New research finds that a family of mammals with rare and weird characteristics migrated underground to live tens of millions of years ago and survived the 65-million-year-old mass extinction event, which scientists have named Necrolestes. This nickname has always been the creature known as the "grave robber" is considered a marsupial. However, further analysis found that it actually belongs to a completely unexpected branch of mammals on the biological evolution tree, which was believed to be 45 million years before the Necrolestes life. It is completely extinct. This is a typical example of the Lazarus effect, which describes a group of organisms living much longer than originally expected. The following are inconsistent with the original:. ['Necrolestes is a remnant of a mammal more than 100 million years ago.', 'Humans have always been unaware of the existence of Necrolestes.', "Necrolestes's actual lifetime is unexpectedly long.", 'Species identified as extinct may be "rediscovered".']