Examination of the original types and abundant topotype specimens from the Emanuel Formation (Early Ordovician) and the correlative subsurface Nambeet Formation of the Canning Basin in Western Australia confirms a septimembrate species apparatus for Protoprioniodus simplicissimus, the type species of the genus. Species of Protoprioniodus are characterized by having a seximembrate or septimembrate protoramiform–protopectiniform apparatus with a distinctive basal surface well-developed between the basal margin and the basal flange in the constituent elements. The generic concept of Protoprioniodus is re-defined based on its type species and reassessment of all the species previously assigned to this genus. Protoprioniodus might be evolved in late Tremadocian (Early Ordovician) possibly from an unknown species of basal Oistodus. With five species confirmatively assigned to, Protoprioniodus is recognized as a morphologically distinctive conodont clade within family Oistodontidae and biostratigraphically useful for correlation of the uppermost Tremadocian to Middle Ordovician rocks. Protoprioniodus simplicissimus was cosmopolitan while other species seem variably restricted in palaeogeographic distribution.

对来自西澳大利亚坎宁盆地伊曼纽尔组（早奥陶世）和相关地下 Nambeet 组的原始类型和丰富的拓扑型标本的检查证实了该属的模式种Protopriionodus simplicissimus存在七膜物种装置。Protopprioniodus物种的特征是具有六膜或七膜原鸟状-原扇菌状装置，其构成元件中的基部边缘和基部凸缘之间具有明显发达的基部表面。Protoprianodus的属属概念是根据其模式种以及对先前分配给该属的所有物种的重新评估而重新定义的。原虾属可能是在特雷马多世晚期（奥陶世早期）进化而来，可能是从一种未知的基底Oistodus物种进化而来。Protoprianodus已被确认为 5 个物种，被认为是 Oistodontidae 科中形态独特的牙形石进化枝，在生物地层学上可用于将最上面的特雷马多克阶岩石与中奥陶纪岩石进行对比。Protoprianodus simplicissimus是世界性的，而其他物种似乎在古地理分布上受到不同程度的限制。