Marionia elongoreticulata

Order : NUDIBRANCHIA
Suborder : DEXIARCHIA
Infraorder : CLADOBRANCHIA
Parvorder : DENDRONOTIDA
Superfamily : TRITONIOIDEA
Family : Tritoniidae

Note from Nudibase page on facebook on ID by Lindz Warren

I think that Marionia elongoreticulata & Marionia elongoviridis are distinct species. They certainly seem to share some similar characteristics (such as the notal pattern) but the colours are very different.
In M. elongreticulata the secondary gills and the rhinophoral sheaths are tipped in red whereas in M. elongoviridis the secondary gills & rhinophoral sheaths end in green. In IPN – Gosliner, Behrens & Valdés, 2008 also add that they “also differ in radular and reproductive anatomy.” Their body colours are also different