| Ptychagnostidae Temporal range:
| |
|---|---|
| |
| Ptychagnostus gibbus | |
| |
| Ptychagnostus cuyanus | |
Scientific classification 
| |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | †Trilobita (?) |
| Order: | †Agnostida |
| Superfamily: | †Agnostoidea |
| Family: | †Ptychagnostidae Kobayashi, 1939 |
| Type genus | |
| Ptychagnostus Jaekel, 1909
| |
| Genera | |
|
See text | |
Ptychagnostidae is a family of agnostid trilobites from the 5th Stage to the Paibian Age of the Cambrian (509 to 497 million years ago).[1] The family includes several important index fossils.