with egg masses
Phestilla melanobrachia Bergh, 1874
|Maximum size: 40 mm (Kay,
of this species in Hawaii is typically bright orange with many
long, slightly darker orange cerata, giving it a "bushy" or "mop-like"
appearance. The tips of the cerata may be either lighter or darker
orange and the orange rhinophores are long and smooth. Occasionally, it
may be dark brown or pink. (Haris, 1968)
moderately common aeolid in Tubastraea
coral habitat on the undersides of shaded overhangs or in caverns. It
has also been found on the undersides of rocks. It lives in moderately
protected to highly exposed areas from 2-43 m (6-140 ft). In Hawaii,
known to feed on Tubastraea
coccinea but it may also feed on other orange-pink Tubastraea spp. and dendrophyllid
corals. In other parts of its range, it feeds on the green-black Tubastraea diaphana and the
presence of a few dark brown animals suggests that it also feeds on
that species in Hawaii (Scott Johnson).
found by looking for white Tubastraea
coral skeletons from which the living tissue has been removed. The
nudibranchs are typically concealed in adjacent cracks during the day
and are darker orange than the nearby coral polyps. They emerge at
night to feed. The tips of the cerata contain cells that store a clear
viscous liquid, presumably used in defense. Studies by Larry Harris
(1968) showed that
pigments in the coral tissue are taken up in the digestive gland,
giving the nudibranch a coloration similar to its food. Since this
species does not store nematocysts for defense, protective resemblance
is important. It lays a white egg spiral that "flares" at the distal
edge. This is one of the few nudibranchs for which life history data
has been collected. Studies by Larry Harris (1975) showed a
generation time of 60 days from egg to egg, and a lifespan of
approximately 4.5-5.5 months.
Big Island, Maui and Oahu: widely distributed in the Indo-Pacific: also in the eastern Pacific.
means "dark arms" because the original specimens had fed on
green-black vs. orange corals. It's referred to as the "cup coral
nudibranch" in Hoover, 1998 & 2006. It was first reported from
Hawaii in Edmondson, 1946.
found by PF; Molokini; Jan. 15, 1989.
Observations and comments:
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