Open Paleo

Saurolophus

Brown, 1912 saw-ROL-o-fus /sɔːˈrɒləfəs/

From Greek sauros (lizard) and lophos (crest); meaning "lizard crest".

83.6–66.0 million years ago Campanian–Maastrichtian, Late Cretaceous
Late Cretaceous stages

Saurolophus is a genus of large hadrosaurid dinosaur that lived during the Late Cretaceous period of North America and Asia, in what is now the Horseshoe Canyon and Nemegt formations respectively (about 70 to 66 million years ago). It is one of the few dinosaur genera known from multiple continents. The type species, S. osborni, was described by Barnum Brown in 1912 from Canadian fossils. A second valid species, S. angustirostris, is represented by numerous specimens from Mongolia, and was described by Anatoly Konstantinovich Rozhdestvensky. Saurolophus is distinguished by a spike-like crest which projects up and back from the skull. It was a herbivorous dinosaur which could move either bipedally or quadrupedally.

Diagnosis

  1. Long solid median dorsal cranial crest formed by backward prolongation of the nasals, prefrontals, and frontals, extending beyond the parietals
  2. Frontals rising upward at an obtuse angle to the parietals
  3. Postfrontal divided posteriorly by a wedge-like process of the squamosal
  4. Lacrimal triangular and elongate
  5. Dentary teeth with a vertically elongate enamel face bearing a low median carina, the sides nearly flat and the borders smoothly arched

Species (2)

Saurolophus osborni Brown, 1912

Type species

Named in honor of Henry Fairfield Osborn, American paleontologist and president of the American Museum of Natural History, who was a mentor to Barnum Brown.

Holotype
AMNH 5220 , American Museum of Natural History
Material
A nearly complete articulated skeleton with skull, including preserved sclerotic plates.
Horizon
Horseshoe Canyon Formation, Campanian–Maastrichtian, Late Cretaceous , 83.6–66.0 million years ago
Locality
Tolman Ferry, Red Deer River, Alberta, Canada

Saurolophus angustirostris Rozhdestvensky, 1952

From Latin 'angustus' (narrow) and 'rostrum' (snout); 'narrow-snouted', for the elongate skull of the Mongolian species.

Holotype
PIN 551/8 , Paleontological Institute, Russian Academy of Sciences
Material
Subadult skull and skeleton, including a partial sclerotic ring (three to five overlapping plates) preserved in the right orbit.
Notes
Also published as PIN 551/356, which Bell and colleagues (2017) give as the same specimen. No source read says which number the collection now uses.
Horizon
Nemegt Formation, Maastrichtian, Late Cretaceous , 72.2–66.0 million years ago
Locality
Nemegt, Ömnögovi, Mongolia
Diagnosis
  1. Skull at least 20% longer than in the largest adults of S. osborni
  2. Premaxilla with a strongly reflected oral margin and an upturned premaxillary body in lateral view
  3. Broadly arcing anterior margin of the prenarial fossa
  4. Elongate, anteriorly directed spur on the anterior process of the jugal separating the lacrimal and maxilla, more pronounced than in S. osborni
  5. Shallow quadratojugal notch on the quadrate
  6. More strongly bowed quadrate in lateral view

Notable specimens

  • MPC-D 100/764 sensu Hone 2010

    Paleontological Center, Mongolian Academy of Sciences pathology

    Left humerus of a nearly complete skeleton from the Bügiin Tsav locality of the Nemegt Formation, heavily damaged by Tarbosaurus bite marks (punctures, drag marks, and bite-and-drag marks) concentrated on the deltopectoral crest, interpreted as scavenging of an already dead animal.

    Hone & Watabe (2010)

  • MPC-D 100/764 sensu Dewaele 2015

    Paleontological Center, Mongolian Academy of Sciences ontogeny

    Small partial nest from the Dragon's Tomb assemblage of the Nemegt Formation containing three or four perinatal juveniles and two fragmentary eggshells; skull lengths under five percent of adult length document the earliest growth stage and show the crest was poorly developed in infancy.

    Dewaele et al. (2015)

References

  1. Hone, D. W. E.; Watabe, M. (2010). New information on scavenging and selective feeding behaviour of tyrannosaurids. Acta Palaeontologica Polonica 55(4): 627-634. doi:10.4202/app.2009.0133 hone2010a
  2. Dewaele, L.; Tsogtbaatar, K.; Barsbold, R.; Garcia, G.; Stein, K.; Escuillié, F.; Godefroit, P. (2015). Perinatal specimens of Saurolophus angustirostris (Dinosauria: Hadrosauridae), from the Upper Cretaceous of Mongolia. PLOS ONE 10(10): e0138806. Public Library of Science (PLoS). doi:10.1371/journal.pone.0138806 dewaele2015a
  3. Brown, B. (1912). A crested dinosaur from the Edmonton Cretaceous. Bulletin of the American Museum of Natural History 31(14): 131-136. brown1912a
  4. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Ornithischians. Princeton University Press.

    Source of the hip height estimate, and the appearance features.

    jones2026a
  5. Rozhdestvensky, A. K. (1952). Novyi predstavitel' utkonosykh dinozavrov iz verkhnemelovykh otlozhenii Mongolii [A new representative of the duck-billed dinosaurs from the Upper Cretaceous of Mongolia]. Doklady Akademii Nauk SSSR 86(2): 405-408.

    Erects Saurolophus angustirostris on Mongolian material from the Nemegt Formation.

    rozhdestvensky1952a
  6. Bell, P. R. (2011). Cranial osteology and ontogeny of Saurolophus angustirostris from the Late Cretaceous of Mongolia. Acta Palaeontologica Polonica 56(4): 703-722. Institute of Paleobiology, Polish Academy of Sciences. doi:10.4202/app.2010.0061

    Cranial osteology and ontogeny redescription of S. angustirostris; source of the amended diagnosis and holotype description.

    bell2011a
  7. Bell, P. R.; Evans, D. C.; Eberth, D. A.; Fanti, F.; Tsogtbaatar, K.; Ryan, M. J. (2017). Sedimentological and taphonomic observations on the "Dragon's Tomb" Saurolophus (Hadrosauridae) bonebed, Nemegt Formation (Upper Cretaceous), Mongolia. Palaeogeography, Palaeoclimatology, Palaeoecology 494: 75-90. doi:10.1016/j.palaeo.2017.11.034

    Equates the holotype numbers PIN 551/8 and PIN 551/356 and describes the Dragon's Tomb bonebed it came from.

    bell2017b
  8. Bell, P. R. (2012). Standardized terminology and potential taxonomic utility for hadrosaurid skin impressions: a case study for Saurolophus from Canada and Mongolia. PLOS ONE 7(2): e31295. doi:10.1371/journal.pone.0031295

    Describes midline feature-scales in a near-continuous row above the caudal neural spines of S. angustirostris; not confirmed in S. osborni.

    bell2012a