†Ptychagnostus (Ptychagnostus) Jaekel 1909 (artiopod)
Artiopoda - Agnostida - Ptychagnostidae
Parent taxon: Ptychagnostus according to S. R. Westrop et al. 1996
Sister taxa: Ptychagnostus (Acidusus), Ptychagnostus acidusus, Ptychagnostus affinis, Ptychagnostus akanthodes, Ptychagnostus aksayensis, Ptychagnostus atavus, Ptychagnostus convexus, Ptychagnostus cuyanus, Ptychagnostus intermedius, Ptychagnostus karatauensis, Ptychagnostus punctuosus, Ptychagnostus richmondensis, Ptychagnostus seminula, Ptychagnostus sinicus, Ptychagnostus spinosus, Zeteagnostus scarifatus, Zeteagnostus incautus, Triplagnostus (Aristarius) aristarius
Subtaxa: none
Ecology: nektonic suspension feeder
Distribution: found only at USGS 4341-CO - Hillard Limestone, Hilliard Peak area (Cambrian of Alaska)