young, about 4 mm
Thuridilla neona Gosliner, 1995
|Maximum size: 23 mm.
has a brown-cream body with sky blue, black and orange
banding on its parapodia and rhinophores. The parapodia are low and
meet in the center without obvious
chimneys. It can be distinguished from Thuridilla multimarginata by
orange-brown marginal line and the undivided cream patch on top of its
is a common species found on rocky bottoms (including in back reef
It occurs in protected
exposed locations at depths of < 1 to 3 m (< 3 to10 ft) and, rarely, to 12 m (40 ft). Mature
diurnally active and may form mating aggregations. (Note
1) This, combined with its striking color, makes it the most
readily seen of the rock-dwelling plakobranchids
waters. The egg mass is a tightly to loosely coiled orange
and there are granules of bright orange extra-capsular yolk in the
center of the ribbon. The eggs hatch in about 6 days in the laboratory
and the pigmented granules remain in the mass after hatching.
Maui, Lanai, Oahu, Kauai, French Frigate Shoals, Lisianski and Midway: also known from Australia.
recorded in Hawaii from Hale'iwa, Oahu by Earthwatch expedition
participants in July, 1980 and was named after its "neon"
Photo: CP: 10
& 12 mm: Hekili Point, Maui; Dec. 1, 2002.
Observations and comments:
1: On many occasions over a period
of several weeks in Aug. and Sept., 1987 numerous animals were found
crawling in the open on a ridge of senescent Porites compressa at 1-1.5 m (3-5
ft) in the
back reef at Hekili Point, Maui. They occupied an area of around 6-8
square meters with as many as 10-12 sometimes in view at once. The
animals gathered in small groups at the tips of dead P. compressa branches and I believe
I saw copulating pairs in the field. Orange egg masses comparable
to those laid in the laboratory were found on the undersides of coral
rubble in the area. A smaller, though otherwise similar,
aggregation was found in the same area in Sept., 1988. In Sept., 1990
another aggregation was found in a similar location about 2 km east of
Hekili Point. Whether this indicates a tendency to form mating
aggregations or just represents a local concentration of food/habitat