Opisthobranch of the Week Data
Halgerda sp.1 is considered to be rare in okinawan waters and as far as I'm aware it's not been reported from the water's associated with Okinawa's main island. Atsushi Ono reports (pers. comm.) seeing three individuals in the Keramas * but none were collected. The three individuals were all approximately the same size (8~10mm) and the above featured animal was found on a wall of a coral reef off of Zamami Island. Atsushi's photograph is used here with his kind permission. Atsushi has a similar but smaller (5mm) animal posted on Bill Rudman's Sea Slug Forum (Rudman, 2000). In addition, Scott Johnson has an image of a similar appearing Halgerda from Kwajalein posted on his Kwajalein Underwater site (Marshall Islands).
As of early March, 2014, thirteen described species of Halgerda have been featured on these pages, from both Okinawa's main island as well as the Keramas. These thirteen species are:
H. albocristata H. batangas H. brunneomaculata H. carlsoni H. dalanghita H. diaphana H. elegans H. malesso H. okinawa H. onna H. tessellata H. wasinensis H. willeyi
* Keramas = the Kerama Islands Group, located 30 ~ 40 kilometers west of the Okinawa capitol, Naha.