A Pink Icon Reclaims Its Name
Cyerce elegans (Bergh, 1870) is one of the most visually striking butterfly sea slugs at our macro dive sites in Romblon, Philippines. Its body and large leaf-like cerata are a bold, unmistakeable pink. Furthermore, it has a fascinating taxonomic story. For decades, the dive community called this pink species Cyerce sp. 3 or Cyerce sp. 3 (NSSI2). Meanwhile, a different golden species incorrectly carried the name C. elegans. The landmark 2025 molecular revision by Moreno et al. set the record straight — the true Cyerce elegans is this pink species. It belongs to the order Sacoglossa, family Caliphyllidae, and is documented on iNaturalist.
Bold Colour, Bold Defence
Unlike most Cyerce species, Cyerce elegans does not hide. Its pink colouration is aposematic — it warns predators of chemical defence compounds in its body tissue. In addition, like all Cyerce, it performs ceratal autotomy when threatened. The cerata detach and writhe on the seafloor. As a result, the predator targets the moving cerata while the animal escapes. Its close relatives Cyerce nigra, Cyerce blackburnae and Cyerce katiae are all documented in our Marine Life Encyclopedia. Together they represent four of the nine newly revised Cyerce species found in Romblon.
Finding It at Sunset Cove
At Sunset Cove Beach & Dive Resort, our guides find Cyerce elegans on sandy rubble substrate near Udotea green algae patches at 3 to 25 metres. The pink colour makes it easier to spot than other Cyerce. However, approach slowly — it sheds its cerata immediately when startled. For underwater macro photographers in Romblon, the pink cerata photograph beautifully against dark substrate. Consequently, this is one of the most sought-after and photographable butterfly sea slugs at our dive sites.