Pyrirhynchus is a genus of thorny-headed worms.

It is the only genus in the order Heteramorphida and family Pyrirhynchidae.

It contains a single species Pyrirhynchus heterospinus.

[1] It was found in the common sandpiper (Actitis hypoleucos) in Quang Ninh Province, Vietnam.

The proboscis contains 17 to 20 rows of 17 to 19 hooks each, with anterior 9-11 hooks rooted and posterior 6-10 spines without roots.