Yellow Social Ascidian

Pycnoclavella stanleyi

Pycnoclavella stanleyi is a colonial sea squirt characterized by its leathery tunic often covered in sand grains. The individuals are small, typically not exceeding 1 cm in height, and are distinguished by seven rows of gill slits and a gold or yellow-orange pharynx. This species can be confused with the introduced Botrylloides violaceus, which has a chained appearance without clear separation between individuals. Pycnoclavella stanleyi is found along the Eastern Pacific shoreline, from British Columbia to Baja California, inhabiting shallow waters at depths ranging from 0 to 10 meters. It typically encrusts surf-pounded rocks near sandy bottoms and is often associated with seaweed holdfasts. As a sessile filter feeder, Pycnoclavella stanleyi extracts food particles from the water using its pharynx and gill slits. It reproduces both sexually and asexually, with asexual reproduction occurring through budding. Sexual reproduction produces tadpole-like larvae that possess a dark spot, the ocellus, but lack an otolith. Encounters with this species during dives can reveal colonies that create a unique underwater landscape, contributing to the biodiversity of the area. The conservation status of this species has not been evaluated by the IUCN.