[eng] The terrestrial isopod Armadillidium pretusi (Crustacea: Oniscidea: Armadillidiidae), a rare endemic species to the Serra de Tramuntana (Mallorca, Balearic Islands). New observations and morphological remarks. This paper provides new data on the distribution and morphology of the terrestrial isopod Armadillidium pretusi Cruz, 1992, a rare species endemic to the serra de Tramuntana of Mallorca. Until now, this species was only known from the single female specimen on which the description was based. Some of its anatomical features that did not appear in its original description are described for the first time, including its male sexual characteristics, mouthparts and integumentary details. Given the very probable population fragmentation of this rare species, some aspects about its conservation are also discussed.