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R. Barsbold (2018)
On Morphological Diversity in Directed Development of Late Carnivorous Dinosaurs (Theropoda Marsh 1881).
Paleontological Journal 52(14): 1764â1770Â
The late (post-Triassic) carnivorous dinosaurs show a wide morphological diversity, which most probably reached the highest level during the Cretaceous Period, the longest in the Phanerozoic (80 Ma) and represented the time of the last and longest flourishing of the entire group. The Late Cretaceous, which lasted slightly less than half of this period, probably displays the majority of the entire diversity known in the morphological evolution of theropods. This was to a considerable extent facilitated by the especially favorable conditions for preservation of fossils that developed during this time, being the major cause of abundance of the fossil record.