Opisthobranch of the Week Data
Notobryon bijecurum is considered to be very rare off Okinawa's main island as I have seen and collected only the above single individual over a period of well over thirty years of okinawan diving. The specimen was collected during a midmorning dive from 130ft at the Seragaki dive area from an area of mixed sand and coral rubble.
Baba (1937) originally described N. bijecurum from a single 30mm specimen collected in 1936 from Amadaiba, Sagami Bay, Japan.
The following information concerning external morphology and distribution is taken from Pola, et al (2012):
Rie Nakano (2004, p.217) has a photograph of a 30mm specimen of Notobryon bijecurum featured in her book (in Japanese).External morphology: The body is slender, soft, flaccid, and elevated, but laterally compressed. The foot is narrow. The posterior crest is moderately large with an entire margin. The rhinophoral sheaths have a posterior longitudinal crest. The rhinophores are perfoliate with 16 lamellae. The front of the head is expanded in a semicircular veil with a wavy margin. There are two pairs of dorsolateral lobes, the posterior ones are much smaller that the anterior ones. These lobes are nearly continuous at their bases leaving a U-shaped space between them. The margins of the dorsolateral lobes are entire. Each dorsolateral lobe bears four large and dendritic ‘gills’ on their upper surface and one on the tail. The anal papilla is located on the right side, between the two lobes. The genital opening is on the right side, beneath the anterior end of the first lobe.
The body surface is quite smooth, varying from transparent to semitransparent light orange or light yellow with bold opaque marking on the back and the sides. Sometimes there are small light blue spots, some coalescing into usually two larger blotches. The ‘gills’ are mostly transparent. Minute holes or subcutaneous glands of indeterminate function cover the entire body.
Geographical distribution: Currently known only from Japan.
I've also added a second page with two additional images of the same animal as the above featured animal.