Most dinosaurs, and most theropods, had brains no better than present-day reptiles, so far as can be estimated. In a 2001 study of a "Carcharodontosaurus saharicus" endocast, Hans Larsson found that both "C. saharicus" and "Allosaurus" had a ratio of cerebrum to brain volume that was very similar to non-avian reptiles. By contrast, the "Tyrannosaurus" ratio was slightly in the direction of a more bird-like proportion. Since tyrannosaurs are relatively basal coelurosaurs, this is evidence that the advent of the Coelurosauria marks the beginning of a trend in theropod brain enlargement.