Open Paleo

Marshosaurus

Madsen, 1976 MARSH-o-SAWR-us

Named for Othniel Charles Marsh, the pioneering American paleontologist, combined with Greek '-saurus' meaning 'lizard'.

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

Marshosaurus is a genus of carnivorous theropod dinosaur, belonging to the family Piatnitzkysauridae, from the Late Jurassic Morrison Formation of Utah and possibly Colorado.

Diagnosis

  1. Ilium with heavy construction, long low posterior blade, stout pubic peduncle with divided articular surface
  2. Pubic peduncle articular surface divided into anterior and posterior concavities separated by median ridge
  3. Interdental plates separated to their base in maxilla
  4. Maxilla with divided sinus having two lateral fenestrae
  5. Four premaxillary teeth, 15-16 maxillary teeth, 21-22 dentary teeth
  6. Pubis long, slender, anteriorly bowed with teardrop-shaped distal foot

Species

Marshosaurus bicentesimus Madsen, 1976

Type species

Named in honor of the bicentennial of the United States of America, as the species was described around the time of the 1976 American bicentennial celebrations.

Holotype
UMNH VP 6373 , Utah Museum of Natural History
Material
Left ilium with referred cranial and postcranial elements including premaxilla, maxillae, dentaries, pubis, and ischia.
Horizon
Brushy Basin Member, Morrison Formation, Kimmeridgian–Tithonian, Late Jurassic , 154.8–143.1 million years ago
Locality
Cleveland-Lloyd Dinosaur Quarry, Utah, United States

References

  1. Madsen, J. H. (1976). A Second New Theropod Dinosaur from the Late Jurassic of East Central Utah. Utah Geology 3(1): 51-60. Utah Geological Survey. doi:10.34191/ug-3-1_51

    Gives the holotype's coordinate and places it in the Brushy Basin Member, 150 feet below its top.

    madsen1976a