Polymorphida
| Polymorphida | |
|---|---|
| Corynosoma wegeneri | |
| Scientific classification | |
| Domain: | Eukaryota | 
| Kingdom: | Animalia | 
| Phylum: | Acanthocephala | 
| Class: | Palaeacanthocephala | 
| Order: | Polymorphida Petrochenko, 1956 | 
Polymorphida are an order of thorny-headed worms (phylum Acanthocephala). The adults of these parasitic platyzoans feed mainly on fish and aquatic birds.
This order contains 5 families:
- Centrorhynchidae Van Cleave, 1916
- Isthomosacanthidae Smales, 2012
- Plagiorhynchidae Meyer, 1931
- Pyriprobosicidae
- Polymorphidae Meyer, 1931