Figure 2.

Independent contrast least-squares regression through log-transformed olfactory ratio against body mass for theropods. Dashed lines represent 95% CI. Albertosaurus, Gorgosaurus and Alligator were plotted after calculation of the regression. Tyrannosaurids and dromaeosaurids plot above predicted olfactory ratio values and ornithomimosaurs and oviraptorids plot below predicted olfactory ratio values; these clades lie outside the 95% CI. Olfactory ratios for all other theropods, including Archaeopteryx, fall near values predicted by regressions. Alligator plots above the theropod regression line. Black circles, dromaeosaurids; white circles, tyrannosauroids; grey circles, allosauroids; black square, Archaeopteryx; white squares, ornithomimosaurs; grey squares, ceratosaurians; black diamond, oviraptorids; white diamonds, troodontids; grey diamonds, Alligator.