Berthella martensi (Pilsbry, 1896)

As can be seen from the photos below, Berthella martensi is a variable species. Many other color forms can be seen on the Sea Slug Forum. All are characterized by having the mantle split into three lobes, one on each side and one posterior. These lobes can autotomize, or break off, if the animal is disturbed. This species is found in the Marshalls under rocks on lagoon reefs, pinnacles, and seaward reefs at depths of two to at least 20 meters. We have seen specimens at Kwajalein, Enewetak, and Utirik Atolls, as well as one color form from Hawaii. Note the two black eyes on the right side just out from under the anterior dorsal lobe in the first photo below.

The specimen below has lost the rear lobe of its mantle.

Created 27 January 2007
Updated 24 June 2008