- Name Meaning: Hair stomach
- English Common Name: Meiofauna, gastrotrichs, hairybacks
- Two terminal adhesive tubes
- Approximate number of species described: about 690
They are aquatic, and occur in fresh and marine waters, though a few live on land, in the liquid that surrounds soil particles. Their habitat is similar in the water, living around the particles on the bottom, or in the material that falls to the bottom.
They eat detritus.
Their lifespans are extremely short, they live only a few days.
The Phylum has been divided into two orders.
- Order Chaetonotida
- Order Macrodasyida
Worm-like, gastrotrichs have a head region housing a brain and sensory organs, and a trunk with a simple digestive system and reproductive organs.
They have adhesive glands that help them attach to solid surfaces.
The Fossil Record
With a size maximum of 3 mm (0.118 in), and being soft bodied, they're unlikely to have fossilized and no fossils are known.