Six new theropod teeth recovered trom the Blasi 1-3 sites (Upper Maastrichtian) in Arén (Huesca
province, Spain) are described and added to the twenty six teeth already known from these and
other five localities of Late Campanian-Early Maastrichtian age from the Arén and Tremp formations
(Figuero1a 2, Fontllonga 6, L'Abeller, Montrebei and Vicari 4, Lleida province). Eleven theropod
teeth morphotypes are recognised: one belonging to a big size theropod of indeterminate
family (Theropoda indet.), one small Coelurosauria indet. with unserrated teeth, the enigmatic
Euronychodon sp, and eight morphotypes of cf. Dromaesauridae indet. with different denticle
morphology and serration density (which would represent four five different taxa). The tooth previously
described in the Upper Campanian of Lleida as "Richardoestesia Like" could also be assigned
to cf. Dromaeosauridae indet. Theropod diversity in our sites is apparently similar to that of the
rest of Europe, and increases through the Campanian-Maastrichtian transition, although our small
samples is biased towards the youngest sites
