Open Paleo

Mymoorapelta

Kirkland & Carpenter, 1994 mie-MOHR-a-PEL-ta

Named after the Mygatt-Moore Quarry (combining the names of its discoverers) combined with Greek 'pelta' (shield); meaning 'shield from the Mygatt-Moore Quarry'.

154.8–143.1 million years ago Kimmeridgian–Tithonian, Late Jurassic
Late Jurassic stages

Mymoorapelta is a nodosaurid ankylosaur from the Late Jurassic (Kimmeridgian-Tithonian, around 155 to 150 million years ago) Morrison Formation (Brushy Basin Member) of western Colorado and central Utah, USA. The animal is known from a single species, Mymoorapelta maysi, and few specimens are known. The most complete specimen is the holotype individual from the Mygatt-Moore Quarry, which includes osteoderms, a partial skull, vertebrae, and other bones. It was initially described by James Kirkland and Kenneth Carpenter in 1994. Along with Gargoyleosaurus, it is one of the earliest known nodosaurids.

Diagnosis

  1. Centra of dorsal vertebrae cylindrical
  2. Anterior dorsal vertebrae with triangular pit between prezygapophyses
  3. Transverse processes not steeply angled upward
  4. Prezygapophyses of proximal caudal vertebrae small, anteroposteriorly elongate, widely separated, divergent
  5. Ribs triangular in cross section rather than T- or L-shaped
  6. Olecranon process broad and massive
  7. Preacetabular process of ilium curves lateroventrally
  8. Antitrochanter absent
  9. Cervical dermal spine with groove extending from base to tip
  10. Triangular caudal plates with base proportionally shorter relative to height

Species

Mymoorapelta maysi Kirkland & Carpenter, 1994

Type species

Named for Chris Mays, president of the Dinamation International Corporation and Society, who funded the initial excavation of the Mygatt-Moore Quarry where the holotype was found.

Holotype
MWC 1815 , Museums of Western Colorado, Dinosaur Journey
Material
Complete left ilium with numerous grooves interpreted as tooth marks over dorsal surface
Horizon
middle Brushy Basin Member, Morrison Formation, Kimmeridgian–Tithonian, Late Jurassic , 154.8–143.1 million years ago
Locality
Mygatt-Moore Quarry, Colorado, United States

Notable specimens

  • Cactus Park specimen

    MWC 2610 Museums of Western Colorado, Dinosaur Journey exceptional preservation

    Partial skeleton from Cactus Park, Colorado, preserving sacrum, caudals, chevrons, pes, and dermal armor with a more complete sacral shield about 70 cm wide. Its articulated pes and sacral shield make it the only known articulated specimen, and at about 3 meters the largest described individual.

    Foster (2007)Kirkland et al. (1998)

References

  1. Kirkland, J. I.; Carpenter, K. (1994). North America's first pre-Cretaceous ankylosaur (Dinosauria) from the Upper Jurassic Morrison Formation of western Colorado. Brigham Young University Geology Studies 40: 25-42. kirkland1994a
  2. Jones, B. (2026). The Princeton Encyclopedia of Dinosaurs: Ornithischians. Princeton University Press.

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

    jones2026a
  3. Foster, J. (2007). Jurassic West: The Dinosaurs of the Morrison Formation and Their World. 327-329. Indiana University Press, Bloomington. foster2007a
  4. Kirkland, J. I.; Carpenter, K.; Hunt, A. P.; Scheetz, R. D. (1998). Ankylosaur (Dinosauria) specimens from the Upper Jurassic Morrison Formation. The Upper Jurassic Morrison Formation: An Interdisciplinary Study 22: 145-177.

    Published in Modern Geology, volume 22.

    kirkland1998d