Exploring the Intertidal

Check out the intertidal zone and its biodiversity!

Urochordata

Although they just look like slimy sacs, tunicates or sea squirts, are more closely related to humans than any other invertebrate group. This is because larval tunicates have several chordate structures - including a nerve chord and a notochord. These are later lost in most adult forms. Two openings are found on the tunicate: the buccal siphon (water comes in) and the atrial siphon (water goes out). Sea squirts got their name because a gentle squeeze will cause water to shoot out of their atrial siphon! The sedentary adult forms can either be solitary or colonial. A cool fact about tunicates is that they have a long, tubular heart that contracts in two directions!

the soliary ascidian body plan

Cnemidocarpa finmarkiensis (Shiny Red Tunicate)
Description:Bright red or orange with smooth surface.
Range: Alaska to Point Conception, California.
Habitat: Exposed, rocky shores. Low intertidal to 50m.
Cool Fact: Can live up to 540m deep!

Styela montereyensis (Stalked Tunicate)
Description: Red-orange. Vertical grooves.
Range: Vancouver Island to Baja, California.
Habitat: Sheltered and exposed rocky shores. Low intertidal to 30m.
Cool Fact: Grow larger in sheltered areas. Up to 23cm in 3 years!

 to Intertidal Field Guide directory