A new genus, Siemensichthys, from the Upper Jurassic of southern Germany is described. The new genus includes two species, S. macrocephalus (Agassiz) which was formerly in the genus Pholidophorus, and S. siemensi n. sp. The two species share synapomorphies such as only one supramaxillary bone covering the dorsal margin of the maxilla. Both species are described, and their phylogenetic position is analyzed. The phylogenetic analyses, based on 27 taxa and 141 characters, show that Ankylophorus from the Kimmeridgian of Cerin, Siemensichthys and Eurycormus from the Solnhofen Lithographic Limestone of Bavaria, form a monophyletic group. The new extinct clade (preliminarily identified as the Siemensichthys-group) is proposed as the sister-group of Pholidophorus s. str. plus more advanced teleosts. This sister-group relationship is supported by eight characters (e.g., supraoccipital bone extending forward in the roof of the otic region; articular bone fused with both the angular and retroarticular; presence of an elongated posteroventral process of quadrate; presence of dorsal processes at the base of the innermost caudal rays of upper lobe; mobile premaxillary bone). Comparisons with species of Pholidophorus s. str. provide a new understanding of the genus Pholidophorus. At least four synapomorphies are proposed to support the monophyly of Pholidophorus. As a consequence of this new interpretation, the European Late Jurassic species previously assigned to the Pholidophoridae and to the genus Pholidophorus (e.g., 'Ph.' armatus, 'Ph.' falcifer, 'Ph.' micronyx, 'Ph.' microps) should be reexamined because they do not belong to the family nor to the genus. The order Pholidophoriformes Berg is not a monophyletic group as currently constructed. Therefore, all so-called pholidophoriforms are in need of revision.