Juvenile specimens ofEusthenopteron foordiWhiteaves, 1881 (osteolepiform rhipidistian, Pisces) from the Late Devonian of Miguasha, Quebec, Canada

A size series of thirty-five specimens of Eusthenopteron foordi Whiteaves, 1881, shows isometric and allometric changes. As in Recent fishes, the main difference between small (juvenile) and large (adult) specimens is the relative size of the orbit and of the head. The large relative decrease of the orbit diameter from 31% to 12–7% of head length (b = 0.632) explains the positive allometric growth of bones surrounding the orbit, i.e., the change from a palaeoniscoid-like juvenile to a typical rhipidistian with an elongated postorbital region. With the exception of the caudal prolongation, all fin positions remain isometric to standard length.