The hardest thing to figure out about extinct animals is the position of the shoulder girdle, because it hangs independently of the vertebrae column, unlike the hips, which are tightly fixed. Walking dinosaur costume Well-articulated specimens can help out, but even here some displacement of the forelimb might have occumed. The shoulder girdle usually attached to the second long trunk rib via a short and often cartilagenous sternal rib, so when the anterior ribs are properly swept back, we are better able to work out its positioning. In general, it seems that the anterior edge of the shoulder girdle was set just below the juncfure of the neck and trunk vertebrae in big theropods. In smaller theropods it was set further back by a vertebrae or so, the effect making the neck longer. In birds, the coracoid, the bone below the shoulder joint, is very long. Animatronic dinosaur for sale This sets the shoulder joint high on the chest, and makes the shoulder blade horizontal. The protobird theropods were also built this way. But most theropods had more normal, short coracoids, so the shoulder joint was set low and the shoulder blade was much more vertical.
Not much is known of the chest or sternal plates in theropods. Realistic dinosaur costume The few that have been discovered are usually small, aIthough a few protobird theropods had big, birdlike sternums. Elizabeth Nicholls and Anthony Russell showed in 1985 that an extra sternal process, little and slender, is attached to the back of the sternum; in protobirds and birds this becomes fused to the sternal plates. The clavicles of most theropods are as poorly known as the sternals. Some theropods and birds lack clavicles entirely, or they may be small, separate, and paired like in SeEscurus. In some protobirds and most trirds, they are quite the opposite, having enlarged and fused riogether into a kind of “wishbone” furcula . In 1984, Richard Thulborn argued a good case for allosaurs and tyrannosaurs having slender furculas, but since no such furcula has been found in place, I am not convinced. Especially since displaced and cojoined abdominal ribs can look very much like a furcula.