Open Paleo

Parasaurolophus

Parks, 1922 PAR-a-saw-ROL-o-fus /ˌpærəsɔːˈrɒləfəs/

From Greek para (beside, near) and the genus name Saurolophus (crested lizard); meaning "beside crested lizard", reflecting Parks's view that the new genus's affinities lay with Saurolophus from the Edmonton Formation.

83.6–72.2 million years ago Campanian, Late Cretaceous
Late Cretaceous stages

Parasaurolophus is one of the most recognizable lambeosaurine hadrosaurs, distinguished by an elongate hollow cranial crest formed largely of the premaxillae (with the nasals) that projects well posterior to the occiput. Parks erected the genus in 1922 on a skull and partial articulated skeleton (ROM 768) collected by a University of Toronto expedition in 1920 from the Belly River beds of the Red Deer River, Alberta — strata now assigned to the lower Dinosaur Park Formation. Parks raised the question of whether the hollow tubes carried air, anticipating the long-running interpretation that the crest housed elongated nasal passages and may have functioned as a resonating chamber for vocal display. Three further species are recognized today — P. tubicen and P. cyrtocristatus from the San Juan Basin and Kaiparowits regions of the southwestern United States, and the disputed Asian P. jiayinensis (often referred to its own genus, Charonosaurus). Material remains rare across the entire range, and Evans, Bavington and Campione (2009) documented that even the Alberta type material likely represents a subadult, with the crest not yet at its fully developed adult expression.

Diagnosis

  1. Tubular narial crest, short to long and slightly curved, composed largely of the premaxillae — unique among hadrosaurs.
  2. Prefrontals lapping onto the ventral lateral surface of the premaxilla where the skull roof meets the narial crest.
  3. Frontals arising from the posterior base of the crest and extending posteriorly to meet the nasals anterior to the rear extent of the squamosals.
  4. Narial crest divided externally into dorsal and ventral tracts by a longitudinal lateral groove running nearly its full length on each side.
  5. Crest interior comprises parallel thin-walled bony tubes continuous with the external nares.
  6. Anteriorly extended pubic peduncle of the ilium strongly decurved distally and forming an externally overlapping joint with the pubis.
  7. Cervical postzygapophyses on vertebrae 8-13 strongly elongate and curved ventrally, reaching ~110 mm in length.

Species (3)

Parasaurolophus walkeri Parks, 1922

Type species

Honoring Sir Edmund Walker, Chairman of the Board of Trustees of the Royal Ontario Museum, which sponsored the 1920 University of Toronto expedition that recovered the holotype.

Holotype
ROM 768 , Royal Ontario Museum
Material
Articulated skull with complete crest, 13 cervical and 17 dorsal vertebrae, sacrum, six caudal vertebrae, both scapulocoracoids, both fore limbs, partial pelvis (left side only), and left femur, with associated skin impressions; tail and most of the hindlimbs not preserved.
Horizon
Dinosaur Park Formation, Campanian, Late Cretaceous , 83.6–72.2 million years ago
Locality
Sand Creek, Alberta, Canada

Parasaurolophus cyrtocristatus Ostrom, 1961

From Greek 'kyrtos' ('curved') and Latin 'cristatus' ('crested'), referring to the short, strongly downcurved crest.

Holotype
FMNH P27393 , Field Museum of Natural History
Material
Cranial crest, dorso-caudal cranium, left dentary fragment, cervical-caudal vertebrae, scapulae, humeri, forelimb bones, ischia, ilia, pubes, femora, tibiae, ribs, chevrons, phalanges.
Horizon
Fruitland Formation, Campanian, Late Cretaceous , 83.6–72.2 million years ago
Locality
Coal Creek, New Mexico, United States Sternberg's field data give the site as eight miles southeast of Tsaya, which would place the holotype in the Menefee Formation. Sullivan and Williamson (1999) read the direction as northeast instead, putting it at Coal Creek in the Fossil Forest; both places named Tsaya lie in San Juan County rather than McKinley. They judge the horizon to be the upper Fruitland or the Hunter Wash Member of the Kirtland.
Diagnosis
  1. Cranial crest short, about one-third the length of P. walkeri's (~260 mm behind the occiput versus ~860 mm), curving strongly posteroventrally rather than arcing dorsocaudally.
  2. Total skull length exceeding ~1425 mm (versus ~1733 mm in P. walkeri).
  3. Narial passages separated by a median bony septum (as in P. walkeri; absent in P. tubicen).
  4. Internal narial tubes simple and paired, running from the external nares to the crest apex and U-bending forward into the choana.
  5. Lateral diverticula positioned medially between the dorsal and ventral ascending tracts, divided dorsally by a sagittal septum.
  6. Radius (585 mm) longer than the humerus (565 mm), unlike P. walkeri (humerus 520 mm exceeding radius 496 mm).

Parasaurolophus tubicen Wiman, 1931

From Latin 'tubicen' ('trumpeter'), alluding to the elongate, trumpet-like narial crest.

Holotype
PMU.R1250 , Paleontological Museum
Material
Incomplete skull and narial crest, including posterior skull roof (parietal, postorbital, squamosal), basicranium (basioccipital, basisphenoid), right maxilla, jugal, and partial palatine.
Horizon
De-na-zin Member, Kirtland Formation, Campanian, Late Cretaceous , 83.6–72.2 million years ago
Locality
Barrel Springs area, De-na-zin Wash, New Mexico, United States
Diagnosis
  1. Narial crest internally more complex than in P. walkeri, with a pair of dorsal tubes plus two further tube pairs that U-bend and coalesce into a single ventral tube pair.
  2. Lateral diverticula paired, forming a tight U-bend and fusing anteriorly with the ventral ascending tubes before entering the choana.
  3. Dorsal and dorsolateral surfaces of the narial crest bearing anastomosing furrows, absent in P. walkeri.
  4. Narial crest long, in contrast to the short, sharply curved crest of P. cyrtocristatus.

Notable specimens

  • “Joe”

    RAM 14000 Raymond M. Alf Museum of Paleontology, The Webb Schools Found 2009 ontogeny

    The most complete and youngest Parasaurolophus known, a roughly one-year-old juvenile about 2.5 meters long from the Kaiparowits Formation. Its crest is low and hemispherical, not tubular, and it yielded the first cranial endocast for the genus, showing crest growth began earlier than in relatives.

    Farke et al. (2013)

  • NMMNH P-25100

    New Mexico Museum of Natural History and Science Found 1995 complementary

    A second, nearly complete Parasaurolophus tubicen skull from New Mexico, found in 1995. Its CT data underpinned the 1999 monographic treatment of the genus and the modeling of the crest's resonant air passages, which reconstructed the possible sound produced by the more complex tubicen crest.

    Sullivan & Williamson (1999)

References

  1. Farke, A. A.; Chok, D. J.; Herrero, A.; Scolieri, B.; Werning, S. (2013). Ontogeny in the tube-crested dinosaur Parasaurolophus (Hadrosauridae) and heterochrony in hadrosaurids. PeerJ 1: e182. doi:10.7717/peerj.182 farke2013b
  2. Sullivan, R. M.; Williamson, T. E. (1999). A new skull of Parasaurolophus (Dinosauria: Hadrosauridae) from the Kirtland Formation of New Mexico and a revision of the genus. New Mexico Museum of Natural History and Science Bulletin 15: 1-52.

    Revision of the genus with emended generic and species diagnoses; redescribes the ROM 768 holotype and describes the NMMNH P-25100 P. tubicen skull.

    sullivan1999b
  3. Parks, W. A. (1922). Parasaurolophus walkeri, a new genus and species of crested trachodont dinosaur. University of Toronto Studies, Geological Series 13: 1-32.

    Erects the genus on ROM 768, a partial articulated skeleton from the Belly River beds (now lower Dinosaur Park Formation), Red Deer River, Alberta, collected in 1920.

    parks1922a
  4. Evans, D. C.; Bavington, R.; Campione, N. E. (2009). An unusual hadrosaurid braincase from the Dinosaur Park Formation and the biostratigraphy of Parasaurolophus (Ornithischia: Lambeosaurinae) from southern Alberta. Canadian Journal of Earth Sciences 46(11): 791-800. doi:10.1139/E09-050

    Identifies frontal-platform autapomorphies, argues the holotype is a subadult with the crest not yet at adult expression, and restricts the genus to the lower Dinosaur Park Formation.

    evans2009a
  5. Paul, G. S. (2024). The Princeton Field Guide to Dinosaurs (3rd ed.). Princeton University Press.

    Source of the appearance features.

    paul2024a
  6. Ostrom, J. H. (1961). A new species of hadrosaurian dinosaur from the Cretaceous of New Mexico. Journal of Paleontology 35(3): 575-577. Cambridge University Press (CUP).

    Erects Parasaurolophus cyrtocristatus on skull FMNH P27393 from the Fruitland Formation of New Mexico.

    ostrom1961a
  7. Wiman, C. (1931). Parasaurolophus tubicen n. sp. aus der Kreide in New Mexico. Nova Acta Regiae Societatis Scientiarum Upsaliensis, Series IV 7(5): 3-11.

    Erects Parasaurolophus tubicen on Wiman's skull PMU.R1250 from the Kirtland Formation of New Mexico.

    wiman1931a