Open Paleo

Eotriceratops

Wu et al., 2007 EE-oh-tri-SEH-ruh-tops

From Greek eos (dawn) + treis (three) + keras (horn) + ops (face): 'dawn three-horned face', marking it as an early relative of Triceratops.

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

Eotriceratops is a genus of herbivorous ceratopsian dinosaurs which lived in the area of North America during the late Cretaceous period. The only named species is Eotriceratops xerinsularis.

Diagnosis

  1. Tall lamina-like narial process of premaxilla lacking any fossa or recess, with dorsal margin well above ventral border of interpremaxillary fenestra.
  2. Epoccipitals of squamosal frill extremely elongate, spindle-shaped (length/width ratio ~10:1), contacting each other along the frill margin.
  3. Well-demarcated elliptical depression or fossa with thickened borders on the anteroventral surface of the squamosal frill.
  4. Oblique vascular trace on anterior surface of nasal horn core meeting a transverse vascular trace ventrally.
  5. Sharply conical epijugal with pronounced proximoposterior process and separate fossa-like articular facets for jugal and quadratojugal on its proximal surfaces.

Species

Eotriceratops xerinsularis Wu et al., 2007

Type species

From Ancient Greek 'xeros' meaning 'dry' and Latin 'insula' meaning 'island', a reference to the Dry Island Buffalo Jump Provincial Park in Alberta, Canada, where the holotype was found.

Holotype
TMP 2002.057.0007 , Royal Tyrrell Museum of Paleontology
Material
Incomplete and disarticulated skeleton including right rostral, both premaxillae, both maxillae, left supraorbital horn core with lacrimal, prefrontal, frontal, postorbital and jugal, left epijugal, right quadratojugal, left quadrate, partial parietal, left squamosal frill, braincase, syncervical, cervicals 4 and 5, posterior cervicals, anterior dorsals, some ribs and ossified ligaments.
Horizon
middle Carbon Member, Horseshoe Canyon Formation, Maastrichtian, Late Cretaceous , 72.2–66.0 million years ago
Locality
Dry Island Buffalo Jump Provincial Park, Alberta, Canada Eberth and Kamo (2020) place the holotype "in the middle Carbon Member", 13.5 m above the member's base.

References

  1. Wu, X. C.; Brinkman, D. B.; Eberth, D. A.; Braman, D. R. (2007). A new ceratopsid dinosaur (Ornithischia) from the uppermost Horseshoe Canyon Formation (upper Maastrichtian), Alberta, Canada. Canadian Journal of Earth Sciences 44(9): 1243-1265. Canadian Science Publishing. doi:10.1139/e07-011 wu2007a
  2. Eberth, D. A.; Kamo, S. L. (2020). High-precision U-Pb CA-ID-TIMS dating and chronostratigraphy of the dinosaur-rich Horseshoe Canyon Formation (Upper Cretaceous, Campanian- Maastrichtian), Red Deer River valley, Alberta, Canada. Canadian Journal of Earth Sciences.

    Places the holotype 13.5 m above the base of the Carbon Member, converting the describing paper's informal unit 5.

    eberth2020a