White-spotted Sea Squirt, Pycnoclavella diminuta

The White-spotted Sea Squirt (Pycnoclavella diminuta), also known as the White-spotted Ascidian or White-spot Ascidian, is a species of tunicate found in the Indian and West Pacific oceans, and found along Australia, Lord Howe Island, New Caledonia, Indonesia and the Philippines. It lives at depths of 16 to 66 feet in the benthic zone in caves and under ledges. It often occurs in environments with soft corals.

This species lives in colonies composed of small clusters of zooids that originate from a common stalk. Each zooid is about 0.2 to 0.4 inches in length. It is golden yellow-orange in color and has white spots. The spots vary in shape and size, but are well defined, and are consistent throughout the colony.

This species can often be confused with Clavelina flava, which may also have white spots. But the White-spotted Sea Squirt can be differentiated in that the spots are always clearly defined and always constant.

Like all ascidians, this sea squirt is a filter feeder

Image Caption: Pycnoclavella diminuta, White-Spotted Sea Squirts. Credit: Dr. Dwayne Meadows, NOAA