Opisthobranch of the Week Data
I've not personally seen Gastropteron sp. 1 here in the waters of Okinawa's main island, however Atsushi Ono mentions (pers. comm.) seeing in excess of ten specimens in the Keramas*, four of which he has collected and he considers the species to be rare there. The above featured animal was photographed and collected from the waters of Aka Island. In addition, Atsushi reports finding the animals on sandy bottom environments.
I've added a second page with an additional image of Gastropteron sp. 1, this second image is also from the Keramas and kindly furnished by Atsushi.
In addition, I've also added a link to a second unknown Gastropteron species.
* Keramas = the Kerama Islands Group, located 30 ~ 40 kilometers west of the Okinawa capitol, Naha.