Tentaclostoma (lit. "tentacle mouth") are a clade of Gastrozoa from which all mobile Anthostomes descend.
Tentaclostomes first emerged around 4082ma, evolving from Gastrozoans which developed into mobile, bilaterially symmetrical animals as a result of neoteny. Of the various branches of the Anthostoma phylum, the Tentaclostomes are the most thoroughly explored.
As Gastrozoans, Tentaclostomes have a single orifice, from which they eat, release waste, and excrete sex cells. Tentaclostomes have a total of 14 limbs: eight of these are used for locomotion, while the other six are oral tentacles used for feeding. They possess two sensory stalks, each of which are tipped with three eyes.
There are two branches of the Tentaclostome clade:
- Lithostraca: Comprises all marine Tentaclostomes
- Neostoma: Comprises terrestrial and amphibious Tentaclostomes