December 17, 2002
From: Scott Johnson
Here are some images of a Marshall Islands Noumea. It is similar to N. romeri but lacks any trace of the white margin. These animals are a uniform pink all over the body, but the shade of pink varies between specimens. The single specimen found at Enewetak Atoll [Lower Left (e096-1)] was much lighter in color than about a dozen specimens observed at Kwajalein Atoll (including the other two photos here). They range in length up to about 14mm, and like N. romeri, have vibratile gills. Several specimens at Kwajalein have been found feeding on what appears to be the same pink sponge eaten by Noumea simplex in the photos posted Aug. 22, 2001.
Johnson, S., 2002 (Dec 17) Noumea romeri? from Marshall Ids. [Message in] Sea Slug Forum. Australian Museum, Sydney. Available from http://www.seaslugforum.net/find/8483
This animal has certainly a bit of both N. romeri and N. simplex. As you say the vibratile gills are like N. romeri and it general body colour is more like N. simplex. However in N. simplex the gills don't vibrate and they are white with orange-red tips rather than edged with pinkish-red. It also has similarities to Noumea decussata, but in that species the background colour is opaque white and the gills don't vibrate. I guess I will call it Noumea cf. romeri for the time being.