Ercolania endophytophaga

Image courtesy of Anouk Houben
Anilao, Batangas, Philippines

Ercolania endophytophaga Jensen, 1999

This is one of the many sapsucking slugs found in the Indo-Pacific. Its interesting trivial name tells the story of how it feeds and what it feeds on. Several sapsuckers feed in this way but only this one has a name explaining this behavior. Kathe Jensen gave the species this unique name endophytophaga which breaks down in Latin to mean the species is found on the inside (endo) of algal cells (phyto) that it feeds (phaga) on. The slug actually burrows through the cell membrane of bubble algae, and grazes on the inner surface. Preferred bubble algal species are Struvea plumosa and Valonia ventricose.

The body is white with dark green digestive glands in the cerata and rhinophores. So far it has only been found on the Great Barrier Reef and Rottnest Island in Australia and in the Philippine's.


Jensen, K.R. (1999) A new species of Sacoglossa (Mollusca, Opisthobranchia) from Rottnest Island, Western Australia. [In]: D.J.Walker & F.E.Wells (Eds). The Seagrass Flora and Fauna of Rottnest Island, Western Australia. Western Australian Museum, Perth: 377-383.

Dave Behrens
New Braunfels, TX
Aug., 2023
Send Dave email at

Dave and Peg in Texas motif prior to move from
Washington to Texas

Anouk celebrating Birthday while in attendance
at Nudibranch Conference in Philippines, May 2023

Anouk Houben hails from Belgium and is a keen underwater photographer and nudibranch enthusiast. She does most of her diving in Indonesia and the Philippines.

Over the years Anouk has taken part in a number of nudi workshops and expeditions of which most recently the citizen science workshop in Anilao with Terry Gosliner.

Anouk showcases her nudibranch photography on Instagram @nudibranch.ia.

Anouk's camera system consists of a Omsystems OM-1 and 2 Ikelite SD160 strobes.

From left to right, Terry Gosliner, Angel Valdes, Dave Behrens La Jolla, Calif.

Send Dave email at

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