Introduction -- General taxonomy -- Upper Palaeozoic fossil locality in the Oslo Region -- Descriptions -- Morphologic comparisons and discussions -- Phylogeny and taxonomy of osteolepiforms -- A phylogenetic model -- A systematic model.
The group of fishes called Osteolepiformes is of great interest as they are generally accepted ancestors of probably all tetrapods. Since also considered primitive it is a central group in the study of vertebrate evolution. This work includes the following: (1) an introductory part discussing the genral taxonmy of osteolepiforms, as used by other authors and as used in this work; terminological problems; a review of the stratigraphic background as well as surrounding fauna and flora of a new probably Late Carboniferous genus from Norway, and a review of material and methods; (2) a descriptive part treating macrostructures of mainly four groups: the new probably Late Carboniferous Norwegian taxon, Carboniferous material from Great Britain referred to Magalichthys Agassiz, 1835, Late Devonian material from Balticum and Bergisch Gladbach in Germany referred to different species of Latvius Jarvik, 1948, and Middle Devonian material from Great Britain and northeast Greenland, referred, respectively to Osteolepis macrolepidotus Agassiz, 1835, Gyroptychius milleri Jarvik, 1848 and Gyroptychius groenlandicus Jarvik, 1950a; a discussion of variation and possible trends in osteolepiform morphology as well as some functional interpretations of the morphology. This part also includes new descriptions of material of Eusthenopteron foordi Whiteaves, 1881 and Panderichthys rhombolepis (Gross, 1930); and (4) a phylogenetic and taxonomic part that includes a discussion of concepts and methods in the study of phylogeny and taxonomy, a suggested phylogenetic model for osteolepiforms, and a resulting likewise tentative taxonomic model of osteolepiforms with some suggested amended diagnoses.