A Newly Described Species
Cyerce katiae (Moreno, Gosliner, Wilson, Krug & Valdés, 2025) is one of the rarest butterfly sea slugs at our macro dive sites in Romblon, Philippines. Divers previously called it Cyerce sp. 4 or Cyerce sp. 4 (NSSI2). Scientists formally described it in 2025 as part of a major revision of the genus Cyerce. It belongs to the order Sacoglossa, family Caliphyllidae. Its close relatives Cyerce nigra and Cyerce blackburnae are also documented in our Marine Life Encyclopedia.
How It Defends Itself
Like all Cyerce species, Cyerce katiae has large, flattened, leaf-like cerata. These cerata carry a distinctive honeycomb pattern — hence its former dive community name. When a predator attacks, the animal sheds its cerata. The cerata continue to writhe after separation. As a result, the predator focuses on the moving cerata while the animal escapes. This defence is called ceratal autotomy. Furthermore, the species stores chemical compounds as an additional deterrent.
Finding It at Sunset Cove
At Sunset Cove Beach & Dive Resort, Cyerce katiae holds Epic rarity status. This means only one to three confirmed sightings exist at our dive sites. Our guides search sandy rubble substrate near Udotea algae patches at depth. The animal is tiny — just 5 to 15 mm. Therefore, it requires maximum magnification and a very slow approach. For underwater macro photographers in Romblon, spotting this species is one of the most exciting encounters possible on any dive.