Wart slugs are read by their bumps, and this one is read by their height.
Most of the family carries low domes spread evenly over the back. Here three large tubercles stand up along the midline, taller than anything around them, with a smaller fourth sitting behind. In profile the animal has a ridge of raised knobs down its spine rather than an even studded surface, and that silhouette places it before any question of color arises.
The color is the usual family scheme, and deliberately so: pale tubercles capped orange-yellow against black. Half a dozen wart slugs on this reef wear versions of the same warning livery, because a shared pattern is cheaper to teach a predator once than six separate times. A yellow line runs around the margin on some individuals and is missing on others, so it will not settle anything on its own. The printed description also gives a Y-shaped mark beginning between the rhinophores, which is worth looking for on a good photograph.
Under all of it the family arrangement holds. There is no gill plume on the back; that was given up, and these animals breathe through leaflets tucked under the mantle rim. The body is firm, rubbery and loaded with sponge-derived toxins throughout, which is why it grazes in the open in daylight at no particular speed.
It was described in 2000 and is known from this sea and nowhere else, apart from a single record out of the 🌊 Gulf of Oman.
- three tall central tubercles standing well up off the back, with a smaller fourth behind them
- tubercles capped orange-yellow on a black ground
- a yellow line around the margin, present on some animals and absent on others
- the book gives a Y-shaped mark starting between the rhinophores: worth checking
