Julfanautilidae Korn & Ghaderi 2025

Family Julfanautilidae Korn & Ghaderi, 2025 Diagnosis Family of the superfamily Liroceratoidea with a usually pachyconic, subinvolute to involute conch. Whorl profile in the adult stage usually more or less strongly depressed; flanks and venter usually separated by distinct ventrolateral shoulder, venter or concave. Umbilical margin subangular or angular; umbilical wall steep, flattened. Ornament usually consisting of fine growth lines. Septum simple in shape, concavely domed; suture line with shallow lobes on venter and flank (from Korn & Ghaderi 2025). Included genera Julfanautilus Korn & Ghaderi, 2025 (Wuchiapingian); Baghuknautilus gen. nov. (Wuchiapingian); Shahrezanautilus gen. nov. (Wuchiapingian). Remarks The family Julfanautilidae is characterised by a combination of characters not found in any other family of Palaeozoic nautilids. This is the combination of a rather stout conch with a very pronounced umbilical margin and also sometimes pronounced ventrolateral shoulder. While the first character suggests a placement in the superfamily Liroceratoidea, the second and third characters show a closer morphological relationship to the superfamilies Pleuronautiloidea and Grypoceratoidea. Unfortunately, the early ontogenetic development of the conch in the species of the Julfanautilidae is not known. However, the material shows that the pronounced umbilical margin is present early in ontogeny and that this feature can therefore be considered apomorphic, whereas the ventrolateral shoulder does not assume a subangular shape until a late ontogenetic stage, if at all. Therefore, these forms are included here as a new family of the superfamily Liroceratoidea (from Korn & Ghaderi 2025).