Question

Paleontologists long believed that the microscopic spherical structures found in fossilized dinosaur feathers were fossilized bacteria responsible for decomposition. However, in 2008, researchers demonstrated that these structures are actually melanosomes—cellular organelles containing melanin pigments. By comparing the size, shape, and distribution of these fossil structures to the melanosomes of extant birds, the researchers were able to reconstruct the plumage coloration of the theropod dinosaur Anchiornis huxleyi. To establish the reliability of this morphological comparison, the researchers noted that preserved melanosomes in modern bird feathers subjected to simulated fossilization pressures retain their distinctive shape-to-color correlations.

In the context of the passage, the reference to modern bird feathers subjected to simulated fossilization pressures serves primarily to