Distaplia smithi Abbott & Trason 1968

How to Distinguish from Similar Species: Colony shape is similar to that of Sycozoa. Distaplia occidentalis grows in club or mushroom-shaped colonies.

Open coast on rocks. Under ledges, on channel or cave walls in areas with surge or strong current but not direct wave shock.

Geographical Range: Prince William Sound, Alaska to Monterey Bay, CA

Depth Range: Very low intertidal to 15 m depth.

This compound ascidian grows in a cluster of paddle-shaped stalked lobes, each of which contains multiple zooids. The pharynx has 4 rows of stigmata. The tunic of colonies is not encrusted with sand. Each paddle-shaped lobe of the colony is 1-5 cm tall and the distal blade contains 1-9 double rows of zooids. Color from cream to orange-brown

Biology/Natural History: Functional zooids occur only in the flattened blades, not in the stalks. The zooids are arranged in double-rowed "systems" primarily visible from only one side of the blade. Zooids in a system are arranged alternately on opposite sizes of a common cloacal tube that empties out the tip of the blade. The oldest zooids in the system are at the distal edge of the blade and the youngest are proximal. As the colony grows old zooids may be shed from the distal end and new zooids added on the proximal end of the paddle. Sexual reproduction occurs in the first six months of the year. Gonads develop in January and February. The testes develop first then later the ovaries develop. The ripe eggs are orange. Orange developing larvae are kept in brood pouches such as those in Distaplia occidentalis and are visible especially April-June. Most of the tadpole larvae have been liberated by July. In central California, some colonies contain parasitic copepods.