Magnificent Nudibranch

This is the ID guide i found it in; Coral Reef Animals of the Indo-Pacific: Animal Life from Africa to Hawai'i Exclusive of the Vertebrates [Illustrated] [Paperback]
Terrence M. Gosliner (Author), David W. Behrens (Author), Gary C. Williams (Author), Hans Bertsch (Editor), Katie Martin (Editor)

Yes it is difficult, its just i never seen any magnifica in ID guides like this they have always been very distinct, however i have very rarely found a nudibranch that hasnt been in one of my ID guides and this wasnt. I just feel like especially with nudis its really important that people ID them properly otherwise the internet is filled with misinformation and the real stuff gets drowned out, i see where you have got the info from now for this and actually have just consulted a really old guide which does have a similar picture, it could be that they are the same species or two which were never seperated, but guess thiss is the best it can be ID'd without like you say genetic analysis.

But for now i stand corrected, however there are several miss-identified nudibranchs on here ive slowly been working my way through them! good to know you did research it though and didnt just pick up the first identification on the net!

@moralcoral - thanks for comment. I took a long time to fixate on the species for this photo, and in the end I consulted 'nudipixel.net' where Nudibranch experts verify the identification of submitted photographs. I found the positively ID'd submissions [i.e. have the green dot] for this species to be extremely variable in shading and in the colour of the mantle. For example this picture http://www.nudipixel.net/photo/00000520/...

Each book looks to use different criteria or even opinions to identify species, and I like the website as a reference because it is a big collaborative effort and regulated by experts in the field.

But then with nudibranchs, unless you genetically ID them - who really knows?!

Actually i dont think this is Chromodoris magnifica its certainly in the Chromodoris family but magnifica has a thin white band on the edge then a thick orange band followed by a white then black then light blue with a single black line down the middle, this is going from my guide book there are several that are very similar im currently looking at 12 species with only slight variations. This obviously has a very different central pattern with many thin black lines, ive tried to find the ID its not in my book but i have 2 others i will check in to see if i can find the correct one. its just everyone IDs these blue and yellow nudicreanchs as Chromodoris magnifica when in reality they are several different species.
Nice pic though

i love your collection of nudibranch

Great colours.