Aiteng marefugitus is a species of fully terrestrial sea slug found only on the Ulong Island of Palau.

Its excretory system is characterized by a long nephridial duct, which is assumed to reabsorb salt from the slug's urine.

It lays large oocytes, which could supply its young with enough yolk to allow fully terrestrial development of the eggs.

This speciation is predicted to have occurred in the Miocene, roughly the same time the Palauan islands were formed.

A. marefugitus is found at altitudes between 20 and 30 meters above sea level, where it lives within leaf litter.