GEOL 305 Lecture Notes - Lecture 5: Tatisaurus, Lower Lufeng Series, Osteoderm
11 Nov 2016
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Document Summary
The basic characteristic which defines an ornithiscian dinosaur (as opposed to a. Surischian dinosaur) is the general configurations of pelvic bones. In ornithiscians at least part of pubis has been rotated backward to lie close to ischium; orientation is called opisthopubic. (in saurischians, both parts of the pubis point forward). Actual shape of pubis, illium, & ischium & how they are configured can be different depending on the type of ornithiscian studied. Characteristics of pelvis & how they fit together, is no doubt correlated w/ the stance & movement. Ornithischian dinosaurs came in both bipedal & quadrupedal modes of stance. Some are obligate quadrupeds, meaning they must walk / move on all 4 limbs. Some can move in both ways, depending on speed or behavior. Hadrosaurs walked on all fours when moving slowly (eating) Have many shared skull characteristics, which may not be exactly alike. Predentary = unpaired, scoop-shaped bone that capped front of lower jaw.
