Early Mesozoic halecomorphs are highly diverse, but their taxonomy and phylogenetic relationships are still controversial. We describe here a new halecomorph taxon from the Late Jurassic (Kimmeridgian) Nusplingen Lithographic Limestone, southern Germany. Sanctusichthys rieteri, gen. et sp. nov., is characterized by the peculiar patterns of skull roofing bones and cephalic sensory canals, and a unique squamation made of tiny lepisosteoid-type scales with extremely or completely reduced ganoin layer. Very peculiarly, S. rieteri presents a series of bones placed between the frontals and the anamestic supraorbitals, one of them carrying a portion of the main supraorbital sensory canal between the frontal and nasal bones. These bones, here called parafrontals, are so far unknown in other actinopterygians. The new taxon resembles most closely several Late Jurassic Furo-like halecomorphs, which have been classified in the family Furidae and are currently placed in either of the controversial orders Ophiopsiformes or Ionoscopiformes. The close phylogenetic relationships between these taxa are confirmed in a cladistic analysis that retrieves Sanctusichthys within a broadly defined Ionoscopiformes, including the potentially independent Ophiopsiformes. Interestingly, these Furo-like halecomorphs are highly diverse in the Late Jurassic deposits of southern Germany, and they are especially well represented—with four species accounting for 15% of the actinopterygian taxa—in the Nusplingen quarry, which yields one of the three most diverse Jurassic assemblages of these fishes. The paleoecological significance of this high diversity can only be explored after solving the β-taxonomy and phylogenetic relationships of these Furo-like taxa.