Animal Phyla/Gnathostomulida

Gnathostomula paradoxa, a jaw worm.

Gnathostomulida Name Meaning: Jaw orifice English Common Name: Jaw worms Major distinguishing characteristics: Approximate number of species described: about 300

Natural HistoryEdit

Jaw worms are all aquatic and marine. They live in the sand and mud in shallow coastal waters.


There are two recognized orders within the Phylum Gnathostomulida.

  • Filospermoidea
  • Bursovaginoidea


The powerfully jawed mouth is just behind the head end and opens into a blind-ending tube. There is no anus. They have no circulatory or respiratory system.

They are hermaphroditic, with one ovary and two testes.

The Fossil RecordEdit

There is no known fossil record.


References and Further ReadingEdit