Aldisa pikokai
Bertsch & Johnson, 1982
Order: NUDIBRANCHIA
Suborder: DORIDINA
Superfamily: EUDORIDOIDEA
Family: Dorididae
DISTRIBUTION
Known from Hawaii and Marshall Ids.
PHOTO
Oahu, Hawaii. approx 20mm long. Photos: Scott Johnson.
Grows to approx 20mm and ranges in in colour from orange to bright red. These photos are all from Oahu, Hawaii, where it is a relatively common species on shallow subtidal reefs, often found exposed on the reef or feeding on an encrusting red sponge at night. Specimens hide away and are almost never observed during the day. The animals are characterized by the often sharp longitudinal and transverse ridges that crisscross the dorsum, and by three crater-like depressions running along the middorsal line. The craters usually have darker oval spots on their 'floors'. Although we originally thought this was found only in Hawaii, I have since come across two typical specimens at Kwajalein, Marshall Islands. A similar and possibly unnamed species Aldisa sp. 5 from Hawaii shares the same habitat but lacks the ridges and has different dorsal craters.
Note: Aldisa sp. 4 from South Africa may be this species.
- Bertsch, H., & S. Johnson. 1982. Three new species of dorid nudibranchs (Gastropoda: Opisthobranchia) from the Hawaiian Islands. The Veliger, 24(3): 208-218.
Johnson, S., 2002 (March 17) Aldisa pikokai Bertsch & Johnson, 1982. [In] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/aldipiko
Related messages
Aldisa pikokai? from Malaysia
October 8, 2007
From: Kwang Kai Leong
Hi,
I found this nudibranch when I was diving in Tioman. I think it is a Pleurobranchus but not sure of which. Could kindly Identify it.
Locality: Hyde Patch, Tomok Island off Tioman Island, 12.5 meters, Pahang, Malaysia, South China Sea, 17 September 2007, Sandy bottom, with softcorals and sponge in patchs.. Length: 2 to 2.5 inches. Photographer: KL Kwang.
Thanks
K.L. Kwang
klkwang@deloitte.com
Kwang, K. L. , 2007 (Oct 8) Aldisa pikokai? from Malaysia. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/20753
Dear KL,
This is a species of the dorid genus Aldisa, and I am pretty sure it is Aldisa pikokai. Some species of Aldisa seem to mimic sponges by their colour and general shape, in particular the presence of two or three pits on the back which mimic the inhalent siphons or ostia of large sponge colonies. In your photos there appear to be raise tubercles or thick papillae scattered over the mantle. I don't recall those being present in A. pikokai so it is possible this is an unnamed species.
Best wishes,
Bill Rudman
Aldisa pikokai from Hawaii
March 20, 2002
From: Scott Johnson
Hi Bill,
Attached is an addition to the Aldisa section of the Forum. These three Aldisa pikokai range in size up to about 20mm and in color from orange to bright red. These photos are all from Oahu, Hawaii, where it is a relatively common species on shallow subtidal reefs, often found exposed on the reef or feeding on an encrusting red sponge at night. Specimens hide away and are almost never observed during the day. The animals are characterized by the often sharp longitudinal and transverse ridges that crisscross the dorsum, and by three crater-like depressions running along the middorsal line. The craters usually have darker oval spots on their 'floors'. Although we originally thought this was found only in Hawaii, I have since come across two typical specimens at Kwajalein, Marshall Islands. A similar and possibly unnamed species [see separate message]from Hawaii shares the same habitat but lacks the ridges and has different dorsal craters.
Scott
johnson@kmr.ll.mit.edu
Thanks Scott,
After those remarkable phyllidiid mimics such as Aldisa erwinkoehleri, it's nice to see some good old sponge mimics
Bill Rudman
