Phytosaurian Nomenclature: Parasuchia, Phytosauria or Belodontia?

The nomenclatural status of Phytosaurus Jæger is here analyzed in accordance with the International Code of Zoological Nomenclature. In the past, several authors have interpreted it as both a family-group and/or a genus-group name, but each of these approaches fails in several articles of the Code. Phytosaurus Jæger is here interpreted as originally established for a collective-group and cannot be used as a nominal genus in binomina, but takes precedence over any other younger homonym, and the first available one is Phytosaurus Wagler. Being an invalid junior homonym, the class-group name Phytosauria Baur and the family-group name Phytosauridae Lydekker, which are based on Phytosaurus Wagler, are ultimately rejected. Conversely, the class-group names Parasuchia Huxley and Belodontia Brauns, as well as the family-group name Belodontidae Cope, are older but have some taxonomic restrictions in relation to Belodon plieningeri Meyer. To avoid proposing new names for old ones, the solution to fix the higher-order nomenclature for phytosaurs is to designate a neotype for Belodon plieningeri Meyer. Keywords: Parasuchia, Phytosauria, Belodontia, Archosauriformes, Triassic, collective-group.