KEY TO THE SPECIES OF CRISTARMADILLIDIUM AND IBERIARMADILLIDIUM 1. Tegument not covered by strong tubercles ................................................................................................... 2 Tegument covered by strong tubercles .......................................................................................................... 3 2. Tegument smooth ......................................................................................... Cristarmadillidium alticola 3. Tegument with obsolete, but patent tubercles ............................................................................................... 4 4. Pereonite 1 epimera with schisma. Epimera vertical (without bell-shaped transverse body section). Pleopod 1 exopod with rounded apexes ........................................ Cristarmadillidium myrmecophilum Pereonite 1 epimera without schisma. Epimera bent outwards (with bell-shaped transverse body section). Pleopod 1 exopod with pointed distal apex ................................................... Cristarmadillidium breuili 5. Pereonite 1 epimera without schisma ........................................................................................................... 6 Pereonite 1 epimera with schisma ......................................................................... 7 (Iberiarmadillidium) 6. Tubercles hypertrophied in cephalon, pereon, pleon and telson .......... Cristarmadillidium muricatum Small tubercles on cephalon and pleon, larger and elongated in pereonites, absent in telson ..................... ............................................................................................................... Cristarmadillidium zaragozai 7. All tubercles on pleonite 5 equal in size. Tubercles on pereonites rounded, not elongated ........................... .......................................................................................................................... Iberiarmadillidium sakura Middle pair of tubercles on pleonite 5 larger than outer two pairs. Tubercles on pereonites elongated ... 8 8. Tubercles on pereonites elongated but rounded, neither elevated in a keel-like shape nor with a squarish profile. Epimera lighter than dorsal parts .................................... Iberiarmadillidium psammophilum Tubercles on pereonites elongated and elevated, keel-like and squarish in lateral profile, particularly in caudal rows. Uniform coloration ................................................................ Iberiarmadillidium pinicola

Published as part of Recuero, Ernesto, Rodríguez-Flores, Paula C. & García-París, Mario, 2022, Homoplasy and morphological stasis revealed through multilocus phylogeny of new myrmecophilous species in Armadillidiidae (Isopoda: Oniscidea), pp. 1312-1340 in Zoological Journal of the Linnean Society 194 (4) on page 1335, DOI: 10.1093/zoolinnean/zlab066, http://zenodo.org/record/6459236