Uljamin, 1884 : Doliolid|
Phylum Chordata / Subphylum Urochordata / Class Thaliacea / Order Doliolida / Family Doliolidae
Using a mucous net, Dolioletta is a very adept filter feeder on particles ranging up to 100 micrometers in size. Gill slits are located within the relatively large pharynx, which also holds the mucus secreting endostyle. Water is pumped through the mucous net by the action of gill cilia. With their efficient filtering mechanism, dense aggregations of this species can quickly deplete phytoplankton within a wide area. When food is plentiful, Dolioletta is amazingly prolific, with a single oozooid capable of producing thousands of gonozooids in a matter of days. This species can form dense swarms of up to an average of 500 per cubic meter, and may be the most abundant pelagic tunicate off the California coast. It is the most cold tolerant of all the doliolids, ranging farther north than any other species. Although usually oceanic, occasionally dense swarms may inundate nearshore waters. On close approach, their presence is usually revealed when the doliolid attempts to dart away using rapid contractions of the body muscles.
All photographs © David Wrobel and may not be used or copied without permission!