Velvet black with a clean yellow border running around the side lobes and picking out the tips of the forked tail, sometimes with a thin white line along the head shield. Small - 4 cm (1.6 in) - and worth stopping for, because outside this sea nobody gets to see one.
It is a 🌊 Red Sea animal, described in 1983 from these reefs and known essentially from here and the 🌊 Gulf of Aden. Almost every occurrence record in the world's databases falls inside this basin, which makes it one of the clearest endemics in the local slug fauna and a species where a photo from Hurghada or Dahab is genuinely worth uploading.
Like its relatives it hunts acoel flatworms by trail, sliding over open sand between coral heads with the head shield sweeping. The two tail lobes are always unequal, and the reason is plumbing rather than symmetry: water drawn in along one side of the body has to leave along the other, and the longer lobe marks the exit.
- velvety black body with a clean yellow border around the side lobes
- yellow tips on both tail lobes, the left lobe noticeably longer
- thin white line often running along the head shield
- length up to 4 cm
