a severe decline during the Cretaceous-Paleogene extinction event, more severe than that suffered by contemporary eutherians and multituberculates, and were slower to recover diversity.

Morphological and species diversity of metatherians in Laurasia remained low in comparison to eutherians throughout the Cenozoic. The two major groups of Cenozoic Laurasian metatherians, the opossum-like herpetotheriids