Nembrotha kubaryana Bergh, 1877

This has to be one of the most striking nudibranchs around. Nembrotha kubaryana is uncommon at Kwajalein Atoll but not rare. Despite extensive searching, it was never observed at Enewetak Atoll. The dayglo red rhinophores, foot margin, and (usually) gills are hard to miss, especially in a nudibranch that can often exceed 50mm in length. At Kwajalein, it can be found on lagoon pinnacles and interisland reefs, but is also present on the top of the seaward reef front. It lives in ledges and under rocks and is sometimes seen crawling out in the open during the day. In normal daylight, the colors are unmistakable and vivid, and it seems obvious that the fiery red must function as warning coloration. This species eats a dark green colonial tunicate, which appears to be the same tunicate eaten by the similar Nembrotha cristata. Usually we see only one or two specimens of N. kubaryana at a time, unlike N. cristata, which sometimes seems to congregate in larger numbers.

Chowing down on dark green colonial tunicates.

This species can be difficult to photograph. While the red shows up well on film, the black body with dark green spots often seems to suck up the light from a photographer's strobe. The shade of the green does vary among individuals, so one of the tricks to getting good photos is to find a specimen with lighter colored spots.

The two different specimens below have more green on the body and red on the tail, but the gills are mostly green.

The white on and around the rhinophores and gills is unusual for Marshall Islands specimens of this species. The two copulating immediately below were the only ones we have seen with the white coloration so apparent. These were also very small specimens, only about half the length of those we normally see. It is curious that with all the normally colored ones around, these two that that were both unusually small and with an odd coloration managed to find each other and come together to mate. It is almost enough to make one think these could be something closely related but different.

The two below were also unusually small but mature and mating. These have a trace of the white color seen in the specimens above, particularly on the posterior edge of the rhinophores. They were on a lagoon pinnacle reef where several more typical Nembrotha kubaryana were also seen.

Created 3 January 2007
Updated 5 January 2009