Seismosaurus Hip - Vertebrae and Ilium

Hip fossil, vertebrae and ilium
Pronunciation: SIZE-mo-sore-us
Meaning: Earth-shaking lizard
Specimen Number: NMMNH P-3690
Location: Sandoval County, New Mexico
Image By: Isaac T Valdez

Paleontologists distinguish the two main groups of dinosaurs by hip structure. They refer to the pelvis of Seismosaurus as "lizzard-hipped" or saurischian (sore-ISH-ee-an) because it resembles the pelvis of a modern lizard. In contrast, paleontologists term the pelvis of Stegosaurus "bird-hipped" or orinthischian (or-nith-ISH-ee-an) because it somewhat resembles the pelvis of a living bird.

Paleontologists compared the hip and back bones of Seismosaurus to the complete skeleton of the closely-related dinosaur Diplodocus to reconstruct the skeleton of Seismosaurus exhibited here.