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with egg mass

sp. #1

Placida sp. #1
Maximum size:  5 mm.

Identification:  This species has a cream body densely patterned with green branches of the digestive gland. The cerata are spindle shaped, often with constricted tips, and the branches of the digestive gland in their centers have short, irregular side branches. There are usually a few white flecks on the tips of the cerata as well as on the pericardium. Most animals have a dark green spot anterior to the pericardium.

Natural history: Although seldom seen due to it's small size and superb camouflage,  Placida sp. #1 is a common species found on green algae of the genus Codium, particularly Codium edule. It occurs in moderately protected to moderately exposed locations at depths of  < 1 to 2 m (< 3 to 6 ft). It shows a diurnal activity pattern when held in dishes. We've observed it feeding on Codium edule and, when feeding, it flattens its cerata laterally against it's host. It lays a flattened, cream egg mass, usually on its host alga. The eggs hatch in six to nine days in the laboratory.

Distribution:  Big Island, Maui, Oahu and French Frigate Shoals: very similar forms are widespread in the Indo-Pacific.

Taxonomic notes:  This species is part of the Placida dendritica complex. It was first recorded in Hawaii from Napili Bay, Maui by CP on May 14, 1991.

Photo:  CP: 3.5 mm: Ulua Beach, Maui; April 2, 2005.

Observations and comments:

Note 1:  A 3.5 mm animal found on April 2, 2005 and fed Codium edule grew to 5 mm by April 15 while laying multiple egg masses.
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