Estudi sobre la variabilitat de "Xerocrassa nyeli" (Mitre, 1842) (Gastropoda: Hygromiidae) a l'illa de Menorca (Illes Balears)

catalaL'estudi del sistema genital de diverses poblacions considerades com a Xerocrassa ponsi per diversos autors (Hidalgo, 1878; Ortiz de Zarate, 1963; Quintana i Vilella, 2001) ha posat de manifest que no existeixen diferencies anatomiques significatives entre aquest taxon i Xerocrassa nyeli (Mittre 1842), rao per la qual s'han de considerar especies sinonimes. Des d'aquest punt de vista, X. nyeli es una especie molt polimorfa, al presentar una variacio molt important en l'al9ada de la closca (des de lenticular a plana), I'ornamentacio (amb unes costelletes molt fines o molt marcades) i el diametre delllombrigol (que pot ser mes o menys obert). EnglishThe study of the genital system of several populations considered as Xerocrassa ponsi by different authors (Hidalgo, 1878; Ortiz de Zarate, 1963; Quintana & Vilella, 2001) reveal that no significant differences exist with Xerocrassa nyeli (Mittre, 1842), so both can be considered synonym species. In this point of view, X. nyeli is a very variable species. From this point of view, X. nyeli is a very polimorfic species, when displaying a very important variation in the height of the shell (from biconvex to flat), the ornamentation (with very fine ribets or very marked) and the diameter of the navel (that can more or les s be opened).