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Additional Photos
underside
rhinophores
branchia
violet brown
young
feeding
egg mass
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GALLERY
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Jorunna alisonae Marcus, 1976
Maximum size: 20 mm.
Identification:
This
is
a
greenish brown to violet brown dorid blotched with darker
brown and frosted with white. It may be distinguished from Discodoris
lilacina by its soft texture.
Natural history:
Jorunna alisonae
is a common species that is primarily found in the low to mid
intertidal at protected to moderately exposed rocky sites.
Rarely, it can be found to depths of 1.5 m (5 ft). According to Kay
(1979), it feeds on
the violet-brown sponge Haliclona
permollis. However, we have also found it on the same turquoise
sponge (Haliclona caerulea) that is eaten by the similar-appearing Discodoris lilacina. (Note
1) It lays a cream egg mass that hatches in six to seven days in
the laboratory.
Distribution:
Big Island, Maui, Lanai, Oahu and Kauai: also known from Indonesia and the Marshall
Islands.
Taxonomic notes:
There's
some
possibility
that the greenish brown and violet brown
animals might turn out to be different species. It was first reported
from Hawaii in Kay & Young, 1969 (as Jorunna tomentosa).
Photo: CP: 20
mm, greenish brown: Hekili Point, Maui; Sept. 26, 2007.
Observations and comments:
Note
1: On Oct. 17, 2009, two J. alisonae were found on a
turquoise encrusting sponge (Haliclona caerulea) in the low intertidal at Hekili Point,
Maui. Although they weren't observed actively feeding, the presence of
pigment in their digestive glands similar in color to the sponge
supports the suggestion that they were eating it. (see photos) Perhaps, occasional
feeding on this species explains the occurrence of the green color form?
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