Facelinella semidecora (Pease, 1860)
|Maximum size: 16 mm.
Identification: This species ranges from white to
brown in overall appearance depending
amount of pigment on the body and on the color of the cerata. The body
is translucent white with opaque white flecks that can be scattered
over the entire animal. There may also be streaks or reticulations of
rusty orange on the body, head, rhinophores and cephalic tentacles. The
cerata are translucent to clear and are sometimes flecked with white.
They are dark at the base where the digestive gland is visible and
are tipped with white. In some animals, the cerata
have a rust-orange tinge and there is a translucent orange or
translucent white subapical band.
The rhinophores are tipped with white and typically have several low
Facelinella semidecora is a
moderately common species and one of
more commonly encountered aeolids in Hawaii. It is found under rocks in
tide pools and the low intertidal as well as in protected to
highly exposed rocky habitats down to 9 m (30 ft).
It feeds on hydroids.
Big Island, Maui, Kahoolawe, Oahu, Kauai, Midway and Kure.
This species was described from Hawaii and is sometimes listed as Phidiana semidecora. A
similar species, Phidiana anulifera,
from Japan, and some authors consider the Hawaiian animals to be that
species. See the Sea
Slug Forum for further discussion. It was first reported from
Hawaii in Pease, 1860 (as Aeolis semidecora).
Photo: CP: 14
mm: Poipu State Park, Kauai; May 4, 2010.
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