Costasiella sp. 2

Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
Order: Sacoglossa
Family: Costasiellidae
Genus: Costasiella
Species: Costasiella sp. 2

Costasiella sp. 2 is a tiny sacoglossan, or sap-sucking sea slug, in the family Costasiellidae. It has not yet been formally described, so it is known only by this working name.

In these photos it has golden yellow cerata with dark bands, and dark eyes set close together on the head. Costasiella are only a few millimetres long.

Sacoglossans feed by piercing algae and sucking out the cell contents, and Costasiella are found on the algae they eat.

In the Philippines Costasiella are favourites of macro photographers. Search algae patches slowly with a focused light, and use a diopter or high magnification to show the face.

It appears on page 345 of Nudibranchs of the Philippines.

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