, though Parasaurolophus itself was relatively uncommon and may have primarily inhabited upland areas or migrated through the region.
Parasaurolophus cyrtocristatus inhabited the swampy lowlands of the Fruitland Formation in New Mexico, located close to the shore of the Cretaceous Interior Seaway around 75 million years ago. Here, it lived alongside horned dinosaurs like Pentaceratops, dome-headed Stegoceras, and various predatory dinosaurs, although the specific ecosystem was diverse with many less clearly identified dinosaurs sharing the region.
Social Behavior
Whether Parasaurolophus was social or solitary remains unknown, as no bonebeds (mass fossil deposits) of the genus have been found. However, the elaborate crest - likely used for communication - suggests it may have lived in groups. Other hadrosaurs are known from bonebeds, supporting the theory that Parasaurolophus also engaged in social behavior.References & Attributions
Image: Parasaurolophus Scale - User:Slate Weasel, Public domain, via Wikimedia Commons
Image: Parasaurolophus walkeri restoration - Leandra Walters, Phil Senter, James H. Robins, CC BY 2.5, via Wikimedia Commons
Image: Parasaurolophus Skulls - Terry A. Gates, David C. Evans, Joseph J.W. Sertich, CC BY 4.0, via Wikimedia Commons
Image: Artist's Depiction of P. Walkeri in its environment - Marco Antonio Pineda, CC BY-SA 4.0, via Wikimedia Commons
Image: P. cyrtocristatus skeletal mount at the Field Museum of Natural History - Zissoudisctrucker, CC BY-SA 4.0, via Wikimedia Commons
