The intervertebral joint of the longnose gar, Lepisosteus osseus

The intervertebral joint of the longnose gar has been examined by differential histological staining techniques and by scanning electron microscopy. The joint was found to be transitional, being neither a true diarthrosis nor a synchondrosis. The articular cartilage was found to consist of two layers, a superficial layer of fibrocartilage and a deeper layer of hyaline cartilage. The joint cavity was partially filled with fibrocartilaginous adhesions, the number of which varied from joint to joint.The degree of movement in each joint was minimal, in keeping with the heavily armored exoskeleton.