ABSTRACT
The postcranial skeleton forms the framework of the body and functions in support and movement. It can be divided into two components. First, the axial skeleton lies in the longitudinal axis of the body and consists of the notochord, vertebral column, median fins, ribs and intermuscular bones. Second, the appendicular skeleton consists of the pectoral and pelvic girdles and their corresponding fins. In general, the notochord forms the hydrostatic skeleton for the developing embryo. It extends from the skull to the tip of the tail and serves as the foundation for the developing vertebral column. In gonorynchiforms, as well as in other fishes, the notochord and its obliterations set the path along where each centrum will form. Ostariophysan fishes are known for specializations of the anterior vertebral column. The most well-known specialization, diagnostic of the Otophysi, is the Weberian apparatus.
