The second piece of evidence reinforced the first. Crocodilians and chameleon lizards had a semi-erect gait, and when I measured their shoulder joints oriented to a side view, I found that both of these reptiles displayed a joint which slanted so that it faced slightly downward as well as outward and the upper edge of the joint overhung the lower edge. (dinosaur park manufacturer)Fully sprawling lizards didn’t exhibit a trace of this downward slant. On the other hand, dinosaurs all manifested very strong downward slants, so that their entire shoulder socket had been reoriented from the primitive arrange-ment. (life like dinosaur)This strong downward orientation meant that the dinosaur’s upper arm could swing fore to aft in an upright stride. And the upward force of this limb’s stroke would be braced against the downward-facing shoulder socket.
Finally, there was the acid test of fossil footprints. (real size dinosaur)Quadrupedal dinosaur footprints aren’t as common as those left by bipedal types, but each and every set of four-legged footprints showed forepaws working on a very narrow track. Triceratops and the rest of the four-legged Dinosauria did not splay their forelimbs. Marsh had been right in the 1890s, Lull wrong in the 1930s.