Tunicate/sea squirt from Visayan Sea...

Seen this variously described as Clavelina caerulea, Rhopalaea sp., Rhopalaea crassa, etc.

Help please?

It really is confusing, isn't it? I've also seen this animal under a variety of names. In both Colin & Arensen and Gosliner, Behrens, & Williams it's called Rhopalaea sp.

In a 2001 paper on ascidians of the tropical western Pacific by Monniot & Monniot 2001 I found these two descriptions plus color photographs:

Rhopalaea crassa - "The siphons are simple round holes or with six low lobes. The colour of the tunic varies from yellow-green to orange-yellow."

Rhopalaea fusca - "The colour is characteristic and concentrated in the tunic. The thoraces are of an intense blue (Fig. 124E), while the siphons are rimmed with a thin orange line and an irregular blackish band.....This spectacular species is one of the most photographed ascidians in guides to the Indo-Pacific fauna." The Monniots say that one of the photos in GBW is this species. It's also on the web in various places as Clavelina fusca.

I haven't found a reliable reference yet to Clavelina caerulea which was described from Japan.

The Monniots are among the top authorities on tunicates in general & tropical Pacific ones in particular . You might be able to download the paper from http://www.mnhn.fr/publication/zoosyst/z01n2a1.pdf

Thank you The paper is great!