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Gryposaurus

Lambe, 1914 GRIP-o-SAWR-us

From Greek grypos (hook-nosed, curved) and sauros (lizard); meaning 'hooked-nosed lizard', referring to its arched nasal profile

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

Gryposaurus (meaning "hook-nosed lizard"; sometimes incorrectly translated as "griffin (Latin gryphus) lizard") was a genus of duck-billed dinosaur that lived about 80 to 75 million years ago, in the Late Cretaceous (late Santonian to late Campanian stages) of North America. Named species of Gryposaurus are known from the Dinosaur Park Formation in Alberta, Canada, and two formations in the United States: the Lower Two Medicine Formation in Montana and the Kaiparowits Formation of Utah. A possible additional species from the Javelina Formation in Texas may extend the temporal range of the genus to 66 million years ago.

Diagnosis

  1. Nasals highly arched, rising to extraordinary height a short distance in advance of the orbits; nasal apex as high as the summit of the squamosal behind the supratemporal fossa.
  2. Skull uniquely deep anteriorly among Trachodontidae; depth at apex of nasal bones equal to about half the maximum skull length.
  3. Lower anterior border of premaxillae expanded laterally and notched in a regular manner on each side of the median sutural union.
  4. Predentary expanded laterally, deflected in its hinder half, and posteriorly bifurcated below at the midline into two processes received into excavations of the dentaries.
  5. Orbit much smaller than the lateral temporal fossa; lateral temporal fossa more than twice as high as wide.
  6. Body covered with small, polygonal, non-imbricating, tuberculate scales of rather uniform size, varying from 1/8 to 3/8 inch diameter with no definite pattern arrangement.

Species (3)

Gryposaurus notabilis Lambe, 1914

Type species

From Latin 'notabilis' meaning 'notable' or 'remarkable', in reference to the distinctive hooked nasal arch that sets this dinosaur apart from other hadrosaurs.

Holotype
NMC 2278 , Canadian Museum of Nature
Material
Skull with approximately twenty feet of vertebral column, most of the pectoral arch, about half of the ribs, the pelvic arch, one hind limb with part of the foot, and skin impressions from between the femur and base of the tail.
Horizon
Dinosaur Park Formation, Campanian, Late Cretaceous , 83.6–72.2 million years ago
Locality
Alberta, Canada Lambe (1914) names no site beyond the Belly River formation on the Red Deer River. Lull and Wright (1942) give Sandhill Creek for the Kritosaurus incurvimanus holotype, a different specimen.

Synonyms

  • Gryposaurus incurvimanus reassigned

    Combination used for Parks's species once it was referred to Gryposaurus, including by Gates and Sampson (2007).

  • Kritosaurus incurvimanus junior subjective

    Named by Parks (1919) from the Dinosaur Park Formation. Gates and Sampson (2007) rediagnosed it as a valid species, but Prieto-Márquez (2010) found its characters either shared with G. notabilis or indicative of subadults, and treats its specimens as subadult G. notabilis.

Gryposaurus monumentensis Gates & Sampson, 2007

Named for Grand Staircase-Escalante National Monument in southern Utah, where all referred material has been recovered.

Holotype
RAM 6797 , Raymond M. Alf Museum of Paleontology, The Webb Schools
Material
Largely articulated skull lacking most of the right side.
Horizon
middle Kaiparowits Formation, Campanian, Late Cretaceous , 83.6–72.2 million years ago
Locality
Utah, United States The Kaiparowits Formation's middle unit is informal, and Gates and Sampson (2007) place the holotype no more precisely than within the Grand Staircase-Escalante National Monument.
Diagnosis
  1. Infratemporal fenestra anteroposteriorly narrow, about half the width of the orbit (subequal to or larger than the orbit in other species).
  2. Anterodorsal process of maxilla visible through the external naris.
  3. Predentary oral margin with large, pronged, clover-shaped denticles.
  4. Anterior portion of the dentary sharply downturned.
  5. Surangular with a distinct dorsal process on its median ridge.
  6. Mandibular foramen ovoid (subcircular in other species).

Gryposaurus latidens Horner, 1992

From Latin 'latus' (wide) and 'dens' (tooth), for the unusually wide dentary tooth crowns.

Holotype
AMNH FARB 5465 , American Museum of Natural History
Material
Partial skeleton with nearly complete articulated premaxillae, partial nasals, left and fragmentary right dentaries, left surangular, left splenial, cervical, dorsal, sacral and caudal vertebrae, right sternal, both coracoids and nearly complete scapulae, left and partial right humeri, partial left ilium, nearly complete left pubis, left radius and right fibula.
Horizon
Two Medicine Formation, Campanian, Late Cretaceous , 83.6–72.2 million years ago
Locality
Near the Two Medicine River, 19 km southwest of Cut Bank, Glacier County, Montana, United States
Diagnosis
  1. Dentary tooth crowns wide and short (apicobasal length/mesiodistal width 1.7–2.2), most with a single median carina, and with coarse marginal denticulation of large papillae in the ventral and anterior dental battery.
  2. Deep, oval depression on the posterior region of the ventral surface of the premaxilla.
  3. Shallow lacrimal process of the rostral process of the jugal.
  4. Anterolateral oral margin of the premaxilla wider and more smoothly arcuate.
  5. Posterior margin of the narial fenestra wider than the depth of the proximal narial bar, with the nasal crest rising above the frontals in adults and sitting above that margin.
  6. Posteroventral margin of the rostral process of the jugal wide and shallow.
  7. Angle between the proximal margin of the dentary and the alveolar edge of the tooth row greater than 150°.
  8. Proximal constriction of the scapula narrower (minimum/maximum proximal width less than 0.60).

Synonyms of the genus

Name Type Reason
Hadrosauravus nomen nudum Informal name introduced for material now considered referable to Gryposaurus.

References

  1. Lambe, L. M. (1914). On Gryposaurus notabilis, a new genus and species of trachodont dinosaur from the Belly River Formation of Alberta, with a description of the skull of Chasmosaurus belli. The Ottawa Naturalist 27(11): 145-155. lambe1914b
  2. Gates, T. A.; Sampson, S. D. (2007). A new species of Gryposaurus (Dinosauria: Hadrosauridae) from the late Campanian Kaiparowits Formation, southern Utah, USA. Zoological Journal of the Linnean Society 151(2): 351-376. Oxford University Press (OUP). doi:10.1111/j.1096-3642.2007.00349.x

    Erects Gryposaurus monumentensis on skull RAM 6797 from the late Campanian Kaiparowits Formation of southern Utah.

    gates2007b
  3. Lull, R. S.; Wright, N. E. (1942). Hadrosaurian Dinosaurs of North America. Geological Society of America Special Papers 40: 1-272. Geological Society of America. doi:10.1130/spe40-p1 lull1942a
  4. Parks, W. A. (1920). The osteology of the trachodont dinosaur Kritosaurus incurvimanus. University of Toronto Studies, Geological Series 11: 1-74.

    Describes a row of large dermal callosities along the midline of the back in the holotype of Kritosaurus incurvimanus, now regarded as a subadult G. notabilis.

    parks1920a
  5. Prieto-Márquez, A. (2010). The braincase and skull roof of Gryposaurus notabilis (Dinosauria, Hadrosauridae), with a taxonomic revision of the genus. Journal of Vertebrate Paleontology 30(3): 838-854. Informa UK Limited. doi:10.1080/02724631003762971

    Revises the genus, sinking G. incurvimanus into G. notabilis as subadult specimens and rebutting the diagnosis of Gates and Sampson (2007).

    prieto-márquez2010d
  6. Horner, J. R. (1992). Cranial morphology of Prosaurolophus (Ornithischia: Hadrosauridae) with descriptions of two new hadrosaurid species and an evaluation of hadrosaurid phylogenetic relationships. Museum of the Rockies Occasional Paper 2: 1-119.

    Names G. latidens from the lower Two Medicine Formation of Montana.

    horner1992a
  7. Prieto-Márquez, A. (2012). The skull and appendicular skeleton of Gryposaurus latidens, a saurolophine hadrosaurid (Dinosauria: Ornithopoda) from the early Campanian (Cretaceous) of Montana, USA. Canadian Journal of Earth Sciences 49(3): 510-532. Canadian Science Publishing. doi:10.1139/e11-069

    Redescribes the G. latidens holotype and referred material, with a revised diagnosis.

    prieto-márquez2012c
  8. Paul, G. S. (2024). The Princeton Field Guide to Dinosaurs (3rd ed.). Princeton University Press.

    Source of the G. latidens body length and mass estimates.

    paul2024a
  9. Parks, W. A. (1919). Preliminary description of a new species of trachodont dinosaur of the genus Kritosaurus, Kritosaurus incurvimanus. Transactions of the Royal Society of Canada, series 3 13: 51-59. parks1919a