Which Unicorn?

[Deefstes]

OK, this one really has me stumped. It should be a straight forward identification but my literature seems to be inconsistent.

The book I have calls it an Orangespine Unicorn (Naso lituratus). I have a software application that says the same. However, when I look at the FishBase entry for Orangespine Unicorn (Naso lituratus) I see a fish that doesn't resemble mine at all. According to FishBase this species does not even occur in Southern African waters.

The FishBase entry for Elegant Unicorn (Naso elegans) on the other hand seems to be an exact match but neither my book nor my software app has any entries for Elegant Unicorn.

I'm confused The Orangespine Unicorn of FishBase does not have an orange spine while the Elegant Unicorn has no other feature more prominent than an orange spine. Could it be that FishBase got this one wrong?

Here are my pics:

 

[joshjensen]

That is definitely Naso elegans. N. lituratus lives in the Pacific, N. elegans in the Indian Ocean and Red Sea.

Obviously a very closely related species, pretty safe guess that one evolved from the other - chances are lituratus came first.
Nice pics.

 

[Deefstes]

Thanks a lot. I've come to that conclusion since and it turns out this fish is actually a very common fish in our waters (I'm a noob diver) but you are absolutely correct, this is indeed N. elegans and my book has it wrong.

To be fair, the book probably hasn't really got it wrong but is perhaps just dated. Here's what Fishbase says about N. lituratus:
"Once regarded a wide-ranging Indo-Pacific species, the Indian Ocean population is now recognized as a separate species, Naso elegans."

Thanks again.