Opisthobranch of the Week Data
Cyerce sp. 1 is considered to be very rare on Okinawa as I have seen and collected only the above individual. Rudman (2002) reports in the Sea Slug Forum seeing this sacoglossan in the southwestern Pacific, so in addition to its Japanese distribution it may well have a wide tropical Pacific dispersion. This apparently undescribed attractive sacoglossan has flattened pustulose cerata and the margin of each ceras is smooth and rounded with a broken yellow line. There are a few black irregular spots, near the margin of the cerata. The rhinophores are long and bifurcate. I've added a second page with two additional images of the same animal showing a bit more detail.
Cyerce sp. 1 was collected during a mid-day SCUBA excursion under spring tide conditions (34cm level) from a large patch of red algae (Acanthophora and Laurencia spp.) in a mixed live/dead stony coral reef near the reef drop-off. Cyerce sp. 1 would appear to be identical or at least very similar to Cyerce sp. 3 as featured on the Sea Slug Forum, photographed by Nishina Masayoshi (2002) from Hachijo Island, Japan.
The only described species of Cyerce found on Okinawa's main island as of the current date is Cyerce kikutarobabai. In addition to the above featured animal, several other undescribed or unknown species have been found here as well.