Open Paleo

Denversaurus

Bakker, 1988 DEN-ver-SAWR-us

From "Denver" (for the City of Denver and the Denver Museum of Natural History, which holds the holotype) and Greek "sauros" (lizard); meaning "Denver lizard".

72.2–66.0 million years ago Maastrichtian, Late Cretaceous
Late Cretaceous stages

Denversaurus is a genus of panoplosaurin nodosaurid dinosaur from the late Maastrichtian of Late Cretaceous Western North America. Although at one point treated as a junior synonym of Edmontonia by some taxonomists, current research indicates that it is its own distinct nodosaurid genus.

Diagnosis

  1. Orbits and postorbital boss displaced far posteriorly, with orbital center lying above the posterior edge of the suborbital flare and the boss apex crowded close to the paroccipital tip in dorsal view
  2. Lateral temporal fenestra reduced to a narrow slit in lateral view, due to extreme posterior orbital displacement
  3. Basituberal rugosities expanded to cover nearly the entire ventral surface of the basicranium between the condyle and basipterygoid process, with muscle scars extending alongside the condyle on either side
  4. Internal nares shifted far posteriorly

Species

Denversaurus schlessmani Bakker, 1988

Type species

Named for the Schlessman Family Foundation, which funded dinosaur research at the Denver Museum of Natural History.

Holotype
DMNH 468 , Denver Museum of Nature and Science
Material
Nearly complete skull, several teeth, and some small bony armor plates.
Horizon
lower Hell Creek Formation, Maastrichtian, Late Cretaceous , 72.2–66.0 million years ago
Locality
South Dakota, United States

Notable specimens

  • “Tank”

    FPDM-V9673, BHI 127327 Fukui Prefectural Dinosaur Museum Found 1988 complementary

    Referred partial nodosaurid skeleton nicknamed Tank from the Lance Formation of Niobrara County, Wyoming, comprising a fragmentary skull, parts of the postcranial skeleton, and 75 osteoderms, preserving postcranial anatomy absent in the skull-and-armor-only holotype.

    Derstler (1994)Carpenter et al. (2013)Sonoda & Noda (2016)

References

  1. Bakker, R. T. (1988). Review of the Late Cretaceous nodosauroid Dinosauria: Denversaurus schlessmani, a new armor-plated dinosaur from the Latest Cretaceous of South Dakota, the last survivor of the nodosaurians, with comments on Stegosaur-Nodosaur relationships. Hunteria 1(3): 1-23. bakker1988a
  2. Brown, B.; Schlaikjer, E. M. (1943). A study of the troödont dinosaurs with the description of a new genus and four new species. Bulletin of the American Museum of Natural History 82(5): 115-150.

    Equates the "Lance formation" label carried by Corson County specimens of this era with the Hell Creek beds.

    brown1943a
  3. Bruns, M. E. (2015). Intraspecific variation in the armoured dinosaurs (Dinosauria: Ankylosauria). Doctoral thesis, University of Alberta. doi:10.7939/R39K46485

    PhD thesis on ankylosaur intraspecific variation, supporting Denversaurus as distinct from Edmontonia.

    bruns2015a
  4. Raven, T. J.; Barrett, P. M.; Joyce, C. B.; Maidment, S. C. R. (2023). The phylogenetic relationships and evolutionary history of the armoured dinosaurs (Ornithischia: Thyreophora). Journal of Systematic Palaeontology 21(1): 2205433. doi:10.1080/14772019.2023.2205433

    Thyreophoran phylogeny supporting Denversaurus as a genus distinct from Edmontonia.

    raven2023a
  5. Soto-Acuña, S.; Vargas, A. O.; Kaluza, J. (2024). A new look at the first dinosaur discovered in Antarctica: reappraisal of Antarctopelta oliveroi (Ankylosauria: Parankylosauria). Advances in Polar Science 35(1): 78-107. doi:10.12429/j.advps.2023.0036

    Antarctopelta reappraisal whose phylogeny supports Denversaurus as distinct from Edmontonia.

    soto-acuña2024a
  6. Paul, G. S. (2024). The Princeton Field Guide to Dinosaurs (3rd ed.). Princeton University Press.

    Source of the length and mass estimates.

    paul2024a
  7. Derstler, K. (1994). Dinosaurs of the Lance Formation in eastern Wyoming. The Dinosaurs of Wyoming 127-146. Wyoming Geological Association.

    Wyoming Geological Association Guidebook, 44th Annual Field Conference. Initial description of the Tank specimen.

    derstler1994a
  8. Carpenter, K.; DiCroce, T.; Kinneer, B.; Simon, R. (2013). Pelvis of Gargoyleosaurus (Dinosauria: Ankylosauria) and the origin and evolution of the ankylosaur pelvis. PLOS ONE 8(11): e79887. doi:10.1371/journal.pone.0079887 carpenter2013a
  9. Sonoda, T.; Noda, Y. (2016). Transfer of museum collection from the Hayashibara Museum of Natural Sciences to the Fukui Prefectural Dinosaur Museum. Memoir of the Fukui Prefectural Dinosaur Museum 15: 93-98. sonoda2016a
  10. Carpenter, K.; Breithaupt, B. (1986). Latest Cretaceous occurrence of nodosaurid ankylosaurs (Dinosauria, Ornithischia) in western North America and the gradual extinction of the dinosaurs. Journal of Vertebrate Paleontology 6(3): 251-257. doi:10.1080/02724634.1986.10011619

    Original description of the holotype as Edmontonia sp., placing it in the lower Hell Creek Formation of Corson County.

    carpenter1986a