Mechanical preparation of a specimen of Eusthenopteron foordi has revealed the articulated anterior portion of the vertebral column, allowing for a comprehensive redescription and analysis of this region. Neural arches are smaller than more posterior trunk segments, and do not fuse dorsally as neural spines. Incipient zygapophyses occur lateral or ventrolateral to the nerve cord. Intercentra are paired, but do fuse in some specimens. Large blade-like supraneural spines are present above neural arches 1, 3, and 5, but not 2 or 4. The supraneural spines supported a muscular complex involved in feeding not only through raising the snout, but also by depression of the lower jaws induced by the forward swing of the quadrate. Flexion of the intracranial joint is likely responsible for the initiation of jaw closure during feeding.
Vertebrata; Sarcopterygii; Osteolepiformes; Devonian; Canada; Functional anatomy