Animal Phyla/Gnathostomulida

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

Gnathostomula paradoxa, a jaw worm.

Natural History

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

Taxonomy

There are two recognized orders within the Phylum Gnathostomulida.

• Filospermoidea
• Bursovaginoidea

Anatomy

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 Record

There is no known fossil record.

Quiz

• Gnathostomulida Quiz

References and Further Reading

• [Gnathostumulida] at Wikipedia
• Gnathostumulida at Tree of Life
• Gnathostumulida at Encyclopedia of Life