Open Paleo

Nevadadromeus

Bonde et al., 2022 nuh-VAH-duh-DROH-me-us

Named after Nevada, the US state where it was found, combined with Greek 'dromeus' (runner); meaning 'Nevada runner'.

100.5–93.9 million years ago Cenomanian, Late Cretaceous
Late Cretaceous stages

Nevadadromeus is an extinct genus of small thescelosaurine ornithischian dinosaur, from the Willow Tank Formation of Nevada, United States. The genus contains a single species, N. schmitti, which represents the first non-avian dinosaur named from Nevada.

Under dispute

Nevadadromeus is a thescelosaurid whose subfamily placement is unresolved. Its describers favor Thescelosaurinae on femoral characters, their analysis yielding no consistent result (Bonde and colleagues, 2022), whereas Fonseca and colleagues (2024) recover it within Orodrominae.

Diagnosis

  1. Femoral head projects from plane of shaft at angle slightly more obtuse than 100° and sits slightly above level of greater trochanter
  2. Femoral neck with little constriction nor tuberosities
  3. Greater trochanter anteroposteriorly expanded, robust, and slightly concave on lateral surface
  4. Lesser trochanter separated from greater trochanter by prominent and deep intertrochanteric notch, reaching triangular apex at roughly same level as top of greater trochanter
  5. Lesser trochanter base projects anteriorly away from greater trochanter, sweeping posteriorly toward it along its length

Species

Nevadadromeus schmitti Bonde et al., 2022

Type species

Named for geologist James G. Schmitt, who initially described the geology of the Willow Tank Formation where the holotype was found.

Holotype
NSC 2008-002 , Nevada Science Center
Material
Proximal left femur, proximal right femur, four complete vertebral centra, three pedal unguals, two complete pedal phalanges, unidentified fragments, and fragments of ossified tendons.
Horizon
upper Willow Tank Formation, Cenomanian, Late Cretaceous , 100.5–93.9 million years ago
Locality
Valley of Fire State Park, Nevada, United States

References

  1. Bonde, J. W.; Hall, R. L.; Krumenacker, L. J.; Varricchio, D. J. (2022). Nevadadromeus schmitti (gen. et sp. nov.), a New Basal Neornithischian with Affinities to the Thescelosaurinae, from the Upper Cretaceous (Cenomanian) Willow Tank Formation of Southern Nevada. Journal of the Arizona-Nevada Academy of Science 50(1). JANAS. doi:10.2181/036.050.0101

    Named Nevadadromeus and favored Thescelosaurinae on femoral characters.

    bonde2022a
  2. Fonseca, A. O.; Reid, I. J.; Venner, A.; Duncan, R. J.; Garcia, M. S.; Müller, R. T. (2024). A comprehensive phylogenetic analysis on early ornithischian evolution. Journal of Systematic Palaeontology 22: 2346577. doi:10.1080/14772019.2024.2346577

    Recovered Nevadadromeus within Orodrominae.

    fonseca2024a
  3. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Ornithischians. Princeton University Press.

    Treats Nevadadromeus as a thescelosaurine.

    jones2026a