Mesozoic marine revolution

The Mesozoic marine revolution (MMR) refers to the increase in shell-crushing (durophagous) and boring predation in shallow-sea (neritic) and some deep-sea marine organisms throughout the Mesozoic era (251 Mya to 66 Mya), along with bulldozing and sediment remodelling in benthic marine habitats. The term was first coined by Geerat J. Vermeij, who based his work on that of Steven M. Stanley. While the MMR was initially restricted to the Cretaceous (145 Mya to 66 Mya), more recent studies have suggested that the beginning of this ecological succession/evolutionary arms race extends as far back as the Triassic, with the MMR now being considered to have started in the Anisian or the Aalenian. It coincided with the rise of large secondarily adapted marine reptiles such as ichthyosaurs, sauropterygians (plesiosaurs, nothosaurs, placodonts), thalattosaurs and thalattosuchians, proliferation of shell-destroying mesopredators such as teleosts, stomatopods and decapods, a trend toward benthos infaunalization, and extinction/habitat restriction of sessile organisms incapable of reattachment once dislodged.

The MMR is an important evolutionary transition from the Paleozoic fauna to the more modern-looking fauna, which occurred throughout the Mesozoic. It was, however, not the first bout of increased predatory pressure; that occurred around the end of the Ordovician. There is some evidence of adaptation to durophagy during the Paleozoic, particularly in crinoids.