Abstract

Many Lepidotes species were recorded worldwide during most parts of the twentieth century, even in the Brazilian sedimentary basins. Among the Brazilian sedimentary basins, the Late Jurassic "L." piauhyensis is one the best described, especially because the relatively great amount of well-preserved and articulated specimens. As suggested in the most recent phylogenetic analysis, Lepidotes should be restrict to the Lower Jurassic of Central Europe and all the Lepidotes species recorded beyond this interval belong to other genera. Herein "L." piauhyensis was revised and presents new morphological and ontogenetic information, which allow us to propose a new genus, Quasimodichthys. This study reveals additional characters that Quasimodichthys piauhyensis shares with Hoyasotes tanyrhis, Lepidohyas microrhis and Neosemionotus puntanus. Additionally, four distinct ontogenetic stages were observed in Quasimodichthys piauhyensis, juvenile (1 and 2), sub-adult, and adult.